Edgar Filing: AMERICAN CAMPUS COMMUNITIES INC

Use these links to rapidly review the document
TABLE OF CONTENTS
AMERICAN CAMPUS COMMUNITIES, INC. AND SUBSIDIARIES INDEX TO UNAUDITED PRO FORMA CONSOLIDATED FINANCIAL STATEMENTS
ANNEX A

As filed with the Securities and Exchange Commission on April 23, 2008

Registration No. 333-150059

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

Amendment No. 1 to
FORM S-4
REGISTRATION STATEMENT
UNDER
THE SECURITIES ACT OF 1933

AMERICAN CAMPUS COMMUNITIES, INC.
(Exact Name of Registrant as Specified in its Charter)

Maryland		6798		76-0753089
(State or Other Jurisdiction of Incorporation or Organization)		(Primary Standard Industrial Classification Code Number)		(I.R.S. Employee Identification No.)

805 Las Cimas Parkway, Suite 400
Austin, Texas 78746
(512) 732-1000
(Address, Including Zip Code, and Telephone Number, Including Area Code, of Registrant's Principal Executive Offices)

William C. Bayless, Jr.
President and Chief Executive Officer
American Campus Communities, Inc.
805 Las Cimas Parkway, Suite 400
Austin, Texas 78746
(512) 732-1000
(Name, Address, Including Zip Code, and Telephone Number, Including Area Code, of Agent for Service)

Copies to:

Bryan L. Goolsby, Esq.
Toni Weinstein, Esq.
Locke Lord Bissell & Liddell LLP
2200 Ross Avenue, Suite 2200
Dallas, Texas 75201
(214) 740-8000
Facsimile: (214) 740-8800

Gilbert G. Menna, Esq.
Suzanne D. Lecaroz, Esq.
Goodwin Procter LLP
Exchange Place
Boston, Massachusetts 02109
(617) 570-1000
Facsimile No: (617) 523-1231

Approximate date of commencement of proposed sale to the public: As soon as practicable after the effectiveness of this registration statement and the satisfaction or waiver of all conditions under the merger agreement described herein.

If the securities being registered on this form are being offered in connection with the formation of a holding company and there is compliance with General Instruction G, check the following box. o

If this form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. o

If this form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. o

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of "large accelerated filer," "accelerated filer" and "smaller reporting company" in Rule 12b-2 of the Exchange Act. (Check one):

Large Accelerated filer ý

Accelerated filer o

Non-accelerated filer o
(Do not check if a smaller
reporting company)

Smaller reporting company o

The Registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8 of the Securities Act or until this Registration Statement shall become effective on such date as the Commission, acting pursuant to said Section 8, may determine.

Dear Shareholder:

On behalf of our Board of Trustees, I cordially invite you to attend a special meeting of shareholders of GMH Communities Trust, or GMH, a Maryland real estate investment trust, to be held on June 10, 2008 at 11:00 a.m. local time. The special meeting will take place at Philadelphia Marriott West, 111 Crawford Avenue, West Conshohocken, Pennsylvania 19428.

At the special meeting, we will ask you to consider and approve the merger of American Campus Acquisition LLC, a Delaware limited liability company and a wholly-owned subsidiary of American Campus Communities Operating Partnership LP, the operating partnership of American Campus Communities, Inc., or ACC, with and into GMH. Upon completion of the merger, holders of our common shares will have the right to receive, in exchange for each common share owned, (i) $3.36 in cash and (ii) 0.07642 of a common share of ACC, without interest and less any required withholding tax, as more fully described in the enclosed proxy statement/prospectus. On April , 2008, the last trading date prior to the printing of the proxy statement/prospectus that accompanies this letter, the closing price of ACC's common shares as reported on the New York Stock Exchange was $ per share.

In addition, holders of our common shares are expected to receive, upon completion of the sale of GMH's military housing division to Balfour Beatty, Inc., a U.S. subsidiary of Balfour Beatty plc, a net distribution of approximately $4.08 per share/unit, subject to adjustment as described in this proxy statement/prospectus. The closing of the military housing sale is a condition to the obligations of GMH and ACC to consummate the merger.

After careful consideration, our Board of Trustees unanimously approved the merger, the merger agreement and the other transactions contemplated by the merger agreement, and has declared each to be advisable and in the best interests of GMH and its shareholders. Our Board of Trustees recommends that you vote "FOR" the approval of the merger.

The affirmative vote of holders of at least two-thirds of our outstanding common shares that are entitled to vote at the special meeting is required to approve the merger. The proxy statement/prospectus accompanying this letter provides you with more specific information concerning the special meeting, the merger agreement and the other transactions contemplated by the merger agreement. We encourage you to read carefully the enclosed proxy statement/prospectus, including the appendices.

Your vote is very important, regardless of the number of common shares that you own. Whether or not you plan to attend the special meeting, we request that you cast your vote in accordance with the instructions set forth on the enclosed proxy card. If you attend the special meeting, you may continue to have your shares voted as instructed in the proxy, or you may withdraw your proxy at the special meeting and vote your shares in person. If you fail to vote by proxy or in person, or fail to instruct your broker on how to vote, it will have the same effect as a vote against approval of the merger.

Please do not send your common share certificates at this time. If the merger is approved, we will send specific instructions regarding the exchange of your certificates.

Thank you for your cooperation and continued support.

		Very truly yours,

		Gary M. Holloway, Sr. Chairman, President and Chief Executive Officer

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved, or passed upon the merits or fairness, of the merger, the merger agreement or the other transactions contemplated by the merger agreement, or passed upon the adequacy or accuracy of the enclosed proxy statement/prospectus. Any representation to the contrary is a criminal offense.

This proxy statement/prospectus is dated April , 2008 and is first being mailed to our shareholders on or about April , 2008.

SOURCES OF ADDITIONAL INFORMATION

This proxy statement/prospectus incorporates important business and financial information about ACC and GMH that is not included or delivered with this document. This information is available without charge to ACC and GMH shareholders upon written or oral request. You can obtain the documents incorporated by reference in this proxy statement/prospectus by requesting them in writing or by telephone from the appropriate company at the following addresses and telephone numbers:

American Campus Communities, Inc.
805 Las Cimas Parkway, Suite 400
Austin, Texas 78746
Attention: Investor Relations
Telephone: (512) 732-1000

GMH Communities Trust
10 Campus Boulevard
Newtown Square, Pennsylvania 19073
Attention: Investor Relations
Telephone: (610) 355-8000

To obtain timely delivery of requested documents prior to the special meeting of GMH shareholders, you must request them no later than June 3, 2008, which is five business days prior to the date of the meeting.

Also see "Where You Can Find More Information" on page 139 of this proxy statement/prospectus.

ELECTRONIC AND TELEPHONE PROXY AUTHORIZATION

GMH shareholders of record on the close of business on April 21, 2008, the record date for the GMH special meeting, may authorize their proxies to vote their shares by telephone or Internet by following the instructions on their proxy card or voting form. If you have any questions regarding how to authorize your proxy by telephone or by Internet, please call Georgeson Inc. toll-free at 1-888-867-7098.

GMH COMMUNITIES TRUST
10 Campus Boulevard
Newtown Square, Pennsylvania 19073

NOTICE OF SPECIAL MEETING OF SHAREHOLDERS TO BE HELD ON JUNE 10, 2008

Dear GMH Shareholder:

You are cordially invited to attend a special meeting of the shareholders of GMH Communities Trust, a Maryland real estate investment trust, on June 10, 2008, beginning at 11:00 a.m. local time, at Philadelphia Marriott West, 111 Crawford Avenue, West Conshohocken, Pennsylvania 19428. The special meeting is being held for the purpose of acting on the following matters:

1.: To consider and vote on a proposal to approve the merger of American Campus Acquisition LLC, a Delaware limited liability company and a wholly-owned subsidiary of American Campus Communities Operating Partnership LP, the operating partnership of American Campus Communities, Inc., with and into GMH Communities Trust, pursuant to the Agreement and Plan of Merger, dated as of February 11, 2008, by and among GMH Communities Trust, GMH Communities, Inc., GMH Communities, LP, American Campus Communities, Inc., American Campus Communities Operating Partnership LP, American Campus Acquisition LLC and American Campus Acquisition Limited Partnership LP, referred to as the merger agreement; and
2.: To consider and vote on a proposal to approve any adjournment or postponement of the special meeting for the purpose of soliciting additional proxies if there are not sufficient votes at the time of the special meeting to approve the merger.

The merger agreement, which explains the merger, is attached to this proxy statement/prospectus as Annex A. Only shareholders of record as of the close of business on April 21, 2008 will be entitled to notice of or to vote at the special meeting or any adjournment or postponement of that special meeting.

We encourage you to read the attached proxy statement/prospectus carefully. If you have any questions or need assistance voting your shares, please call our proxy solicitor, Georgeson Inc., toll-free at 1-888-867-7098.

		By Order of the Board of Trustees,

		Joseph M. Macchione Executive Vice President, General Counsel and Secretary
Newtown Square, Pennsylvania April , 2008

TABLE OF CONTENTS

		Page
SUMMARY		1
	The Companies	1
	The Mergers	2
	Military Housing Sale	3
	Home Office and Disposition Properties	3
	The GMH Special Meeting	4
	Risk Factors	5
	GMH's Recommendation to its Shareholders	5
	Opinion of GMH's Financial Advisor	5
	Ownership of ACC Following the Mergers	5
	Conditions to the Mergers	6
	Termination	7
	Termination Fees and Expenses	8
	Financing of the Mergers	9
	Interests of GMH's Trustees and Executive Officers in the Mergers	11
	Accounting Treatment	11
	Material U.S. Federal Income Tax Consequences to GMH Shareholders of the REIT Merger and Distributions	11
	Regulatory Matters	12
	Appraisal or Dissenters' Rights	12
	The Rights of GMH Shareholders Will Change	12
	Selected Historical Financial Data of ACC	13
	Selected Historical Financial Data of GMH	14
	Summary Unaudited Pro Forma Consolidated Financial Information	16
	Comparative Per Share Data	17
	Comparative Per Share Market Price and Dividend Information	17
	Comparative Market Data	19
QUESTIONS AND ANSWERS ABOUT THE MERGERS		20
RISK FACTORS		27
	Risk Factors Relating to the Mergers	27
	Risk Factors Relating to ACC Following the Mergers	32
CAUTIONARY STATEMENT CONCERNING FORWARD-LOOKING STATEMENTS		34
THE GMH SPECIAL MEETING		35
	Date, Time and Place	35
	Purpose	35
	Recommendation of GMH's Board of Trustees	35
	Voting by Trustees and Executive Officers	35
	Record Date; Outstanding Shares and Voting Rights	35
	Vote Required; Quorum	35
	Voting of Proxies	36
	Proxy Authorization Electronically or by Telephone	36
	Appraisal or Dissenters' Rights	37
	Revocation of Proxies	37
	Solicitation of Proxies; Expenses	37

THE MERGERS AND RELATED TRANSACTIONS		39
	General	39
	Background of the Mergers	39
	GMH's Reasons for the Mergers	45
	Military Housing Sale	49
	Home Office and Disposition Properties	50
	Certain Effects of the Mergers	51
	Effects on GMH if the Mergers are Not Completed	51
	ACC's Reasons for the Mergers	52
	Financing of the Mergers	53
	Opinion of GMH's Financial Advisor	56
	Accounting Treatment for the Mergers	64
	Regulatory Matters	64
	Delisting and Deregistration of GMH Common Shares; Listing of ACC Common Stock Issued in Connection with the Mergers	64
INTERESTS OF TRUSTEES AND EXECUTIVE OFFICERS OF GMH IN THE MERGERS		65
	Equity Compensation Awards	65
	Employment Agreements	65
	Success Fees	65
	Put Agreement	66
	Indemnification	66
	Appointment to ACC's Board of Directors	67
THE MERGER AGREEMENT		68
	The Mergers	68
	The Merger Consideration and Effects of the Mergers	69
	Representations and Warranties of the GMH Parties	71
	Representations and Warranties of the ACC Parties	74
	Covenants Related to Conduct of Business of GMH	76
	Covenants Related to Conduct of Business of ACC	80
	Other Covenants	81
	Non-Solicitation	81
	Debt Financing	83
	Home Office and Disposition Properties	83
	Military Housing Sale	84
	Fidelity Agreement	84
	Conditions to the Mergers	84
	Termination	86
	Termination Fees and Expenses	87
	Remedies	88
	Amendment of the Merger Agreement	88
MATERIAL U.S. FEDERAL INCOME TAX CONSIDERATIONS		89
	Material U.S. Federal Income Tax Consequences to GMH Shareholders of the REIT Merger and Distributions	90
	Material U.S. Federal Income Tax Considerations Applicable to Holders of ACC Common Stock	94
ACC'S POLICIES WITH RESPECT TO CERTAIN ACTIVITIES		114
	Investment Policies	114
	Dispositions	115

	Financing Policies	115
	Conflict of Interest Policies	115
	Interested Director and Officer Transactions	116
	Business Opportunities	116
	Policies with Respect to Other Activities	116
GMH'S POLICIES WITH RESPECT TO CERTAIN ACTIVITIES		117
	Investment Approval Policy	117
	Leverage Ratio Target	117
	Investments in Securities or Entities	118
	Lending Policies	118
	Equity Capital Policies	119
	Review, Approval or Ratification of Transactions with Related Persons	119
COMPARISON OF RIGHTS OF STOCKHOLDERS OF ACC AND SHAREHOLDERS OF GMH		121
	Capitalization	121
	Composition of Boards	121
	Vacancies on and Removal from the Boards	122
	Charter and Bylaw Amendments	122
	Transactions Outside the Ordinary Course of Business	122
	Advance Notice of Director Nominations and New Business	123
	Limits on Ownership and Transfer of Shares	124
	Stockholder Meetings	127
	Business Combination Act	127
	Control Share Acquisition Act	127
DESCRIPTION OF ACC CAPITAL STOCK		129
	General	129
	Common Stock	129
	Preferred Stock	130
	Restrictions on Transfer	130
	Transfer Agent and Registrar	133
SELLING STOCKHOLDERS		134
	Exchange of Units	134
	Selling Stockholders	135
	Plan of Distribution	136
SHAREHOLDER PROPOSALS		137
LEGAL MATTERS		138
EXPERTS		138
WHERE YOU CAN FIND MORE INFORMATION		139
AMERICAN CAMPUS COMMUNITIES, INC. AND SUBSIDIARIES INDEX TO UNAUDITED PRO FORMA CONSOLIDATED FINANCIAL STATEMENTS		F-1
Annex A—Agreement and Plan of Merger
Annex B—Opinion of Wachovia Capital Markets, LLC

iii

SUMMARY

This summary, together with the "Questions and Answers About the Mergers," summarizes the material information in this proxy statement/prospectus. To understand the mergers fully and for a more complete description of the legal terms of the mergers, you should read carefully this entire document and the documents to which we have referred you. This summary also highlights, to a limited extent, the sale of GMH's military housing division, which closing is a condition to the obligations of American Campus Communities, Inc. and GMH Communities Trust to consummate the mergers. See "Where You Can Find More Information." Page references have been included parenthetically to direct you to a more complete description of the topics in this document.

The Companies

American Campus Communities, Inc.

805 Las Cimas Parkway, Suite 400
Austin, Texas 78746
(512) 732-1000

American Campus Communities, Inc., or ACC, is a fully integrated, self-managed and self-administered equity real estate investment trust, or REIT. Through its controlling interest in American Campus Communities Operating Partnership LP, or the ACC Operating Partnership, ACC is one of the largest owners, managers and developers of high quality student housing properties in the United States in terms of beds owned and under management with expertise in the acquisition, design, financing, development, construction management, leasing and management of student housing properties. As of December 31, 2007, its property portfolio contained 44 student housing properties with approximately 28,600 beds and approximately 9,500 apartment units, consisting of 38 owned off-campus properties that are in close proximity to colleges and universities, two American Campus Equity (ACE™) on-campus properties currently under development that will be owned and operated under long-term ground/facility leases with a related university system and four on-campus participating properties operated under ground/facility leases with the related university systems. These communities contain modern housing units, offer resort-style amenities and are supported by a resident assistant system and other student-oriented programming.

ACC also provides construction management and development services primarily for student housing properties owned by colleges and universities, charitable foundations and others. As of December 31, 2007, ACC provided third-party management and leasing services for 19 properties (seven of which it served as the third-party developer and construction manager) that represented approximately 15,200 beds in approximately 6,000 units. Third-party management and leasing services are typically provided pursuant to multi-year management contracts that have initial terms that range from one to five years. As of December 31, 2007, ACC's total owned and managed portfolio included 63 properties with approximately 43,800 beds in approximately 15,500 units.

Each of American Campus Acquisition LLC and American Campus Acquisition Limited Partnership LP is a newly-formed subsidiary of American Campus Communities, Inc. that was formed solely for the purpose of effecting the mergers. Neither American Campus Acquisition LLC nor American Campus Acquisition Limited Partnership LP has conducted, nor will it conduct, any business prior to the mergers. ACC, the ACC Operating Partnership, American Campus Acquisition LLC and American Campus Acquisition Limited Partnership LP are collectively referred to as the ACC Parties in this proxy statement/prospectus.

GMH Communities Trust

10 Campus Boulevard
Newtown Square, Pennsylvania 19073
(610) 355-8000

GMH Communities Trust, or GMH, is a self-advised, self-managed, specialty housing company that focuses on providing housing to college and university students residing off-campus and to members of the U.S. military and their families. Through GMH Communities, LP, or the GMH Operating Partnership, GMH owns and operates its student housing properties and owns equity interests in joint ventures that own its military housing privatization projects. GMH generally provides the development, construction, renovation and management services for its military housing privatization projects and the property management services for student housing properties owned by others. In addition, through the GMH Operating Partnership, GMH provides consulting services with respect to the management of certain student housing properties owned by others, including colleges, universities and other private owners. GMH is one of the leading providers of housing, lifestyle and community solutions for students and members of the U.S. military and their families.

As of December 31, 2007, GMH owned or had ownership interests in 72 student housing properties, containing a total of 13,232 units and 42,670 beds and seven undeveloped or partially developed parcels of land held for development as student housing properties. Of this portfolio, it held a 10% interest in joint ventures that own eight of these student housing properties, covering a total of 1,140 units and 4,160 beds and provided management services for all of these properties. In addition to properties held through joint ventures, as of March 15, 2008, GMH managed a total of 12 student housing properties owned by others, containing a total of 2,239 units and 7,156 beds, including 48 units and 262 beds currently under construction. As of December 31, 2007, the GMH Operating Partnership had an ownership interest in and, through various wholly-owned subsidiaries, operated 12 military housing privatization projects, comprising an aggregate of approximately 25,288 end-state housing units on 37 military bases.

GMH Communities, Inc. is a newly-formed subsidiary of GMH Communities Trust that was formed solely for the purpose of effecting the mergers. GMH Communities, Inc. has not conducted, nor will it conduct, any business prior to the mergers. GMH, the GMH Operating Partnership and GMH Communities, Inc. are collectively referred to as the GMH Parties in this proxy statement/prospectus.

The Mergers (Page 68)

The merger agreement provides for the merger of American Campus Acquisition LLC, or the REIT Merger Sub, with and into GMH. In this proxy statement/prospectus, we refer to this merger as the REIT merger. Next, GMH, as the surviving entity, will be merged with and into GMH Communities, Inc., or the Delaware Company. In this proxy statement/prospectus, we refer to this merger as the reincorporation merger. Finally, American Campus Acquisition Limited Partnership LP, or the Partnership Merger Sub, will be merged with and into the GMH Operating Partnership. In this proxy statement/prospectus, we refer to this merger as the partnership merger. We also collectively refer to the REIT merger, the reincorporation merger and the partnership merger as the mergers. Each common share of GMH not owned by ACC, GMH or any of their respective subsidiaries and each unit of limited partnership in the GMH Operating Partnership not owned by GMH, the GMH Operating Partnership or its general partner will be entitled to receive at the closing of the REIT merger and the partnership merger, respectively, 0.07642 of a share of ACC's common stock and $3.36 in cash, without interest, except, subject to certain conditions, in lieu of the receipt of ACC common stock, the holders of units in the GMH Operating Partnership may elect to receive 0.07642 of a common unit in the ACC Operating Partnership in the partnership merger.

This proxy statement/prospectus does not constitute a solicitation of consents in respect of the partnership merger and does not constitute an offer to convert units of limited partnership in the GMH Operating Partnership that you may own for or into a common unit in the ACC Operating Partnership.

Military Housing Sale (Page 49)

Concurrently with entering into the merger agreement, GMH and the GMH Operating Partnership entered into a securities purchase agreement with Balfour Beatty, Inc. (a U.S. subsidiary of Balfour Beatty plc), or Balfour Beatty, and, solely for the purpose of Article 8 of the securities purchase agreement, Balfour Beatty plc, for the sale of GMH's military housing division. Pursuant to the securities purchase agreement, Balfour Beatty will acquire GMH's military housing division by purchasing all of the issued and outstanding capital stock and limited liability company interests of the three GMH subsidiaries owned by GMH and the GMH Operating Partnership and through which the military housing business is conducted.

As consideration for the military housing sale, GMH will receive $350.0 million in cash, subject to adjustment pursuant to the terms of the securities purchase agreement. This amount may be increased or decreased to the extent the estimated working capital (including unrestricted cash and accounts receivable) of the military housing division as of the closing of the military housing sale, plus any project investments made during 2008 (other than investments in Fort Hamilton), exceeds or is below $14.5 million. Following the completion of the military housing sale, GMH intends to distribute to its shareholders and unitholders the proceeds from the sale plus excess cash, if any, above the minimum working capital generated by the military housing division, net of expenses from the sale. GMH anticipates making two separate distributions relating to the military housing sale—one shortly after the closing of the military housing sale (which will exclude such amounts to be held back as determined at the discretion of GMH's board of trustees) and one immediately prior to the completion of the REIT merger (which will include such held back amounts, plus interest earned which has not been previously distributed). We refer to these distributions in this proxy statement/prospectus as the military sale distributions. The military housing sale is currently anticipated to result in total distributions to GMH shareholders and unitholders of approximately $4.08 per share/unit, subject to adjustment as described in this proxy statement/prospectus.

Home Office and Disposition Properties (Page 49)

In connection with the mergers, GMH anticipates selling its home office immediately prior to the closing of the mergers, and will have the right, but not the obligation, to sell certain student housing properties, referred to in this proxy statement/prospectus as the disposition properties. A percentage of the amount received, if any, in connection with the sale of the home office and certain of the disposition properties is allowed to be paid under the merger agreement to GMH shareholders and unitholders as a special distribution preceding the closing of the mergers. Any amounts distributed as a special distribution will be in addition to the merger consideration.

GMH's board of trustees has established a committee of independent trustees, chaired by Denis J. Nayden, to sell the home office immediately prior to the closing of the mergers. This committee will decide whether or not to exercise GMH's rights under the put agreement. The home office committee has engaged Binswanger Corporation, a real estate broker, to market the home office.

The GMH Special Meeting

The Meeting Time and Place (Page 35)

The special meeting will be held on June 10, 2008, at Philadelphia Marriott West, 111 Crawford Avenue, West Conshohocken, Pennsylvania 19428, starting at 11:00 a.m., local time.

Shareholders Entitled to Vote (Page 35)

Holders of record of GMH common shares at the close of business on the record date of April 21, 2008 are entitled to notice of, and to vote at, the special meeting. On the record date, there were 41,669,879 GMH common shares outstanding, each of which will be entitled to one vote on each matter to be acted upon at the special meeting. The approval of ACC stockholders is not required to consummate the mergers.

Share Ownership of Directors and Executive Officers (Page 35)

As of the close of business on April 21, 2008, the trustees and executive officers of GMH held and were entitled to vote, in the aggregate, 640,442 GMH common shares, representing approximately 1.5% of the outstanding GMH common shares. GMH currently expects that the trustees and executive officers of GMH will vote all of their GMH common shares "FOR" the approval of the REIT merger and, if necessary, in favor of adjournment to solicit additional proxies.

Proposals to be Considered at the Meeting (Page 35)

At the special meeting, GMH shareholders will be asked to consider and vote upon:

•: the proposal to approve the REIT merger; and
•: any adjournment or postponement of the special meeting.

The persons named in the accompanying proxy will also have discretionary authority to vote upon other business, if any, that properly comes before the special meeting and any adjournment or postponement of the special meeting.

Vote Required (Page 35)

The REIT merger requires the approval of the shareholders of GMH by the affirmative vote of at least two-thirds of the outstanding GMH common shares held of record as of the close of business on April 21, 2008. Abstentions will be counted for quorum purposes and will have the same effect as votes "AGAINST" approval of the REIT merger proposal since the REIT merger proposal requires the affirmative vote of two-thirds of outstanding GMH common shares.

Risk Factors (Page 27)

In evaluating the REIT merger, you should carefully consider the "Risk Factors" beginning on page 27.

GMH's Recommendation to its Shareholders (Page 35)

GMH's board of trustees voted unanimously to approve the merger agreement, the mergers and the transactions contemplated under the merger agreement. GMH's board of trustees believes that the REIT merger is in the best interests of GMH and its shareholders and recommends that GMH shareholders vote "FOR" the REIT merger.

Opinion of GMH's Financial Advisor (Page 56)

In connection with the mergers, GMH's board of trustees received a written opinion, dated February 11, 2008, from GMH's financial advisor, Wachovia Capital Markets, LLC, referred to in this proxy statement/prospectus as Wachovia Securities, as to the fairness, from a financial point of view and as of the date of such opinion, of the merger consideration, taken together with the payment of the military sale distributions, to be received by holders of GMH common shares and holders of GMH Operating Partnership units (other than GMH, the general partner of the GMH Operating Partnership and other subsidiaries of GMH). For purposes of its opinion, Wachovia Securities took into account, in the case of holders of GMH Operating Partnership units, only the merger consideration (taken together with the payment of the military sale distributions) that would be received by such holders if, prior to the consummation of the mergers, they converted their GMH Operating Partnership units into GMH common shares in accordance with the terms of the limited partnership agreement of the GMH Operating Partnership. The full text of Wachovia Securities' written opinion, dated February 11, 2008, which sets forth, among other things, the assumptions made, procedures followed, matters considered and limitations on the review undertaken in connection with such opinion, is attached as Annex B to this proxy statement/prospectus and is incorporated by reference in its entirety into this proxy statement/prospectus. This summary is qualified in its entirety by reference to the full text of the opinion. Wachovia Securities provided its opinion for the information and assistance of GMH's board of trustees in connection with its evaluation of the merger consideration, taken together with the payment of the military sale distributions, from a financial point of view. Wachovia Securities' opinion does not address any other aspect of the mergers or any related transaction, does not address the relative merits of the mergers or any related transaction and does not constitute a recommendation as to how any securityholder should vote or act in connection with the mergers (including, in the case of holders of GMH Operating Partnership units, as to whether such holder should elect to receive ACC Operating Partnership units, in lieu of ACC common stock, in the mergers) or any other matters.

Ownership of ACC Following the Mergers

Based on the capitalization of GMH and ACC as of April 21, 2008, the record date for the special meeting, assuming all of the partnership units are converted into ACC common stock, holders of outstanding GMH common shares and partnership units in the GMH Operating Partnership will be entitled to receive as a result of the mergers a total of approximately 5,449,832 shares of ACC common stock, representing approximately 16.6% of the shares of ACC common stock outstanding following the mergers. Based on the capitalization of GMH and ACC as of the date of this proxy statement/prospectus, after the consummation of ACC's offering of 9.2 million shares of its common stock, which occurred on April 23, 2008, holders of outstanding GMH common shares and partnership units in the GMH Operating Partnership will hold approximately 13.0% of the shares of ACC common stock outstanding following the mergers.

Conditions to the Mergers (Page 84)

The obligations of the parties to complete the mergers are subject to the following mutual conditions:

•: approval of the REIT merger by the required vote of GMH shareholders;
•: effectiveness of the registration statement on Form S-4 of which this proxy statement/prospectus is a part and the absence of a stop order or proceedings threatened or initiated by the SEC for that purpose;
•: authorization by the New York Stock Exchange, or the NYSE, of the listing of the ACC common stock to be issued in the mergers, subject to official notice of issuance;
•: receipt of all the material approvals, authorizations and consents of any governmental authority required to consummate the mergers (all of which must be in full force and effect), and expiration or termination of all waiting periods relating to the approvals, authorizations and consents;
•: absence of any injunction, order, decree or ruling issued by a governmental authority in the United States which is then in effect and would make consummation of the mergers illegal or prohibits the consummation of the mergers (provided, that the party claiming such factor has used commercially reasonable efforts to prevent the entry of such injunction or order and to appeal as promptly as possible any injunction or other order that may be entered); and
•: consummation of the military housing sale in accordance with the securities purchase agreement; provided, however, if the securities purchase agreement has been terminated, GMH may sell the military housing subsidiaries to a substitute buyer reasonably satisfactory to ACC upon such terms and conditions substantially similar to those in the securities purchase agreement.

The obligations of the ACC Parties to complete the mergers are further conditioned on:

•: the truth and correctness of the GMH Parties' representations and warranties (subject to the GMH material adverse effect standard in the merger agreement);
•: the performance in all material respects of GMH's covenants and agreements under the merger agreement at or prior to the REIT merger effective time;
•: there having occurred no change that would, individually or in the aggregate, constitute a GMH material adverse effect since February 11, 2008;
•: receipt by ACC of a certificate signed on GMH's behalf by an officer of GMH as to the satisfaction of the three conditions described in the three preceding bullet points;
•: receipt by ACC of a written opinion of Reed Smith LLP, to the effect that GMH has been organized and operated in conformity with the requirements for qualification as a REIT under the Internal Revenue Code, or the Code, for all taxable periods commencing with GMH's taxable year ended December 31, 2004 until the closing of the mergers;
•: receipt by GMH of consents from certain lenders in form and substance reasonably satisfactory to ACC; and

•: approval of the settlement agreement relating to the pending securities litigation by the United States District Court for the Eastern District of Pennsylvania, and satisfaction of all payments and other material obligations thereunder.

The obligations of the GMH Parties to complete the mergers are further conditioned on:

•: the truth and correctness of the ACC Parties' representations and warranties (subject to the ACC material adverse effect standard in the merger agreement);
•: performance in all material respects of ACC's covenants and agreements under the merger agreement at or prior to the REIT merger effective time;
•: there having occurred no change that would, individually or in the aggregate, constitute an ACC material adverse effect since February 11, 2008;
•: receipt by GMH of a certificate signed on ACC's behalf by an officer of ACC as to the satisfaction of the three conditions described in the three preceding bullet points; and
•: receipt by GMH of a written opinion of Locke Lord Bissell & Liddell LLP, to the effect that ACC has been organized and operated in conformity with the requirements for qualification as a REIT under the Code for all taxable periods commencing with ACC's taxable year ended December 31, 2004 through and including the closing date.

Termination (Page 86)

The merger agreement may be terminated prior to the REIT merger effective time, whether before or after the required GMH shareholder approval for the REIT merger is obtained:

•: by mutual written consent of ACC and GMH;
•: by either GMH or ACC, if GMH shareholders fail to approve the REIT merger at a duly held meeting (including any adjournment or postponement of such meeting);
•: by either GMH or ACC, if the REIT merger effective time has not occurred by July 31, 2008 (provided that this right will not be available to a party whose failure to fulfill any obligation under the merger agreement materially contributed to the failure of the REIT merger effective time to occur on or before this date);
•: by either GMH or ACC, if any governmental authority issues a final and non-appealable injunction, order, decree or ruling or takes any other action which makes consummation of the mergers illegal or otherwise prohibits consummation of the mergers (provided that the terminating party has used commercially reasonable efforts to oppose and have vacated the injunction, order, decree, ruling or action);
•: by ACC, if any of the GMH Parties breaches or fails to perform any of its representations, warranties, or covenants contained in the merger agreement in either case such that the related conditions to the obligations of ACC to close the mergers would be incapable of being satisfied on July 31, 2008;
•: by GMH, if any of the ACC Parties breaches or fails to perform any of its representations, warranties or covenants contained in the merger agreement in either case such that the related conditions to the obligations of GMH to close the mergers would be incapable of being satisfied by July 31, 2008;

•: by GMH, if any GMH Party enters into certain acquisition agreements in accordance with, and subject to the terms and conditions of, the non-solicitation covenant in the merger agreement (provided that for the termination of the merger agreement pursuant to this provision to be effective, GMH will simultaneously pay the termination fee and expenses of ACC as described below);
•: by ACC, if prior to receipt of the approval of GMH shareholders, (1) GMH's board of trustees or any committee of GMH's board of trustees (a) withdraws, qualifies, or modifies or proposes publicly to withdraw, qualify or modify, in each case, in a manner adverse to ACC, its approval or recommendation of the mergers or (b) approves or recommends, or proposes publicly to approve or recommend, an acquisition proposal, (2) GMH enters into an acquisition agreement, (3) a tender offer or exchange offer relating to GMH's common shares is commenced by a third party and GMH's board of trustees does not recommend that GMH shareholders reject such tender or exchange offer within 10 business days following commencement of such tender offer or exchange offer, (4) GMH breaches in any material respect its obligation to call or hold the special meeting, (5) GMH breaches in any material respect its obligations under the non-solicitation covenant, (6) GMH fails to include in this proxy statement/prospectus the recommendation of approval of the REIT merger by GMH's board of trustees, or (7) GMH or GMH's board of trustees (or any committee thereof) authorizes or publicly proposes any of the foregoing;
•: by ACC, if none of the ACC Parties is in material breach of its obligations under the merger agreement, if the military housing sale is not closed prior to the REIT merger effective time; or
•: by GMH, if none of the GMH Parties is in material breach of its obligations under the merger agreement, if the military housing sale is not closed prior to the REIT merger effective time (provided that for the termination of the merger agreement pursuant to this provision to be effective, GMH will simultaneously pay the expenses of ACC as described below).

Termination Fees and Expenses (Page 87)

GMH will pay to ACC a termination fee of $16.0 million plus the reasonable out-of-pocket costs and expenses incurred by ACC and its subsidiaries in connection with the merger agreement up to an aggregate maximum amount of $7.5 million if the merger agreement is terminated:

•: by GMH, if GMH enters into an acquisition agreement in accordance with, and subject to the terms and conditions of, the non-solicitation covenant of the merger agreement;
•: by ACC, if prior to receipt of the approval of GMH shareholders, (1) GMH's board of trustees or any committee of GMH's board of trustees (a) withdraws, qualifies, or modifies or proposes publicly to withdraw, qualify or modify, in each case, in a manner adverse to ACC, its approval or recommendation of the mergers or (b) approves or recommends, or proposes publicly to approve or recommend, an acquisition proposal, (2) GMH enters into an acquisition agreement, (3) a tender offer or exchange offer relating to GMH's common shares is commenced by a third party and GMH's board of trustees does not recommend that GMH shareholders reject such tender or exchange offer within 10 business days following commencement of such tender offer or exchange offer, (4) GMH breaches in any material respect its obligation to call or hold the special meeting, (5) GMH breaches in any material respect its obligations under

the non-solicitation covenant, (6) GMH fails to include in this proxy statement/prospectus the recommendation of approval of the REIT merger by GMH's board of trustees, or (7) GMH or GMH's board of trustees (or any committee thereof) authorizes or publicly proposes any of the foregoing; or

•: by either GMH or ACC, if prior to the special meeting, any qualifying acquisition proposal is publicly proposed or publicly disclosed and not withdrawn at or prior to the time of the special meeting and, concurrently with or within 12 months after the date of termination, GMH enters into a definitive agreement with respect to or consummates any qualifying acquisition proposal and the merger agreement is terminated (1) for failure to obtain GMH shareholder approval or (2) because the REIT merger effective time has not occurred before July 31, 2008 (provided that ACC did not breach its obligations with regards to SEC filings under the merger agreement).

In addition, GMH will pay to ACC the reasonable out-of-pocket costs and expenses incurred by ACC and its subsidiaries in connection with the merger agreement up to an aggregate maximum amount of $7.5 million if the merger agreement is terminated:

•: by either GMH or ACC, if GMH shareholders fail to approve the REIT merger at the special meeting (including any adjournment or postponement of such meeting);
•: by ACC, if none of the ACC Parties is in material breach of its obligations under the merger agreement, if any of the GMH Parties breaches or fails to perform any of its representations, warranties or covenants contained in the merger agreement, in either case such that the related conditions to the obligations of the ACC Parties to close the mergers would be incapable of being satisfied by July 31, 2008;
•: by ACC, if none of the ACC Parties is in material breach of its obligations under the merger agreement, if the military housing sale is not closed prior to the REIT merger effective time; or
•: by GMH, if none of the GMH Parties is in material breach of its obligations under the merger agreement, if the military housing sale is not closed prior to the REIT merger effective time.

ACC will pay to GMH the reasonable out-of-pocket costs and expenses incurred by GMH and its subsidiaries in connection with the merger agreement up to an aggregate maximum amount of $7.5 million if the merger agreement is terminated by GMH, if none of the GMH Parties is in material breach of its obligations under the merger agreement, if any of the ACC Parties breaches or fails to perform any of its representations, warranties or covenants contained in the merger agreement in either case such that the related conditions to the obligations of GMH to close the mergers would be incapable of being satisfied by July 31, 2008. The parties are also entitled to specific performance with respect to the merger agreement in addition to any other remedy at law or equity (including injunctions).

Financing of the Mergers (Page 53)

In connection with the mergers, ACC has entered into a commitment letter with KeyBank National Association, or KeyBank, for the arrangement of a senior secured term loan of $200.0 million for the ACC Operating Partnership, which may be expanded by up to an additional $100.0 million if one or more lenders agree to assume such increase. The commitment letter expires on July 31, 2008. ACC has also entered into a commitment letter with KeyBank to increase the existing senior unsecured revolving credit facility of the ACC Operating Partnership from $115.0 million to $160.0 million, with

the ability, subject to the satisfaction of certain conditions, to expand this facility by up to an additional $65.0 million. The commitment letter for the facility and the closing facility are subject to customary conditions for this type of financing, including (1) the absence of a material adverse change in the business, assets, operations, conditions (financial or otherwise) or prospects of ACC or the ACC Operating Partnership, (2) the negotiation and execution of definitive loan documentation and (3) the absence of defaults under any of ACC's financial obligations.

The merger agreement does not contain a financing condition. Under the terms of the merger agreement, ACC agreed that if any portion of the debt financing becomes unavailable on the terms and conditions contemplated in the commitment letter or the commitment letter is terminated for any reason, ACC will use reasonable commercial efforts to obtain alternative financing from alternative sources in an amount sufficient to consummate the mergers and pay any related costs and expenses, and, if obtained, ACC is obligated to provide GMH with a copy of the new financing commitment. ACC acknowledged and agreed in the merger agreement that the receipt of the debt financing or any other replacement financing is not a condition to the obligations of ACC to consummate the mergers.

Also in connection with the mergers, ACC and the ACC Operating Partnership have entered into a contribution agreement with Fidelity Real Estate Growth Fund III, L.P., or Fidelity, pursuant to which ACC and Fidelity will, immediately prior to the effective time of the REIT merger, form a joint venture and ACC will cause certain property-owning subsidiaries of GMH to contribute to the joint venture 15 student housing properties with an estimated value of approximately $325.9 million, including approximately $210.2 million in assumed debt. ACC will retain a 10% minority interest in the joint venture and will provide property management services for the properties contributed to the joint venture. ACC will use the anticipated $105.7 million proceeds from this transaction to finance a portion of the cash consideration and merger costs.

ACC closed the public offering of 9.2 million shares of its common stock at a price of $28.75 per share, which includes 1.2 million shares issued as a result of the underwriters' exercise of their over-allotment option in full at the closing, on April 23, 2008. ACC received approximately $252.4 million in net proceeds from this offering after deducting the underwriting discount and fee and estimated expenses of the offering. ACC intends to use the net proceeds of this offering to fund a portion of the cash consideration payable in the mergers.

If the term loan or the joint venture transaction do not close, ACC will need to finance a portion of the cash consideration and other merger costs by other means, which may result in ACC incurring increased interest costs on replacement financing. See "Risk Factors—Risk Factors Relating to the Mergers—If the term loan or the joint venture transaction do not close, ACC will need to replace the funding that will be used to finance a portion of the cash consideration and other merger costs."

If all other closing conditions have been satisfied or waived but ACC fails to obtain adequate financing to complete the mergers, such failure will constitute a breach of its covenants under the merger agreement. In that event, so long as the GMH Parties are not in material breach of their obligations under the merger agreement, the GMH Parties would be entitled to terminate the merger agreement and receive from ACC the reasonable out-of-pocket costs and expenses incurred by GMH and its subsidiaries in connection with the merger agreement up to an aggregate maximum amount of $7.5 million. GMH is also entitled to specific performance with respect to the merger agreement in addition to any other remedy at law or equity (including injunctions). See "The Merger Agreement—Termination Fees and Expenses."

Interests of GMH's Trustees and Executive Officers in the Mergers (Page 65)

Some of GMH's trustees and executive officers have interests in the mergers that are different from, or in addition to, yours, including the following:

•: restricted shares issued to trustees and executive officers pursuant to GMH's equity incentive plan that are not yet vested will become fully vested and any restrictions on such GMH restricted shares will terminate or lapse at the REIT merger effective time and will automatically be converted into the right to receive the merger consideration; and
•: each of GMH's executive officers have entered into employment agreements which, upon the completion of the mergers and the transactions contemplated by the merger agreement, will result in (i) accelerated vesting of any unvested equity awards, (ii) an entitlement to certain cash payments if GMH or a successor entity terminates the executive's employment without "cause" or the executive resigns for "good reason" and (iii) the payment of certain retention bonuses.

Certain of GMH's executive officers will be entitled to reimbursement from GMH of certain excise taxes. Gary M. Holloway, Sr. is entitled to a gross-up payment estimated to be approximately $1,614,705. Additionally, if GMH's home office is not sold to a third party unaffiliated with GMH prior to the closing of the mergers, then Mr. Holloway is contractually obligated to purchase the home office pursuant to the put agreement by no later than one business day prior to the REIT merger effective time for the sum of $8.0 million.

Subject to the approval of GMH's board of trustees, certain of GMH's executive officers and/or trustees will be paid a success fee in the aggregate amount of $2.0 million for closing the military housing sale, the mergers and the transactions contemplated by the merger agreement, the allocation of the aggregate amount to be determined by GMH's board of trustees (or a committee thereof).

Also, GMH's trustees and executive officers are entitled to continued indemnification arrangements and directors' and officers' insurance coverage for a period of six years following the REIT merger effective time.

GMH's board of trustees was aware of the foregoing interests of GMH's trustees and executive officers in the military housing sale, the mergers and the transactions contemplated by the merger agreement and considered them, among other matters, in reaching its decision to approve the mergers and the transactions contemplated by the merger agreement.

Accounting Treatment (Page 64)

The mergers will be accounted for under the purchase method for accounting and financial reporting purposes.

Material U.S. Federal Income Tax Consequences to GMH Shareholders of the REIT Merger and Distributions (Page 89)

The receipt of the merger consideration in exchange for GMH common shares pursuant to the REIT merger will be a taxable transaction for U.S. federal income tax purposes. Generally, a GMH shareholder will recognize gain or loss for U.S. federal income tax purposes measured by the difference, if any, between (1) the amount of cash received and the fair market value, as of the

effective date of the REIT merger, of the ACC common stock received and (2) the GMH shareholder's adjusted tax basis in the GMH common shares exchanged for the merger consideration.

The receipt of the military sale distributions and the special distribution, if any (to the extent not designated as a capital gains dividend), will be taxable as ordinary income to the extent that GMH's earnings and profits for 2008 are allocable to the distributions; any such distribution in excess of earnings and profits will be treated as a return of capital and will reduce the tax basis of a GMH shareholder in its shares (but not below zero); and any such distribution in excess of tax basis is taxable as capital gain. Any part of the military sale distributions and special distribution designated as a capital gains dividend will be taxable as long-term capital gain or "unrecaptured Section 1250 gain" to the extent it does not exceed GMH's actual net capital gain for the year.

GMH shareholders should read "Material U.S. Federal Income Tax Considerations—Material U.S. Federal Income Tax Consequences to GMH Shareholders of the REIT Merger and Distributions" beginning on page 90 for a more complete discussion of the U.S. federal income tax consequences to GMH shareholders of the REIT merger, the military sale distributions and the special distribution, if any. Tax matters can be complicated and the tax consequences of the REIT merger, military sale distributions and special distribution to a GMH shareholder will depend on such holder's particular circumstances.

GMH shareholders should consult their own tax advisors to determine the particular tax consequences to them (including the application and effect of any state, local or non-U.S. income and other tax laws) of the REIT merger, military sale distributions and special distribution, if any.

Regulatory Matters (Page 64)

Neither ACC nor GMH is aware of any material U.S. federal or state regulatory approvals that must be obtained in connection with the mergers. However, the closing of the military housing sale (which is a condition precedent to the closing of the mergers) is subject to (a) obtaining necessary regulatory approvals, which include the expiration of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, and (b) receipt of notice that the military housing sale is not subject to the Exon-Florio amendments to The Defense Production Act of 1950. GMH and Balfour Beatty each filed a Notification and Report Form with the Federal Trade Commission and the Antitrust Division of the U.S. Department of Justice. The waiting period expired at 11:59 p.m. on March 31, 2008, without any request for additional information. A voluntary notice filing under the Exon-Florio amendments to the Defense Production Act of 1950 was submitted on March 11, 2008 to the Committee on Foreign Investment in the United States, or CIFIUS.

On April 10, 2008, GMH received a letter that CIFIUS had reviewed the submissions provided to it regarding the military housing sale and determined that there were no unresolved national security concerns and that action under the Exon-Florio amendments to the Defense Protection Act of 1950 was concluded.

Appraisal or Dissenters' Rights (Page 37)

Maryland law does not provide any appraisal rights or dissenters' rights for ACC or GMH shareholders in connection with the mergers.

The Rights of GMH Shareholders Will Change (Page 121)

The rights of GMH shareholders are determined by Maryland law and by GMH's charter and bylaws. When the merger is completed, GMH shareholders will become stockholders of ACC. The rights of ACC stockholders are determined by Maryland law and ACC's charter and bylaws. As a result of these different organizational documents, GMH shareholders will have different rights as ACC stockholders than they currently have as GMH shareholders.

Selected Historical Financial Data of ACC

ACC's historical financial data for the annual periods presented below has been derived from its audited financial statements previously filed with the SEC. This information is only a summary and you should read it together with ACC's historical financial statements and related notes contained in the annual reports, quarterly reports and other information that ACC has filed with the SEC and incorporated by reference. See "Where You Can Find More Information."

The following table sets forth selected financial and operating data on a consolidated historical basis for ACC and on a combined historical basis for its predecessor. Results for the year ended December 31, 2004 represent the combined historical data for its predecessor for the period from January 1, 2004 to August 16, 2004 as well as the consolidated results for ACC for the period from August 17, 2004 to December 31, 2004.

		As of and for the Year Ended December 31,
		2007			2006		2005		2004			2003
		(in thousands, except per share data)
Statements of Operations Information:
Revenues		$	147,135		$	118,953	$	82,522	$	56,230		$	52,792
(Loss) income from continuing operations			(1,686	)		1,662		1,751		(1,350	)		(186	)
Discontinued operations:
	Income (loss) attributable to discontinued operations		—			2,287		2,028		50			(774	)
	Gain (loss) from disposition of real estate		—			18,648		5,883		(39	)		16
Net (loss) income			(1,686	)		22,597		9,662		(1,339	)		(944	)
Per Share and Distribution Data:
Earnings per diluted share:
	(Loss) income from continuing operations	$	(0.07	)	$	0.08	$	0.12	$	0.05	(1)
	Discontinued operations		—			1.09		0.53		0.10	(1)
	Net (loss) income		(0.07	)		1.17		0.65		0.15	(1)
Cash distributions declared per share / unit			1.35			1.35		1.35		0.1651	(1)
Cash distributions declared			32,931			25,287		20,180		2,084	(1)
Balance Sheet Data:
Total assets		$	1,076,296		$	884,381	$	550,862	$	367,628		$	330,566
Secured debt			533,430			432,294		291,646		201,014			267,518
Unsecured revolving credit facility			9,600			—		—		—			—
Capital lease obligations			2,798			2,348		1,679		598			410
Stockholders' and predecessor owners' equity(2)			444,377			369,474		223,227		138,229			27,658

(1): Represents per share information and cash distributions declared during the period from August 17, 2004 (the IPO date) through December 31, 2004.
(2): Information for the years ended December 31, 2007, 2006, 2005 and 2004 reflects stockholders' equity as a result of and subsequent to the IPO while the previous year reflects ACC's predecessor owners' equity.

Selected Historical Financial Data of GMH

GMH's combined financial data for the annual periods presented below has been derived from its audited consolidated financial statements previously filed with the SEC. This information is only a summary and you should read it together with GMH's historical financial statements and related notes contained in the annual reports, quarterly reports and other information that GMH has filed with the SEC and incorporated by reference. See "Where You Can Find More Information."

The following table sets forth selected financial and operating data on a consolidated historical basis for GMH and on a combined historical basis for its predecessor. Results for the year ended December 31, 2004 represent the combined historical data for its predecessor for the period from January 1, 2004 to November 2, 2004 as well as the consolidated results for GMH for the period from November 2, 2004 to December 31, 2004.

			For the Year Ended December 31,
			GMH												Predecessor Entities
			2007			2006			2005			2004			2003
			(in thousands, except per share data)
Operating Data:
Revenue:
Rental revenue			$	188,889		$	169,166		$	118,741		$	23,778		$	636
Expense reimbursements
	Related party			86,860			64,230			57,930			33,309			3,273
	Third party			8,942			7,668			5,361			7,237			7,318
Fee income
	Related party			11,429			8,481			7,005			4,355			3,892
	Third party			2,877			3,167			3,774			3,986			2,624
Other fee income-related party				32,790			21,635			18,321			8,460			842
Other income				735			546			368			913			230

		Total revenue		332,522			274,893			211,500			82,038			18,815
Expenses:
Property operating expenses				90,684			78,878			51,423			20,258			9,218
Reimbursed expenses				95,802			71,898			63,291			40,546			10,591
Real estate taxes				17,773			16,050			10,921			1,736			83
Administrative expenses				17,410			17,682			12,254			6,006			1,405
Securities Litigation & Audit/Special Committee expense				1,844			7,821			—			—			—
Profits interest and employee initial public offering bonus expense				—			—			—			37,502			—
Depreciation and amortization				44,679			40,207			31,006			6,624			822
Interest				61,816			51,752			28,370			5,622			396

		Total expenses		330,008			284,288			197,265			118,294			22,515
Gain on sale to joint venture and development land				24,341			—			—			—			—

Income (loss) before equity in earnings of unconsolidated entities, minority interest, and income taxes				26,855			(9,395	)		14,235			(36,256	)		(3,700	)
Equity in earnings of unconsolidated entities				4,524			3,523			3,073			—			751

Income (loss) before minority interest and income taxes from continuing operations				31,379			(5,872	)		17,308			(36,256	)		(2,949	)
Income taxes				7,616			4,733			5,580			312			—

Income (loss) before minority interest from continuing operations				23,763			(10,605	)		11,728			(36,568	)		(2,949	)

Minority interest (income) loss attributable to continuing operations				(10,252	)		4,625			(5,700	)		256			—

Income (loss) from continuing operations				13,511			(5,980	)		6,028			(36,824	)		(2,949	)

Discontinued Operations:
Income (loss) from discontinued operations before minority interest			2,125			1,762			60			(187	)		—
Gains on sales of student housing properties			29,339			—			—			—			—
Minority interest (income) loss attributable to discontinued operations			(13,544	)		(768	)		(29	)		9			—

Income (loss) from discontinued operations			17,920			994			31			(178	)		—

Net income (loss)		$	31,431		$	(4,986	)	$	6,059		$	(37,002	)	$	(2,949	)

Earnings (loss) per common share—basic(1)
	Continuing operations	$	0.33		$	(0.14	)	$	0.19		$	0.01
	Discontinued operations		0.43			0.02			0.00			0.00

		$	0.76		$	(0.12	)	$	0.19		$	0.01

Earnings (loss) per common share—diluted
	Continuing operations	$	0.33		$	(0.14	)	$	0.18		$	0.01
	Discontinued operations		0.43			0.02			0.00			0.00

		$	0.76		$	(0.12	)	$	0.18		$	0.01

(1): Basic and diluted earnings per share reflect GMH's operations for the period November 2, 2004 (the date of the closing of its initial public offering) to December 31, 2004. Net income for this period was $251,000.

	As of December 31,
	GMH								Predecessor Entities
	2007		2006		2005		2004(1)		2003
	(in thousands)
Balance Sheet Data:
Real estate investments, net	$	1,324,064	$	1,592,567	$	1,181,216	$	634,730	$	—
Corporate office, net		8,560		8,425		7,613		11,384		6,963
Cash and cash equivalents		15,727		22,539		2,240		60,926		575
Total assets		1,488,846		1,713,990		1,277,951		773,061		16,146
Mortgage notes payable and line of credit		1,015,136		1,227,725		728,069		370,007		10,977
Total liabilities		1,085,344		1,298,718		792,452		395,242		12,552
Minority interest		136,422		157,972		188,633		182,118		—
Equity		267,080		257,300		296,866		195,701		3,594

Summary Unaudited Pro Forma Consolidated Financial Information

In the table below, ACC presents summary unaudited pro forma consolidated balance sheet information for ACC and GMH for the year ended December 31, 2007, as if the mergers and the sale by GMH of approximately $96.0 million of assets related to its military housing division had occurred on December 31, 2007 and summary unaudited pro forma consolidated statement of operations information for the year ended December 31, 2007 as if such transactions had occurred on January 1, 2007. The unaudited pro forma consolidated financial statements also give effect to properties acquired by ACC during 2007, ACC's October 2007 offering of 3.5 million shares of its common stock, the reclassification of 10 properties owned by GMH to Assets Held for Sale and the formation of a joint venture by ACC and Fidelity with respect to 15 properties owned by GMH, but do not give effect to the results of operations of ACC or GMH subsequent to December 31, 2007, including ACC's offering of 9.2 million shares of its common stock that closed on April 23, 2008. The mergers will be, and have been for purposes of the pro forma data, accounted for under the purchase method of accounting in accordance with Statement of Financial Accounting Standards No. 141, "Business Combinations."

The pro forma consolidated financial information should be read together with the respective historical consolidated financial statements and financial statement notes of ACC and GMH incorporated by reference into this proxy statement/prospectus. See "Where You Can Find More Information." The unaudited pro forma statement of operations information is presented for comparative and illustrative purposes only and is not necessarily indicative of what the actual combined results of operations of ACC and GMH would have been for the periods presented, nor does this information purport to represent the results of future periods that the combined entity will experience after the mergers. See "American Campus Communities, Inc. and Subsidiaries Unaudited Pro Forma Consolidated Financial Statements" beginning on page F-1.

	ACC Pro Forma
	(in thousands, except per share information)
Statement of Operations Information:
Revenues	$	285,772
Loss from continuing operations		(20,912	)
Per Share Information:
Loss from continuing operations per share—basic	$	(0.65	)
Loss from continuing operations per share—diluted		(0.63	)
Balance Sheet Information:
Total assets	$	2,242,877
Secured debt		1,457,489
Credit facility		43,666
Total stockholders' equity		597,853

It is important to remember that this information is hypothetical and does not necessarily reflect the financial performance that would have actually resulted if the mergers had been completed on those dates. Furthermore, this information does not necessarily reflect future financial performance if the mergers actually occur.

See "American Campus Communities, Inc. and Subsidiaries Unaudited Pro Forma Consolidated Financial Statements" attached to this proxy statement/prospectus for a more detailed explanation of this analysis.

Comparative Per Share Data

Set forth below are net income, book value and cash dividends per share data for ACC and GMH on a historical basis, for ACC and GMH on a pro forma basis and on a pro forma basis per GMH equivalent share.

The pro forma data was derived by combining the historical consolidated financial information of ACC and GMH using the purchase method of accounting.

You should read the information below together with the historical financial statements and related notes contained in the annual reports and other information that ACC and GMH have filed with the SEC and incorporated by reference. See "Where You Can Find More Information." The unaudited pro forma combined data below is for illustrative purposes only. The companies might have performed differently had they always been combined. You should not rely on this information as being indicative of the historical results that would have been achieved had the companies always been combined or the future results that the combined company will experience after the mergers.

	ACC Historical Data			GMH Historical Data		ACC Pro Forma Combined Data
	(Year ended December 31, 2007)
Loss (income) per share from continuing operations available to common stockholders—basic	$	(0.07	)	$	0.33	$	(0.65	)
Loss (income) per share from continuing operations available to common stockholders—diluted	$	(0.07	)	$	0.33	$	(0.63	)
Book value per share of common stock	$	16.29		$	6.42	$	18.27
Cash dividends per share of common stock	$	1.35		$	0.66	$	1.35

Comparative Per Share Market Price and Dividend Information

At the close of business on April 21, 2008, the record date for the special meeting, there were approximately 14,000 holders of record of ACC common stock and approximately 32 holders of record of GMH common shares.

ACC common stock is listed on the NYSE under the symbol "ACC." The following table sets forth the high and low sale prices per share of ACC common stock as reported by the NYSE, based on published financial sources for the quarterly periods indicated:

		ACC Common Stock
		High		Low		Dividend Per Share
2006:
	First Quarter	$	28.58	$	24.24	$	0.3375
	Second Quarter	$	26.20	$	22.40	$	0.3375
	Third Quarter	$	26.27	$	23.80	$	0.3375
	Fourth Quarter	$	30.23	$	24.85	$	0.3375
2007:
	First Quarter	$	32.52	$	28.35	$	0.3375
	Second Quarter	$	31.68	$	27.12	$	0.3375
	Third Quarter	$	29.56	$	24.30	$	0.3375
	Fourth Quarter	$	30.52	$	23.18	$	0.3375
2008:
	First Quarter	$	29.50	$	24.84		N/A
	Second Quarter (through April , 2008)	$		$			N/A

GMH common shares are listed on the NYSE under the symbol "GCT." The following table sets forth the high and low sale prices per GMH common share as reported by the NYSE, based on published financial sources for the quarterly periods indicated:

		GMH Common Shares
		High		Low		Dividend Per Share
2006:
	First Quarter	$	17.10	$	10.80	$	0.2275
	Second Quarter	$	13.18	$	10.75	$	0.2275
	Third Quarter	$	13.73	$	11.80	$	0.2275
	Fourth Quarter	$	14.18	$	10.04	$	0.1650	(1)
2007:
	First Quarter	$	10.84	$	9.14	$	0.1650
	Second Quarter	$	10.99	$	9.40	$	0.1650
	Third Quarter	$	10.05	$	7.51	$	0.1650
	Fourth Quarter	$	7.99	$	5.44	$	0.1650	(2)
2008:
	First Quarter	$	9.10	$	4.50	$	0.1650	(3)
	Second Quarter (through April , 2008)	$		$			N/A

(1): Declared on December 18, 2006 and paid on February 1, 2007 to shareholders of record as of the close of business on December 29, 2007.
(2): Declared on December 12, 2007 and paid on January 15, 2008 to shareholders of record as of the close of business on December 27, 2007.
(3): Declared on March 20, 2008 and paid on April 15, 2008 to shareholders of record at the close of business on March 31, 2008.

The following table sets forth the closing sale prices per GMH common shares as reported on the NYSE on February 11, 2008, the last trading day before ACC and GMH announced the proposed mergers, and on April , 2008, the most recent practicable trading day before the date on which this proxy statement/prospectus was mailed to GMH shareholders.

Date		GMH Price Per Common Share
February 11, 2008		$	5.59
April , 2008		$

GMH is restricted by the terms of the merger agreement from paying regular dividends other than the regular cash distribution at a rate not in excess of $0.165 per GMH common share for the first quarter of 2008 and certain dividends required for GMH to maintain its REIT status, to eliminate U.S. federal income tax liability and as set forth below.

The closing of the military housing sale is a condition precedent to the mergers and is currently expected to occur on or before May 12, 2008. The military housing sale does not require shareholder approval and accordingly, is expected to close prior to the special meeting. GMH's board of trustees has determined that, if the mergers are not completed for any reason, GMH expects to continue with the military housing sale. As consideration for the military housing sale, GMH will receive $350.0 million in cash, subject to adjustment pursuant to the terms of the securities purchase agreement. This amount may be increased or decreased to the extent the estimated working capital (including unrestricted cash and accounts receivable) of the military housing division as of the closing

of the military housing sale, plus any project investments made during 2008 (other than investments in Fort Hamilton), exceeds or is below $14.5 million. Following the completion of the military housing sale, GMH intends to distribute to its shareholders and unitholders the proceeds from the sale plus excess cash, if any, above the minimum working capital generated by the military housing division, net of expenses from the sale. GMH anticipates making two separate distributions relating to the military housing sale—one shortly after the closing of the military housing sale (which will exclude such amounts to be held back as determined at the discretion of GMH's board of trustees) and one immediately prior to the completion of the REIT merger (which will include such held back amounts, plus interest earned which has not been previously distributed). The military housing sale is currently anticipated to result in total distributions to GMH's common shareholders and unitholders of approximately $4.08 per share/unit, subject to adjustment as described in this proxy statement/prospectus. See "The Mergers and Related Transactions—Military Housing Sale."

In connection with the mergers, GMH anticipates selling its home office immediately prior to the closing of the mergers, and will have the right, but not the obligation, to sell certain disposition properties. A percentage of the amount received, if any, in connection with the sale of the home office and certain of the disposition properties is allowed to be paid under the merger agreement as a special distribution to GMH shareholders and unitholders preceding the closing of the mergers. Any amounts distributed as a special distribution will be in addition to the merger consideration.

Comparative Market Data

The following table presents trading information for ACC common stock and GMH common shares for February 11, 2008 and April , 2008. February 11, 2008 was the last full trading day prior to the public announcement of the proposed mergers. April , 2008 was the last practicable trading day for which information was available prior to the date of the first mailing of this proxy statement/prospectus. The GMH pro forma equivalent closing share price is equal to $3.36, without interest (the cash portion of the consideration for each GMH common share in the mergers) plus the closing price of a share of ACC common stock on each such date multiplied by 0.07642 (the exchange ratio for the issuance of ACC common stock in the mergers). These prices will fluctuate prior to the special meeting and the closing date of the mergers, and GMH shareholders are urged to obtain current market quotations prior to making any decision with respect to the REIT merger.

		ACC Common Stock Close			GMH Common Share Close			GMH Pro Forma Equivalent Close
February 11, 2008		$	28.43		$	5.59		$	5.53
April , 2008		$			$		(1)	$		(1)

(1): Excludes any distributions that will be made to GMH shareholders related to the military housing sale.

QUESTIONS AND ANSWERS ABOUT THE MERGERS

The following are some questions that you, as a shareholder of GMH, may have regarding the mergers and the other matters being considered at the special meeting and the answers to those questions. GMH and ACC urge you to read carefully the remainder of this proxy statement/prospectus because the information in this section does not provide all the information that might be important to you with respect to the special meeting and the proposed mergers. Additional important information is contained in the annexes to, and the documents included and incorporated by reference in, this proxy statement/prospectus, including the merger agreement, a copy of which is attached as Annex A.

Q:: Why am I receiving these materials?
A:: ACC and GMH have agreed to the acquisition of GMH by ACC under the terms of a merger agreement that is described in this proxy statement/prospectus. For the mergers to occur, holders of two-thirds of the outstanding GMH common shares must approve the REIT merger. GMH will hold a special meeting of its shareholders to obtain the necessary shareholder approval. This proxy statement/prospectus contains important information about the mergers and the meeting of the shareholders of GMH. ACC and GMH are sending you these materials to help you decide whether to approve the REIT merger.
Q:: What will I receive in the mergers?
A:: If the mergers are completed, you will receive $3.36 in cash, without interest, and 0.07642 of a share of ACC common stock for each GMH common share you own. ACC common stock is listed on the NYSE under the symbol "ACC." The closing price per share of ACC common stock on February 11, 2008, the day before the mergers were publicly announced, was $28.43, which would imply a value of $5.53 for each GMH common share (excluding the value of the amounts payable to GMH shareholders from the military housing sale and the sale, if any, of certain of the disposition properties and the home office). Based on the closing price per share of ACC common stock on April , 2008, the most recent practicable trading day before the date on which this proxy statement/prospectus was mailed to GMH shareholders (which was $ per share), you would receive cash and ACC common stock having an aggregate implied value of $ for each GMH common share you own share (excluding the value of the amounts payable to GMH shareholders from the military housing sale and the sale, if any, of certain of the disposition properties and the home office). However, because the stock exchange ratio is fixed at 0.07642 of a share of ACC common stock for each GMH common share, the value of the stock portion of the merger consideration will fluctuate with the market price per share of ACC common stock prior to the closing of the mergers. Accordingly, the value of the merger consideration at the time the mergers are completed may be different from the value at the time the merger agreement was signed or the GMH special meeting is held. ACC and GMH urge you to obtain a current market quotation for ACC common stock before voting at the special meeting. See "Risk Factors—Risks Relating to the Mergers—GMH shareholders cannot be certain of the market value of the shares of ACC common stock that will be issued in the REIT merger."

You will not receive any fractional shares of ACC common stock in the REIT merger. Instead, you will be paid cash (without interest) in lieu of the fractional share interest to which you would otherwise be entitled as described under "The Merger Agreement—The Merger Consideration and Effects of the Mergers—Fractional Shares." You will not be entitled to dividends, voting rights or any other rights in respect of any fractional share of ACC common stock.

Q:: What will I receive upon completion of the sale of GMH's military housing division?
A:: In addition to the merger consideration, holders of GMH common shares are expected to receive, upon completion of the sale of GMH's military housing division to Balfour Beatty, a net distribution of approximately $4.08 per share/unit, subject to adjustment as described in this proxy statement/prospectus. See "The Mergers and Related Transactions—Military Housing Sale." The closing of the military housing sale is a condition to the obligations of GMH and ACC to consummate the mergers.
Q:: Will I continue to receive dividends?
A:: Yes. Under the terms of the merger agreement, GMH is permitted to continue to declare and pay its regular first quarter dividend of $0.165 per share. GMH declared the first quarter dividend on March 20, 2008, which was paid on April 15, 2008 to GMH shareholders of record at the close of business on March 31, 2008. After March 31, 2008, GMH may not pay its regular quarterly dividend and may declare and pay dividends only as required for GMH to maintain its REIT status, to eliminate U.S. federal income tax liability and as set forth below.

As consideration for the military housing sale, GMH will receive $350.0 million in cash, subject to adjustment pursuant to the terms of the securities purchase agreement. This amount may be increased or decreased to the extent the estimated working capital (including unrestricted cash and accounts receivable) of the military housing division as of the closing of the military housing sale, plus any project investments made during 2008 (other than investments in Fort Hamilton), exceeds or is below $14.5 million. Following the completion of the military housing sale, GMH intends to distribute to its shareholders and unitholders the proceeds from the sale plus excess cash, if any, above the minimum working capital generated by the military housing division, net of expenses from the sale. GMH anticipates making two separate distributions relating to the military housing sale—one shortly after the closing of the military housing sale (which will exclude such amounts to be held back as determined at the discretion of GMH's board of trustees) and one immediately prior to the completion of the REIT merger (which will include such held back amounts, plus interest earned which has not been previously distributed). The military housing sale is currently anticipated to result in total distributions to GMH shareholders and unitholders of approximately $4.08 per share/unit, subject to adjustment as described in this proxy statement/prospectus. See "The Mergers and Related Transactions—Military Housing Sale."

In connection with the mergers, GMH anticipates selling its home office immediately prior to the closing of the mergers, and will have the right, but not the obligation, to sell certain disposition properties. A percentage of the amount received, if any, in connection with the sale of the home office and certain of the disposition properties is allowed to be paid under the merger agreement as a special distribution to GMH shareholders and unitholders preceding the closing of the mergers. Any amounts distributed as a special distribution will be in addition to the merger consideration.

Q:: Is the receipt of the merger consideration, military sale distributions or special distribution taxable?
A:: Yes. The receipt of the merger consideration in exchange for GMH common shares pursuant to the REIT merger will be a taxable transaction for U.S. federal income tax purposes. Generally, a GMH shareholder will recognize gain or loss for U.S. federal income tax purposes measured by the difference, if any, between (1) the amount of cash received and the fair market value, as of the effective date of the REIT merger, of the ACC common stock received and (2) the GMH shareholder's adjusted tax basis in the GMH common shares exchanged for the merger consideration.

The receipt of the military sale distributions and the special distribution, if any (to the extent not designated as a capital gains dividend), will be taxable as ordinary income to the extent that GMH's earnings and profits for 2008 are allocable to the distributions; any such distribution in excess of earnings and profits will be treated as a return of capital and will reduce the tax basis of a GMH shareholder in its shares (but not below zero); and any such distribution in excess of tax basis is taxable as capital gain. Any part designated as a capital gains dividend will be taxable as long-term capital gain or "unrecaptured Section 1250 gain" to the extent it does not exceed GMH's actual net capital gain for the year.

GMH shareholders should read "Material U.S. Federal Income Tax Considerations—Material U.S. Federal Income Tax Consequences to GMH Shareholders of the REIT Merger and Distributions" beginning on page 90 for a more complete discussion of the U.S. federal income tax consequences to GMH shareholders of the REIT merger, the military sale distributions and the special distribution, if any. Tax matters can be complicated and the tax consequences to GMH shareholders of the REIT merger, military sale distributions and special distribution to a GMH shareholder will depend on such holder's particular circumstances.

GMH shareholders should consult their own tax advisors to determine the particular tax consequences to them (including the application and effect of any state, local, or non-U.S. income and other tax laws) of the REIT merger, military sale distributions and special distribution, if any.

Q:: What will happen to GMH as a result of the mergers?
A:: American Campus Acquisition LLC, a wholly-owned subsidiary of the ACC Operating Partnership, will be merged with and into GMH, which will be followed by the merger of GMH with and into GMH Communities, Inc. GMH Communities, Inc. will continue as the surviving entity of these mergers and will be a subsidiary of the ACC Operating Partnership. However, at the effective time of the REIT merger, GMH shareholders will cease to have direct ownership interests in GMH and will instead become holders of ACC common stock. After the REIT merger effective time, GMH will no longer be required to file periodic reports with the SEC. See "The Mergers and Related Transactions—Certain Effects of the Mergers" on page 49 for further information.
Q:: Will the shares of ACC common stock issued in the mergers be listed for trading on the NYSE?
A:: Yes. The shares of ACC common stock to be issued in the mergers will be listed, upon official notice of issuance, on the NYSE under the symbol "ACC."
Q:: Why are ACC and GMH proposing to enter into the mergers?
A:: In making its determination with respect to the mergers, GMH's board of trustees considered a number of factors. See "The Mergers and Related Transactions—GMH's Reasons for the Mergers" for a discussion of such factors. Similarly, ACC's board of directors also considered a number of factors in reaching its determination to approve the merger agreement. See "The Mergers and Related Transactions—ACC's Reasons for the Mergers" for a discussion of such factors.
Q:: How does GMH's board of trustees recommend that I vote?
A:: GMH's board of trustees unanimously recommends that GMH shareholders vote "FOR" the proposal to approve the REIT merger and "FOR" the proposal to approve any adjournment or

postponement of the special meeting to solicit additional proxies. For a more complete description of the recommendation of GMH's board of trustees, see page 35.

Q:: Do any of the GMH's trustees and executive officers have any interest in the mergers that is different from mine?
A:: Some of GMH's trustees and executive officers have interests in the mergers that are different from, or in addition to, yours. Restricted shares issued to trustees and executive officers that are not yet vested will become fully vested and any restrictions on such GMH restricted shares will terminate or lapse at the REIT merger effective time and will automatically be converted into the right to receive the merger consideration. Pursuant to the terms of their employment agreements, GMH's executive officers will be entitled to certain cash payments and benefits following the closing of the REIT merger in certain circumstances. In addition, certain of GMH's executive officers and/or trustees may be paid a success fee in the aggregate amount of $2.0 million for closing the military housing sale, the mergers and the transactions contemplated by the merger agreement. Also, GMH's trustees and executive officers are entitled to continued indemnification arrangements and directors' and officers' insurance coverage for a period of six years following the REIT merger effective time. Please see "Interests of Trustees and Executive Officers of GMH in the Mergers" on page 65 for additional information about possible interests that GMH's trustees and executive officers may have in the mergers that are different from yours.
Q:: Where and when is the special meeting?
A:: The special meeting will take place at Philadelphia Marriott West, 111 Crawford Avenue, West Conshohocken, Pennsylvania 19428, on June 10, 2008, at 11:00 a.m., local time.
Q:: What vote is required to approve the REIT merger?
A:: Holders of two-thirds of the outstanding GMH common shares must affirmatively vote to approve the REIT merger. Abstentions will be counted for quorum purposes and will have the same effect as votes "AGAINST" approval of the REIT merger proposal since the REIT merger proposal requires the affirmative vote of two-thirds of outstanding GMH common shares.
Q:: What vote of our common shareholders is required to approve an adjournment of the special meeting?
A:: Approval of any adjournment of the special meeting to solicit additional proxies requires the affirmative vote of at least a majority of votes cast on the matter in person or by proxy at the special meeting. For the purpose of this proposal, if you fail to attend the special meeting or vote by proxy, you will not be considered present in person or represented by proxy. However, the failure to vote your common shares will not have any effect on the outcome of this proposal. Abstentions and broker non-votes are considered present but are not considered votes cast. The special meeting may also be adjourned or postponed under other circumstances.
Q:: Who can vote and attend the special meeting?
A:: All common shareholders of GMH of record as of the close of business on April 21, 2008, the record date for the special meeting, are entitled to receive notice of and to attend and vote at the special meeting or any adjournments or postponements thereof. Each share is entitled to one vote on each matter properly brought before the special meeting.

Q:

What happens if I sell my shares before the special meeting?

A:

The record date for the special meeting, the close of business on April 21, 2008, is earlier than the date of the special meeting. If you held your GMH common shares on the record date but transfer them prior to the effective time of the REIT merger, you will retain your right to vote at the special meeting, but not the right to receive the merger consideration for GMH common shares. The right to receive such merger consideration will pass to the person who owns the shares you previously owned when the REIT merger becomes effective.

Q:

What do I need to do now?

A:

After you have read this proxy statement/prospectus carefully, please authorize your proxy promptly—by telephone, by Internet or by signing, dating and returning the enclosed proxy card in the prepaid envelope provided. You should authorize your proxy now, even if you expect to attend the special meeting and vote in person. Authorizing your proxy now will not prevent you from later canceling or revoking your proxy and changing your vote at any time before the vote at the special meeting and will ensure that your shares are voted if you later find you cannot attend the special meeting.

Q:

How will proxy holders vote my shares?

A:

If you authorize your proxy by telephone or by the Internet, or properly execute and return the proxy card enclosed with this proxy statement/prospectus prior to the special meeting, your shares will be voted as you authorize. If you execute your proxy card but no direction is otherwise made, your shares will be voted FOR approval of the REIT merger and FOR approval of any adjournment or postponement of the special meeting for the purpose of soliciting additional proxies.

Q:

What should I do if I hold my shares in "street name," i.e., through a bank, broker or other custodian?

A:

Please follow the instructions provided by your bank, broker or other custodian, in order to direct such custodian to vote your shares on your behalf.

Q:

Can my broker vote my shares, which are held in "street name"?

A:

Your broker is not able to vote your shares that are held in "street name" for you without your instructions. If you do not provide your broker with instructions on how to vote your shares held in "street name," your broker will not be permitted to vote your shares on the proposals being presented at the special meeting. Because the approval of the REIT merger requires the affirmative vote of the holders of two-thirds of GMH's outstanding common shares, a failure to provide your broker instructions will have the same effect as a vote against the REIT merger. You should therefore be sure to provide your broker with instructions on how to vote your shares.

Q:

What do I do if I want to change my vote?

A:

You may change your vote in three ways:

•: by delivering a written notice to the corporate secretary of GMH prior to the voting of the shares stating that you would like to revoke your proxy;
•: by signing and delivering a later-dated proxy card (or authorizing a later-dated proxy by telephone or by the Internet); or

•: by attending the special meeting and voting in person; however, your attendance alone will not revoke your proxy or change your vote.

If you have instructed a broker how to vote your shares, you must follow the directions provided by your broker to change those instructions.

Q:: What rights do I have if I oppose the mergers?
A:: You can either abstain from voting or vote against the REIT merger by indicating a vote against the proposal on your proxy card and signing and mailing your proxy card in accordance with the instructions provided, or by voting against the REIT merger in person at the special meeting. Pursuant to Maryland law, however, you are not entitled to dissenters' or appraisal rights with respect to the mergers.
Q:: Should I send my certificates representing my GMH common shares?
A:: No, do not submit your share certificates at this time. After ACC and GMH complete the mergers, ACC will send former holders of GMH common shares written instructions for exchanging their share certificates.
Q:: When do you expect to complete the mergers?
A:: ACC and GMH are working toward completing the mergers as quickly as possible. GMH must first obtain the approval of GMH shareholders at the special meeting and close the military housing sale. ACC and GMH expect to complete the mergers during the second quarter of 2008 assuming that the other conditions in the merger agreement are satisfied or waived. However, ACC and GMH cannot assure you as to when, or if, the mergers will occur.
Q:: If the mergers are completed, when can I expect to receive the merger consideration for my shares?
A:: As soon as practicable after the completion of the REIT merger, you will receive a letter of transmittal describing how you may exchange your shares for the merger consideration. At that time, you must send your completed letter of transmittal to the exchange agent (and, for GMH common shares represented by a certificate(s) only, your share certificate(s)) in order to receive the merger consideration. You should not send your share certificate(s) to ACC or GMH or anyone else until you receive the letter of transmittal.
Q:: What risks should I consider before I vote on the merger proposal?
A:: ACC and GMH encourage you to read carefully the detailed information about the mergers contained and incorporated by reference in this proxy statement/prospectus, including the section entitled "Risk Factors" beginning on page 27.
Q:: Where can I find more information about the companies?
A:: ACC and GMH each file reports and other information with the SEC. You may read and copy this information at the SEC's public reference facilities. Please call the SEC at 1-800-732-0330 for information about these facilities. This information is also available at the Internet site the SEC maintains at www.sec.gov. In addition, GMH's SEC filings are available at the Internet site GMH maintains at www.gmhcommunities.com, and ACC's SEC filings are available at the Internet site ACC maintains at www.studenthousing.com. Information contained on ACC's website, GMH's website or the website of any other person is not incorporated by reference into this proxy statement/prospectus, and you should not consider information contained on

those websites as part of this proxy statement/prospectus. You can also request copies of these documents from ACC or GMH. See "Where You Can Find More Information" on page 139.

Q:: Who can help answer my questions?
A:: If you have more questions about the mergers or need assistance voting your shares, please contact Georgeson Inc. at 1-888-867-7098.

If you would like additional copies of this proxy statement/prospectus, you should contact Georgeson Inc. at 1-888-867-7098.

RISK FACTORS

In addition to general investment risks and the other information contained in or incorporated by reference into this proxy statement/prospectus, you should carefully consider the following factors in evaluating the proposals to be voted on at the special meeting.

Risk Factors Relating to the Mergers

GMH shareholders cannot be certain of the market value of the shares of ACC common stock that will be issued in the REIT merger.

Upon the completion of the REIT merger, each GMH common share outstanding immediately prior to the REIT merger will be converted into the right to receive 0.07642 of a share of ACC common stock and $3.36 in cash, without interest. Because the exchange ratio is fixed at 0.07642 of a share of ACC common stock for each GMH common share, the market value of the ACC common stock issued in the REIT merger will depend upon the market price of a share of ACC common stock upon completion of the REIT merger. The market value of ACC common stock will fluctuate prior to the completion of the REIT merger and therefore may be different at the time the REIT merger is consummated than it was at the time the merger agreement was signed and at the time of the special meeting. Stock price changes may result from a variety of factors that are beyond ACC's control, including general market and economic conditions and changes in business prospects. Accordingly, GMH shareholders cannot be certain of the market value of the ACC common stock that will be issued in the REIT merger or the market value of ACC common stock at any time after the mergers.

If the REIT merger is consummated, such consummation will not occur until after the special meeting and the satisfaction or waiver of all of the conditions to the REIT merger. Therefore, at the time of the special meeting you will not know the precise dollar value of the merger consideration you will become entitled to receive at the effective time of the REIT merger. You are urged to obtain a current market quotation for ACC common stock.

The market price of ACC common stock and ACC's earnings per share may decline as a result of the mergers.

The market price of ACC common stock may decline as a result of, among other things, the mergers if ACC does not achieve the perceived benefits of the mergers as rapidly or to the extent anticipated by financial or industry analysts or if the effect of the mergers on ACC's financial results is not consistent with the expectations of financial or industry analysts. In addition, the failure to achieve expected benefits and unanticipated costs relating to the mergers could reduce ACC's future financial performance.

There may be unexpected delays in the consummation of the mergers, which would delay GMH shareholders' receipt of the merger consideration and could impact ACC's ability to timely achieve cost savings associated with the mergers.

The mergers are expected to close during the second quarter of 2008 assuming that all of the conditions in the merger agreement are satisfied or waived. The merger agreement provides that either ACC or GMH may terminate the merger agreement if the REIT merger effective time has not occurred by July 31, 2008 (provided that this right will not be available to a party whose failure to fulfill any obligation under the merger agreement materially contributed to the failure of the REIT merger effective time to occur on or before this date). Certain events may delay the consummation of the mergers. If these events were to occur, the receipt of cash and shares of ACC common stock by GMH shareholders would be delayed. Some of the events that could delay the consummation of the

REIT merger include difficulties in obtaining the approval of GMH shareholders, closing the military housing sale or satisfying the other closing conditions to which the mergers are subject.

The mergers and the military housing sale are each subject to a number of conditions which, if not satisfied or waived, would adversely impact ACC's and GMH's ability to complete the transactions.

The mergers, which are expected to close during the second quarter of 2008, are subject to certain closing conditions, including among other things, (a) the military housing sale, (b) obtaining regulatory approvals, if any, (c) the effectiveness of a registration statement on Form S-4 of ACC of which this proxy statement/prospectus is a part, (d) the approval of the REIT merger by at least two-thirds of all the votes entitled to be cast on the matter by the holders of all of GMH's outstanding common shares, (e) obtaining certain lender consents, (f) completion of all payments and performance of all other material obligations under GMH's settlement agreement relating to its class action litigation, (g) accuracy of the other parties' representations and warranties and compliance with covenants, subject in each case to materiality standards, and (h) delivery of tax opinions. There can be no assurance that all of the various conditions will be satisfied or waived, if permitted, or the occurrence of any effect, event, development or change will not transpire. Therefore, there can be no assurance with respect to the timing of the closing of the mergers or whether the mergers will be completed at all.

The military housing sale, which is a condition precedent to the closing of the mergers and which is expected to close on or before May 12, 2008, is subject to certain closing conditions, including, among other things, (a) obtaining approvals from GMH's government partners in its military housing privatization projects and certain lenders and other parties that are parties to the agreements and related documents covering these projects, (b) obtaining regulatory approvals, if any, (c) receipt of notice that the military housing sale is not subject to the Exon-Florio amendments to The Defense Production Act of 1950, (d) repayment of all amounts under GMH's note facility, including evidence of the release of all liens related to the note facility, (e) the distribution of all the capital stock of College Park Management TRS, Inc. to the GMH Operating Partnership, and (f) accuracy of the other parties' representations and warranties and compliance with covenants, and the absence of an effect, event, development or change that could give rise to a termination of the securities purchase agreement, subject in each case to materiality standards. There can be no assurance that all of the various conditions will be satisfied or waived, if permitted, or the occurrence of any effect, event, development or change will not transpire. Therefore, there can be no assurance with respect to the timing of the closing of the military housing sale or whether the military housing sale will be completed at all.

Failure to complete the military housing sale and/or the mergers could negatively impact GMH's operations and business and financial results.

If either the military housing sale or the mergers are not completed, GMH's business and operations may be harmed to the extent that there is uncertainty surrounding the future direction of GMH and management's strategy. If the military housing sale is not completed, then GMH's ability to win additional awards of future military housing privatization projects could be negatively impacted were the Department of Defense to question GMH's ability to sustain its operations in the ordinary course going forward or become reluctant to enter into new relationships with a party that has been held for sale. In addition, in the event that the mergers are not completed, GMH's student housing residents, third-party management contract clients, vendors and others may similarly view GMH and its operations as unstable in the long-term and may attempt to terminate existing relationships or refuse to enter into new relationships with GMH. Moreover, in the event that the military housing sale is completed and the mergers are not, then GMH will have terminated its note facility with Merrill Lynch, Pierce, Fenner & Smith Incorporated, or Merrill Lynch, which GMH uses to fund continuing operations for its student housing business and general working capital. While management expects to

retain an amount of the consideration received from the military housing sale necessary to provide sufficient working capital through the anticipated closing of the mergers or until a new credit facility can be established if the mergers are not completed, there can be no assurance that the retained cash proceeds will be sufficient to fund GMH's operations through the mergers, or going forward in the event the mergers are not completed. Also, if the military housing sale is completed and the mergers are not, then GMH's overall operations will be reduced to only its student housing division, which could significantly impact GMH's overall financial condition going forward.

If the mergers and the military housing sale are not completed for any reason, GMH will be subject to several risks, including but not limited to the following:

•: the requirement that, under certain circumstances, including if GMH signs a definitive agreement with respect to a superior proposal from another potential buyer of GMH, GMH pay a termination fee of $8.0 million to Balfour Beatty and $16.0 million plus ACC expenses of up to $7.5 million to ACC;
•: the requirement that, under certain circumstances, including if GMH breaches the merger agreement, GMH pay the costs and expenses of ACC in connection with the mergers up to $7.5 million;
•: the incurrence of certain costs relating to the mergers and the military housing sale that are payable whether or not these transactions are completed;
•: the fact that activities relating to the mergers and the military housing sale and related uncertainties may lead to a loss of revenue that GMH may not be able to regain if these transactions do not occur;
•: the focus of GMH management being directed toward the mergers and the military housing sale and integration planning instead of on its core business and other opportunities that could have been beneficial to GMH; and
•: the loss of executive personnel and other employees integral to the continued operations of GMH whereby its continued management operations may be adversely impacted.

If the military housing sale and/or the mergers are not completed, there can be no assurance to GMH shareholders that these risks will not materialize or materially adversely affect GMH's business, its financial condition, its operating results, and its cash flows, including its ability to service debt and to make distributions to its shareholders.

Provisions of the securities purchase agreement and the merger agreement may deter alternative business combinations and could negatively impact GMH's business and operations if the agreements are terminated in certain circumstances.

Restrictions in the securities purchase agreement with Balfour Beatty generally prohibit GMH from soliciting any proposal to acquire GMH's military housing business, including a proposal that might be advantageous to its shareholders when compared to the terms and conditions of the military housing sale. In addition, there are restrictions in the merger agreement that generally prohibit GMH from soliciting any acquisition proposal or offer for a merger or business combination with any other party, including a proposal that might be advantageous to GMH shareholders when compared to the terms and conditions of the mergers. However, GMH does have the ability to terminate the merger agreement if it receives an acquisition proposal that its board of trustees determines in good faith constitutes a superior proposal, GMH is not in breach of the merger agreement non-solicitation provisions, and GMH provides ACC three business days to make any adjustments to the terms and

conditions of the merger agreement. If the military housing sale is not completed, GMH may be unable to conclude another sale of its military housing division on as favorable terms, in a timely manner, or at all; and if the mergers are not completed, GMH may be unable to conclude another merger, sale or combination on as favorable terms, in a timely manner, or at all. If the securities purchase agreement or the merger agreement is terminated, GMH, in certain specified circumstances, may be required to pay a termination fee of up to $8.0 million to Balfour Beatty and $16.0 million plus ACC expenses of up to $7.5 million to ACC. In addition, under certain circumstances, GMH may be required to reimburse ACC for its expenses up to $7.5 million. These provisions may deter third parties from proposing or pursuing alternative business combinations that might result in greater value to GMH shareholders than the mergers and the military housing sale.

If the term loan or the joint venture transaction do not close, ACC will need to replace the funding that will be used to finance a portion of the cash consideration and other merger costs.

ACC will need additional funding to consummate the mergers. ACC may obtain funding to consummate the mergers through borrowings under its existing credit facility and senior secured term loan and has received a commitment from KeyBank to fund up to $200.0 million of the merger costs and received approximately $252.4 million in net proceeds from its offering of 9.2 million shares of its common stock that closed on April 23, 2008.

ACC has entered into a contribution agreement with Fidelity pursuant to which ACC and Fidelity will, immediately prior to the effective time of the REIT merger, form a joint venture and ACC will cause certain property-owning subsidiaries of GMH to contribute to the joint venture 15 student housing properties with an estimated value of approximately $325.9 million, including approximately $210.2 million in assumed debt. ACC will retain a 10% equity interest in the joint venture and will provide property management services for the properties contributed to the joint venture. ACC will use the anticipated $105.7 million of proceeds from this transaction to finance a portion of the cash consideration and other merger costs. The closing of the joint venture is subject to various conditions. There can be no assurance these conditions will be satisfied or waived, if permitted, or the occurrence of any effect, event, development or change will not transpire. Therefore, there can be no assurance with respect to the timing of the closing of the Fidelity transaction or whether this transaction will be completed at all. In addition, if any condition in favor of Fidelity with respect to three or fewer properties is not satisfied as of the closing date, Fidelity may terminate the contribution agreement with respect to such properties and the contribution value will be adjusted. If there are four or more properties with such an unsatisfied condition, Fidelity may terminate the contribution agreement with respect to all of the properties.

There can be no assurance that ACC will receive such funding, that ACC will finance the mergers as described or will not subsequently enter into alternative financing arrangements, including debt or equity financing or the potential sales of assets to third parties, to fund all or a portion of the cash consideration and other merger costs. If the funding transactions are not consummated, ACC will need to finance a portion of the cash consideration and other merger costs by other means, which may result in ACC incurring increased interest costs on replacement financing. The interest rate on replacement financing will depend on prevailing market conditions at the time. If ACC is unable to obtain adequate funding for the cash consideration and other merger costs, ACC will be unable to consummate the mergers.

Uncertainty regarding the mergers and the military housing sale may cause GMH's clients, vendors, business partners and others to delay or defer decisions concerning their business with GMH, which may harm its results of operations in the future if the military housing sale and/or the mergers are not completed.

Because the mergers and the military housing sale are subject to several closing conditions, including, with respect to the mergers, the approval of the REIT merger by the required vote of GMH shareholders, uncertainty exists regarding the completion of these transactions. With respect to GMH's military housing business, this uncertainty may cause GMH's government and other business partners, vendors/suppliers, and service parties associated with GMH's military housing projects to delay or defer decisions concerning their business with GMH, which could negatively affect its military housing operations. In addition, with respect to GMH's student housing business, the uncertainly of the mergers may cause its tenants, third-party management contract customers, vendors/suppliers and others to delay or defer decisions concerning their business with GMH, which could negatively affect GMH's student housing business and results of operations.

Certain of GMH's trustees and executive officers may have interests in the mergers that are different from, or in addition to, the interests of GMH shareholders generally.

In considering the recommendation of GMH's board of trustees with respect to the REIT merger, GMH shareholders should be aware that certain of GMH's trustees and executive officers may have material financial interests in the mergers that are different from, or in addition to, the interests of GMH shareholders generally. See "Interests of Trustees and Executive Officers of GMH in the Mergers."

If ACC is unable to successfully integrate the operations of GMH, its business and earnings may be negatively affected.

The mergers with GMH will involve the integration of companies that have previously operated independently. Successful integration of the operations of GMH will depend primarily on ACC's ability to consolidate operations, systems procedures, properties and personnel and to eliminate redundancies and costs. The mergers will also pose other risks commonly associated with similar transactions, including unanticipated liabilities, unexpected costs and the diversion of management's attention to the integration of the operations of ACC and GMH. ACC may not be able to integrate GMH's operations without encountering difficulties, including, but not limited to, the loss of key employees, the disruption of its respective ongoing businesses or possible inconsistencies in standards, controls, procedures and policies. Estimated cost savings are projected to come from various areas that ACC's management has identified through the due diligence and integration planning process. If ACC has difficulties with any of these integrations, it might not achieve the economic benefits it expects to result from the mergers, and this may hurt its business and financial results. In addition, ACC may experience greater-than-expected costs or difficulties relating to the integration of the business of GMH and/or may not realize expected cost savings from the mergers within the expected time frame, if at all.

After the mergers are completed, GMH shareholders who receive ACC common stock in the REIT merger will have different rights that may be less advantageous than their current rights.

After the closing of the REIT merger, GMH shareholders who receive ACC common stock in the REIT merger for their GMH common shares will have different rights than they currently have. You may conclude that your rights as a stockholder of ACC may be less advantageous than the rights you have as a shareholder of GMH. For a detailed discussion of your rights as a stockholder of ACC and the significant differences between your rights as a shareholder of GMH and your rights as a stockholder of ACC, see "Comparison of Rights of Stockholders of ACC and Shareholders of GMH."

A portion of the gain from the military housing sale may not be qualifying income for REIT purposes.

Certain gains generated from the military housing sale may not be qualifying income for purposes of one or more of the REIT income test requirements. Furthermore, the Internal Revenue Service, or the IRS, could seek to challenge the allocation of the purchase price among the assets sold as part of the military housing sale, causing a larger portion of the gain to constitute additional nonqualifying income. While GMH expects that it will have sufficient qualifying income in 2008 to satisfy the requirements for taxation as a REIT, this may not be the case. Therefore, there is a risk that the military housing sale could cause GMH to fail to qualify as a REIT. This risk may be significantly higher in the event that the mergers are not completed.

While Reed Smith LLP at the closing of the mergers will provide ACC an opinion, to the effect that GMH has been organized and operated in conformity with the requirements for qualification as a REIT under the Code for all taxable periods commencing with GMH's taxable year ended December 31, 2004 until the closing of the mergers, opinions of counsel are not binding upon the IRS or any court and there can be no assurances that GMH has in fact met the requirements for taxation as a REIT. Furthermore, in providing its opinion, Reed Smith LLP is relying, as to certain factual matters, upon the statements and representations contained in the certificates provided to Reed Smith LLP by GMH.

Risk Factors Relating to ACC Following the Mergers

ACC's business, operations and financial condition are subject to various risks. Some of these risks are described below; however, this section does not describe all risks applicable to ACC, its industry or its business, and it is intended only as a summary of certain material factors. Additional risks are described in ACC's Annual Report on Form 10-K for the fiscal year ended December 31, 2007 and are incorporated herein by reference. If any of the following risks actually occur, ACC's business could be materially and adversely affected.

The market price of ACC common stock after the mergers may be affected by factors different from those affecting the shares of GMH currently.

The businesses of ACC and GMH are different and, accordingly, the results of operations of ACC and the market price of ACC's common stock may be affected by factors different from those currently affecting the results of operations and market prices of GMH's common shares. For a discussion of the businesses of ACC and GMH and of certain factors to consider in connection with those businesses, see the documents incorporated by reference in this proxy statement/prospectus and referred to under "Where You Can Find More Information."

ACC would incur adverse tax consequences if it or GMH failed to qualify as a REIT for U.S. federal income tax purposes.

In order to qualify as a REIT, GMH must be owned by 100 or more persons. Following the REIT merger, if no further action is taken, GMH will fail this test. Accordingly, ACC anticipates that it will allow 100 or more persons to acquire preferred stock in GMH. However, if ACC is unable to find enough investors, or if the interests of the investors are disregarded by the IRS, GMH may fail to qualify as a REIT. If GMH has failed or fails to qualify as a REIT for any reason, including the 100 shareholder test discussed above, and the mergers are completed, ACC would succeed to or incur significant tax liabilities (including the significant tax liability that would result from the military housing sale and the sale of the disposition properties). Furthermore, if GMH has failed or fails to qualify as a REIT, ACC's ownership of GMH could result in ACC failing to qualify as a REIT.

REITs are subject to a range of complex organizational and operational requirements. As REITs, ACC and GMH must each distribute with respect to each year at least 90% of its REIT taxable income to its stockholders. Other restrictions apply to a REIT's income and assets. For any taxable year that ACC or GMH fails to qualify as a REIT, it will not be allowed a deduction for dividends paid to its stockholders in computing taxable income and thus would become subject to U.S. federal income tax as if it were a regular taxable corporation. In such an event, it could be subject to potentially significant tax liabilities. Unless entitled to relief under certain statutory provisions, ACC or GMH, as the case may be, would also be disqualified from treatment as a REIT for the four taxable years following the year in which it lost its qualification. If ACC or GMH failed to qualify as a REIT, the market price of ACC's common stock may decline and ACC may need to reduce substantially the amount of distributions to its stockholders because of its increased tax liability.

While Reed Smith LLP at the closing of the mergers will provide ACC an opinion to the effect that GMH has been organized and operated in conformity with the requirements for qualification as a REIT under the Code for all taxable periods commencing with GMH's taxable year ended December 31, 2004 until the closing of the mergers, opinions of counsel are not binding upon the IRS or any court and there can be no assurances that GMH has in fact met the requirements for taxation as a REIT. Furthermore, in providing its opinion, Reed Smith LLP is relying, as to certain factual matters, upon the statements and representations contained in the certificates provided to Reed Smith LLP by GMH.

Additionally, while Locke Lord Bissell & Liddell LLP has provided ACC (and at the closing of the mergers will provide GMH) an opinion that ACC has been organized and, for the taxable year ended December 31, 2004 through the taxable year ended December 31, 2007, ACC has operated in conformity with the requirements for qualification and taxation as a REIT under the Code, and ACC's current manner of organization and proposed method of operation will enable it to continue to satisfy the requirements for qualification and taxation as a REIT under the Code in the future, opinions of counsel are not binding upon the IRS or any court and there can be no assurances that ACC has in fact met the requirements for taxation as a REIT. Furthermore, in providing its opinion, Locke Lord Bissell & Liddell LLP is relying, as to certain factual matters, upon the statements and representations contained in certificates provided to Locke Lord Bissell & Liddell LLP by ACC.

CAUTIONARY STATEMENT CONCERNING FORWARD-LOOKING STATEMENTS

This proxy statement/prospectus, including information included or incorporated by reference in this proxy statement/prospectus, may contain forward-looking statements. These forward-looking statements include, but are not limited to, statements about the benefits of the mergers, including future financial and operating results and performance; statements about ACC's and GMH's plans, objectives, expectations and intentions with respect to future operations, products and services; and other statements identified by words such as "expects," "anticipates," "intends," "plans," "believes," "seeks," "estimates," "should," "may" or words of similar meaning. These forward-looking statements are based upon the current beliefs and expectations of ACC's and GMH's management and are inherently subject to significant business, economic and competitive uncertainties and contingencies, many of which are difficult to predict and generally beyond the control of ACC and GMH. In addition, these forward-looking statements are subject to assumptions with respect to future business strategies and decisions that are subject to change. Actual results may differ materially from the anticipated results discussed in these forward-looking statements.

The following factors, among others, could cause actual results to differ materially from the anticipated results or other expectations expressed in the forward-looking statements:

•: those discussed and identified in public filings with the SEC made by ACC and GMH;
•: the failure to satisfy conditions to completion of the mergers, including the vote of GMH shareholders on the REIT merger at the special meeting;
•: the failure of the mergers and the military housing sale to close for any other reason;
•: ACC's ability to integrate the GMH business and to achieve expected synergies, operating efficiencies and other benefits within expected time-frames or at all, or within expected cost projections, and to preserve the goodwill of the acquired business;
•: risks that the proposed transactions disrupt current plans and operations;
•: the occurrence of any effect, event, development or change that could give rise to the termination of the merger agreement;
•: the amount of expenses and other liabilities incurred or accrued between the date of the signing of the merger agreement and date of the closing of the mergers; and
•: GMH and ACC each being able to maintain its qualification as a REIT.

You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this proxy statement/prospectus or the date of any document incorporated by reference in this proxy statement/prospectus. All subsequent written and oral forward-looking statements concerning the mergers or other matters addressed in this proxy statement/prospectus and attributable to ACC or GMH or any person acting on their behalf are expressly qualified in their entirety by the cautionary statements contained or referred to in this section. Except to the extent required by applicable law or regulation, ACC and GMH undertake no obligation to update these forward-looking statements to reflect events or circumstances after the date of this proxy statement/prospectus or to reflect the occurrence of unanticipated events.

THE GMH SPECIAL MEETING

Date, Time and Place

There will be a special meeting of the shareholders of GMH on June 10, 2008, at 11:00 a.m., local time, at Philadelphia Marriott West, 111 Crawford Avenue, West Conshohocken, Pennsylvania 19428.

Purpose

At the special meeting, the holders of GMH common shares will be asked to consider and vote upon a proposal to approve the REIT merger described in this proxy statement/prospectus and to consider and vote upon any adjournment or postponement of the meeting.

Recommendation of GMH's Board of Trustees

GMH's board of trustees voted unanimously to approve the merger agreement, the merger and the transactions contemplated under the merger agreement. GMH's board of trustees has declared the REIT merger and merger agreement advisable, fair to and in the best interests of GMH and its shareholders. Accordingly, GMH's board of trustees recommends that GMH shareholders vote "FOR" approval of the REIT merger and "FOR" the proposal to approve any adjournment or postponement of the special meeting to solicit additional proxies. See "The Mergers and Related Transactions—Background of the Mergers" and "Interests of Trustees and Executive Officers of GMH in the Mergers."

Voting by Trustees and Executive Officers

As of the close of business on April 21, 2008, the record date of the special meeting, the trustees and executive officers of GMH held and were entitled to vote, in the aggregate, 640,442 GMH common shares, representing approximately 1.5% of the outstanding GMH common shares. GMH currently expects that the trustees and executive officers of GMH will vote all of their GMH common shares "FOR" approval of the REIT merger and, if necessary, in favor of adjournment to solicit additional proxies.

Record Date; Outstanding Shares and Voting Rights

GMH's board of trustees has fixed the close of business on April 21, 2008, as the record date for the special meeting. Accordingly, only holders of record of issued and outstanding GMH common shares at the close of business on the record date are entitled to vote at the special meeting. At the close of business on the record date, there were 41,669,879 GMH common shares outstanding, held by approximately 32 holders of record. Each holder is entitled to one vote for each GMH common share held on the record date. Only common shareholders of record at the close of business on the record date may vote at the special meeting. Holders of units in the GMH Operating Partnership are not shareholders of GMH and therefore may not vote their shares at meetings of GMH's common shareholders.

Vote Required; Quorum

Approval of the REIT merger proposal requires the affirmative vote of the holders of at least two-thirds of GMH's common shares outstanding as of the record date.

Although it is not currently expected, the special meeting may be adjourned for the purpose of soliciting additional proxies if GMH has not received sufficient proxies to constitute a quorum or sufficient votes for approval of the REIT merger at the special meeting of shareholders. The special meeting may be adjourned by the affirmative vote of at least a majority of the votes cast on the matter

in person or by proxy at the special meeting, whether or not a quorum exists. The special meeting may also be adjourned for other reasons in accordance with GMH's charter and bylaws. Any adjournment may be made to a date not more than 120 days after the original record date without notice, other than by an announcement at the special meeting. Any adjournment of the special meeting for the purpose of soliciting additional proxies will allow shareholders who have already sent in their proxies to revoke them at any time prior to their use.

At any time prior to convening the special meeting, GMH's board of trustees may postpone the special meeting for any reason without the approval of its shareholders. If postponed, as required by law, GMH will provide at least ten days' notice of the new meeting date. Although it is not currently expected, GMH's board of trustees may postpone the special meeting for the purpose of soliciting additional proxies if it has not received sufficient proxies to constitute a quorum or sufficient votes for approval of the REIT merger. Similar to adjournments, any postponement of the special meeting for the purpose of soliciting additional proxies will allow shareholders who have already sent in their proxies to revoke them at any time prior to their use.

The presence, in person or by properly executed proxy, of the holders of a majority of the GMH common shares entitled to vote at the special meeting is necessary to constitute a quorum at the special meeting. GMH common shares represented in person or by proxy will be counted for the purposes of determining whether a quorum is present at the special meeting. Abstentions will be counted for quorum purposes and will have the same effect as votes "AGAINST" approval of the REIT merger proposal since the REIT merger proposal requires the affirmative vote of two-thirds of outstanding GMH common shares. Under NYSE rules, brokers and nominees holding shares of record for customers are not entitled to vote on the REIT merger proposal unless they receive specific voting instructions from the beneficial owner of the shares. If a broker or nominee holding shares of record for a customer submits a properly executed proxy, but indicates that it does not have discretionary authority to vote as to a particular matter, those shares, which are referred to as broker non-votes, will be treated as present and entitled to vote at the special meeting for purposes of determining whether a quorum exists. Broker non-votes will have the same effect as shares voted "AGAINST" approval of the REIT merger.

If a quorum is not present, the shareholders entitled to vote at the special meeting, present in person or by proxy, may adjourn the meeting from time to time to a date not more than 120 days after the original record date without notice other than an announcement at the meeting. Any business may be transacted at an adjourned meeting, which might have been transacted at the special meeting as originally called.

Voting of Proxies

All GMH common shares that are entitled to vote and are represented at the special meeting by properly executed proxies received prior to or at the meeting, and not revoked, will be voted at the meeting in accordance with the instructions indicated on such proxies. GMH shareholders may choose to vote for or against or abstain from voting on the approval of the REIT merger. If a GMH shareholder returns a signed proxy card or initiates a proxy by telephone or by Internet, but does not indicate how the shares are to be voted (with the exception of broker non-votes), the underlying GMH common shares will be voted "FOR" the REIT merger. If a GMH shareholder does not return a signed proxy card or otherwise authorize a proxy by telephone or by Internet, that shareholder's shares will not be voted and will have the same effect as a vote against the approval of the REIT merger.

Proxy Authorization Electronically or by Telephone

Shareholders of record and many shareholders who hold their shares through a broker or bank will have the option to authorize their proxies to vote their shares electronically through the Internet or

by telephone. Please note that there are separate arrangements for using the Internet and telephone depending on whether your shares are registered in GMH's share records in your name or in the name of a broker, bank or other nominee who holds your shares. If you hold your shares through a broker, bank or other nominee, you should check your proxy card or voting instruction card forwarded by your broker, bank or other nominee who holds your shares to see which options are available.

In addition to submitting the enclosed proxy by mail, GMH shareholders of record may authorize their proxies by telephone or Internet by following the instructions on their proxy card or voting form. If you have any questions regarding how to authorize your proxy by telephone or by Internet, please call Georgeson Inc. at 1-888-867-7098.

Appraisal or Dissenters' Rights

Under Section 3-202 of the Maryland General Corporation Law, GMH shareholders do not have the right to receive the appraised value of their shares in connection with the REIT merger because GMH common shares are listed on the NYSE. GMH shareholders can vote against the REIT merger by indicating a vote against the proposal on their proxy card and signing and mailing their proxy card (or delivering a proxy by telephone or Internet) in accordance with the instructions provided, or by voting against the REIT merger in person at the special meeting. If the requisite number of GMH shareholders vote in favor of the REIT merger, all GMH shareholders will be bound by the terms of the REIT merger under the merger agreement, and each of their GMH common shares, including the shares of those GMH shareholders that did not vote in favor of the REIT merger, will be converted into the right to receive 0.07642 of a share of ACC common stock and $3.36 in cash, without interest.

Revocation of Proxies

A proxy card is enclosed. Any shareholder who executes and delivers the proxy card may revoke the authority granted under the proxy at any time before the shares are voted by:

•: delivering to the corporate secretary of GMH, at or before the vote is taken at the special meeting, a later-dated written notice stating that the shareholder would like to revoke its proxy and change its vote;
•: properly executing and delivering a new proxy card bearing a later date relating to the same shares (or authorize a later-dated proxy by telephone or Internet); or
•: attending the special meeting and voting in person, although attendance at the special meeting will not in and of itself constitute a revocation of a proxy or a change of the shareholder's vote.

If the shareholder has instructed its broker to vote its shares and the shareholder wishes to revoke those instructions, the shareholder must follow its broker's revocation procedures.

Any written notice of revocation or subsequent proxy should be sent to GMH Communities Trust, 10 Campus Boulevard, Newtown Square, Pennsylvania 19073, Attention: Secretary, so as to be received prior to the special meeting, or hand delivered to the corporate secretary of GMH at or before the taking of the vote at the special meeting. Shareholders that have instructed a broker to vote their shares must follow directions received from such broker in order to change their vote or to vote at the special meeting.

Solicitation of Proxies; Expenses

All expenses of GMH's solicitation of proxies, including the cost of mailing this proxy statement/prospectus to GMH shareholders, will be paid by GMH. In addition to solicitation by mail,

GMH shareholders, trustees, officers and employees may solicit proxies by telephone, e-mail, fax or other means of communication. Such shareholders, trustees, officers and employees will not be additionally compensated, but may be reimbursed for reasonable out-of-pocket expenses in connection with such solicitation. Arrangements will also be made with brokerage houses, custodians, nominees and fiduciaries for forwarding of proxy solicitation materials to beneficial owners of shares held of record by such brokerage houses, custodians, nominees and fiduciaries, and GMH will reimburse such brokerage houses, custodians, nominees and fiduciaries for their reasonable expenses incurred in forwarding such materials. GMH has retained Georgeson Inc., a proxy soliciting firm, to assist GMH in the solicitation of proxies. Georgeson Inc.'s solicitation fee is not to exceed $8,500, plus out-of-pocket expenses.

GMH SHAREHOLDERS SHOULD NOT SEND IN THEIR SHARE CERTIFICATES WITH THE PROXY CARD. YOU WILL RECEIVE SEPARATE WRITTEN INSTRUCTIONS ON HOW TO EXCHANGE YOUR GMH SHARE CERTIFICATES FOR THE MERGER CONSIDERATION IF THE REIT MERGER IS COMPLETED.

THE MERGERS AND RELATED TRANSACTIONS

General

This proxy statement/prospectus is being furnished to you in connection with the proposed merger of American Campus Acquisition LLC with and into GMH, which will be followed by the merger of GMH with and into GMH Communities, Inc. GMH Communities, Inc. will continue as the surviving entity of these mergers and will be a subsidiary of the ACC Operating Partnership. The merger agreement also provides for the merger of American Campus Acquisition Limited Partnership LP with and into the GMH Operating Partnership, with the GMH Operating Partnership continuing as the surviving entity of this merger. The mergers will be carried out as provided in the merger agreement. A copy of the merger agreement is attached as Annex A to this proxy statement/prospectus and is incorporated by reference in this proxy statement/prospectus.

This proxy statement/prospectus has been sent to you because you were a holder of GMH common shares on April 21, 2008, the record date set by GMH's board of trustees for a special meeting of GMH shareholders, to consider and vote upon a proposal to approve the REIT merger and to consider and vote upon any adjournment or postponement of the meeting. This proxy statement/prospectus also constitutes a prospectus of ACC, which is a part of the Registration Statement on Form S-4 filed by ACC with the SEC under the Securities Act in order to register the shares of ACC common stock to be issued to GMH shareholders and unitholders in the mergers and the shares of ACC common stock issuable to unitholders upon the exchange of units in the ACC Operating Partnership issued in the partnership merger.

Background of the Mergers

From time to time, GMH's board of trustees, in consultation with its senior management, reviewed alternative plans for achieving GMH's business objectives and enhancing shareholder value, including, among others, potential strategic initiatives, joint ventures and business combinations, in light of changing real estate capital market conditions.

On March 10, 2006, at GMH's board of trustees meeting, Gary M. Holloway, Sr., GMH's chairman and chief executive officer, informed the board of trustees that he was considering making an offer to purchase GMH and subsequently filed an amendment to his Schedule 13D to that effect with the SEC.

In response to Mr. Holloway's indication of interest, GMH formed a special committee of independent trustees to consider and analyze strategic and financial alternatives to remaining independent, including without limitation, any offer that might be made by Mr. Holloway, and on March 13, 2006, publicly announced that GMH's board of trustees had formed the special committee for that purpose. The special committee engaged two financial advisors, referred to as Financial Advisor A and Financial Advisor B. With assistance from Financial Advisor A and Financial Advisor B, the special committee solicited indications of interest from third parties to acquire GMH or portions of GMH. In connection with this multiround process, referred to as the 2006 Process, these financial advisors distributed a confidential information memorandum and contacted more than fifty potential bidders, including, but not limited to, private firms active in the real estate sector, public real estate companies, as well as institutional investors and advisors, of which approximately forty entered into confidentiality and standstill agreements and received non-public confidential information concerning GMH. The potential bidders that had signed confidentiality and standstill agreements were granted access to such information regarding GMH through access to an electronic data room. Senior management, with assistance from Financial Advisor A and Financial Advisor B, held multiple discussions with potential bidders and responded to their questions concerning GMH, its business and its assets.

On July 10, 2006, Mr. Holloway informed GMH's board of trustees that he no longer intended to make an offer to purchase GMH. Mr. Holloway also publicly announced his decision in an amendment on Schedule 13D filed with the SEC.

Between July 2006 and December 2006, discussions and meetings continued with potential interested parties regarding a possible transaction involving GMH.

In December 2006, the special committee announced that the 2006 Process had been terminated because, among other reasons, the special committee had not received any firm offers for GMH.

Following this decision, GMH implemented a targeted operating initiative, which involved, among other things, the refinancing of certain assets, the sale of certain assets and joint venture transactions.

On March 7, 2007, Mr. Holloway received an unsolicited, non-binding indication of interest from Company A, a real estate management and investment firm, to acquire all of the outstanding common shares of GMH for a purchase price of $10.50 per share in cash. Company A had previously received confidential information regarding GMH during the 2006 Process. The non-binding indication of interest indicated that Company A had allocated $7.00 per share for the acquisition of the student housing business and $3.50 per share for the acquisition of the military housing business. The letter stated that Company A would need, among other things, to complete its due diligence review and receive updated GMH financial statements for the months most recently preceding its indication of interest. Following a discussion of this non-binding indication of interest at a meeting of GMH's board of trustees held on March 12, 2007, senior management advised Company A that the non-binding indication of interest did not, in the board of trustees' view, provide adequate value to GMH's shareholders in light of GMH's experience with its previously announced operating initiatives and the current trading price of its common shares, which were trading during the period between January 1, 2007 and March 12, 2007 in the range of $9.14 to $10.84 per share. However, Mr. Joseph Macchione, executive vice president, general counsel and secretary of GMH, asked Company A to stay in contact with GMH over the next several months while GMH implemented its strategic operating initiatives.

During the summer of 2007, at the direction of the board of trustees, senior management of GMH undertook a valuation review of the military housing business and, in connection therewith, provided non-public confidential information regarding the military housing business to several financial institutions, following the execution of confidentiality agreements by these parties.

Following the valuation review, at a board of trustees meeting held on July 31, 2007, senior management informed GMH's board of trustees that the financial institutions had provided informal preliminary valuations ranging from approximately $250.0 million to $370.0 million for the military housing business. GMH's board of trustees directed senior management to continue discussions with these financial institutions with the expectation that the parties would provide a more definitive valuation of the military housing business.

In mid-August, senior management reported to the board of trustees that further discussions with the financial institutions had resulted in valuations in the range of $225.0 million to $360.0 million for the military housing business. Senior management noted that the high range assumed the availability of subordinated debt to finance a potential transaction.

In July 2007, Company B, a financial services company, orally communicated to senior management of GMH that it had an interest in a possible acquisition of only the assets of the student housing business at an approximate price of $5.00 per share. This oral non-binding indication of interest did not include the acquisition of GMH's third party management agreements or its student housing joint ventures (including certain land owned by the student housing business). In response, GMH provided confidential non-public information to Company B following the execution of a

confidentiality agreement, and senior management engaged in multiple discussions with Company B and responded to questions regarding the student housing business.

In late August 2007, senior management of GMH had several informal conversations with senior management of Balfour Beatty plc, a U.K.-based diversified company that focuses on engineering and construction, regarding the value of the military housing business. A U.S. subsidiary of Balfour Beatty plc, Balfour Beatty Construction, is a primary contractor for GMH's military housing business and, accordingly, was familiar with GMH's military housing business. These conversations were of a general nature and did not result in the receipt of a written offer for the military housing business from Balfour Beatty. Balfour Beatty had not participated in the 2006 Process.

On September 28, 2007, Messrs. Holloway and Macchione received an unsolicited telephone call from Mr. William C. Bayless, Jr., the President and Chief Executive Officer of ACC. ACC had previously received certain confidential information regarding GMH during the 2006 Process. During this call, Mr. Bayless inquired in general terms whether GMH would be interested in either a potential business combination pursuant to which ACC would acquire the student housing business in exchange for either a combination of cash and stock of ACC or all cash. Mr. Macchione informed each member of GMH's board of trustees that GMH had been contacted by ACC and described the nature of the conversation with Mr. Bayless. There was a consensus from the board of trustees that an in-person, confidential meeting with senior management of ACC would be an appropriate next step.

On October 9, 2007, Messrs. Holloway and Macchione met in person with Messrs. Bayless and Mr. Brian Nickel, ACC's current senior executive vice president and chief investment officer. The parties had preliminary discussions regarding the value of the student housing business and discussed in general terms GMH's assets and operations with regard to the student housing business. The parties determined that further discussions were warranted.

In early October, Mr. Holloway received an unsolicited telephone call from the president of Company A. During this conversation, the president of Company A expressed Company A's continued interest in a potential acquisition of the student housing and military housing business. Later that week, Mr. Macchione discussed with the chief financial officer and managing director of Company A general terms regarding a potential transaction.

Following these discussions with Company A and ACC, each of Company A and ACC received updated confidential information about GMH, including internal projections and other data prepared by GMH's management.

At a meeting of GMH's board of trustees held on October 31, 2007, Mr. Holloway updated the board of trustees with regard to senior management's discussions with potential bidders, including Company A, Company B, ACC and Balfour Beatty, that had expressed preliminary interest in acquiring the student housing and/or the military housing divisions.

During the early part of November 2007, senior management of GMH had communications with potential bidders, including Company A, Company B, ACC, and Balfour Beatty, regarding their interest in pursuing a potential transaction with GMH and the timing for submitting preliminary indications of interest in writing. In the course of these conversations, Company A indicated it would be interested in acquiring only certain student housing assets. Senior management responded that GMH was not seeking to sell only certain student housing assets but rather was currently seeking bids for the entire student housing division and/or the entire military housing division. Given the expected receipt of bids from other potential interested parties in the near term, senior management suggested that Company A submit an initial bid promptly and offered to meet in-person with representatives of Company A.

On November 28, 2007, members of ACC senior management attended an in-person meeting in Philadelphia with members of GMH senior management. The parties discussed the possibility of a

business combination with ACC and GMH, following a sale of the military housing business, and the possible structure of such a combination, along with trailing twelve month and pro forma financial data related to GMH and a potential business combination with ACC.

On November 29, 2007, representatives of Company C delivered a letter to a member of GMH's board of trustees expressing an interest in acquiring all or part of the student housing business through a joint venture with Company C and a state pension fund. No indication of value was set forth in the letter.

On November 30, 2007, representatives of Company D, an investment arm of a publicly-traded financial services company, delivered a letter to Messrs. Holloway and Robinson which included a non-binding indication of interest to acquire the military housing business of GMH. This letter indicated that, based on limited due diligence and certain assumptions, Company D was prepared to make a non-binding indication of interest of approximately $285.0 million for the net equity of the military housing business. The non-binding indication of interest was subject to, among other things, satisfactory completion of Company D's due diligence review and necessary internal approvals.

On December 3, 2007, Mr. Macchione received an e-mail from the chief financial officer of Company A which indicated a preliminary valuation of the student housing business (excluding GMH's management business, joint ventures and land) that would result in the GMH shareholders receiving approximately $4.50 to $5.00 per share. Mr. Macchione indicated to Company A's representative that senior management believed Company A's valuation of GMH was inadequate and asked that Company A reevaluate its valuation. Company A's representative stated that any future proposals by Company A would be made directly to GMH's board of trustees.

On December 5, 2007, GMH received a written non-binding indication of interest from Balfour Beatty regarding the acquisition of the military housing business. This indication of interest stated that Balfour Beatty's preliminary valuation for the military housing business was approximately $315.0 to $330.0 million, and that it was subject to completion of satisfactory due diligence and approval of its parent, Balfour Beatty plc, but was not subject to any financing contingency.

On December 12, 2007, GMH received a written non-binding indication of interest from ACC regarding the acquisition of the student housing business. This indication of interest stated that ACC estimated that the per share valuation to GMH shareholders would be approximately $6.68 prior to transaction expenses. The non-binding indication of interest stated that ACC believed that it could utilize its UPREIT structure to design a transaction in a tax efficient manner to maximize the value to GMH shareholders and GMH unitholders. The non-binding indication of interest also stated that it was not contingent on the receipt of financing and that ACC had conducted significant business, financial and property due diligence and was prepared to complete all remaining components of its due diligence review expeditiously.

On December 12, 2007, at a special telephonic meeting of GMH's board of trustees, the board of trustees reviewed with senior management the non-binding indications of interest received from potential bidders, including Company A, Company B, Company D, ACC and Balfour Beatty. It was noted that, unlike ACC and Balfour Beatty, Company A and Company B had not come forward with a written proposal letter. GMH's board of trustees also discussed the desirability of engaging a financial advisor to assist with a potential sale of the student and military housing business. Following this meeting, GMH engaged Wachovia Securities as its financial advisor and Goodwin Procter LLP and Reed Smith LLP as its outside corporate and real estate counsel, respectively, in connection with GMH's consideration of possible sale transactions involving the student housing business and the military housing business.

On December 14, 2007, Mr. Peter Zinkin, the planning and development director of Balfour Beatty, communicated to Mr. Holloway via e-mail that Balfour Beatty would be willing to increase its initial non-binding indication of value of the military housing business to $337.5 million.

On December 26, 2007, Goodwin Procter circulated a draft securities purchase agreement to Balfour Beatty's counsel, Allen & Overy LLP. Throughout the next several weeks, the parties' respective management teams, with the assistance of the parties' respective legal and financial advisors, negotiated the terms of the securities purchase agreement, including among others, representations and warranties, termination fees and triggers, closing conditions and the terms of a possible working capital adjustment.

On January 8, 2008, Goodwin Procter provided a draft merger agreement to ACC's outside legal counsel, Locke Lord Bissell & Liddell LLP. Due to the fact that Company A and Company B had not submitted indications of interest in writing, Company A and Company B did not receive a draft of the merger agreement.

On January 16, 2008, Company E, a publicly traded real estate company, submitted a written non-binding indication of interest to the management of GMH expressing interest in acquiring the military housing business for a valuation range of $340.0 to $360.0 million, subject to additional analysis and due diligence review. Company E had previously received certain confidential information during the 2006 Process.

On January 17, 2008, in accordance with GMH's directives, representatives of Wachovia Securities communicated to Company E's financial advisor that GMH would grant Company E an additional period to submit a more definitive proposal reflecting a specified price rather than a valuation range and that GMH would provide additional financial information.

On January 18, 2008, representatives of GMH and representatives of Goodwin Procter discussed with representatives of Company E the structure for the acquisition of the student housing business, following the sale of the military housing business. Also, GMH supplied Company E with certain additional financial information, including internal projections.

On January 21, 2008, Locke Lord responded with a mark-up of the merger agreement. Throughout the next several weeks, the parties' respective management teams, with the assistance of the parties' respective legal and financial advisors, negotiated the terms of the mergers, including, among others, the proposed structure of the transactions, the form of the consideration to be received by GMH shareholders and GMH unitholders, which would ultimately consist of a mix of cash and shares of ACC common stock with a fixed exchange ratio (with GMH unitholders being afforded an election to receive ACC Operating Partnership common units in lieu of ACC common stock), termination fees and triggers and closing conditions, including, among others, the receipt of certain lender consents. The parties agreed that GMH would have the right but not the obligation to sell certain disposition properties and GMH's home office immediately prior to the closing of the mergers with the possibility of a special distribution to GMH shareholders upon the sale of certain of these disposition properties. (See "—Home Office and Disposition Properties").

On January 22, 2008, representatives of Company E's financial advisor orally conveyed to GMH's financial advisor that Company E was interested in acquiring the military housing business for $350.0 million, subject to additional due diligence review, and indicated further that Company E would need an additional five business days to complete its due diligence review. Company E also indicated that it expected that GMH would not announce a transaction with another party during this diligence period.

On January 28, 2008, GMH's board of trustees convened a special telephonic meeting for the purpose of discussing the current proposals of each of ACC, Balfour Beatty and Company E. Senior management gave an overview of the proposed structure of the transaction with ACC and the transaction with Balfour Beatty and noted that based on current transaction valuations, GMH would receive approximately $350.0 million in cash, such price to be increased or decreased depending on the estimated working capital of the military housing business as of the closing of this sale, as a result of the military housing sale to Balfour Beatty. Furthermore, GMH and ACC continued to negotiate the

total value of the per share price to be received by GMH shareholders upon the closing of the mergers. In addition, representatives of Goodwin Procter and Reed Smith reviewed the current status of the negotiations with each of ACC and Balfour Beatty with respect to the merger agreement, securities purchase agreement and the ancillary agreements, including fiduciary-out provisions, termination fees and triggers, closing conditions, lender consents and the sale of the disposition properties and the home office. There was also a discussion of possibly consummating the military housing sale whether or not the mergers occurred. Although the sale of the disposition properties or the home office would not be a condition precedent to the closing of the mergers, representatives of Goodwin Procter explained that the GMH shareholders could possibly receive special distributions related to the disposition of certain of these assets. (See "—Home Office and Disposition Properties"). The board of trustees also discussed at length the preliminary indication of interest submitted by Company E. In light of the level of Company E's bid and the timing associated with Company E's additional due diligence request, the board of trustees determined not to pursue Company E's proposal at that time for, among other reasons, the risk that Balfour Beatty would terminate its advanced negotiations with GMH, although, if Company E were to submit an enhanced proposal at a higher price and with an accelerated timeline, the board of trustees would reconsider its decision.

Subsequent to the meeting, Company E was informed of the decision of GMH's board of trustees. Shortly thereafter, Company E sent a letter to GMH stating that it was no longer interested in pursuing an acquisition of the military housing business.

During the period from January 28 through February 8, 2008, the parties and their respective representatives continued to negotiate the terms of the merger agreement, securities purchase agreement and ancillary agreements. In addition, representatives of ACC negotiated the terms of a contribution agreement with regard to the sale of certain joint venture assets concurrently with the closing of the mergers (See "—Financing of the Mergers—Joint Venture").

On February 8, 2008, GMH's board of trustees convened a special telephonic meeting for the purpose of updating the board of trustees on the current proposals of each of ACC and Balfour Beatty. Members of senior management and representatives of Goodwin Procter, Reed Smith and Wachovia Securities provided the board of trustees with an overview of the status of the negotiations with each of ACC and Balfour Beatty. It was noted that, with regard to the military housing sale, Balfour Beatty had increased its purchase price from $337.5 million to $350.0 million, reflecting the agreement reached by the parties on the estimated working capital required to be present at the closing, such price to be increased or decreased depending on the estimated working capital of the military housing business as of the closing of the military housing sale, and that, with regard to the mergers, ACC and GMH had reached agreement on the price of ACC common stock to be used in determining the merger consideration. It was further noted that GMH unitholders would have the right to receive the same merger consideration as the GMH shareholders but could, at the holder's option, elect to receive common units in the ACC Operating Partnership in lieu of shares of ACC common stock. Representatives of Goodwin Procter then reviewed with respect to each agreement, among other things, the current provisions regarding closing conditions, termination rights and break-up fees and termination expenses. After further discussion, the board of trustees authorized GMH's senior management, with assistance from GMH's legal and financial advisors, to continue to negotiate with ACC and Balfour Beatty.

During the period from February 8 through February 11, 2008, the parties and their respective representatives continued to negotiate the merger agreement, the securities purchase agreement and ancillary agreements.

In the morning of February 11, 2008, ACC's board of directors held a special meeting to consider the proposed merger agreement with GMH at which ACC's board of directors approved the merger agreement and the transactions contemplated by this agreement.

In the afternoon of February 11, 2008, GMH's board of trustees held a special meeting to consider the proposed merger agreement and securities purchase agreement with ACC and Balfour Beatty, respectively. Members of the senior management team and representatives of GMH's legal and financial advisors also participated in the meeting. Prior to the meeting, the members of the board of trustees were provided with near-final drafts of the merger agreement and securities purchase agreement, a detailed summary of each of the agreements and various other materials. Representatives of Goodwin Procter reviewed with GMH's board of trustees the terms of the merger agreement and securities purchase agreement, including with regard to each agreement, closing conditions, termination rights and provisions regarding break-up fees and termination expenses. The disposition properties and sale of GMH's home office also was discussed and it was explained that the GMH shareholders could potentially receive an additional special distribution as a result of certain asset sales. In addition, the board of trustees formed a special committee, chaired by Denis Nayden, to oversee and implement the sale of GMH's home office and the enforcement of the put agreement. Also at this meeting, Wachovia Securities reviewed with GMH's board of trustees its financial analysis of the merger consideration (taken together with the payment of the distributions from the military housing sale) and rendered to the board of trustees an oral opinion, which opinion was confirmed by delivery of a written opinion, dated February 11, 2008, to the effect that, as of that date and based on and subject to various assumptions made, procedures followed, matters considered and limitations described in such opinion, the merger consideration, taken together with the payment of the distributions from the military housing sale, to be received by holders of GMH common shares and holders of GMH Operating Partnership units (other than GMH, the general partner of the GMH Operating Partnership and other subsidiaries of GMH) was fair, from a financial point of view, to such holders. For purposes of its opinion, Wachovia Securities took into account, in the case of holders of GMH Operating Partnership units, only the merger consideration (taken together with the payment of the distributions from the military housing sale) that would be received by such holders if, prior to the consummation of the mergers, they converted their GMH Operating Partnership units into GMH common shares in accordance with the terms of the limited partnership agreement of GMH Operating Partnership. After further discussion, the board of trustees approved the merger agreement and securities purchase agreement with ACC and Balfour Beatty and the transactions contemplated by these agreements.

After the meetings of the board of trustees of GMH and the board of directors of ACC adjourned on February 11, 2008, the definitive documentation for the transactions was finalized and the merger agreement was executed late that evening. Contemporaneously with the execution and delivery of the merger agreement, GMH entered into the securities purchase agreement with Balfour Beatty.

On the morning of February 12, 2008, press releases were issued announcing the transactions.

GMH's Reasons for the Mergers

After careful consideration, GMH's board of trustees determined that the mergers and the other transactions contemplated by the merger agreement are advisable and in the best interests of GMH and its shareholders, and have unanimously approved the merger agreement, the mergers and the other transactions contemplated by the merger agreement. In evaluating the mergers and the other transactions contemplated by the merger agreement, GMH's board of trustees consulted with members of GMH's senior management as well as GMH's legal and financial advisors and, in reaching its decision to approve the merger agreement, the mergers and the other transactions contemplated by the merger agreement, GMH's board of trustees considered a number of factors that GMH's board of trustees believed supported its decision, including the following:

•: the trustees' knowledge of the current environment in the real estate industry, both on an historical and on a prospective basis, including national and regional economic conditions, capital markets conditions, and the overall challenges of implementing GMH's operating plans in the absence of the proposed transactions;

•: GMH's future prospects, including market conditions, the future performance of its assets and the potential risks to successful execution of its business strategy;
•: the belief that the mergers and the transactions contemplated by the merger agreement, including the military housing sale, were more favorable to GMH shareholders than other strategic alternatives available to GMH after conducting comprehensive reviews of strategic alternatives during the several months;
•: the extensive solicitation effort that was undertaken from March 2006 through December 2006 to explore a possible sale of GMH to third parties (See, the 2006 Process as described in "—Background of the Mergers");
•: the scale, scope, strength and diversification of markets and expected synergies that could be achieved by combining the student housing division of GMH with ACC;
•: the absence of a bid from another party or group of parties that would be more desirable than that from ACC and Balfour Beatty, notwithstanding the fact that GMH actively solicited interests in a potential transaction involving GMH in the 2006 Process;
•: the fact that the financial and other terms and conditions of the merger agreement and the transactions contemplated thereby were the product of extensive arm's-length negotiations among the parties;
•: its belief that selling the student housing division and the military housing division to two different buyers would produce a greater value for GMH shareholders than selling all of GMH to one buyer;
•: its belief that the merger agreement and the transactions contemplated thereby were more favorable to shareholders than other strategic alternatives reasonably available to GMH and its shareholders due to the fact that as a result of the merger, GMH shareholders will immediately realize the value of their investment in GMH through their receipt of the per share/unit distribution of approximately $4.08 following the closing of the military housing sale, plus the per share/unit merger consideration of $3.36 in cash and 0.07642 of a share of ACC common stock from the REIT merger, while still maintaining the opportunity for GMH shareholders to participate in future earning or growth and benefit from any appreciation in value of ACC common shares/units;
•: the fact that the per share/unit price of approximately $9.61 (based on the ACC stock price of $28.43 per share on the last trading day before the mergers were announced) being paid for each GMH common share in the merger agreement and for the military housing sale represented a premium of 72% based on the closing price of GMH's common shares on February 11, 2008 (the last full trading day before the announcement of the mergers);
•: the opportunity for GMH shareholders to benefit from any increase in the trading price of ACC common stock between the announcement of the mergers and the completion of the mergers because a portion of the merger consideration consists of a fixed number of shares of ACC common stock;
•: the fact that GMH's unitholders have the option to receive units in the ACC Operating Partnership in lieu of shares of ACC common stock, enabling holders of GMH Operating Partnership units, upon their election, to obtain favorable tax treatment on a portion of their consideration;

•: the written opinion of Wachovia Securities, dated February 11, 2008, to GMH's board of trustees as to the fairness, from a financial point of view and as of the date of such opinion and based on and subject to the matters set forth in such opinion, of the merger consideration, taken together with the payment of the military sale distributions, to be received by holders of GMH common shares and holders of GMH Operating Partnership units (other than GMH, the general partner of the GMH Operating Partnership and other subsidiaries of GMH), as more fully described under the caption "—Opinion of GMH's Financial Advisor." For purposes of its opinion, Wachovia Securities took into account, in the case of holders of GMH Operating Partnership units, only the merger consideration (taken together with the payment of the military sale distributions) that would be received by such holders if, prior to the consummation of the mergers, they converted their GMH Operating Partnership units into GMH common shares in accordance with the terms of the limited partnership agreement of the GMH Operating Partnership;
•: the fact that, subject to compliance with the terms and conditions of the merger agreement, GMH is permitted to terminate the merger agreement in order to enter into an agreement with respect to a superior proposal (as defined in the section entitled "The Merger Agreement—Non-Solicitation"), upon the payment to ACC of a $16.0 million termination fee and up to $7.5 million of expenses (see "The Merger Agreement—Termination" and "The Merger Agreement—Termination Fees and Expenses");
•: the fact that the completion of the mergers is subject to approval by GMH shareholders and the right of its board of trustees, under certain circumstances specified in the merger agreement, to change its recommendation that GMH shareholders vote in favor of the REIT merger, subject to ACC's right to terminate the merger agreement and receive the termination fee and expense amount;
•: the fact that GMH may terminate the securities purchase agreement if GMH exercises its fiduciary out under the merger agreement;
•: GMH's ability to take action to cause specific performance and require ACC to complete the mergers;
•: GMH's management team's recommendation in favor of the mergers and the military housing sale to GMH's board of trustees;
•: the receipt by ACC of an executed commitment letter from its source of debt financing for the mergers;
•: the fact that completion of the mergers and the military housing sale is not based upon the receipt of financing by ACC or Balfour Beatty, respectively;
•: the fact that ACC agreed to appoint Mr. Macchione to its board of directors so that the interests of GMH shareholders would continue to be represented following the mergers; and
•: GMH's right, but not the obligation, to sell certain disposition properties and its home office, which could result in the payment of the special distribution (as described in "The Merger Agreement—Home Office and Disposition Properties").

GMH's board of trustees also considered a variety of risks and other potentially negative factors concerning the merger agreement, the mergers and the other transactions contemplated by the merger agreement, including the following:

•: the fact that the mergers and the military housing sale are each subject to a number of conditions which, if not satisfied or waived, would adversely impact GMH's ability to complete the transactions;
•: the risk that the failure to complete the military housing sale and/or the mergers could negatively impact GMH's operations and business and financial results;
•: the risk that provisions of the securities purchase agreement and the merger agreement may deter alternative business combinations and could negatively impact GMH's business and operations if the agreements are terminated in certain circumstances;
•: the risk that uncertainty regarding the mergers and the military housing sale may cause GMH's clients, vendors, business partners and others to delay or defer decisions concerning their business with GMH, which may harm its results of operations in the future if the military housing sale and/or the mergers are not completed;
•: the fact that the receipt of the merger consideration in exchange for GMH shares (including the share component of the merger consideration) pursuant to the REIT merger and the receipt by shareholders of the distribution from the military housing sale and the sale of the disposition properties will be taxable for U.S. federal income tax purposes;
•: the possibility that GMH shareholders could be adversely affected by a decrease in the trading price of ACC common stock between the announcement of execution of the merger agreement and the closing of the mergers because a portion of the merger consideration consists of a fixed number of shares of ACC common stock;
•: the restrictions on the conduct of GMH's business prior to the completion of the mergers, requiring GMH to conduct its business in all material respects only in the ordinary course, subject to specific limitations, which may delay or prevent GMH from undertaking business opportunities that may arise during the term of the merger agreement, whether or not the mergers are consummated;
•: the fact that GMH shareholders do not have the right under Maryland law to seek appraisal of their shares;
•: the limitations contained in the merger agreement on GMH's ability to declare and pay dividends (other than the military sale distributions and the special distribution);
•: the fact that the net proceeds received on the sales, if any, of the disposition properties and home office prior to closing may not exceed agreed target levels, and that GMH shareholders should not assume that the special distribution would be made; and
•: the fact that certain GMH trustees and executive officers may have material financial interests in the transaction that are different from, or in addition to, those of its shareholders (see "Interest of Trustees and Executive Officers of GMH in the Mergers").

The foregoing discussion summarizes the material factors considered by GMH's board of trustees in its consideration of the mergers and the transactions contemplated by the merger agreement. After considering these factors, GMH's board of trustees concluded that the positive factors relating to the mergers and the transactions contemplated by the merger agreement outweighed the negative factors. In view of the wide variety of factors considered by GMH's board of trustees, the trustees did not find it practicable to quantify or otherwise assign relative weights to the foregoing factors. In addition, individual members of GMH's board of trustees may have assigned different

weights to various factors. GMH's board of trustees considered all these factors as a whole and overall deemed the factors to be favorable to, and to support, its determination.

In addition, the general partner of the GMH operating partnership, as the sole general partner of the GMH operating partnership, approved the merger agreement, the partnership merger and the other transactions contemplated by the merger agreement.

For the reasons set forth above, GMH's board of trustees unanimously determined that the mergers, the merger agreement and the transactions contemplated by the merger agreement are advisable and in the best interests of GMH and its shareholders, and unanimously approved and adopted the merger agreement. GMH's board of trustees unanimously recommends that GMH shareholders vote "FOR" the proposal to approve the REIT merger.

Military Housing Sale

Concurrently with entering into the merger agreement, GMH and the GMH Operating Partnership entered into a securities purchase agreement with Balfour Beatty, Inc. (a U.S. subsidiary of Balfour Beatty plc), or Balfour Beatty, and, solely for the purpose of Article 8 of the securities purchase agreement, Balfour Beatty plc, for the sale of GMH's military housing division. Pursuant to the securities purchase agreement, Balfour Beatty will acquire GMH's military housing division by purchasing all of the issued and outstanding capital stock and limited liability company interests of three GMH subsidiaries owned by GMH and the GMH Operating Partnership and through which the military housing business is conducted: GMH Communities TRS, Inc., GMH Military Housing Investments, LLC and GMH AF Housing Construction LLC.

The military housing sale is a condition precedent to the mergers and is currently expected to close on or before May 12, 2008. The securities purchase agreement provides that the parties will close no earlier than April 30, 2008. The military housing sale does not require shareholder approval and accordingly, is expected to close prior to the special meeting. GMH's board of trustees has determined that, if the mergers are not completed for some reason, GMH expects to continue with the military housing sale.

Purchase Price for Military Housing Sale

As consideration for the military housing sale, GMH will receive $350.0 million in cash, subject to adjustment pursuant to the terms of the securities purchase agreement. This amount may be increased or decreased to the extent the estimated working capital (including unrestricted cash and accounts receivable) of the military housing division as of the closing of the military housing sale, plus any project investments made during 2008 (other than investments in Fort Hamilton), exceeds or is below $14.5 million. Following the completion of the military housing sale, GMH intends to distribute to its shareholders and unitholders the proceeds from the sale plus excess cash, if any, above the minimum working capital generated by the military housing division, net of expenses from the sale. GMH anticipates making two separate distributions relating to the military housing sale—one shortly after the closing of the military housing sale (which will exclude such amounts to be held back as determined at the discretion of GMH's board of trustees) and one immediately prior to the completion of the REIT merger (including such held back amounts, plus interest earned which has not been previously distributed). The military housing sale is currently anticipated to result in total distributions to GMH's common shareholders and unitholders of approximately $4.08 per share/unit, subject to adjustment as described in this proxy statement/prospectus. See "The Mergers and Related Transactions—Military Housing Sale."

Representations, Warranties and Covenants; Non-Solicitation

GMH and Balfour Beatty have made customary representations, warranties and covenants in the securities purchase agreement, including, among others, GMH's covenant not to solicit alternative transactions with respect to the military housing division by a third party or, subject to certain limited

exceptions, participate in discussions relating to an acquisition of the military housing division to a third party or furnish non-public information relating to an acquisition of the military housing division. In view of the merger transaction, however, this covenant is subject to a significant exception. If a proposal for the entire company (i.e., both the military housing division and the student housing division) is made that complies with the exception to the non-solicitation provisions of the merger agreement (see "The Merger Agreement—Non-Solicitation"), then GMH may participate in discussions concerning that alternative proposal and terminate the securities purchase agreement if it terminates the merger agreement to accept the alternative proposal. This exception to the prohibition on addressing alternative proposals for acquiring the military housing division is only applicable in the context of proposals for GMH's entire business and are not applicable to alternative proposals solely for the military housing division.

Termination

The securities purchase agreement contains certain customary termination rights for GMH and Balfour Beatty, as well as a right for GMH to terminate the securities purchase agreement if it has terminated the merger agreement in order to take a superior proposal, and it terminates the securities purchase agreement within ten business days of the merger agreement being terminated. If GMH terminates the securities purchase agreement for this reason, or if Balfour Beatty terminates the securities purchase agreement because of a material breach of representations, warranties or covenants by GMH, GMH will be required to pay a termination fee of $8.0 million to Balfour Beatty. Alternatively, if GMH terminates the securities purchase agreement on account of a material breach of representations, warranties or covenants by Balfour Beatty, Balfour Beatty must reimburse GMH's expenses, up to a maximum of $12.0 million, which amount may include the amount GMH will be obligated to reimburse ACC for its expenses pursuant to the merger agreement.

Closing

The military housing sale is subject to certain closing conditions, including, among other things, (a) obtaining approvals from GMH's government partners in its military housing privatization projects and certain lenders and other parties that are parties to the agreements and related documents covering these projects, (b) obtaining regulatory approvals, if any, (c) receipt of notice that the military housing sale is not subject to the Exon-Florio amendments to The Defense Production Act of 1950, (d) repayment of all amounts under GMH's note facility, including evidence of the release of all liens related to the note facility, (e) the distribution of all the capital stock of College Park Management TRS, Inc. to the GMH Operating Partnership, and (f) accuracy of the other parties' representations and warranties and compliance with covenants, and the absence of an effect, event, development or change that could give rise to a termination of the securities purchase agreement, subject in each case to materiality standards.

On April 10, 2008, GMH received a letter that CFIUS had reviewed the submissions provided to it regarding the military housing sale and determined that there were no unresolved national security concerns and that action under the Exon-Florio amendments to the Defense Protection Act of 1950 was concluded. The consummation of the military housing sale is not subject to any financing condition.

Home Office and Disposition Properties

In connection with the mergers, GMH anticipates selling its home office immediately prior to the closing of the mergers, and will have the right, but not the obligation, to sell certain disposition properties. A percentage of the amount received, if any, in connection with the sale of the home office and certain of the disposition properties is allowed to be paid under the merger agreement to GMH shareholders and unitholders as a special distribution preceding the closing of the mergers. Any amounts distributed as a special distribution will be in addition to the merger consideration.

If the home office is not sold to a third party unaffiliated with GMH prior to the closing of the mergers, then Gary M. Holloway, Sr., GMH's chairman, chief executive officer and president, is contractually obligated to purchase the home office pursuant to the put agreement. GMH's board of trustees has established a committee of independent trustees, chaired by Denis J. Nayden, referred to as the home office committee, to sell the home office immediately prior to the closing of the mergers. This committee will decide whether or not to exercise GMH's rights under the put agreement. The home office committee has engaged Binswanger Corporation, a real estate broker, to market the home office. Binswanger Corporation is periodically reporting to the home office committee on the success of its marketing efforts.

In addition, GMH has received interest in some of the disposition properties and certain of these disposition properties have either been placed under a contract for sale or are the subject of a letter of intent that may lead to a contract for sale. As of the date of this proxy statement/prospectus, in those cases in which a disposition property is subject to a contract for sale, the contract terms include due diligence review periods and conditions precedent to the purchasers' obligations to proceed with the sale. Accordingly, there can be no assurance that any of these disposition properties will be sold and, if they are sold, that the proceeds from the sale will be sufficient in amount to enable GMH to make a special distribution prior to the closing of the mergers. GMH will update its shareholders and unitholders through the use of press releases as and when it becomes more certain as to whether any one or more of the disposition properties or the home office are likely to be sold prior to the closing of the mergers.

Certain Effects of the Mergers

At the REIT merger effective time, GMH shareholders will cease to have direct ownership interests in GMH and will instead become holders of ACC common stock. Therefore, current GMH shareholders will participate in future earnings or growth of GMH and benefit from any appreciation in the value of GMH only indirectly through their investment in ACC.

GMH common shares are currently registered under the Securities Exchange Act of 1934, as amended, or the Exchange Act, and are listed on the NYSE under the symbol "GCT." As a result of the mergers, there will be no public market for GMH common shares. After the mergers, GMH common shares will cease to be listed on the NYSE. In addition, registration of the GMH common shares under the Exchange Act will be terminated. After the REIT merger effective time, GMH will also no longer be required to file periodic reports with the SEC.

At the effective time of the reincorporation merger, the directors and officers of American Campus Acquisition LLC will be the directors and officers of the surviving entity. At the effective time of the reincorporation merger, the charter and bylaws of GMH Communities, Inc. in effect immediately prior to the effective time will be the charter and bylaws of the surviving entity.

Immediately following the effective time of the partnership merger, ACC's board of directors will be increased by one member and ACC's board of directors will appoint Joseph M. Macchione, the executive vice president, general counsel and secretary of GMH, to ACC's board of directors. Mr. Macchione will serve until the next annual meeting of ACC stockholders and will be nominated for reelection to ACC's board of directors at the next subsequent annual meeting of ACC stockholders.

Effects on GMH if the Mergers are Not Completed

If the REIT merger is not approved by GMH shareholders or if the mergers are not completed for any other reason, GMH shareholders will not receive any payment for their shares in connection with the REIT merger. GMH shareholders will, however, receive distributions of approximately $4.08 following the closing of the military housing sale less such amounts to be held back as determined at the discretion of GMH's board of trustees. In this event, GMH will remain an independent public company and its common shares will continue to be listed and traded on the NYSE.

GMH expects to close the military housing sale on or before May 12, 2008, which is prior to the closing of the mergers. The military housing sale does not require shareholder approval and accordingly, is expected to close prior to the special meeting. GMH's board of trustees has determined that, if the mergers are not completed for some reason, GMH expects to continue with the military housing sale. If the mergers are not completed, GMH expects that management will operate the student housing business in a manner similar to that in which it is being operated today and that GMH shareholders will continue to be subject to the same risks and opportunities relating to the student housing business as they currently are, including, among other things, the nature of the student housing industry on which GMH's business depends, and general industry, economic and market conditions, as well as other risks associated with operating GMH without the military housing division that are discussed in the section entitled "Risk Factors—Risk Factors Relating to the Mergers." As noted in "Risk Factors—Risk Factors Relating to the Mergers—A portion of the gains from the military housing sale may not be qualifying income for REIT purposes," certain gains generated from the military housing sale may not be qualifying income for purposes of one or more of the REIT income test requirements. Furthermore, the IRS could seek to challenge the allocation of the purchase price among the assets sold as part of the military housing sale, causing a larger portion of the gain to constitute nonqualifying income. While GMH expects that it will have sufficient qualifying income in 2008 to satisfy the requirements for taxation as a REIT, this may not be the case. Therefore, there is a risk that the military housing sale could cause GMH to fail to qualify as a REIT. This risk may be significantly higher in the event that the mergers are not completed.

If the mergers are not consummated, there can be no assurance as to the effect of these risks and opportunities on the future value of GMH common shares. See "Risk Factors—Risk Factors Relating to the Mergers—Failure to complete the military housing sale and/or the mergers could negatively impact GMH's operations and business and financial results." From time to time, GMH's board of trustees will evaluate and review the business operations, properties, dividend policy and capitalization of GMH, among other things, make such changes as are deemed appropriate and continue to seek to identify strategic alternatives to maximize shareholder value. If the merger agreement is not adopted by GMH shareholders or if the mergers are not consummated for any other reason, there can be no assurance that any other transaction acceptable to GMH will be offered, or that the business, prospects or results of operations of GMH will not be adversely impacted.

Additionally, if the mergers are not consummated, the costs involved in connection with pursuing the mergers, the substantial management time and effort required to effectuate the mergers and the related disruption of GMH's operations (including the military housing sale and potential loss of key employees) would be borne by GMH.

If the merger agreement is terminated under certain circumstances, GMH may be required to pay ACC a termination fee of $16.0 million plus the reasonable out-of-pocket costs and expenses incurred by ACC and its subsidiaries in connection with the merger agreement up to an aggregate maximum amount of $7.5 million. For a description of the circumstances triggering payment of the termination fee or reimbursement of ACC's costs and expenses, see "The Merger Agreement—Termination Fees and Expenses."

ACC's Reasons for the Mergers

The factors that ACC's board of directors of directors considered in reaching its determination to approve the merger agreement were as follows:

•: the mergers present an opportunity to solidify ACC's position as the dominant student housing platform in the U.S.;
•: the assets being acquired from GMH are expected to provide ACC with a significant opportunity for net asset value appreciation with improved operational performance for these assets;

•: the acquired assets compare favorably with ACC's current investment criteria and portfolio;
•: the mergers will provide ACC with a presence in 39 new university markets presenting growth opportunities;
•: the mergers are expected to provide significant synergies;
•: the mergers will provide ACC with the ability to sell both GMH's assets and ACC's existing assets, enabling ACC to fund its owned development pipeline; and
•: the belief of ACC's board of directors that the overall terms of the merger agreement are in the best interests of ACC and its stockholders.

ACC's board of directors of directors also considered certain potentially negative factors that could arise from the proposed mergers. The material potentially negative factors considered were as follows:

•: the potential difficulties that ACC might experience integrating the GMH businesses into ACC's existing businesses;
•: the risk and costs to ACC if the mergers do not close;
•: the risk that GMH shareholders might not approve the REIT merger; and
•: the risk that the anticipated benefits of the mergers might not be fully realized.

The foregoing discussion addresses the material information and factors considered by ACC's board of directors in its consideration of the mergers. In view of the variety of factors and the amount of information considered, ACC's board of directors did not find it practicable to, and did not, make specific assessments of, quantify or otherwise assign relative weights to, the specific factors considered in reaching its determination. The determination of ACC's board of directors was made after consideration of all the factors as a whole. In addition, individual members of ACC's board of directors may have given different weights to different factors.

Financing of the Mergers

Debt Financing

In connection with the mergers, ACC has entered into a commitment letter with KeyBank for the arrangement of a senior secured term loan of $200.0 million for the ACC Operating Partnership, which may be expanded by up to an additional $100.0 million if one or more lenders agree to assume such increase. The loan will bear interest at a variable rate, at ACC's option, based upon a base rate or one-, two-, three-, or six-month LIBOR plus, in each case, a spread based upon its total leverage. There is no prepayment penalty on the term loan and the ACC Operating Partnership pays interest only on the loan until maturity, which is three years from the effective time of the REIT merger with a one-year extension option. The ACC Operating Partnership expects to repay the term loan from using the proceeds from future equity offerings, asset sales, additional borrowings and its working capital. The commitment letter is subject to customary conditions for this type of financing, including (1) the absence of a material adverse change in the financial condition, business, operations, assets or prospects of ACC or the ACC Operating Partnership, (2) the absence of a material adverse change in the market for syndicated loans of the same type as the term loan, (3) the absence of a material disruption of, or material adverse change in, financial, banking or capital market conditions which materially and adversely affect the market for syndication of a facility of the same type as the term loan, (4) the negotiation and execution of definitive loan documentation consistent with the commitment letter and any term sheet, and (5) the absence of defaults under any of ACC's financial obligations. The commitment letter expires on July 31, 2008.

ACC has also entered into a commitment letter with KeyBank to increase the existing senior unsecured revolving credit facility of the ACC Operating Partnership from $115.0 million to $160.0 million, with the ability, subject to the satisfaction of certain conditions to expand this facility by up to an additional $65.0 million. Under this arrangement, a swingline of $15.0 million and letters of credit up to $15.0 million will also be available to the ACC Operating Partnership. The facility bears interest at a variable rate, at ACC's option, based upon a base rate or one-, two-, three-, or six-month LIBOR plus, in each case, a spread based upon its total leverage. The facility matures August 17, 2009 and ACC guarantees the ACC Operating Partnership's obligations under the facility. Availability under the revolving credit facility is limited to an "aggregate borrowing base amount" equal to the lesser of (i) 65% of the value of certain properties, calculated as set forth in the credit facility, and (ii) the adjusted net operating income from these properties divided by a formula amount. Additionally, ACC is required to pay an unused commitment fee ranging from 0.15% to 0.20% per annum, depending on the aggregate unused balance. As of December 31, 2007, the balance outstanding on the revolving credit facility totaled $9.6 million, bearing interest at a weighted average rate of 6.97%, with remaining availability under the facility (subject to the satisfaction of certain financial covenants) totaling approximately $103.8 million. The terms of the facility include certain restrictions and covenants, which limit, among other items, the incurrence of additional indebtedness, liens, and the disposition of assets. The facility contains customary affirmative and negative covenants and also contains financial covenants that, among other things, require ACC to maintain certain minimum ratios of "EBITDA" (earnings before interest, taxes, depreciation and amortization) to fixed charges. ACC may not pay distributions that exceed 100% of funds from operations for any four consecutive quarters. The financial covenants also include consolidated net worth and leverage ratio tests. As of December 31, 2007, ACC was in compliance with all such covenants.

The ACC Operating Partnership expects to repay the term loan from the proceeds from future equity offerings, asset sales, additional borrowings and its working capital. The commitment letter for the facility and the closing facility are subject to customary conditions for this type of financing, including (1) the absence of a material adverse change in the business, assets, operations, conditions (financial or otherwise) or prospects of ACC or the ACC Operating Partnership, (2) the negotiation and execution of definitive loan documentation (3) the absence of defaults under any of ACC's financial obligations.

Joint Venture

In connection with the mergers, ACC and the ACC Operating Partnership have entered into a contribution agreement with Fidelity pursuant to which ACC and Fidelity will, immediately prior to the effective time of the REIT merger, form a joint venture and ACC will cause certain property-owning subsidiaries of GMH to contribute to the joint venture 15 student housing properties with an estimated value of approximately $325.9 million, including approximately $210.2 million in assumed debt. ACC will retain a 10% minority interest in the joint venture and will provide property management services for the properties contributed to the joint venture. ACC will use the anticipated $105.7 million proceeds from this transaction to finance a portion of the cash consideration and merger costs.

The closing of the joint venture is subject to various conditions, including the following:

•: the performance by ACC, the ACC Operating Partnership and the property-owning subsidiaries of GMH in all material respects of their material obligations under the contribution agreement at or prior to closing;
•: the satisfaction or waiver of all conditions to the mergers described below under "The Merger Agreement—Conditions to the Mergers," delivery of all documents necessary to cause the mergers to close and become effective into escrow and the closing of the mergers immediately after the closing of the joint venture;
•: the representations and warranties of ACC contained in the contribution agreement and those of GMH contained in the merger agreement relating to the properties to be contributed to the joint venture being true and correct in all material respects;
•: the conveyance of good and marketable title to the properties to subsidiaries of the joint venture subject to specified exceptions and the title company having issued or being committed to issue title insurance for those properties;
•: the absence of certain material adverse effects on the properties;
•: the delivery of approval of the assumptions of the loans on the properties from the lenders thereunder;
•: the absence of gross negligence, willful misconduct, bad faith and similar acts by ACC with respect to the joint venture transaction;
•: the continuation of William C. Bayless, Jr. or a specified successor as the chief executive officer of ACC; and
•: the absence of an ACC bankruptcy.

If any condition in favor of Fidelity with respect to three or fewer properties is not satisfied as of the closing date, Fidelity may terminate the contribution agreement with respect to such properties and the contribution value will be adjusted. If there are four or more properties with such an unsatisfied condition, Fidelity may terminate the contribution agreement with respect to all of the properties.

In the merger agreement, GMH agreed to reasonably cooperate with ACC in order to consummate the joint venture transaction immediately prior to the effective time of the REIT merger so long as GMH receives a written letter from ACC prior to the consummation of such transaction, in form and substance reasonably satisfactory to ACC, confirming that all of the conditions to the obligations of ACC to consummate the mergers have been irrevocably satisfied or waived. ACC acknowledged in the merger agreement that the closing of the joint venture transactions is not a condition to the obligations of the ACC to consummate the mergers.

Public Offering

Failure to Obtain Financing

If the term loan or the joint venture transaction do not close, ACC will need to finance the mergers by other means, which may result in ACC incurring increased interest costs on replacement financing. See "Risk Factors—Risk Factors Relating to the Mergers—If the term loan or the joint venture transaction do not close, ACC will need to replace the funding that will be used to finance a portion of the cash consideration and other merger costs."

Opinion of GMH's Financial Advisor

GMH retained Wachovia Securities to act as its financial advisor in connection with the mergers and the military housing sale. In connection with this engagement, GMH requested that Wachovia Securities evaluate the fairness, from a financial point of view, of the merger consideration, taken together with the payment of the military sale distributions, to be received by holders of GMH common shares and holders of GMH Operating Partnership units (other than GMH, the general partner of the GMH Operating Partnership and other subsidiaries of GMH). In selecting Wachovia Securities as GMH's financial advisor, GMH considered, among other things, Wachovia Securities' reputation and experience in similar transactions and its familiarity with GMH. Wachovia Securities, as part of its investment banking business, is continuously engaged in the evaluation of businesses and debt and equity securities in connection with mergers and acquisitions; underwritings, private placements and other securities offerings; senior credit financings; valuations; and general corporate advisory services.

On February 11, 2008, at a meeting of GMH's board of trustees held to evaluate the mergers and related transactions, Wachovia Securities delivered to GMH's board of trustees its oral opinion, which was confirmed in writing, to the effect that, as of February 11, 2008 and based on and subject to various assumptions made, procedures followed, matters considered and limitations on the review undertaken in connection with the opinion, its experience as investment bankers and other factors it deemed relevant, the merger consideration, taken together with the payment of the military sale distributions, to be received by holders of GMH common shares and holders of GMH Operating Partnership units (other than GMH, the general partner of the GMH Operating Partnership and other subsidiaries of GMH) was fair, from a financial point of view, to such holders. For purposes of its opinion, Wachovia Securities took into account, in the case of holders of GMH Operating Partnership units, only the merger consideration (taken together with the payment of the military sale distributions) that would be received by such holders if, prior to the consummation of the mergers, they converted their GMH Operating Partnership units into GMH common shares in accordance with the terms of the limited partnership agreement of the GMH Operating Partnership. The full text of Wachovia Securities' written opinion to GMH's board of trustees, which sets forth, among other things, the assumptions made, procedures followed, matters considered and limitations on the review undertaken in connection with such opinion, is attached as Annex B to this proxy statement/prospectus and is incorporated by reference in its entirety into this proxy statement/prospectus. The following summary is qualified in its entirety by reference to the full text of the opinion. Wachovia Securities provided its opinion for the information and assistance of GMH's board of trustees in connection with its evaluation of the merger

consideration, taken together with the payment of the military sale distributions, from a financial point of view. Wachovia Securities' opinion does not address any other aspect of the mergers or any related transaction, does not address the relative merits of the mergers or any related transaction and does not constitute a recommendation as to how any securityholder should vote or act in connection with the mergers (including, in the case of holders of GMH Operating Partnership units, as to whether such holder should elect to receive ACC Operating Partnership units, in lieu of ACC common stock, in the mergers) or any other matters.

In arriving at its opinion, Wachovia Securities, among other things:

•: reviewed the merger agreement and the securities purchase agreement, including the financial terms of those agreements;
•: reviewed Annual Reports to Shareholders and Annual Reports on Form 10-K for GMH and ACC for the last three years ended December 31, 2006;
•: reviewed certain interim reports to shareholders and Quarterly Reports on Form 10-Q for GMH and ACC;
•: reviewed certain business, financial and other information regarding GMH and ACC that was publicly available;
•: reviewed certain business, financial and other information regarding GMH that was furnished to Wachovia Securities by GMH's management, including financial forecasts prepared by GMH's management, and discussed with GMH's management the operations and prospects of GMH, including the historical financial performance and trends in the results of operations of GMH;
•: reviewed certain business, financial and other information regarding ACC that was furnished to Wachovia Securities by ACC's management, including financial forecasts prepared by ACC's management, and discussed with the managements of GMH and ACC the operations and prospects of ACC, including the historical financial performance and trends in the results of operations of ACC;
•: reviewed reported prices and trading activity for GMH common shares and ACC common stock;
•: compared certain financial data for GMH and ACC with similar data regarding certain other publicly traded companies that Wachovia Securities deemed relevant;
•: compared the proposed financial terms of the merger agreement and the securities purchase agreement with the financial terms of certain other business combinations and transactions that Wachovia Securities deemed relevant;
•: analyzed the net asset values of GMH and ACC based upon financial forecasts and other estimates relating to GMH and ACC prepared by the managements of GMH and ACC and capitalization rates and other assumptions discussed with and confirmed as reasonable by the managements of GMH and ACC;
•: analyzed the estimated present value of the future cash dividends of GMH and ACC based upon financial forecasts and other estimates relating to GMH and ACC prepared by the managements of GMH and ACC and other assumptions discussed with and confirmed as reasonable by the managements of GMH and ACC;
•: reviewed the potential pro forma impact of the mergers on ACC's forecasted financial statements based upon financial forecasts and other estimates relating to GMH and ACC, including estimated synergies resulting from the mergers, prepared by the managements of GMH and ACC and other assumptions discussed with and confirmed as reasonable by the managements of GMH and ACC;

•: participated in discussions and negotiations among representatives of GMH, ACC, Balfour Beatty and their respective advisors;
•: discussed with GMH's senior executives certain strategic alternatives previously considered by a special committee of GMH's board of trustees with respect to GMH, including the results of the process undertaken by GMH in 2006 with respect to the possible sale of all or a portion of GMH and preliminary discussions held by or on behalf of GMH with third parties in connection with that process; and
•: considered other information such as financial studies, analyses and investigations, as well as financial and economic and market criteria, that Wachovia Securities deemed relevant.

In connection with its review, Wachovia Securities relied upon the accuracy and completeness of the foregoing financial and other information, including all accounting, tax and legal information, and Wachovia Securities did not make, and did not assume any responsibility for, any independent verification of such information. Wachovia Securities relied upon assurances of the managements of GMH and ACC that they were not aware of any facts or circumstances that would make such information about GMH or ACC inaccurate or misleading. With respect to the financial forecasts and other estimates relating to GMH and ACC, Wachovia Securities was advised and, at GMH's direction, assumed that they were reasonably prepared and reflected the best current estimates, judgments and assumptions of the managements of GMH and ACC, as the case may be, as to the future financial performance of GMH and ACC. Wachovia Securities assumed no responsibility for, and expressed no view as to, such forecasts or estimates or the judgments or assumptions upon which they were based. In arriving at its opinion, Wachovia Securities neither made nor was it provided with any evaluations or appraisals of the assets or liabilities (contingent or otherwise) of GMH or ACC, including the disposition properties and the home office, which are referred to in this section, collectively, as the disposition assets. Wachovia Securities is not a real estate appraiser and expressed no opinion as to the value of any individual property of GMH or ACC, or the price at which any such property might be transferable, at any time.

In rendering its opinion, Wachovia Securities assumed that the mergers and related transactions, including the military housing sale and the military sale distributions, would be consummated in accordance with the terms described in the merger agreement and the securities purchase agreement and in compliance with all applicable laws, without waiver of any material terms or conditions, and that in the course of obtaining any necessary legal, regulatory or third-party consents or approvals, no restrictions would be imposed or other actions would be taken that would have an adverse effect on GMH, ACC or the mergers or any related transaction. Wachovia Securities was advised by the managements of GMH and ACC that each of GMH and ACC were operated in conformity with the requirements for qualification as a REIT for federal income tax purposes since its formation as a REIT and assumed that the mergers and related transactions would not adversely affect the status or operations of GMH or ACC as a REIT. Wachovia Securities' opinion was necessarily based on economic, market, financial and other conditions and the information made available to Wachovia Securities as of the date of its opinion. Although subsequent developments may affect its opinion, Wachovia Securities does not have any obligation to update, revise or reaffirm its opinion.

Wachovia Securities' opinion only addressed the fairness, from a financial point of view, of the merger consideration to the extent expressly specified in the opinion and did not address any other terms or aspects of mergers or any related transaction, including, without limitation:

•: the form or structure of the mergers or any tax or accounting aspects of the mergers;
•: the form or structure of the merger consideration, the relative fairness of the merger consideration between the holders of GMH common shares and the holders of GMH Operating Partnership units or any aspect or implication of the ability of holders of the

GMH Operating Partnership units to elect to receive ACC Operating Partnership units, in lieu of ACC common stock, in the mergers;

•: any aspect or implication of the military housing sale, the sale of any disposition assets or the military sale distributions (other than, in the case of the military sale distributions, to the extent expressly taken into account for purposes of Wachovia Securities' opinion), including the fairness of the consideration to be received by GMH and the GMH Operating Partnership in the military housing sale or the sale of any disposition assets or the allocation between the holders of GMH common shares and the holders of GMH Operating Partnership units of the military sale distributions or the distribution of proceeds of the sale of any disposition assets; or
•: any arrangements to sell to any holders of GMH common shares and/or GMH Operating Partnership units any of the disposition assets (including the put agreement between GMH Operating Partnership and Gary M. Holloway, Sr.) or any other agreements, arrangements or understandings entered into in connection with the mergers, the military housing sale, the sale of any disposition assets or otherwise.

In addition, Wachovia Securities' opinion did not address the fairness of the amount or nature of, or any other aspects relating to, any compensation to be received by any officers, directors or employees of any parties to the mergers, or any class of such persons, relative to the merger consideration (taken together with the payment of the military sale distributions). Wachovia Securities was not requested to, and it did not, solicit indications of interest or proposals from third parties with respect to a possible acquisition of all or a portion of GMH. Wachovia Securities also was not requested to, and it did not, participate in the negotiation or structuring of the sale of any disposition assets, including the transactions contemplated by the put agreement. Wachovia Securities' opinion did not address the relative merits of the mergers or any related transaction compared with other business strategies or transactions available or that were or might be considered by GMH's management or board of trustees regarding GMH, nor did its opinion address the merits of the underlying decision by GMH to enter into the merger agreement or the securities purchase agreement. Wachovia Securities did not consider, and Wachovia Securities expressed no opinion with respect to, the price at which GMH common shares might trade following the announcement of the mergers or the prices at which ACC common stock would trade at any time. Except as described above, GMH imposed no other instructions or limitations on Wachovia Securities with respect to the investigations made or the procedures followed by it in rendering its opinion. The issuance of Wachovia Securities' opinion was approved by an authorized committee of Wachovia Securities.

The summary set forth below does not purport to be a complete description of the analyses performed by Wachovia Securities, but describes, in summary form, the material analyses performed by Wachovia Securities in connection with Wachovia Securities' opinion. The preparation of an opinion is a complex process and is not necessarily susceptible to partial analysis or summary description. In arriving at its opinion, Wachovia Securities considered the results of all of its analyses as a whole and did not attribute any particular weight to any analysis or factor considered by it. Accordingly, the analyses reflected in the tables and described below must be considered as a whole, and considering any portion of the analyses, without considering all analyses, could create a misleading or incomplete view of the processes underlying Wachovia Securities' analyses and opinion. For purposes of the "GMH Financial Analyses" summarized below, the "implied per share total consideration value" refers to the $9.61 implied per share value based on the sum of the following:

•: the per share cash portion of the merger consideration of $3.36;
•: the per share value of the stock portion of the merger consideration based on the merger exchange ratio of 0.07642 and the closing price of ACC common stock on February 11, 2008; and

•: the military sale distributions, as estimated by GMH's management, of $4.08 per share.

GMH Financial Analyses

Net Asset Value Analysis. Wachovia Securities performed a net asset valuation of GMH based on internal estimates and other data of GMH's management. The estimated value of GMH's student housing portfolio was calculated as follows:

•: in the case of assets anticipated to be retained by ACC, a selected range of economic capitalization rates of 6.25% to 6.75% was applied to GMH's estimated calendar year 2008 net operating income, referred to as NOI, attributable to those assets;
•: in the case of assets to be acquired by ACC's joint venture with Fidelity, the acquisition value ascribed to such assets by the joint venture parties, which reflected an implied economic capitalization rate of 6.53%, was utilized; and
•: in the case of disposition properties, the amount of mortgage debt associated with such disposition properties, less a range of estimated reserves for potential write-downs recognized upon disposition, was utilized.

The estimated value of GMH's military housing portfolio was calculated by applying a range of discount rates of 10.0% to 12.0% to the 50-year projected future cash flows that GMH's military housing portfolio could generate, which, in the case of cash flows attributed to future unidentified projects, were probability-adjusted downward by 25.0% based on the assessments of GMH's management. The estimated value of GMH's operating assets was calculated by applying a selected range of multiples of 4.0x to 6.0x to GMH's calendar year 2008 estimated management income and by applying a selected range of multiples of 2.0x to 4.0x to GMH's calendar year 2008 estimated development revenue. Other asset and liability values were calculated based on the book values of such assets and liabilities as reflected on GMH's balance sheet as of December 31, 2007 prepared by GMH's management, adjusted, in the case of liabilities, for the estimated mark-to-market value of GMH's outstanding debt. This analysis indicated the following implied per share equity reference range for GMH, as compared to the implied per share total consideration value:

Implied Per Share Equity Reference Range for GMH		Implied Per Share Total Consideration Value
$7.79 - $10.06		$9.61

Dividend Discount Analysis. Wachovia Securities calculated the estimated present value of GMH's future cash dividends during calendar year 2008 through calendar year 2010 based on internal estimates of GMH's management. Wachovia Securities calculated a range of terminal values for GMH by applying a range of funds from operations, referred to as FFO, terminal value multiples of 8.0x to 12.0x to GMH's estimated calendar year 2010 FFO. The cash dividends and terminal values were then discounted to present value using a range of discount rates of 10.0% to 11.0%. This analysis indicated the following implied per share equity reference range for GMH, as compared to the implied per share total consideration value:

Implied Per Share Equity Reference Range for GMH		Implied Per Share Total Consideration Value
$5.93 - $8.25		$9.61

Selected Public Company Analysis. Using publicly available information, including research analysts' estimates and public filings, Wachovia Securities reviewed financial and stock market

information for the following 14 selected publicly held REITs in the student housing and multifamily housing sectors:

Student Housing REITs		Multifamily Housing REITs
•	ACC	•	Apartment Investment and Management Company
•	Education Realty Trust, Inc.	•	Associated Estates Realty Corporation
		•	AvalonBay Communities, Inc.
		•	BRE Properties, Inc.
		•	Camden Property Trust
		•	Colonial Properties Trust
		•	Essex Property Trust, Inc.
		•	Home Properties, Inc.
		•	Investors Real Estate Trust
		•	Mid-America Apartment Communities, Inc.
		•	Post Properties, Inc.
		•	UDR, Inc.

Wachovia Securities reviewed, among other things, closing stock prices of the selected companies on February 11, 2008 as a multiple of calendar year 2008 estimated FFO per share. Wachovia Securities then applied a selected range of calendar year 2008 FFO per share multiples derived from the selected companies to corresponding financial data of GMH. Financial data of the selected companies were based on publicly available research analysts' estimates, public filings and other publicly available information. Financial data of GMH were based on internal estimates of GMH's management. This analysis indicated the following implied per share equity reference range for GMH, as compared to the implied per share total consideration value:

Implied Per Share Equity Reference Range for GMH		Implied Per Share Total Consideration Value
$7.32 - $9.31		$9.61

Selected Transactions Analysis. Using publicly available information, including public filings and equity research, Wachovia Securities reviewed the following nine selected transactions involving publicly held real estate companies announced since October 4, 2004:

Announcement Date		Acquiror		Target
•	10/23/2007	•	BPG Properties, Ltd.	•	Boston Capital Real Estate Investment Trust, Inc.
•	6/25/2007	•	Sentinel Real Estate Corp.	•	America First Apartment Investors, Inc.
•	5/29/2007	•	Tishman Speyer Real Estate Venture VII, L.P./Lehman Brothers Holdings Inc.	•	Archstone-Smith Trust
•	8/31/2006	•	Babcock & Brown Ltd.	•	BNP Residential Properties, Inc.
•	12/19/2005	•	Morgan Stanley Real Estate/ONEX Corporation	•	The Town and Country Trust
•	10/24/2005	•	Prime Property Fund, LLC	•	AMLI Residential Properties Trust
•	6/7/2005	•	ING Groep NV	•	Gables Residential Trust
•	10/25/2004	•	Colonial Properties Trust	•	Cornerstone Realty Income Trust, Inc.
•	10/4/2004	•	Camden Property Trust	•	Summit Properties Inc.

Wachovia Securities reviewed the purchase prices paid for the target company's equity as a multiple of latest 12 months' FFO. Wachovia Securities then applied a selected range of latest

12 months' FFO multiples derived from the selected transactions to GMH's calendar year 2007 estimated FFO. Financial data for the selected transactions were based on public filings and publicly available financial information at the time of announcement of the relevant transaction. Financial data for GMH were based on internal estimates of GMH's management. This analysis indicated the following implied per share equity reference range for GMH, as compared to the implied per share total consideration value:

Implied Per Share Equity Reference Range for GMH		Implied Per Share Total Consideration Value
$7.36 - $11.37		$9.61

ACC Financial Analyses

Selected Public Company Analysis. Using publicly available information, including research analysts' estimates and public filings, Wachovia Securities compared selected financial and stock market data of ACC with selected financial and stock market information for GMH and the selected companies referred to above under "—GMH Analyses—Selected Public Company Analysis." Wachovia Securities reviewed, among other things, closing stock prices of GMH and the selected companies on February 11, 2008 as a multiple of calendar years 2007, 2008 and 2009 estimated FFO per share. Wachovia Securities then compared these multiples with corresponding multiples implied for ACC based on the closing price of ACC common stock on February 11, 2008. Financial data of ACC, GMH and the selected companies were based on publicly available research analysts' estimates, public filings and other publicly available information. This analysis indicated the following implied low, median, mean and high multiples for GMH and the selected companies, as compared to the multiples implied for ACC:

	Implied Multiples for Selected Companies
Closing Stock Price on 2/11/08 as Multiple of:	Implied Multiples for Selected Companies				Implied Multiples for ACC
Closing Stock Price on 2/11/08 as Multiple of:	Low	Median	Mean	High	Implied Multiples for ACC
Calendar year 2007 FFO	9.4x	12.9x	14.2x	21.0x	27.6x
Calendar year 2008 FFO	8.5x	12.5x	13.5x	21.6x	18.2x
Calendar year 2009 FFO	7.8x	12.0x	12.7x	20.6x	17.2x

Dividend Discount Analysis. Wachovia Securities calculated the estimated present value of ACC's future cash dividends during calendar year 2008 through calendar year 2010 based on internal estimates of ACC's management and publicly available research analysts' growth rate assumptions discussed with ACC's management. Wachovia Securities calculated a range of terminal values for ACC by applying a range of FFO terminal value multiples of 17.2x to 19.2x to ACC's calendar year 2010 estimated FFO, excluding FFO attributable to ACC's on-campus participating properties, referred to as modified FFO. The cash dividends and terminal values were then discounted to present value using a range of discount rates of 9.25% to 9.75%. This analysis indicated the following implied per share equity reference range for ACC, as compared to the closing price of ACC common stock on February 11, 2008:

Implied Per Share Equity Reference Range for ACC		Closing Price of ACC Common Stock on 2/11/08
$28.10 - $31.36		$28.43

Net Asset Value Analysis. Wachovia Securities performed a net asset valuation of ACC based on internal estimates and other data of ACC's management. The estimated value of ACC's off-campus properties portfolio was calculated by applying a selected range of economic capitalization rates of 5.75% to 6.25% to ACC's estimated calendar year 2008 NOI attributable to those assets. The estimated value of ACC's development portfolio was calculated by applying a selected range of economic capitalization rates of 6.75% to 7.25% to ACC's estimated stabilized NOI attributable to those assets.

In addition, a multiple of 7.0x was applied to ACC's estimated calendar year 2008 revenue attributable to ACC's on-campus participating properties and to ACC's estimated calendar year 2008 third-party development and management income. Other asset and liability values (excluding debt associated with ACC's on-campus participating properties) were calculated based on the book values of such assets and liabilities as reflected on ACC's estimated balance sheet as of June 30, 2008, adjusted, in the case of liabilities, for the estimated mark-to-market value of ACC's outstanding debt. This analysis indicated the following implied per share equity reference range for ACC, as compared to the closing price of ACC common stock on February 11, 2008:

Implied Per Share Equity Reference Range for ACC		Closing Price of ACC Common Stock on 2/11/08
$28.00 - $32.47		$	28.43

Pro Forma Accretion/Dilution Analysis.

Wachovia Securities reviewed the potential pro forma financial effect of the mergers on ACC's estimated calendar year 2008 modified FFO per share after giving effect to estimated synergies resulting from the mergers based on discussions with GMH's management. Estimated financial data of ACC were based on internal estimates of ACC's management and estimated financial data of GMH were based on internal estimates of GMH's management. This analysis indicated that the mergers could be accretive to ACC's estimated calendar year 2008 modified FFO per share. The actual results achieved by the combined company may vary from projected results and the variations may be material.

Miscellaneous

In performing its analyses, Wachovia Securities considered industry performance, general business and economic conditions and other matters, many of which are beyond GMH's and ACC's control. No company, transaction or business used in the analyses described above is identical or directly comparable to GMH, ACC, the mergers or the military housing sale. Accordingly, a complete analysis of the results of the foregoing cannot be limited to a quantitative review of such results and involves complex considerations and judgments concerning the differences in the financial characteristics of the selected companies, transactions or businesses and other factors that could affect the value of the selected companies, transactions or businesses. Any estimates underlying Wachovia Securities' analyses are not necessarily indicative of future results or actual values, which may be significantly more or less favorable than those suggested by such estimates.

The analyses performed were prepared solely as a part of Wachovia Securities' analysis of the fairness, from a financial point of view, of the merger consideration, taken together with the payment of the military sale distributions. These analyses were conducted in connection with the delivery by Wachovia Securities of its opinion dated February 11, 2008 to GMH's board of trustees. The analyses do not purport to be appraisals or to reflect the prices at which a company or business might actually be sold or the prices at which any securities have traded or may trade at any time in the future. The type and amount of consideration payable in the mergers and the military housing sale were determined through negotiations between GMH and ACC and between GMH and Balfour Beatty, respectively. Wachovia Securities did not recommend any specific consideration to GMH's board of trustees or that any given consideration constituted the only appropriate consideration for the mergers or the military housing sale. The decision to enter into the merger agreement and the securities purchase agreement was solely that of GMH's board of trustees. As described above, Wachovia Securities' opinion and analyses were only one of many factors taken into consideration by GMH's board of trustees in evaluating the merger and the military housing transaction. Wachovia Securities' analyses summarized above should not be viewed as determinative of the views of GMH's board of trustees or management with respect to the mergers or the merger consideration or the military housing sale or the military sale distributions.

Wachovia Securities is a trade name of Wachovia Capital Markets, LLC, an investment banking subsidiary and affiliate of Wachovia Corporation. Wachovia Securities has been engaged to act as financial advisor to GMH in connection with the mergers and the military housing sale and will receive for such services a customary fee, a portion of which was payable upon delivery of its opinion and a significant portion of which will be payable upon the consummation of the mergers and the military housing sale. In addition, GMH has agreed to reimburse certain of Wachovia Securities' expenses and indemnify it against certain liabilities that may arise out of its engagement.

Wachovia Securities and its affiliates provide a full range of financial advisory, securities and lending services in the ordinary course of business, for which Wachovia Securities and such affiliates receive customary fees. In connection with unrelated matters, Wachovia Securities or its affiliates in the past have provided investment banking and other financial services to the GMH Operating Partnership and certain of its affiliates, for which Wachovia Securities and its affiliates have received fees, including having acting in the past as administrative agent for, and lender under, certain credit facilities of the GMH Operating Partnership and certain of its affiliates. Wachovia Securities also may provide similar or other such services to, and maintain relationships with, GMH, ACC, Balfour Beatty and their respective affiliates in the future. In the ordinary course of its business, Wachovia Securities may actively trade or hold the securities of GMH, ACC and Balfour Beatty for its own account and for the accounts of its customers and, accordingly, may at any time hold a long or short position in such securities.

Accounting Treatment for the Mergers

The mergers will be accounted for under the purchase method of accounting, with ACC treated as the acquirer. Under this method of accounting, GMH's assets and liabilities will be recorded by ACC at their respective fair values as of the closing date of the mergers and added to those of ACC. Financial statements of ACC issued after the mergers will reflect these values, but will not be restated retroactively to reflect the historical financial position or results of operations of GMH prior to the mergers. The results of operations of GMH will be included in the results of operations of ACC beginning on the effective date of the REIT merger.

Regulatory Matters

Neither ACC nor GMH is aware of any material U.S. federal or state regulatory approvals that must be obtained in connection with the mergers. However, the closing of the military housing sale (which is a condition precedent to the closing of the mergers) is subject to (a) obtaining necessary regulatory approvals, which includes the expiration of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, and (b) receipt of notice that the military housing transaction is not subject to the Exon-Florio amendments to The Defense Production Act of 1950. GMH and Balfour Beatty each filed a Notification and Report Form with the Federal Trade Commission and the Antitrust Division of the U.S. Department of Justice. The waiting period expired at 11:59 p.m. on March 31, 2008, without any request for additional information. A voluntary notice under the Exon-Florio amendments to the Defense Production Act of 1950 was submitted on March 11, 2008 to CIFIUS. On April 10, 2008, GMH received a letter that CFIUS had reviewed the submissions provided to it regarding the military housing sale and determined that there were no unresolved national security concerns and that action under the Exon-Florio amendments to the Defense Protection Act of 1950 was concluded.

Delisting and Deregistration of GMH Common Shares; Listing of ACC Common Stock Issued in Connection with the Mergers

GMH common shares are currently listed on the NYSE under the symbol "GCT." Upon completion of the REIT merger, GMH common shares will be delisted from the NYSE and deregistered under the Exchange Act. It is a condition to the consummation of the mergers that the shares of ACC common stock to be issued in connection with the mergers be approved for listing on the NYSE, subject to official notice of issuance. Following the mergers, ACC expects that the shares of ACC common stock will continue to trade on the NYSE under the symbol "ACC."

INTERESTS OF TRUSTEES AND EXECUTIVE OFFICERS OF
GMH IN THE MERGERS

In considering the recommendation of GMH's board of trustees that you vote to approve the REIT merger, you should be aware that some of GMH's executive officers and trustees have interests in the mergers and have arrangements that may be considered to be different from, or in addition to, those of GMH shareholders. GMH's board of trustees was aware of these interests and considered them, among other matters, in reaching its decision to approve the mergers and the transactions contemplated by the merger agreement and to recommend that you vote in favor of the REIT merger.

Equity Compensation Awards

All restricted GMH common shares issued to GMH's executive officers and trustees pursuant to GMH's equity incentive plan that are not yet vested will become fully vested and any restrictions on such restricted GMH restricted shares will terminate or lapse at the REIT merger effective time and will automatically be converted into the right to receive the merger consideration. This treatment of restricted shares issued to GMH's executive officers and trustees is consistent with the treatment of restricted shares issued to all employees.

Employment Agreements

GMH has entered into employment agreements with each of Messrs. Holloway, Robinson, O'Grady, DeRiggi and Macchione. Pursuant to the employment agreements, the completion of the mergers and the transactions contemplated by the merger agreement will result in (i) accelerated vesting of any of the executives' unvested equity awards, (ii) the executive becoming entitled to certain cash payments if GMH or a successor entity terminates the executive's employment without "cause" or the executive resigns for "good reason" (as such terms are defined in the employment agreements) and (iii) the payment of certain retention bonuses. In addition, each of Messrs. Holloway and Robinson is entitled to reimbursement from GMH for taxes imposed under Section 4999 of the Code. Mr. Holloway is entitled to a gross-up payment estimated to be approximately $1,642,902. Mr. Robinson is expected to waive various severance payments in connection with the receipt of an offer of employment with the military housing subsidiaries.

The following table sets forth the total amount of cash payments that is expected to be paid to Messrs. Holloway, DeRiggi, Macchione and O'Grady pursuant to the employment agreements in connection with the closing of the mergers, assuming a closing date of May 31, 2008:

Executive	Total Amount of Payments
Gary M. Holloway, Sr.	$	5,742,416
John DeRiggi	$	1,796,907
Joseph M. Macchione	$	1,593,777
J. Patrick O'Grady	$	1,774,606

Mr. O'Grady is also a participant in an account balance-type deferred compensation plan funded through corporate-owned life insurance. As of March 31, 2008, Mr. O'Grady's balance in this plan was approximately $79,000. It is anticipated that this plan will be terminated upon closing of the mergers and Mr. O'Grady's balance at that time will be distributed to him.

Success Fees

Subject to the approval of GMH's board of trustees, a total of $2.0 million will be paid to certain executive officers and/or trustees as a success fee for closing the military housing sale, the mergers and the transactions contemplated by the merger agreement. GMH's compensation committee has allocated $350,000 to Mr. Robinson in connection with the military housing sale. The allocation of

the remaining aggregate amount will be determined by GMH's board of trustees (or a committee thereof).

Put Agreement

Prior to the closing of the mergers, GMH anticipates selling its home office. If the home office is not sold to a third party unaffiliated with GMH prior to the closing of the mergers, then Mr. Holloway is contractually obligated to purchase the home office pursuant to the put agreement by no later than one business day prior to the REIT merger effective time for the sum of $8.0 million. GMH's board of trustees has established a committee of independent directors, chaired by Denis J. Nayden, to sell the home office immediately prior to the closing of the mergers. This committee will decide whether or not to exercise GMH's rights under the put agreement. The home office committee has engaged Binswanger Corporation, a real estate broker, to market the home office.

Indemnification

The merger agreement provides that from and after the REIT merger effective time, the ACC Parties will, jointly and severally, (i) indemnify and hold harmless each current and former director, officer, trustee, manager, employee, agent or fiduciary of GMH and acting in its capacity as such or any of its subsidiaries or as a fiduciary under or with respect to any employee benefit plan (collectively, the "Indemnified Parties") to the fullest extent authorized or permitted by law, against any Claims and any losses, Claims damages, liabilities, costs, Expenses, judgments, fines, penalties and amounts paid in settlement (including all interest, assessments and other charges paid or payable in connection with or in respect of any thereof) resulting therefrom; and (ii) promptly pay on behalf of or, within 30 days after any request for advancement, advance to each of the Indemnified Parties, to the fullest extent authorized or permitted by applicable law, any Expenses incurred in defending, serving as a witness with respect to or otherwise participating with respect to any Claim in advance of the final disposition of such Claim, including payment on behalf of or advancement to the Indemnified Party of any Expenses incurred by such Indemnified Party in connection with enforcing any rights with respect to such indemnification and/or advancement, in each case without the requirement of any bond or other security, but subject to (x) receipt of documentation by ACC reasonably evidencing the need for such advancement, and (y) ACC's receipt of an undertaking by or on behalf of such Indemnified Party, to repay such Expenses if it is ultimately determined under applicable laws that such Indemnified Party is not entitled to be indemnified); provided, that the ACC Parties will have no obligation under the merger agreement to any Indemnified Party when and if a court of competent jurisdiction ultimately determines, and such determination will have become final and non-appealable, that indemnification by the Indemnifying Parties is prohibited by applicable law.

The merger agreement also provides that all rights to indemnification and exculpation from liabilities for acts or omissions occurring at or prior to the REIT merger effective time existing in favor of the current or former directors and officers of GMH or any of its subsidiaries as provided in the GMH charter and bylaws (or, as applicable, the other organizational documents of any of GMH's subsidiaries), will be assumed by the surviving entity in the mergers at the REIT merger effective time, will survive the mergers and will continue in full force and effect in accordance with their terms for a period of six years from the REIT merger effective time.

For the purposes of this section, "Claim" means any threatened, asserted, pending or completed action, whether instituted by any party hereto, any governmental authority or any other person, that any Indemnified Party in good faith believes might lead to the institution of any action, whether civil, criminal, administrative, investigative or other, including any arbitration or other alternative dispute resolution mechanism, arising out of or pertaining to matters that relate to such Indemnified Party's duties or service as a director, officer, trustee, employee, agent, or fiduciary of GMH, any of its subsidiaries, or any employee benefit plan (within the meaning of Section 3(3) of

ERISA) maintained by any of the foregoing at or prior to the REIT merger effective time; and (y) the term "Expenses" means reasonable attorneys' fees and all other reasonable costs, expenses and obligations (including experts' fees, travel expenses, court costs, retainers, transcript fees, duplicating, printing and binding costs, as well as telecommunications, postage and courier charges) paid or incurred in connection with investigating, defending, being a witness in or participating in (including on appeal), or preparing to investigate, defend, be a witness in or participate in, any Claim for which indemnification is authorized pursuant to the merger agreement, including any action relating to a claim for indemnification or advancement brought by an Indemnified Party.

Under the merger agreement, GMH is required to purchase a directors' and officers' liability insurance policy providing coverage for the current and former trustees and officers of GMH and each GMH subsidiary with a claims period of six years from the REIT merger effective time with respect to directors' and officers' liability insurance for claims arising from facts or events that occurred on or prior to the REIT merger effective time. The policy must have at least the same coverage and amounts and contain terms and conditions that are no less favorable to the trustees and officers as the existing policy or policies of GMH and its subsidiaries; provided that, in no event will GMH be required to expend more than an amount agreed upon by the parties. In the event that GMH would be required to expend more than such amount, GMH must obtain the maximum amount of such insurance obtainable by payment of annual premiums equal to that amount.

Appointment to ACC's Board of Directors

The merger agreement provides that, immediately following the effective time of the partnership merger, ACC's board of directors will be increased by one member and ACC's board of directors will appoint Joseph M. Macchione, the executive vice president, general counsel and secretary of GMH, to ACC's board of directors. Mr. Macchione will serve until the next annual meeting of ACC stockholders and will be nominated for reelection to ACC's board of directors at the next subsequent annual meeting of ACC stockholders.

THE MERGER AGREEMENT

The following is a brief summary of the material provisions of the merger agreement, a copy of which is attached as Annex A and is incorporated by reference in this proxy statement/prospectus.

This summary may not contain all of the information about the merger agreement that is important to you. The merger agreement has been included to provide you with information regarding its terms, and we recommend that you carefully read the merger agreement in its entirety. The merger agreement contains representations and warranties that the parties have made to each other as of specific dates. The assertions embodied in those representations and warranties were made solely for purposes of the contract between the parties, and may be subject to important qualifications and limitations agreed to by the parties in connection with negotiating its terms. Moreover, the representations and warranties are subject to a contractual standard of materiality that may be different from what may be viewed as material to shareholders, and the representations and warranties may have been used for the purpose of allocating risk between the parties rather than establishing matters as facts. For the foregoing reasons, you should not rely on the representations and warranties as statements of factual information.

As used in the summary of the material terms of the merger agreement below and elsewhere in this proxy statement/prospectus, references to GMH's "student housing subsidiaries" do not include GMH's military housing subsidiaries and references to GMH's "subsidiaries" include both its student housing subsidiaries and its military housing subsidiaries.

The Mergers

The merger agreement provides for the merger of REIT Merger Sub with and into GMH. GMH will continue as the surviving entity in accordance with Title 8 of the Corporations and Associations Article of the Annotated Code of Maryland, or the Maryland REIT Law, and the Delaware Limited Liability Company Act, or the DLLCA. In this proxy statement/prospectus, we refer to this merger as the REIT merger.

Next, GMH, as the surviving entity, will be merged with and into the Delaware Company. The Delaware Company will continue as the surviving entity in accordance with the Maryland REIT Law and the Delaware General Corporation Law, or DGCL. In this proxy statement/prospectus, we refer to this merger as the reincorporation merger.

Finally, the Partnership Merger Sub will be merged with and into the GMH Operating Partnership. The GMH Operating Partnership will continue as the surviving partnership in accordance with the Delaware Revised Uniform Limited Partnership Act, as amended, or DRULPA. In this proxy statement/prospectus, we refer to this merger as the partnership merger.

The REIT merger will become effective upon the later of (A) the date of acceptance for record of articles of merger with the State Department of Assessments and Taxation of Maryland, or SDAT, or (B) the date of filing of a Certificate of Merger with the Delaware Secretary of State, or DSOS, or at a later time as the parties agree as specified in such filings in accordance with applicable law. In this proxy statement/prospectus, we refer to this effective time as the REIT merger effective time.

The reincorporation merger will become effective upon the later of (A) the date of acceptance for record of the reincorporation articles of merger with the SDAT or (B) the date of filing of the reincorporation certificate of merger with the DSOS, or at a later time as the parties agree as specified in such filings in accordance with applicable law. In this proxy statement/prospectus, we refer to this effective time as the reincorporation merger effective time.

The partnership merger will become effective upon such time as a certificate of merger has been filed with the DSOS, or at a later time as the parties agree as specified in such filing, in

accordance with DRULPA. The partnership merger will occur on the closing date immediately following the reincorporation merger effective time.

The closing of the mergers will take place as promptly as practicable, but in no event later than the second business day after all of the closing conditions set forth in the merger agreement are satisfied or waived.

The Merger Consideration and Effects of the Mergers

The REIT Merger Consideration and Effects of the REIT Merger

At the REIT merger effective time, each issued and outstanding GMH common share (other than GMH common shares held by GMH, ACC or any of their respective subsidiaries) will automatically be converted into, and cancelled in exchange for, the right to receive (1) 0.07642 of a share of ACC common stock, referred to as the share consideration, plus (2) a cash payment to be paid by ACC equal to the sum of $3.36 per GMH common share without interest, referred to as the cash consideration. In this proxy statement/prospectus, we sometimes refer to the cash consideration, together with the share consideration, as the merger consideration.

If prior to the REIT merger effective time, either GMH or ACC should reclassify its common shares, or effect a recapitalization, split-up, combination, exchange of shares or readjustment, then the share consideration and the cash consideration will be ratably adjusted.

The Reincorporation Merger Consideration and Effects of the Reincorporation Merger

At the reincorporation merger effective time, each surviving company share issued and outstanding immediately prior to the reincorporation merger effective time will convert into one share of common stock of the Delaware Company. The shares of the Delaware Company issued and outstanding prior to the reincorporation merger effective time will be cancelled and retired and no payment will be made with respect thereto.

The Partnership Merger Consideration and Effects of the Partnership Merger

At the partnership merger effective time, each limited partnership unit of the GMH Operating Partnership, referred to as an LP Unit, issued and outstanding immediately prior to the partnership merger effective time (other than LP Units held by GMH), will automatically convert into, and will be cancelled in exchange for, the right to receive (1) the share consideration plus (2) a cash payment to be paid by the ACC Operating Partnership equal to the cash consideration, referred to as the Operating Partnership cash consideration; provided, however, that that in lieu of the receipt of ACC common stock, if but only if (x) the holder of such LP Unit has validly made and not revoked an election to receive per each LP Unit 0.07642 of a common unit in the ACC Operating Partnership, referred to as the Common Unit Consideration, in respect thereof, (y) the issuance of such common units would be exempt from registration under the Securities Act and applicable state securities laws and (z) the holder of such LP Unit has agreed for one year from the closing of the mergers, without the prior written consent of ACC, to not seek redemption of such common units, then each of such holder's LP Units will be converted into the right to receive the cash consideration and the Common Unit Consideration. We refer to the ACC cash consideration and share consideration and/or Common Unit Consideration as the "Partnership Merger Consideration." The common units will be redeemable in accordance with the operating partnership agreement of the ACC Operating Partnership, subject to the foregoing clause (z).

The general partner interests of the GMH Operating Partnership will remain outstanding as general partner interests in the surviving partnership. The general partner interest of Partnership Merger Sub and each LP Unit held by the surviving entity, the general partner or any of surviving entity's subsidiaries immediately prior to the partnership merger effective time will be cancelled. The

limited partnership interest of Partnership Merger Sub will remain outstanding as a limited partnership interest in the surviving partnership.

Treatment of Restricted Shares

Immediately prior to the REIT merger effective time, each outstanding GMH restricted common share will become fully vested and free of any forfeiture restrictions and will be considered outstanding GMH common shares as of the REIT merger effective time for all purposes of the merger agreement, including receipt of the share consideration.

Fractional Shares

No fractional shares of ACC common stock will be issued upon the surrender for exchange of GMH common shares or LP Units. For each fractional share that would otherwise be issued, ACC will pay cash, without interest, in an amount determined by multiplying (x) the fractional share interest to which a holder would otherwise be entitled (rounded to the nearest thousandth when expressed in decimal form) by (y) the average closing price of a share of ACC common stock on the NYSE on the 10 trading days immediately preceding the second (2nd) day prior to the REIT merger effective time (as reported in the Wall Street Journal, or if not reported therein, in another authoritative source), rounded to the nearest one-tenth of a thousand.

Organizational Documents

The declaration of trust of GMH, as in effect immediately prior to the REIT merger effective time, will be the declaration of trust of the surviving company until thereafter amended as provided by law.

The certificate of incorporation and bylaws of the Delaware Company, as in effect immediately prior to the reincorporation merger effective time, will be the charter and bylaws of the surviving entity until thereafter amended as provided by law.

The certificate of limited partnership and the limited partnership agreement of Partnership Merger Sub, as in effect immediately prior to the partnership merger effective time, will be the certificate of limited partnership and the limited partnership agreement of the surviving partnership until thereafter amended as provided by law.

Trustees and Officers

The parties designated by REIT Merger Sub immediately prior to the REIT merger effective time will be the trustees of the surviving company and the officers of REIT Merger Sub immediately prior to the REIT merger effective time, if any, will be the officers of the surviving company, in each case to hold office until their successors are elected and qualified.

The trustees of the surviving company immediately prior to the reincorporation merger effective time will be the directors of the surviving entity and the officers of GMH immediately prior to the reincorporation merger effective time, if any, will be the officers of the surviving entity, in each case to hold office until their successors are elected and qualified.

The general partner of the GMH Operating Partnership will remain the general partner of the surviving partnership following the partnership merger effective time.

No Further Ownership Rights

At the REIT merger effective time, holders of GMH common shares will cease to be GMH shareholders and will have no rights with respect to GMH common shares other than the right to receive the share consideration. The share consideration paid to GMH shareholders in accordance with

the exchange and payment procedures in the merger agreement will be deemed to have been paid in full satisfaction of all rights and privileges pertaining to GMH common shares.

Exchange Procedures

Prior to the REIT merger effective time, ACC will deliver to an exchange agent certificates representing the shares of ACC's common stock sufficient to pay the share consideration and cash in an amount sufficient to pay the aggregate cash consideration (including the estimated amount of cash to be paid in lieu of fractional shares of ACC common stock) and the aggregate Operating Partnership cash consideration, referred to as the Payment Fund.

Promptly after the REIT merger effective time, but in no event later than four business days after the REIT merger effective time, as applicable, the exchange agent will send a letter of transmittal to each holder of GMH common shares that will include detailed instructions on how such holder may exchange such holder's GMH common shares or common units of the GMH Operating Partnership, as applicable, for the applicable merger consideration. The exchange agent will pay GMH shareholders who submit their duly completed letters of transmittal, their share certificates and any other transmittal materials requested by the exchange agent or the surviving entity, (1) the share consideration they are entitled to receive, in particular, a certificate or certificates representing that number of whole shares of common stock of ACC that such holder is entitled to receive pursuant to the merger agreement, plus (2) an amount in cash equal to the ACC cash consideration that such holder is entitled to receive (net of any applicable withholding tax) plus (3) any cash such holder is entitled to receive in lieu of fractional shares of ACC, in each case without interest.

Any portion of the Payment Fund delivered to the exchange agent by ACC that remains unclaimed by the holders of GMH common shares and holders of LP Units for one year after the REIT merger effective time (as well as proceeds from any investment thereof) will be delivered by the exchange agent to ACC.

Representations and Warranties of the GMH Parties

The GMH Parties have made certain representations and warranties to the ACC Parties, subject in certain cases to exceptions disclosed in certain portions of GMH's Form 10-K for the year ended December 31, 2006 filed on March 16, 2007 or in any other report filed with the SEC thereafter and prior to the date of the merger agreement. None of these representations and warranties will survive the closing of the mergers. These representations and warranties include, but are not limited to, the following:

•: the due formation or organization, valid existence and good standing (where applicable) and authority of GMH and its subsidiaries;
•: the absence of direct or indirect ownership by GMH or its subsidiaries of any interest or investment in any other person;
•: the capital structure of GMH and the GMH Operating Partnership;
•: the authority of each of the GMH Parties to enter into the merger agreement and to complete the transactions contemplated by the merger agreement and the enforceability of the merger agreement against each of the GMH Parties;
•: the necessary consents, approvals, authorizations, notifications and filings required under certain loan documents required to consummate the mergers and the transactions contemplated by the merger agreement;
•: the absence of conflicts, violations, defaults, or rights of termination as a result of the transactions contemplated by the merger agreement under the organizational

documents of GMH or the organizational documents of any of GMH's subsidiaries, or the terms of any loan or credit agreement or any note, or any bond, mortgage, indenture, lease, agreement, instrument, permit, franchise or license or other instrument or obligation to which any of the GMH Parties is a party, or violation of any law or order as a result of the transactions contemplated by the merger agreement;

•: the absence or receipt of required consents, approvals, orders, authorizations of, registrations, declarations, filings with, notices to or permits from any governmental authority to complete the transactions contemplated by the merger agreement;
•: GMH's compliance with the rules and regulations of the SEC and its reporting requirements;
•: the implementation and maintenance of adequate disclosure controls and procedures as required by the Exchange Act and the absence of any material weaknesses in design or operation of internal control over financial reporting;
•: the availability of GMH's SEC filings since January 1, 2005 and the financial statements contained therein;
•: the absence of certain changes or events since September 30, 2007;
•: the absence of undisclosed material liabilities;
•: compliance with applicable laws by GMH, the GMH Operating Partnership and its student housing subsidiaries and the possession of permits;
•: the absence of certain litigation;
•: tax matters, including REIT qualification matters;
•: compliance with pension and employee benefit plan regulations and other pension and benefits matters;
•: labor and employment matters affecting GMH, the GMH Operating Partnership and the student housing subsidiaries;
•: intellectual property owned or licensed by GMH, the GMH Operating Partnership and the student housing subsidiaries;
•: environmental matters affecting GMH, the GMH Operating Partnership and the student housing subsidiaries;
•: real property owned by GMH, the GMH Operating Partnership and the student housing subsidiaries;
•: insurance policies of GMH, the GMH Operating Partnership and the student housing subsidiaries, title insurance policies, property restructuring, ground leases, condemnation or rezoning and management agreements;
•: receipt by GMH's board of trustees of the opinion of GMH's financial advisor;
•: the vote of GMH shareholders and the consent of the general partner as general partner of the GMH Operating Partnership required to approve the REIT merger and the partnership merger, respectively, the merger agreement and the other transactions contemplated by the merger agreement;
•: the absence of any undisclosed broker's and finder's fees or commissions;

•: material contracts of GMH, the GMH Operating Partnership and the student housing subsidiaries, the enforceability of those contracts, and the absence of any breach or violation of, or default under, any such material contracts;
•: the inapplicability of state anti-takeover statutes;
•: the accuracy of information provided by or on behalf of GMH or any of its subsidiaries for use in this proxy statement/prospectus;
•: the absence of a shareholders' rights agreement or similar plan or agreement which limits or impairs the ability to purchase equity or debt securities of GMH or any of its subsidiaries;
•: the absence of any undisclosed transactions with affiliates of GMH or any of its subsidiaries;
•: the absence of loans by GMH or any of its subsidiaries to any of their respective employees, officers, trustees or directors;
•: the inapplicability of the Investment Company Act of 1940, as amended; and
•: the disclosure of all agreements, arrangements or understandings made by GMH or its subsidiaries related to the contribution agreement between ACC and Fidelity regarding the joint venture.

For purposes of the merger agreement, "GMH material adverse effect" means any state of facts, event, circumstance, development, change or effect that is materially adverse to the business, assets, properties, financial condition or results of operations of GMH and the GMH Operating Partnership (in each case, other than the military housing subsidiaries) and the student housing subsidiaries, taken as a whole. Certain of GMH's representations in the merger agreement are qualified by the failure of such representations to be true to the extent that such failure would not result in, or be reasonably likely to have, a GMH material adverse effect. A GMH material adverse effect will not have occurred, however, as a result of:

•: any change in general economic or business conditions, except to the extent and only to the extent that such change has a disproportionate impact on GMH and the GMH Operating Partnership (in each case, other than the military housing subsidiaries) and the student housing subsidiaries (taken as a whole) relative to other persons or participants in the student housing industry that operate in the geographic regions affected by such change;
•: any change in financial or securities market conditions generally, including changes in interest or exchange rates, except to the extent and only to the extent that such change has a disproportionate impact on GMH and the GMH Operating Partnership (in each case, other than the military housing subsidiaries) and the student housing subsidiaries (taken as a whole) relative to other persons or participants in the student housing industry that operate in the geographic regions affected by such change;
•: any change generally affecting the business or industry in which GMH and the GMH Operating Partnership (in each case, other than the military housing subsidiaries) and the student housing subsidiaries (taken as a whole) operate, except and only to the extent that such change has a disproportionate impact on GMH and the GMH Operating Partnership (in each case, other than the military housing subsidiaries) and the student housing subsidiaries (taken as a whole) relative to other persons or participants in the student housing industry that operate in the geographic regions affected by such change;

•: any change in legal, political or regulatory conditions generally or in any geographic region in which any of the student housing subsidiaries operates that, in each such case, generally impacts the student housing industry, except and only to the extent that such change has a disproportionate impact on GMH and the GMH Operating Partnership (in each case, other than the military housing subsidiaries) and the student housing subsidiaries (taken as a whole) relative to other persons or participants in the student housing industry that operate in the geographic regions affected by such change;
•: the negotiation, announcement of, the execution or the performance of the merger agreement, the securities purchase agreement or the contribution agreement between ACC and Fidelity;
•: any change arising from the compliance with the terms of, or the taking of any action permitted by, the merger agreement;
•: changes in law or GAAP, in each case applicable to the student housing industry, except and only to the extent that such event has a disproportionate impact on GMH and the GMH Operating Partnership (in each case, other than the military housing subsidiaries) and the student housing subsidiaries (taken as a whole) relative to other persons or participants in the student housing industry that operate in the geographic regions affected by such change; or
•: act of God, casualty, fire, flood, hurricane, earthquake, other severe weather, natural disaster, terrorism or act of war (whether declared or undeclared), except and only to the extent that such event has a disproportionate impact on GMH and the GMH Operating Partnership (in each case, other than the military housing subsidiaries) and the student housing subsidiaries (taken as a whole) relative to other persons or participants in the student housing industry that operate in the geographic regions affected by such change, or would prevent the GMH and/or its subsidiaries from consummating the transactions contemplated by the merger agreement or performing their respective obligations thereunder.

Representations and Warranties of the ACC Parties

The ACC Parties have made certain representations and warranties to the GMH Parties subject in certain cases to exceptions disclosed in certain portions of ACC's Form 10-K for the year ended December 31, 2006 filed on March 16, 2007 or in any other SEC report filed thereafter and prior to the date of the merger agreement. None of these representations and warranties will survive the closing of the mergers. These representations and warranties include, but are not limited to, the following:

•: the due formation or organization, valid existence and good standing (where applicable) and authority of ACC, the ACC Operating Partnership and its subsidiaries;
•: the absence of direct or indirect ownership by ACC or its subsidiaries of any interest or investment in any other person;
•: the capital structure of ACC and the ACC Operating Partnership;
•: the authority of each of the ACC Parties to enter into the merger agreement and to complete the transactions contemplated by the merger agreement and the enforceability of the merger agreement against each of the ACC Parties;
•: the absence of conflicts, violations, defaults, or rights of termination as a result of the transactions contemplated by the merger agreement under the organizational documents of ACC or the organizational documents of any of ACC's subsidiaries, or

the terms of any loan or credit agreement or any note, or any bond, mortgage, indenture, lease, agreement, instrument, permit, franchise or license or other instrument or obligation to which any of the GMH Parties is a party, or violation of any law or order as a result of the transactions contemplated by the merger agreement;

•: the absence or receipt of required consents, approvals, orders, authorizations of, registrations, declarations, filings with, notices to or permits from any governmental authority to complete the transactions contemplated by the merger agreement;
•: ACC's compliance with the rules and regulations of the SEC and its reporting requirements;
•: the implementation and maintenance of adequate disclosure controls and procedures as required by the Exchange Act and the absence of any material weaknesses in design or operation of internal control over financial reporting;
•: the availability of ACC's SEC filings since January 1, 2005 and the financial statements contained therein;
•: the absence of certain changes or events since September 30, 2007;
•: the absence of undisclosed material liabilities;
•: compliance with applicable laws by ACC, the ACC Operating Partnership and its subsidiaries and the possession of permits;
•: the absence of certain litigation;
•: tax matters, including REIT qualification matters;
•: compliance with pension and employee benefit plan regulations and other pension and benefits matters;
•: the consent of the general partner as general partner of the ACC Operating Partnership is required to approve the merger, the merger agreement and the other transactions contemplated by the merger agreement;
•: the absence of any undisclosed broker's and finder's fees or commissions;
•: material contracts of ACC, the ACC Operating Partnership and any of their subsidiaries, the enforceability of those contracts, and the absence of any breach or violation of, or default under, any such material contracts;
•: the compliance with the organizational documents of ACC or the organizational documents of any of ACC's subsidiaries regarding the payment of the share consideration;
•: the accuracy of information provided by or on behalf of GMH or any of its subsidiaries for use in this proxy statement/prospectus;
•: the validity of the commitment letter from KeyBank;
•: the inapplicability of the Investment Company Act of 1940, as amended; and
•: the disclosure of all agreements, arrangements or understanding made by ACC or its subsidiaries related to the contribution agreement between ACC and Fidelity regarding the joint venture.

For purposes of the merger agreement, "ACC material adverse effect" means any state of facts, event, circumstances, development, change or effect that is materially adverse to the business, assets,

properties, financial condition or results of operations of ACC and its subsidiaries, taken as a whole. Certain of the representations made by the ACC Parties in the merger agreement are qualified by the failure of such representations to be true to the extent that such failure would not result in, or be reasonably likely to have an ACC material adverse effect. An ACC material adverse effect will not have occurred, however, as a result of:

•: any change in general economic or business conditions, except to the extent and only to the extent that such change has a disproportionate impact on ACC and its subsidiaries (taken as a whole) relative to other persons or participants in the student housing industry that operate in the geographic regions affected by such change;
•: any change in financial or securities market conditions generally, including changes in interest or exchange rates, except to the extent and only to the extent that such change has a disproportionate impact on ACC and its subsidiaries (taken as a whole) relative to other persons or participants in the student housing industry that operate in the geographic regions affected by such change;
•: any change generally affecting the business or industry in which ACC and its subsidiaries operate, except to the extent and only to the extent that such change has a disproportionate impact on ACC and its subsidiaries (taken as a whole) relative to other persons or participants in the student housing industry that operate in the geographic regions affected by such change;
•: any change in legal, political or regulatory conditions generally or in any geographic region in which ACC or its subsidiaries operate that, in each such case, generally impacts the student housing industry, except to the extent and only to the extent that such change has a disproportionate impact on ACC and its subsidiaries (taken as a whole) relative to other persons or participants in the student housing industry that operate in the geographic regions affected by such change;
•: the negotiation, announcement of the execution or the performance of the merger agreement, the securities purchase agreement or the contribution agreement between ACC and Fidelity;
•: any change arising from the compliance with the terms of, or the taking of any action permitted by, the merger agreement;
•: changes in law or GAAP, in each case applicable to the student housing industry, except to the extent and only to the extent that such change has a disproportionate impact on ACC and its subsidiaries (taken as a whole) relative to other persons or participants in the student housing industry that operate in the geographic regions affected by such change; or
•: act of God, casualty, fire, flood, hurricane, earthquake, other severe weather, natural disaster, terrorism or act of war (whether declared or undeclared), except and only to the extent that such event has a disproportionate impact on ACC and its subsidiaries (taken as a whole) relative to other persons or participants in the student housing industry that operate in the geographic regions affected by such change, or would prevent ACC and its subsidiaries from consummating the transactions contemplated by the merger agreement or performing their respective obligations thereunder.

Covenants Related to Conduct of Business of GMH

During the period from February 11, 2008 to the earlier of the partnership merger effective time or the termination of the merger agreement in accordance with its terms, subject to certain

exceptions, GMH will, and will cause each of the GMH Operating Partnership and each of the student housing subsidiaries to, (1) carry on their respective businesses in the usual, regular and ordinary course consistent with past practice, (2) to the extent consistent with the foregoing clause (1), use its reasonable best efforts to preserve intact their respective current business organizations, ongoing businesses and relationships with customers, suppliers, lenders and others having business dealings with it and to keep available the services of their present officers and employees, (3) maintain the status of GMH as a REIT and the status of the GMH Operating Partnership as a partnership (and not an association or publicly traded partnership) within the meaning of the Code, (4) use commercially reasonable efforts to comply with all applicable laws wherever their respective businesses are conducted, including the timely filing of reports, forms and other documents with the SEC, and (5) not knowingly take any other action that would reasonably be anticipated to prevent or delay the consummation of the mergers or the transactions contemplated by the merger agreement. Without limiting the generality of the foregoing, subject to certain exceptions and certain events included in the disclosure schedules to the merger agreement, the GMH Parties have agreed not to (except to the extent that ACC otherwise consents in writing, which consent will not be unreasonably withheld or delayed):

•: declare, set aside for payment or pay any dividends on, or make any other distributions (whether in cash, shares or property) in respect of any of GMH's equity securities or the partnership interests, shares, stock or other equity interests in any of GMH's subsidiaries, other than (1) regular cash distributions at a rate not in excess of $0.165 per GMH common share, declared and paid quarterly in accordance with historic practice by GMH, subject to certain exceptions; provided that GMH shall not declare, set aside or pay its regular cash distribution in respect of any fiscal quarter after the first fiscal quarter of 2008, (2) corresponding distributions payable to each holder of partnership units of the GMH Operating Partnership, (3) the distribution of all of the capital stock of College Park Management TRS, Inc. to GMH Operating Partnership, (4) a distribution to the holders of partnership units of the GMH Operating Partnership of the entire amount of the net proceeds resulting from the military housing sale, the sale of the home office and disposition assets, if any, and a corresponding distribution to the holders of the holders of GMH common shares; (5) dividends or distributions, declared, set aside or paid by any wholly-owned GMH subsidiary to GMH or any of its subsidiaries that is, directly or indirectly, wholly-owned by GMH; and (6) any dividends or distributions to the extent made to maintain GMH's REIT status as a REIT or to eliminate any U.S. federal income tax liability;
•: split, combine or reclassify any shares, stock, partnership interests or other equity interest or issue or authorize the issuance of any securities in substitution for such shares, stock, partnership interests or other equity interests;
•: purchase, redeem (except for the redemption of LP Units for GMH common shares in accordance with the partnership agreement of the GMH Operating Partnership) or otherwise acquire (subject to certain exceptions set forth in the merger agreement) any GMH common shares, stock, other equity interests or securities of GMH or the partnership interests, stock, other equity interests or securities of any of GMH subsidiary or any options, warrants or rights to acquire, or security convertible into, GMH common shares, stock, other equity interest or securities of GMH or the partnership interest, stock or other equity interests in any GMH subsidiary;
•: other than issuances in respect of the redemption of LP Units for GMH common shares in accordance with the partnership agreement of the GMH Operating Partnership, authorize for issuance, issue, deliver, sell, grant or agree to issue, deliver, sell or grant, any GMH common shares, shares of stock, units, interests, any other

voting or redeemable or convertible securities (including partnership interests), options, warrants or stock-based performance units of GMH or its subsidiaries, or pledge or otherwise encumber shares of capital stock or securities in GMH or any of its subsidiaries;

•: amend any term of any outstanding security of the GMH or its subsidiaries, the GMH organizational documents, or any other organizational documents, limited partnership agreements, limited liability company agreements or similar documents, of the GMH Operating Partnership or any student housing subsidiary;
•: (A) merge or consolidate with any person, except as provided in the merger agreement, (B) acquire (by merger, consolidation or acquisition) any corporation, partnership or other entity or (C) purchase any equity interest in or assets of, any person or any division or business thereof;
•: make, undertake or enter into commitments obligating GMH, the GMH Operating Partnership or any student housing subsidiary to make, any capital expenditures in excess of 105% of the total amounts set forth as capital expenditures or development costs in the GMH 2007 capital budget, referred to as the Budget, except capital expenditures in the ordinary course of business and consistent with past practice necessary to repair and/or prevent damage to any of the properties of GMH or any of its subsidiaries as is necessary in the event of an emergency situation, in which event GMH will provide written notice thereof to ACC within two business days thereafter;
•: incur any indebtedness, except for purposes of (A) funding expenditures pursuant to the Budget, (B) funding other transactions permitted by the merger agreement, (C) working capital in the ordinary course of business consistent with past practice (including to the extent necessary to pay dividends permitted pursuant to the merger agreement, (D) making payments to holders of any indebtedness existing as of the date of the merger agreement and (E) paying any transaction expenses incurred in connection with the transactions contemplated by the merger agreement;
•: mortgage, pledge, create or suffer any lien, or otherwise encumber any assets or securities of GMH, the GMH Operating Partnership or any student housing subsidiary;
•: prepay, refinance or amend any existing indebtedness;
•: sell, lease (other than leases as landlord in the ordinary course of business) or otherwise dispose of any of the GMH properties, including by the disposition or issuance of equity securities in an entity that owns a GMH property, except the transactions contemplated by the merger agreement;
•: sell, lease, or otherwise dispose of any of its personal property or assets, except dispositions of obsolete personal property or in connection with sales of any GMH properties as permitted by the merger agreement;
•: make any loans, capital contributions or investments in any other person, other than in the ordinary course of business consistent with past practice;
•: make or rescind any election relating to taxes (in each case, except to the extent (1) any such election is required by law, (2) any such election expressly provided for in the merger agreement, (3) an election for or on behalf of the GMH Operating Partnership or any of its subsidiaries under Section 754 of the Code, (4) any other election regarding taxes made in the ordinary course of GMH's business that could not reasonably be expected to have a material adverse effect on GMH and any subsidiary of GMH or any ACC Party upon or following the REIT merger effective time or

(v) necessary to preserve GMH's status as a REIT or the partnership status of the GMH Operating Partnership or the status of any other subsidiary of GMH which files tax returns as a partnership for U.S. federal income tax purposes or as a qualified REIT subsidiary or a taxable REIT subsidiary under the applicable provisions of Section 856 of the Code, provided that in such events, GMH will promptly notify ACC of such election and will not fail to make such election in a timely manner);

•: (1) fail to maintain its books and records in all material respects in accordance with GAAP consistently applied, (2) change any of its methods, principles or practices of financial accounting in effect, other than as required by GAAP, (3) settle or compromise any claim, action, suit, litigation, proceeding, arbitration, investigation, audit or controversy relating to taxes, other than settlements or compromises (a) relating to an increase in the payment of real property taxes or sales taxes in an amount not to exceed $1.0 million, individually or in the aggregate, or (b) that do not result in a tax liability of GMH, the GMH Operating Partnership or any student housing subsidiary that materially exceeds the amount reserved, in accordance with GAAP, with respect to such claim, action, or other proceeding, or (c) revalue in any material respect any of its assets, including writing-off accounts receivable, except, in each of the foregoing cases, as may be required by the SEC, applicable law or GAAP (in which case, GMH will promptly inform ACC of such changes);
•: except as required by applicable law or any GMH employee benefit plan in effect as of the date of the merger agreement, amend, modify, alter or terminate any such plan (other than immaterial amendments, modifications, alterations or terminations that have no economic effect) or adopt any new plan that would be a GMH employee benefit plan if it had been in existence on the date of the merger agreement (other than the renewal or continuation of any existing GMH employee benefit plan that is expiring in accordance with its terms on terms that are substantially similar to such existing GMH employee benefit plan);
•: except as set forth in the disclosure schedules to the merger agreement, increase the compensation, bonus or fringe or other benefits of, or pay any discretionary bonus of any kind or amount whatsoever to, any current or former trustee, director, officer, employee or consultant;
•: except as set forth in the disclosure schedules to the merger agreement, grant or pay any severance, change of control or termination pay or termination benefits to, or increase in any manner the severance, change of control or termination pay or termination benefits of, any current or former trustee, director, officer, employee or consultant of GMH or any of its subsidiaries, except the retention bonuses in the amounts set forth in the disclosure schedules to the merger agreement or grant any increase in, or otherwise alter or amend, any right to receive any severance, change of control or termination pay or termination benefits or enter into or otherwise amend or alter any employment, loan, retention, consulting, indemnification, termination, change of control, severance, incentive plan, equity award or similar agreement or arrangement with any employee,
•: except as set forth in the disclosure schedules to the merger agreement, establish, pay, agree to grant or increase any stay bonus, retention bonus or any similar benefit under any plan, agreement, award or arrangement or hire new employees, except for replacement hires below the level of vice president, or enter into any new employment agreement with any permitted new hire, or grant any severance, change of control or

termination pay or termination benefits to any permitted new hire other than severance and retention arrangements in an aggregate amount not to exceed $100,000;

•: waive, release, assign, settle or compromise any pending or threatened litigation, action or claim, including any shareholder derivative or class action claims, other than settlements or compromises for litigation providing solely for the payment of money damages where the amount paid, in settlement or compromise, does not exceed $500,000, which settlement or compromise provides for a complete release of GMH and each of its applicable subsidiaries for all claims and which do not provide for any admission of liability by GMH or any of its subsidiaries or impose any obligation or restriction on the ACC Parties, the surviving entity, the surviving partnership or any of their subsidiaries after the REIT merger effective time;
•: waive compliance in any material respect with, amend or terminate the terms of or breaches under, or assign any rights or claims under, any material contract;
•: except with ACC's prior written consent, which will not be unreasonably withheld or delayed, enter into any material contract, terminate, or modify or amend in any material respect, any material contract to which GMH or any of the student housing subsidiaries is a party;
•: modify, amend or change any existing tax protection agreement in a manner that would adversely affect GMH, the GMH Operating Partnership, any student housing subsidiary, the surviving entity, surviving partnership, ACC or any subsidiary of ACC, or enter into any new tax protection agreement;
•: deliver a response to any buy/sell or other similar notices in respect of the joint venture assets of the student housing subsidiaries;
•: except as provided in the merger agreement, authorize, recommend, propose, adopt or announce an intention to adopt a plan of complete or partial liquidation, dissolution, merger, consolidation, restructuring, recapitalization or other reorganization of GMH or any of its student housing subsidiaries (other than the transactions contemplated by the merger agreement);
•: fail to pay all premiums due and payable for material insurance policies and/or fail to keep material insurance policies in full force and effect;
•: fail to perform its obligations under any agreement relating to any outstanding indebtedness of GMH, the GMH Operating Partnership or any student housing subsidiary such that any such failure would result in an event of default under any such agreement (in each case after giving effect to any applicable waivers); or
•: agree in writing to take any action inconsistent with any of the foregoing.

Covenants Related to Conduct of Business of ACC

relationships with customers, suppliers and others having business dealings with them and maintain the status of ACC as a REIT within the meaning of the Code.

During the period from February 11, 2008 to the earlier of the partnership merger effective time or the termination of the merger agreement in accordance with its terms, subject to certain exceptions or to the extent that GMH otherwise consents in writing which consent will not be unreasonably withheld or delayed, ACC and the ACC Operating Partnership will not and will cause the other ACC subsidiaries not to: (1) engage in any transaction (other than the transactions contemplated by the merger agreement) that would (a) require the approval of the ACC shareholders, (b) require ACC to include the information relating to such transaction in the pro forma financial statements that are required to be contained in this proxy statement/prospectus, or (c) require ACC to amend or restate such pro forma financial statements in any material manner; (2) engage in any material securities offering, or acquisition of the business, assets or capital stock of any entity by ACC or any of its subsidiaries, in any event that would reasonably be likely to cause a material delay in the consummation of the mergers or the transactions contemplated by the merger agreement; or (3) knowingly take any other action that would reasonably be likely to prevent or delay the consummation of the mergers or the transactions contemplated by the merger agreement.

Other Covenants

The parties to the merger agreement have agreed to various other covenants in the merger agreement. Some of these covenants are mutual, while others have been made either only by GMH or ACC and their subsidiaries that are party to the merger agreement.

Non-Solicitation

Upon execution of the merger agreement, GMH, the GMH Operating Partnership and GMH's subsidiaries agreed to cease immediately and cause to be terminated any and all existing activities, discussions, solicitations or negotiations previously conducted with any parties with respect to an Acquisition Proposal by or on behalf of GMH, the GMH Operating Partnership or any of their representatives. GMH is required to use its reasonable commercial efforts to cause (including by written request) each person with whom it has executed a confidentiality agreement within the 12 months prior to February 11, 2008 in connection with its consideration of any Acquisition Proposal to return or destroy all confidential or other non-public information heretofore furnished to such person by or on behalf of GMH, the GMH Operating Partnership or any of their representatives.

From February 11, 2008 until the earlier of the REIT merger effective time or the termination of the merger agreement, the GMH Parties will not, and will not authorize or permit any of their subsidiaries, or any of its or their officers, trustees, directors, partners, affiliates or employees or any investment banker, financial advisor, attorney, accountant or other representative retained by it or any of its subsidiaries, referred to collectively as the Representatives, directly or indirectly, to (1) solicit, initiate or knowingly encourage or knowingly facilitate (including by way of furnishing non-public information) any inquiries, proposals or offers or any other efforts or attempts that constitute or that reasonably may be expected to lead to, any Acquisition Proposal or (2) initiate or participate in any discussions or negotiations (other than to seek clarifications with respect to an Acquisition Proposal) regarding, or that reasonably may be expected to lead to, an Acquisition Proposal or (3) approve or recommend, or publicly propose to approve or recommend, an Acquisition Proposal or enter into any merger agreement, share purchase agreement, asset purchase agreement or share exchange agreement, option agreement or other similar binding agreement relating to an Acquisition Proposal or requiring GMH to terminate the merger agreement, referred to as an Acquisition Agreement, except as permitted by the merger agreement.

For purposes of the merger agreement, "Acquisition Proposal" means any proposal or offer for, whether in one transaction or a series of related transactions, any (1) merger, consolidation or similar transaction involving GMH, the GMH Operating Partnership or any of the student housing subsidiaries, (2) sale, lease or other disposition, directly or indirectly, by merger, consolidation, share exchange or otherwise, of any assets of GMH or its subsidiaries representing 20% or more of the fair market value of the assets of GMH and its subsidiaries (other than the military housing subsidiaries), taken as a whole, (3) issuance, sale or other disposition of (including by way of merger, consolidation, share exchange or any similar transaction) of securities (or options, rights or warrants to purchase, or securities convertible into, such securities) representing 20% or more of the votes associated with the outstanding securities of GMH, (4) tender offer or exchange offer in which any person or "group" (as such term is defined under the Exchange Act) will acquire beneficial ownership (as such term is defined in Rule 13d-3 under the Exchange Act), or the right to acquire beneficial ownership, of 20% or more of the outstanding GMH common shares, (5) recapitalization, restructuring, liquidation, dissolution or other similar type of transaction with respect to GMH or any of its subsidiaries or (6) transaction which is similar in form, substance or purpose to any of the foregoing transactions; provided, however, that the term "Acquisition Proposal" will not include the contemplated transactions or any proposal for a transaction involving solely the military housing subsidiaries or the assets thereof.

Notwithstanding these restrictions, at any time prior to the receipt of the GMH shareholder approval, if GMH receives a bona fide written Acquisition Proposal from a third party (which was not solicited, initiated, knowingly encouraged or knowingly facilitated in violation of the merger agreement after February 11, 2008), GMH (1) may furnish, or cause to be furnished, non-public information with respect to GMH and the subsidiaries of GMH to the person who made such Acquisition Proposal and to its financing sources and persons or entities working in concert with it, referred to collectively as a third party, and (2) may participate in discussions and negotiations regarding such Acquisition Proposal, if, in either case above, (a) prior to taking such action, GMH enters into a confidentiality agreement with the person who made such Acquisition Proposal with confidentiality provisions no less favorable to such third party than the GMH confidentiality agreement is to ACC, (b) GMH's board of trustees determines in good faith, after consultation with its outside legal counsel and independent financial advisors, that such Acquisition Proposal is, or is reasonably likely to lead to, a Superior Proposal and (c) concurrently with furnishing or causing to be furnished non-public information with respect to GMH and the subsidiaries of GMH to a third party, GMH furnishes or causes to be furnished such information to ACC to the extent not previously provided. The GMH Parties will not, and will cause each of the GMH's subsidiaries not to, enter into any confidentiality agreement with any person subsequent to the date hereof which prohibits the GMH Parties from providing such information to ACC.

The GMH Parties are required to provide prompt (within 24 hours following receipt thereof) oral and written notice to ACC of (1) the receipt of any Acquisition Proposal, or any material modification or amendment to any Acquisition Proposal, by any GMH Party, any GMH subsidiary or any of their representatives, (2) a summary of the material terms and conditions of such Acquisition Proposal, and (3) the identity of such person or entity making any such Acquisition Proposal. The GMH Parties must also keep ACC reasonably informed on a current basis, to the extent reasonably practicable, but in any event as promptly as practicable, of the status and material details (including any change to the material terms and conditions) of any such Acquisition Proposal. The GMH Parties will not, and will cause each of the GMH's subsidiaries not to, enter into any confidentiality agreement with any person subsequent to the date hereof which prohibits the GMH Parties from providing such information to ACC.

"Superior Proposal" means an Acquisition Proposal (on its most recently amended and modified terms, if amended and modified, and except that, for purposes of this definition, the references in the definition of "Acquisition Proposal" to "20%" will be replaced by "50%") made by a

third party that GMH's board of trustees determines (after taking into account any amendments to the merger agreement entered into or which ACC irrevocably covenants to enter into) in its good faith judgment after taking into account all material legal, financial, regulatory and other aspects of the proposal, including the financing terms thereof and the likelihood and timing of consummation (as compared to the mergers) is, if consummated, superior from a financial point of view to the GMH shareholders than the mergers.

GMH will not take any action to exempt any person (other than ACC or any of its affiliates and other than in connection with an Acquisition Agreement following a subsequent determination) from the restrictions on "control share acquisitions" contained in the Maryland Control Share Acquisition Act, as amended (or any similar provisions of the Maryland REIT Law) or otherwise cause such restrictions not to apply.

Debt Financing

The ACC Parties have represented that they have no reason to believe that any of the conditions relating to the funding of the full amount of the debt financing under the terms of the commitment letter from KeyBank will not be satisfied on or prior to the closing of the mergers.

If the financing commitment or the commitment letter expires, is terminated or otherwise becomes unavailable prior to the closing, for any reason including a failure of a financing source to provide financing to ACC on the terms set forth in the commitment letter, ACC must (1) immediately notify GMH of such expiration, termination or other unavailability and the reasons therefor and (2) use commercially reasonable efforts to obtain alternative financing as contemplated by the commitment letter from alternative sources in an amount sufficient to consummate the mergers and the transactions contemplated by the merger agreement and to pay any related costs and expenses. If applicable, ACC will provide GMH with a copy of a new financing commitment.

The receipt of the debt financing or any other replacement financing is not a condition to the obligations of the ACC Parties to consummate the mergers.

Home Office and Disposition Properties

In connection with the mergers, GMH anticipates selling its home office immediately prior to the closing of the mergers, and will have the right, but not the obligation, to sell certain disposition properties. A percentage of the amount received, if any, in connection with the sale of the home office and certain of the disposition properties is allowed to be paid under the merger agreement to GMH shareholders and unitholders as a special distribution preceding the closing of the mergers. Any amounts distributed as a special distribution will be in addition to the merger consideration.

include due diligence review periods and conditions precedent to the purchasers' obligations to proceed with the sale. Accordingly, there can be no assurance that any of these disposition properties will be sold and, if they are sold, that the proceeds from the sale will be sufficient in amount to enable GMH to make a special distribution prior to the closing of the mergers. GMH will update its shareholders and unitholders through the use of press releases as and when it becomes more certain as to whether any one or more of the disposition assets are likely to be sold prior to the closing of the mergers.

It is not a condition to the completion of the mergers that the home office or any of the disposition properties be sold prior to the REIT merger effective time.

Military Housing Sale

GMH and the GMH Operating Partnership are required to use commercially reasonable efforts to take or cause to be taken all actions and to do or cause to be done all things necessary, proper or advisable to consummate the military housing sale on substantially the terms and conditions described in the securities purchase agreement, including using commercially reasonable efforts to: (1) satisfy on a timely basis all terms, covenants and conditions set forth in the securities purchase agreement, (2) enforce its rights under the securities purchase agreement, and (3) consummate the military housing sale prior to the REIT merger effective time.

GMH will not amend or alter, or agree to amend or alter, or permit to be amended or altered, the securities purchase agreement in any manner that (1) materially and adversely affects the rights and obligations of the ACC Parties under the merger agreement, (2) subjects any of the ACC Parties to any post-closing liability relating to the military housing subsidiaries to a greater extent than the securities purchase agreement, or (3) would reasonably be likely to cause a delay of the closing of the mergers beyond July 31, 2008 without the prior written consent of ACC.

The consummation of the military housing sale is a condition to the obligations of the GMH Parties and ACC Parties to consummate the mergers.

Fidelity Agreement

GMH and the GMH Operating Partnership each agree to reasonably cooperate with ACC in order to consummate the transactions contemplated by the agreement between Fidelity and ACC immediately prior to the REIT merger effective time; provided that GMH receives a written letter from the ACC Parties prior to the consummation of such transactions, in form and substance reasonably satisfactory to GMH, confirming that all of the conditions to the obligations of the ACC Parties to consummate the mergers have been irrevocably satisfied or waived.

For the avoidance of doubt, the closing of the transactions contemplated by the agreement with Fidelity is not a condition to the obligations of the ACC Parties to consummate the mergers.

Conditions to the Mergers

The parties' obligations to complete the mergers are subject to the conditions specified in the merger agreement. Some of the conditions are mutual, meaning that if the condition is not satisfied, none of the parties would be obligated to close the mergers. In addition, the merger agreement includes additional conditions in favor of either the GMH Parties or the ACC Parties, meaning that if the condition is not satisfied, that party could waive it to the extent legally permissible and the other party would remain obligated to close the mergers.

The obligations of the parties to complete the mergers are subject to the following mutual conditions:

•: approval of the REIT merger by the required vote of GMH shareholders;

•: effectiveness of the registration statement on Form S-4 of which this proxy statement/prospectus is a part and the absence of a stop order or proceedings threatened or initiated by the SEC for that purpose;
•: authorization by the NYSE of the listing of the ACC common stock to be issued in the mergers, subject to official notice of issuance;
•: receipt of all the material approvals, authorizations and consents of any governmental authority required to consummate the mergers (all of which must be in full force and effect), and expiration or termination of all waiting periods relating to the approvals, authorizations and consents;
•: absence of any injunction, order, decree or ruling issued by a governmental authority in the United States which is then in effect and would make consummation of the mergers illegal or prohibits the consummation of the mergers (provided, that the party claiming such factor has used commercially reasonable efforts to prevent the entry of such injunction or order and to appeal as promptly as possible any injunction or other order that may be entered); and
•: consummation of the military housing sale in accordance with the securities purchase agreement; provided, however, if the securities purchase agreement has been terminated, GMH may sell the military housing subsidiaries to a substitute buyer reasonably satisfactory to ACC upon such terms and conditions substantially similar to those in the securities purchase agreement.

The obligations of the ACC Parties to complete the mergers are further conditioned on:

•: the truth and correctness of the GMH Parties' representations and warranties (subject to the GMH material adverse effect standard in the merger agreement);
•: the performance in all material respects of GMH's covenants and agreements under the merger agreement at or prior to the REIT merger effective time;
•: there having occurred no change that would, individually or in the aggregate, constitute a GMH material adverse effect since February 11, 2008;
•: receipt by ACC of a certificate signed on GMH's behalf by an officer of GMH as to the satisfaction of the three conditions described in the three preceding bullet points;
•: receipt by ACC of a written opinion of Reed Smith LLP, to the effect that GMH has been organized and operated in conformity with the requirements for qualification as a REIT under the Code for all taxable periods commencing with GMH's taxable year ended December 31, 2004 until the closing of the mergers;
•: receipt by GMH of consents from certain lenders in form and substance reasonably satisfactory to ACC; and
•: approval of the settlement agreement relating to the pending securities litigation by the United States District Court for the Eastern District of Pennsylvania, and satisfaction of all payments and other material obligations thereunder.

The obligations of the GMH Parties to complete the mergers are further conditioned on:

•: the truth and correctness of the ACC Parties' representations and warranties (subject to the ACC material adverse effect standard in the merger agreement);
•: performance in all material respects of ACC's covenants and agreements under the merger agreement at or prior to the REIT merger effective time;

•: there having occurred no change that would, individually or in the aggregate, constitute an ACC material adverse effect since February 11, 2008;
•: receipt by GMH of a certificate signed on ACC's behalf by an officer of ACC as to the satisfaction of the three conditions described in the three preceding bullet points; and
•: receipt by GMH of a written opinion of Locke Lord Bissell & Liddell LLP, to the effect that ACC has been organized and operated in conformity with the requirements for qualification as a REIT under the Code for all taxable periods commencing with ACC's taxable year ended December 31, 2004 through and including the closing date.

Termination

The GMH merger agreement may be terminated prior to the REIT merger effective time, whether before or after the required GMH shareholder approval for the REIT merger is obtained:

•: by mutual written consent of ACC and GMH;
•: by either GMH or ACC, if GMH shareholders fail to approve the REIT merger at a duly held meeting (including any adjournment or postponement of such meeting);
•: by either GMH or ACC, if the REIT merger effective time has not occurred by July 31, 2008 (provided that this right will not be available to a party whose failure to fulfill any obligation under the merger agreement materially contributed to the failure of the REIT merger effective time to occur on or before this date);
•: by either GMH or ACC, if any governmental authority issues a final and non-appealable injunction, order, decree or ruling or takes any other action which makes consummation of the mergers illegal or otherwise prohibits the consummation of the mergers (provided that the terminating party has used commercially reasonable efforts to oppose and have vacated the injunction, order, decree, ruling or action);
•: by ACC, if any of the GMH Parties breaches or fails to perform any of its representations, warranties, or covenants contained in the merger agreement in either case such that the related conditions to the obligations of ACC to close the mergers would be incapable of being satisfied by July 31, 2008;
•: by GMH, if any of the ACC Parties breaches or fails to perform any of its representation, warranties or covenants contained in the merger agreement in either case such that the related conditions to the obligations of GMH to close the mergers would be incapable of being satisfied by July 31, 2008;
•: by GMH, if any GMH Party enters into an Acquisition Agreement in accordance with, and subject to the terms and conditions of, the non-solicitation covenant of the merger agreement described above (provided that for the termination of the merger agreement pursuant to this provision to be effective, GMH will simultaneously pay the termination fee and expenses of ACC as described below);
•: by ACC, if prior to receipt of the approval of GMH shareholders, (1) GMH's board of trustees or any committee of GMH's board of trustees (a) withdraws, qualifies, or modifies or proposes publicly to withdraw, qualify or modify, in each case, in a manner adverse to ACC, its approval or recommendation of the mergers or (b) approves or recommends, or proposes publicly to approve or recommend, an Acquisition Proposal, (2) GMH enters into an Acquisition Agreement, (3) a tender offer or exchange offer relating to GMH's common shares is commenced by a third party and GMH's board of trustees does not recommend that GMH shareholders reject such tender or exchange

offer within 10 business days following commencement of such tender offer or exchange offer, (4) GMH breaches in any material respect its obligation to call or hold the special meeting, (5) GMH breaches in any material respect its obligations under the no solicitation covenant, (6) GMH fails to include in this proxy statement/prospectus the recommendation of approval of the REIT merger by GMH's board of trustees, or (7) GMH or GMH's board of trustees (or any committee thereof) authorizes or publicly proposes any of the foregoing;

•: by ACC, if none of the ACC Parties is in material breach of its obligations under the merger agreement, if the military housing sale is not closed prior to the REIT merger effective time; or
•: by GMH, if none of the GMH Parties is in material breach of its obligations under the merger agreement, if the military housing sale is not closed prior to the REIT merger effective time (provided that for the termination of the merger agreement pursuant to this provision to be effective, GMH will simultaneously pay the expenses of ACC as described below).

A terminating party is required to provide written notice of termination to the other parties to the merger agreement, specifying with particularity the basis for such termination. If more than one reason to terminate the merger agreement is available, a terminating party may rely on any or all available reasons for any such termination.

Termination Fees and Expenses

Upon termination of the merger agreement for any of the foregoing, and subject to the payment of any termination fees and expenses, the merger agreement will become void and of no further force or effect and the mergers will be abandoned without any further action on the part of any party to the merger agreement, subject to certain exceptions.

The GMH Parties have agreed that GMH will pay to ACC a termination fee of $16.0 million plus the reasonable out-of-pocket costs and expenses incurred by ACC and its subsidiaries in connection with the merger agreement up to an aggregate maximum amount of $7.5 million if the merger agreement is terminated:

•: by GMH, if any GMH Party enters into an Acquisition Agreement in accordance with, and subject to the terms and conditions, of the no solicitation covenant of the merger agreement;
•: by ACC, if prior to receipt of the approval of GMH shareholders, (1) GMH's board of trustees or any committee of GMH's board of trustees (a) withdraws, qualifies, or modifies or proposes publicly to withdraw, qualify or modify, in each case, in a manner adverse to ACC, its approval or recommendation of the mergers or (b) approves or recommends, or proposes publicly to approve or recommend, an Acquisition Proposal, (2) GMH enters into an Acquisition Agreement, (3) a tender offer or exchange offer relating to GMH's common shares is commenced by a third party and GMH's board of trustees does not recommend that GMH shareholders reject such tender or exchange offer within 10 business days following commencement of such tender offer or exchange offer, (4) GMH breaches in any material respect its obligation to call or hold the special meeting, (5) GMH breaches in any material respect its obligations under the non-solicitation covenant, (6) GMH fails to include in this proxy statement/prospectus, the recommendation of approval of the REIT merger by GMH's board of trustees, or (7) GMH or GMH's board of trustees (or any committee thereof) authorizes or publicly proposes any of the foregoing; or

•: by either GMH or ACC, if prior to the special meeting, any qualifying Acquisition Proposal is publicly proposed or publicly disclosed and not withdrawn at or prior to the time of GMH shareholders' meeting and, concurrently with or within 12 months after the date of termination, any GMH Party enters into a definitive agreement with respect to or consummates any qualifying Acquisition Proposal and the merger agreement is terminated (1) for failure to obtain GMH shareholder approval or (2) because the REIT merger effective time did not occur before July 31, 2008 (provided that ACC did not breach its obligations with regards to SEC filings under the merger agreement).

In addition, GMH will pay ACC the reasonable out-of-pocket costs and expenses incurred by ACC and its subsidiaries in connection with the merger agreement up to an aggregate maximum amount of $7.5 million if the merger agreement is terminated:

•: by either GMH or ACC, if GMH shareholders fail to approve the REIT merger at the special meeting (including any adjournment or postponement of such meeting);
•: by ACC, if none of the ACC Parties is in material breach of its obligations under the merger agreement, if any of the GMH Parties breaches or fails to perform any of its representations, warranties, or covenants contained in the merger agreement, in either case such that the related conditions to the obligations of the ACC Parties to close the mergers would be incapable of being satisfied by July 31, 2008;
•: by ACC, if none of the ACC Parties is in material breach of its obligations under the merger agreement, if the military housing sale is not closed prior to the REIT merger effective time; or
•: by GMH, if none of the GMH Parties is in material breach of its obligations under the merger agreement, if the military housing sale is not closed prior to the REIT merger effective time.

ACC will pay GMH the reasonable out-of-pocket costs and expenses incurred by GMH and its subsidiaries in connection with the merger agreement up to an aggregate maximum amount of $7.5 million if the merger agreement is terminated by GMH, if none of the GMH Parties is in material breach of its obligations under the merger agreement, if any of the ACC Parties breaches or fails to perform any of its representations, warranties or covenants contained in the merger agreement in either case such that the related conditions to the obligations of GMH to close the mergers would be incapable of being satisfied by July 31, 2008.

Remedies

The parties are entitled to specific performance with respect to the merger agreement in addition to any other remedy at law or equity (including injunctions).

Amendment of the Merger Agreement

The parties may amend the merger agreement in writing at any time prior to the REIT merger effective time, provided that after the GMH shareholder approval, no amendment to the merger agreement can be made that would require the approval of GMH shareholders without first obtaining such shareholder approval.

MATERIAL U.S. FEDERAL INCOME TAX CONSIDERATIONS

The following discussion summarizes certain material U.S. federal income tax consequences of the REIT merger, military sale distributions and special distribution to holders of GMH common shares and certain material U.S. federal income tax considerations generally applicable to holders of ACC common stock. The summary is based on the Code, existing and proposed Treasury regulations issued under the Code, and administrative and judicial interpretations thereof, each as in effect as of the date hereof, all of which are subject to change at any time, possibly with retroactive effect. We have not requested, and do not plan to request, any rulings from the Internal Revenue Service, or IRS, relating to the U.S. federal income tax consequences of the foregoing, and the statements in this proxy statement/prospectus are not binding on the IRS or any court. As a result, GMH and ACC cannot assure you that the IRS would not assert, or that a court would not sustain a position contrary to any of the tax consequences set forth below.

This summary assumes that GMH common shares and ACC common stock are held as capital assets within the meaning of Section 1221 of the Code and does not address all aspects of taxation that may be relevant to particular holders in light of their personal investment or tax circumstances or to persons that are subject to special tax rules. In addition, this summary does not address the tax treatment of special classes of holders of GMH common shares, including, for example:

•: banks and other financial institutions;
•: insurance companies;
•: regulated investment companies and real estate investment trusts;
•: tax-exempt entities or persons holding GMH common shares or ACC common stock in a tax-deferred or tax advantaged account (except to the limited extent discussed in "Material U.S. Federal Income Tax Considerations Applicable to Holders of ACC Common Stock—Taxation of Tax-Exempt Holders");
•: mutual funds;
•: subchapter S corporations;
•: dealers in securities or currencies;
•: traders in securities that elect to use a mark-to-market method of accounting for their securities holdings;
•: persons whose functional currency is not the U.S. dollar;
•: persons holding GMH common shares or ACC common stock as part of a hedging or conversion transaction or as part of a "straddle" or a constructive sale;
•: U.S. expatriates;
•: persons subject to the alternative minimum tax;
•: holders that are properly classified as a partnership or otherwise as a pass-through entity under the Code; and
•: non-U.S. holders, as defined below, that hold their shares in connection with the conduct of a trade or business in the U.S. or that are individuals that are present in the U.S. for 183 days or more during the taxable year.

For purposes of this discussion, the term "U.S. holder" means a beneficial owner of GMH common shares that is for U.S. federal income tax purposes:

•: a citizen or individual resident of the U.S.;

•: a corporation (or other entity treated as a corporation for U.S. federal income tax purposes) created or organized under the laws of U.S., any State thereof or the District of Columbia;
•: a trust if it (1) is subject to the primary supervision of a court within the U.S. and one or more "United States persons" (as defined in the Code) have the authority to control all substantial decisions of the trust, or (2) has a valid election in effect under applicable U.S. Treasury regulations to be treated as a "United States person"; or
•: an estate the income of which is subject to U.S. federal income tax regardless of its source.

A holder of GMH common shares (other than a partnership or other entity or arrangement treated as a partnership for U.S. federal income tax purposes) that is not a U.S. holder is referred to herein as a "non-U.S. holder."

This summary assumes the following expected tax treatment of the mergers: the REIT merger will be treated as a taxable sale by the shareholders of GMH of all of the GMH common shares to the ACC Operating Partnership in exchange for the merger consideration; the reincorporation merger is expected to be treated as an "F reorganization" within the meaning of Section 368 of the Code; and the partnership merger will be treated as a taxable sale of the interests of the GMH Operating Partnership by GMH unitholders, not including the general partner of the GMH Operating Partnership, to the extent of interests exchanged for cash or ACC common stock, and a tax-deferred contribution pursuant to Section 721 of the Code to the extent of interests exchanged for interests in the ACC Operating Partnership.

THIS SUMMARY IS FOR GENERAL INFORMATION ONLY, IS NOT TAX ADVICE AND IS NOT INTENDED TO CONSTITUTE A COMPLETE DESCRIPTION OF ALL TAX CONSEQUENCES RELATING TO THE REIT MERGER, THE MILITARY SALE DISTRIBUTIONS, THE SPECIAL DISTRIBUTION OR THE PURCHASE, OWNERSHIP AND DISPOSITION OF ACC SECURITIES. PLEASE CONSULT WITH YOUR TAX ADVISOR REGARDING THE PARTICULAR TAX CONSEQUENCES TO YOU (INCLUDING THE APPLICATION AND EFFECT OF ANY STATE, LOCAL OR NON-U.S. INCOME AND OTHER TAX LAWS) OF THE REIT MERGER, THE MILITARY SALE DISTRIBUTIONS, THE SPECIAL DISTRIBUTION AND THE PURCHASE, OWNERSHIP AND DISPOSITION OF ACC SECURITIES. YOU SHOULD ALSO CONSULT YOUR TAX ADVISOR REGARDING THE IMPACT OF POTENTIAL CHANGES IN THE APPLICABLE TAX LAWS.

Material U.S. Federal Income Tax Consequences to GMH Shareholders of the REIT Merger and Distributions

Goodwin Procter LLP, counsel to GMH, has reviewed this summary and has delivered an opinion to GMH to the effect that the discussion herein accurately sets forth the material U.S. federal income tax consequences to GMH shareholders of the REIT merger, the military sale distributions and the special distribution, in each case subject to the limitations and qualifications set forth in this summary and in Goodwin Procter LLP's opinion (See Exhibit 8.2 of the registration statement).

The following discussion assumes that GMH has been organized and operated in conformity with the requirements for qualification as a REIT under the Code for all taxable periods commencing with GMH's taxable year ended December 31, 2004 until the closing of the mergers and that GMH (and its successors) will continue to qualify as a REIT for the remainder of the taxable year that includes the REIT merger and distributions. While Reed Smith LLP at the closing of the mergers will provide ACC an opinion to the effect that GMH has been organized and operated in conformity with the requirements for qualification as a REIT under the Code for all taxable periods commencing with

GMH's taxable year ended December 31, 2004 until the closing of the mergers, opinions of counsel are not binding upon the Internal Revenue Service or any court and there can be no assurances that GMH has in fact met the requirements for taxation as a REIT. Furthermore, in providing its opinion, Reed Smith LLP is relying, as to certain factual matters, upon the statements and representations contained in the certificates provided to Reed Smith LLP by GMH.

Consequences of the REIT Merger and Distributions to U.S. Holders

REIT Merger—General. A U.S. holder's receipt of cash and ACC common stock in exchange for GMH common shares pursuant to the REIT merger will be a taxable transaction for U.S. federal income tax purposes. In general, a U.S. holder will recognize capital gain or loss equal to the difference, if any, between (1) the amount of cash received and the fair market value as of the effective date of the REIT merger of the ACC common stock received and (2) the holder's adjusted tax basis in the GMH common shares exchanged for the merger consideration pursuant to the REIT merger, after taking into account any reductions in basis attributable to the military sale distributions or the special distribution, as discussed below. Generally, such capital gain or loss will constitute long-term capital gain or loss if a U.S. holder has held the GMH common shares for more than one year as of the effective time of the REIT merger. The deductibility of capital losses may be subject to limitations. If a U.S. holder holds blocks of GMH common shares which were acquired at different times or prices, a U.S. holder must separately calculate their gain or loss and holding period for each block of shares.

REIT Merger—Special Rule for U.S. Holders Who Have Held Shares For Less than Six Months. A U.S. holder who has held GMH common shares for less than six months at the effective time of the REIT merger, taking into account certain holding period rules, and who recognizes a loss on the exchange of GMH common shares in the REIT merger, generally will be treated as recognizing a long-term capital loss to the extent of any capital gain dividends received from GMH, or such holder's share of any designated retained capital gains, with respect to those shares.

Military Sale Distributions and Special Distribution. GMH shareholders will receive cash distributions representing the military sale distributions and special distribution. ACC is required pursuant to the merger agreement to designate pre-closing dividends as capital gain dividends to the maximum extent permitted by law. To the extent not designated as capital gains dividends, the military sale distributions and special distribution will be taxable as ordinary income to the extent of GMH's earnings and profits for 2008 that are allocable to the distributions, which may include earnings attributable to periods after the mergers. Any distribution in excess of earnings and profits will be treated as a return of capital and will reduce the tax basis of a U.S. holder in its shares of GMH (but not below zero) and any distribution in excess of a U.S. holder's tax basis is taxable to the U.S. holder as capital gain. Any part of such distributions designated as a capital gains dividend by GMH will be taxable as long-term capital gain or "unrecaptured Section 1250 gain" to the extent it does not exceed GMH's actual net capital gain for the year. Long-term capital gains of non-corporate taxpayers are generally taxed at preferential rates. The highest marginal individual income tax rate is currently 35%. The maximum tax rate on long-term capital gains currently applicable to non-corporate taxpayers is 15%. However, to the extent that any capital gains represent depreciation on depreciable real property, such gain will be designated as "unrecaptured Section 1250 gain" and will be taxable at a maximum rate of 25% for non-corporate taxpayers.

Consequences of the REIT Merger and Distributions to Non-U.S. Holders

The rules governing U.S. federal income taxation of non-U.S. holders are complex. This section is only a summary of such rules. GMH urges non-U.S. holders to consult their own tax advisors to determine the impact of federal, state, and local income tax laws on the disposition and ownership of GMH common shares, including any reporting requirements.

REIT Merger. A non-U.S. holder's gain or loss from the REIT merger will be determined in the same manner as that of a U.S. holder. A non-U.S. holder of GMH common shares should not be subject to U.S. federal income taxation on any gain recognized from the REIT merger, unless (1) the gain is effectively connected with a U.S. trade or business of the non-U.S. holder, (2) the holder is an individual who has been present in the U.S. for 183 days or more during the taxable year of disposition and certain other conditions are satisfied, or (3) the holder's GMH common shares constitute a "U.S. real property interest," (a "USRPI") within the meaning of the Foreign Investment in Real Property Tax Act of 1980 ("FIRPTA").

If the non-U.S. holder's GMH common shares constitute a USRPI under FIRPTA, such holder will be subject to U.S. federal income tax on the gain recognized in the REIT merger on a net basis in the same manner as a U.S. holder. A non-U.S. holder's GMH common shares generally will constitute a USRPI if (1) GMH is not a "domestically controlled qualified investment entity" on the effective date of the REIT merger and (2) the selling non-U.S. holder owned (after application of certain constructive ownership rules) more than 5% of GMH's common shares at any time during the five years preceding the effective time of the REIT merger or such shares are not "regularly traded" (as defined by applicable Treasury regulations) on an established securities market in the U.S.

Assuming GMH qualifies as a REIT, GMH would be a "domestically controlled qualified investment entity" on the effective date of the REIT merger if non-U.S. holders held less than 50% of the value of GMH's outstanding equity interests at all times during the lesser of (1) the 5-year period ending with the effective date of the REIT merger and (2) the period during which GMH has been in existence. No assurances can be given that the actual ownership of GMH's outstanding equity interests has been or will be sufficient for GMH to qualify as a "domestically controlled qualified investment entity" at the effective time of the REIT merger or that GMH common shares will be "regularly traded" on an established securities market in the U.S.

Military Sale Distributions and Special Distribution. GMH shareholders will receive cash representing the military sale distributions and special distribution. ACC is required pursuant to the Merger Agreement to designate pre-closing dividends as capital gain dividends to the maximum extent permitted by law. To the extent not designated as capital gains dividends or attributable to gain from sales or exchanges by GMH of USPRIs, such distributions will be taxable as ordinary income to the extent of GMH's earnings and profit for 2008 that are allocable to the distributions, which may include earnings attributable to periods after the mergers. A withholding tax equal to 30% of the gross amount of the dividend will ordinarily apply to dividends of this kind to non-U.S. holders, unless an applicable income tax treaty reduces that tax.

Any distribution in excess of earnings and profits will be treated as a return of capital and will reduce the tax basis of a non-U.S. holder in its shares of GMH (but not below zero) and any distribution in excess of a non-U.S. holder's tax basis is taxable to the non-U.S. holder as capital gain in the same manner as gain recognized in the REIT merger, as described above.

For any year in which GMH qualifies as a REIT, distributions that are attributable to gain from sales or exchanges by GMH of USRPIs generally will be taxed to a non-U.S. holder under the provisions of FIRPTA. Under this statute, these dividends generally are taxed to a non-U.S. holder as if the gain were effectively connected with a U.S. trade or business of the non-U.S. holder. A non-U.S. holder whose gain is effectively connected with the conduct of trade or business in the U.S. will be subject to U.S. federal income tax on such gain on a net basis in the same manner as a U.S. holder. In addition, a non-U.S. holder that is a corporation may be subject to a branch profits tax equal to 30% (or lesser rate under an applicable income tax treaty) on such effectively connected gain. GMH is required by applicable Treasury regulations to withhold 35% for non-U.S. holders of any distribution that could be designated as a capital gains dividend. This amount is creditable against a non-U.S. holder's FIRPTA tax liability. However, a distribution that is attributable to gain from a sale of a

USRPI will not be treated as effectively connected income with respect to a non-U.S. holder that owns 5% or less of GMH's common shares at any time during the one year period ending on the date of distribution, provided GMH's common shares are "regularly traded" on an established securities market in the U.S. No assurances can be given that GMH common shares will be "regularly traded" (as defined by applicable Treasury regulations) on an established securities market in the U.S. To the extent a non-U.S. holder receives a distribution that would be subject to FIRPTA but for this exception, such non-U.S. holder shall be treated as receiving an ordinary dividend instead, which generally will be subject to 30% withholding tax as described above.

Income Tax Treaties

If a non-U.S. holder is eligible for benefits under an income tax treaty with the U.S., the non-U.S. holder may be able to reduce or eliminate certain of the U.S. federal income tax consequences discussed above. Non-U.S. holders should be aware that there are significant limitations on the applicability of many U.S. tax treaties to dividends from REITs, as well as limitations on the eligibility of non-U.S. holders to claim treaty benefits in general. Non-U.S. holders should consult their tax advisors regarding possible relief under an applicable income tax treaty.

Reportable Transactions

If a U.S. holder, or in certain cases a non-U.S. holder, participates in a "reportable transaction" generally they are required to attach a disclosure schedule to their U.S. federal income tax return disclosing such person's participation in the transaction. Subject to various exceptions, a reportable transaction can include, among other transactions, a transaction that results in a loss exceeding certain thresholds. Failure to comply with these and other reporting requirements could result in the imposition of significant penalties. U.S. holders and non-U.S. holders are urged to consult their tax advisors regarding the potential applicability of any disclosure requirements to them.

Information Reporting and Backup Withholding

Information reporting and backup withholding may apply to payments made in connection with the REIT merger. Backup withholding will not apply, however, to a holder who (a) in the case of a U.S. holder, furnishes a correct taxpayer identification number and certifies that it is not subject to backup withholding on IRS Form W-9 or successor form, (b) in the case of a non-U.S. holder, furnishes an applicable IRS Form W-8 or successor form, or (c) is otherwise exempt from backup withholding and complies with other applicable rules and certification requirements. Any amounts withheld under the backup withholding rules may be allowed as a refund or a credit against such holder's U.S. federal income tax liability provided the required information is furnished to the IRS on a timely basis.

State, Local and Foreign Taxes

GMH and/or its shareholders may be subject to state, local or foreign taxation in various jurisdictions, including those in which it or they transact business, own property or reside. The state, local or foreign tax treatment of GMH and its shareholders may not conform to the U.S. federal income tax treatment discussed above. Shareholders should consult their tax advisors regarding the application and effect of state, local and foreign income and other tax laws on the REIT merger, military sales distributions and special distribution.

Material U.S. Federal Income Tax Considerations Applicable to Holders of ACC Common Stock

Taxation of ACC

ACC has elected to be taxed as a REIT under Sections 856 through 860 of Code, commencing with the taxable year ended December 31, 2004.

Locke Lord Bissell & Liddell LLP has provided ACC (and at the closing of the mergers will provide GMH) an opinion that ACC has been organized and, for the taxable year ended December 31, 2004 through the taxable year ended December 31, 2007, ACC has operated in conformity with the requirements for qualification and taxation as a REIT under the Code, and ACC's current manner of organization and proposed method of operation will enable it to continue to satisfy the requirements for qualification and taxation as a REIT under the Code in the future. You should be aware, however, that opinions of counsel are not binding upon the IRS or any court. In providing its opinion, Locke Lord Bissell & Liddell LLP is relying, as to certain factual matters, upon the statements and representations contained in certificates provided to Locke Lord Bissell & Liddell LLP by ACC.

ACC's qualification as a REIT will depend upon its continuing satisfaction of the requirements of the Code relating to qualification for REIT status. Some of these requirements depend upon actual operating results, distribution levels, diversity of stock ownership, asset composition, source of income and record keeping. Accordingly, while ACC intends to continue to qualify to be taxed as a REIT, the actual results of its operations for any particular year might not satisfy these requirements. Furthermore, ACC has assumed that GMH has qualified and will continue to qualify as a REIT for U.S. federal income tax purposes and that ACC will be able to continue to qualify as a REIT following the mergers. However, if GMH has failed or fails to qualify as a REIT and the mergers are completed, ACC would succeed to or incur significant tax liabilities (including the significant tax liability that would result from the military housing sale, the contribution of assets to the Fidelity joint venture and the sale of the disposition properties and home office). Locke Lord Bissell & Liddell LLP will not monitor ACC's compliance with the requirements for REIT qualification on an ongoing basis. Accordingly, no assurance can be given that the actual results of its operation for any particular taxable year will satisfy such requirements. For a discussion of the tax consequences of the failure to qualify as a REIT. See "—Failure to Qualify as a REIT" below.

The sections of the Code relating to qualification and operation as a REIT, and the federal income taxation of a REIT and its stockholders, are highly technical and complex. The following discussion sets forth only the material aspects of those sections. This summary is qualified in its entirety by the applicable Code provisions and the related rules and regulations.

As a REIT, ACC generally is not subject to federal income tax on the taxable income that it distributes to its stockholders. The benefit of that tax treatment is that it avoids the "double taxation," or taxation at both the corporate and stockholder levels, that generally results from owning shares in a corporation. Distributions, however, will generally not be eligible for (i) the lower rate of tax applicable to dividends received by an individual from a "C corporation" (as defined below) or (ii) the corporate dividends received deduction. Further, ACC will be subject to federal tax in the following circumstances:

•: First, it will have to pay tax at regular corporate rates on any undistributed real estate investment trust taxable income, including undistributed net capital gains.
•: Second, under certain circumstances, it may have to pay the alternative minimum tax on items of tax preference.
•: Third, if it has (a) net income from the sale or other disposition of "foreclosure property," as defined in the Code, which is held primarily for sale to customers in the

ordinary course of business or (b) other non-qualifying income from foreclosure property, it will have to pay tax at the highest corporate rate on that income.

•: Fourth, if it has net income from "prohibited transactions," as defined in the Code, it will have to pay a 100% tax on that income. Prohibited transactions are, in general, certain sales or other dispositions of property, other than foreclosure property, held primarily for sale to customers in the ordinary course of business. ACC does not intend to engage in prohibited transactions. ACC cannot assure you, however, that it will only make sales that satisfy the requirements of the safe harbors or that the IRS will not successfully assert that one or more of such sales are prohibited transactions.
•: Fifth, if it should fail to satisfy the 75% gross income test or the 95% gross income test, as discussed below under "—Requirements for Qualification," but it has nonetheless maintained its qualification as a REIT because it has satisfied other requirements necessary to maintain REIT qualification, it will have to pay a 100% tax on an amount equal to (a) the gross income attributable to the greater of (i) 75% of its gross income over the amount of gross income that is qualifying income for purposes of the 75% test, and (ii) 95% of its gross income over the amount of gross income that is qualifying income for purposes of the 95% test, multiplied by (b) a fraction intended to reflect its profitability.
•: Sixth, beginning in the 2005 taxable year, if it fails, in more than a de minimis fashion, to satisfy one or more of the asset tests under the REIT provisions of the Code for any quarter of a taxable year, but nonetheless continues to qualify as a REIT because it qualifies under certain relief provisions, it will likely be required to pay a tax of the greater of $50,000 or a tax computed at the highest corporate rate on the amount of net income generated by the assets causing the failure from the date of failure until the assets are disposed of or we otherwise return to compliance with the asset test.
•: Seventh, if it fails to satisfy one or more of the requirements for REIT qualification under the REIT provisions of the Code (other than the income tests or the asset tests), it nevertheless may avoid termination of its REIT election in such year if the failure is due to reasonable cause and not due to willful neglect and it pays a penalty of $50,000 for each failure to satisfy the REIT qualification requirements.
•: Eighth, if it should fail to distribute during each calendar year at least the sum of (1) 85% of its real estate investment trust ordinary income for that year, (2) 95% of its real estate investment trust capital gain net income for that year and (3) any undistributed taxable income from prior periods, it would have to pay a 4% excise tax on the excess of that required dividend over the amounts actually distributed.
•: Ninth, if it acquires any appreciated asset from a C corporation in certain transactions in which it must adopt the basis of the asset or any other property in the hands of the C corporation as its basis of the asset in its hands, and it recognizes gain on the disposition of that asset during the 10-year period beginning on the date on which it acquired that asset, then it will have to pay tax on the built-in gain at the highest regular corporate rate. In general, a "C corporation" means a corporation that has to pay full corporate-level tax.
•: Tenth, if it receives non-arm's-length income from one of its taxable REIT subsidiaries (as defined under "—Requirements for Qualification"), it will be subject to a 100% tax on the amount of its non-arm's-length income.

Requirements for Qualification

To qualify as a REIT, ACC must elect to be treated as a REIT, and it must meet various (a) organizational requirements, (b) gross income tests, (c) asset tests, and (d) annual dividend requirements.

Organizational Requirements

The Code defines a REIT as a corporation, trust or association:

•: that is managed by one or more trustees or directors;
•: the beneficial ownership of which is evidenced by transferable shares, or by transferable certificates of beneficial interest;
•: that would otherwise be taxable as a domestic corporation, but for Sections 856 through 859 of the Code;
•: that is neither a financial institution nor an insurance company to which certain provisions of the Code apply;
•: the beneficial ownership of which is held by 100 or more persons;
•: during the last half of each taxable year, not more than 50% in value of the outstanding stock of which is owned, directly or constructively, by five or fewer individuals, as defined in the Code to also include certain entities; and
•: which meets certain other tests, described below, regarding the nature of its income and assets.

The Code provides that the conditions described in the first through fourth bullet points above must be met during the entire taxable year and that the condition described in the fifth bullet point above must be met during at least 335 days of a taxable year of 12 months, or during a proportionate part of a taxable year of less than 12 months.

ACC expects that it will satisfy the conditions described in the first through fifth and the seventh bullet points of the preceding paragraph and believes that it will also satisfy the condition described in the sixth bullet point of the preceding paragraph. In addition, its charter provides for restrictions regarding the ownership and transfer of its capital stock. These restrictions are intended to assist ACC in continuing to satisfy the share ownership requirements described in the fifth and sixth bullet points of the preceding paragraph. The ownership and transfer restrictions pertaining to the stock are described in this proxy statement/prospectus under the heading "Description of ACC Capital Stock—Restrictions on Transfer."

For purposes of determining share ownership under the sixth bullet point, an "individual" generally includes a supplemental unemployment compensation benefits plan, a private foundation, or a portion of a trust permanently set aside or used exclusively for charitable purposes. An "individual," however, generally does not include a trust that is a qualified employee pension or profit sharing trust under the federal income tax laws, and beneficiaries of such a trust will be treated as holding ACC's shares in proportion to their actuarial interests in the trust for purposes of the sixth bullet point.

A corporation that is a "qualified REIT subsidiary" is not treated as a corporation separate from its ACC REIT. All assets, liabilities, and items of income, deduction, and credit of a "qualified REIT subsidiary" are treated as assets, liabilities, and items of income, deduction, and credit of the REIT. A "qualified REIT subsidiary" is a corporation, all of the capital stock of which is owned by the REIT. Thus, in applying the requirements described herein, any "qualified REIT subsidiary" that ACC

owns will be ignored, and all assets, liabilities, and items of income, deduction, and credit of such subsidiary will be treated as ACC's assets, liabilities, and items of income, deduction, and credit.

An unincorporated domestic entity, such as a limited liability company, that has a single owner, generally is not treated as an entity separate from its owner for federal income tax purposes. An unincorporated domestic entity with two or more owners is generally treated as a partnership for federal income tax purposes. In the case of a REIT that is a partner in a partnership, the REIT is treated as owning its proportionate share of the assets of the partnership and as earning its allocable share of the gross income of the partnership for purposes of the applicable REIT qualification tests.

If, as in the case of ACC, a REIT is a partner in a partnership, Treasury Regulations provide that the REIT will be deemed to own its proportionate capital share of the assets of the partnership and will be deemed to be entitled to the income of the partnership attributable to that capital share. In addition, the character of the assets and gross income of the partnership will retain the same character in the hands of the REIT for purposes of Section 856 of the Code, including satisfying the gross income tests and the asset tests. Thus, ACC's proportionate share of the assets, liabilities and items of income of the ACC Operating Partnership, which is ACC's principal asset, will be treated as ACC's assets, liabilities and items of income for purposes of applying the requirements described in this section. In addition, actions taken by the ACC Operating Partnership or any other entity that is either a disregarded entity (including a qualified REIT subsidiary) or partnership in which ACC owns an interest, either directly or through one or more tiers of disregarded entities (including qualified REIT subsidiaries) or partnerships such as the ACC Operating Partnership, can affect ACC's ability to satisfy the REIT income and assets tests and the determination of whether it has net income from prohibited transactions. Accordingly, for purposes of this discussion, when ACC discusses its actions, income or assets it intends that to include the actions, income or assets of the ACC Operating Partnership or any entity that is either a disregarded entity (including a qualified REIT subsidiary) or partnership for U.S. federal income tax purposes in which ACC maintains an interest through multiple tiers of disregarded entities (including qualified REIT subsidiaries) or partnerships.

Taxable REIT Subsidiaries

A taxable REIT subsidiary, or a "TRS" is any corporation in which a REIT directly or indirectly owns stock, provided that the REIT and that corporation make a joint election to treat that corporation as a taxable REIT subsidiary. The election can be revoked at any time as long as the REIT and the TRS revoke such election jointly. In addition, if a TRS holds directly or indirectly, more than 35% of the securities of any other corporation (by vote or by value), then that other corporation is also treated as a TRS. A corporation can be a TRS with respect to more than one REIT. ACC has made a TRS election for ACC Services, Inc., its taxable REIT subsidiary.

A TRS is subject to federal income tax at regular corporate rates (maximum rate of 35%), and may also be subject to state and local taxation. Any dividends paid or deemed paid by any one of ACC's taxable REIT subsidiaries will also be subject to tax, either (i) to itself if it does not pay the dividends received to ACC stockholders as dividends, or (ii) to its stockholders if it does pay out the dividends received to its stockholders. Further, the rules impose a 100% excise tax on transactions between a TRS and a REIT or the REIT's tenants that are not conducted on an arm's-length basis. ACC may hold more than 10% of the stock of a TRS without jeopardizing its qualification as a REIT notwithstanding the rule described below under "—Asset Tests" that generally precludes ownership of more than 10% (by vote or value) of any issuer's securities. However, as noted below, in order for ACC to qualify as a REIT, the securities of all of the taxable REIT subsidiaries in which ACC has invested either directly or indirectly may not represent more than 20% of the total value of its assets. ACC expects that the aggregate value of all of its interests in taxable REIT subsidiaries will represent less than 20% of the total value of its assets, and will, to the extent necessary, limit the activities of the Services Company or take other actions necessary to satisfy the 20% value limit. ACC cannot, however,

assure that it will always satisfy the 20% value limit or that the IRS will agree with the value we assign to the Services Company and any other TRS in which we own an interest.

A TRS is not permitted to directly or indirectly operate or manage a "lodging facility." A "lodging facility" is defined as a "hotel, motel or other establishment more than one-half of the dwelling units in which are used on a transient basis." ACC believes that the Services Company will not be considered to operate or manage a lodging facility. Although the Services Company is expected to lease certain of ACC's student housing properties on a short term basis during the summer months and occasionally during other times of the year, ACC believes that such limited short term leasing will not cause the Services Company to be considered to directly or indirectly operate or manage a lodging facility. ACC's belief in this regard is based in part on Treasury Regulations interpreting similar language applicable to other provisions of the Code. Treasury Regulations or other guidance specifically adopted for purposes of the TRS provisions might take a different approach, and, even absent such guidance, the IRS might take a contrary view. In such an event, ACC might be forced to change its method of operating the Services Company, which could adversely affect ACC, or could cause the Services Company to fail to qualify as a TRS, in which event ACC would likely fail to qualify as a REIT.

ACC may engage in activities indirectly though a TRS as necessary or convenient to avoid receiving the benefit of income or services that would jeopardize its REIT status if we engaged in the activities directly. In particular, ACC would likely engage in activities through a TRS for providing services that are non-customary and services to unrelated parties (such as its third party development and management services) that might produce income that does not qualify under the gross income tests described below. ACC might also hold certain properties in the Services Company, such as its interest in certain of the leasehold properties if it determines that the ownership structure of such properties may produce income that would not qualify for purposes of the REIT income tests described below.

Gross Income Tests

ACC must satisfy two gross income tests annually to maintain its qualification as a REIT.

First, at least 75% of its gross income for each taxable year must consist of defined types of income that it derives, directly or indirectly, from investments relating to real property or mortgages on real property or qualified temporary investment income. Qualifying income for purposes of that 75% gross income test generally includes:

•: rents from real property;
•: interest on debt secured by mortgages on real property, or on interests in real property;
•: dividends or other distributions on, and gain from the sale of, shares in other REITs;
•: gain from the sale of real estate assets; and
•: income derived from the temporary investment of new capital that is attributable to the issuance of shares of beneficial interest or a public offering of debt with a maturity date of at least five years that it receives during the one year period beginning on the date on which it received such new capital.

Second, in general, at least 95% of ACC's gross income for each taxable year must consist of income that is qualifying income for purposes of the 75% gross income test, other types of interest and dividends, gain from the sale or disposition of stock or securities or any combination of these.

Gross income from ACC's sale of property that it holds primarily for sale to customers in the ordinary course of business is excluded from both the numerator and the denominator in both income tests. The following paragraphs discuss the specific application of the gross income tests to ACC.

Rents from Real Property. Rent that ACC receives from its real property will qualify as "rents from real property," which is qualifying income for purposes of the 75% and 95% gross income tests, only if the following conditions are met:

•: First, the rent must not be based in whole or in part on the income or profits of any person. Participating rent, however, will qualify as "rents from real property" if it is based on percentages of receipts or sales and the percentages: (a) are fixed at the time the leases are entered into, (b) are not renegotiated during the term of the leases in a manner that has the effect of basing rent on income or profits, and (c) conform with normal business practice.

More generally, the rent will not qualify as "rents from real property" if, considering the relevant lease and all of the surrounding circumstances, the arrangement does not conform with normal business practice, but is in reality used as a means of basing the rent on income or profits. ACC intends to set and accept rents which are fixed dollar amounts, and not to any extent by reference to any person's income or profits, in compliance with the rules above.
•: Second, ACC must not own, actually or constructively, 10% or more of the stock or the assets or net profits of any lessee, referred to as a related party tenant, other than a TRS. The constructive ownership rules generally provide that, if 10% or more in value of ACC's shares is owned, directly or indirectly, by or for any person, it is considered as owning the stock owned, directly or indirectly, by or for such person.
ACC does not own any stock or any assets or net profits of any lessee directly, except that it may lease office or other space to its TRS or another taxable REIT subsidiary. ACC believes that each of the leases will conform with normal business practice, contain arm's-length terms and that the rent payable under those leases will be treated as rents from real property for purposes of the 75% and 95% gross income tests. However, there can be no assurance that the IRS will not successfully assert a contrary position or that a change in circumstances will not cause a portion of the rent payable under the leases to fail to qualify as "rents from real property." If such failures were in sufficient amounts, ACC might not be able to satisfy either of the 75% or 95% gross income tests and could lose its REIT status. In addition, if the IRS successfully reapportions or reallocates items of income, deduction, and credit among and between ACC and its TRS under the leases or any intercompany transaction because it determines that doing so is necessary to prevent the evasion of taxes or to clearly reflect income, ACC could be subject to a 100% excise tax on those amounts. As described above, ACC may own one or more taxable REIT subsidiaries. Under an exception to the related-party tenant rule described in the preceding paragraph, rent that ACC receives from a taxable REIT subsidiary will qualify as "rents from real property" as long as (1) at least 90% of the leased space in the property is leased to persons other than taxable REIT subsidiaries and related party tenants, and (2) the amount paid by the TRS to rent space at the property is substantially comparable to rents paid by other tenants of the property for comparable space. If ACC receives rent from a TRS, it will seek to comply with this exception. Whether rents paid by the TRS are substantially comparable to rents paid by other tenants is determined at the time the lease with the TRS is entered into, extended, and modified, if such modification increases the rents due under such lease. Notwithstanding the foregoing, however, if a

lease with a controlled TRS is modified and such modification results in an increase in the rents payable by such TRS, any such increase will not qualify as "rents from real property." For purposes of this rule, a "controlled TRS" is a TRS in which ACC owns stock possessing more than 50% of the voting power or more than 50% of the total value of the outstanding stock of such TRS.

•: Third, the rent attributable to the personal property leased in connection with a lease of real property must not be greater than 15% of the total rent received under the lease.

The rent attributable to personal property under a lease is the amount that bears the same ratio to total rent under the lease for the taxable year as the average of the fair market values of the leased personal property at the beginning and at the end of the taxable year bears to the average of the aggregate fair market values of both the real and personal property covered by the lease at the beginning and at the end of such taxable year (the "personal property ratio"). With respect to each of ACC's leases, it believes that the personal property ratio generally is less than 15%. Where that is not, or may in the future not be, the case, ACC believes that any income attributable to personal property will not jeopardize its ability to qualify as a REIT.
•: Fourth, ACC cannot furnish or render noncustomary services to the tenants of its properties, or manage or operate its properties, other than through an independent contractor who is adequately compensated and from whom ACC does not derive or receive any income. However, it need not provide services through an "independent contractor," but instead may provide services directly to its tenants, if the services are "usually or customarily rendered" in connection with the rental of space for occupancy only and are not considered to be provided for the tenants' convenience. In addition, ACC may provide a minimal amount of "noncustomary" services to the tenants of a property, other than through an independent contractor, as long as its income from the services does not exceed 1% of its income from the related property. Finally, ACC may own up to 100% of the stock of one or more taxable REIT subsidiaries, which may provide noncustomary services to its tenants without tainting its rents from the related properties.

ACC does not intend to perform any services other than customary ones for its lessees, other than services provided through independent contractors or taxable REIT subsidiaries. If a portion of the rent it receives from a property does not qualify as "rents from real property" because the rent attributable to personal property exceeds 15% of the total rent for a taxable year, the portion of the rent attributable to personal property will not be qualifying income for purposes of either the 75% or 95% gross income test. If rent attributable to personal property, plus any other income that is nonqualifying income for purposes of the 95% gross income test, during a taxable year exceeds 5% of its gross income during the year, ACC could lose its REIT status. By contrast, in the following circumstances, none of the rent from a lease of property would qualify as "rents from real property": (1) the rent is considered based on the income or profits of the lessee; (2) the lessee is a related party tenant or fails to qualify for the exception to the related-party tenant rule for qualifying taxable REIT subsidiaries; or (3) ACC furnishes noncustomary services to the tenants of the property, or manages or operates the property, other than through a qualifying independent contractor or a TRS and its income from the services exceeds 1% of its income from the related property.

Tenants may be required to pay, besides base rent, reimbursements for certain amounts ACC is obligated to pay to third parties (such as utility and telephone companies), penalties for nonpayment or late payment of rent, lease application or administrative fees. These and other similar payments should qualify as "rents from real property."

100

Interest. The term "interest" generally does not include any amount received or accrued, directly or indirectly, if the determination of the amount depends in whole or in part on the income or profits of any person. However, an amount received or accrued generally will not be excluded from the term "interest" solely because it is based on a fixed percentage or percentages of receipts or sales. Furthermore, in the case of a shared appreciation mortgage, any additional interest received on a sale of the secured property will be treated as gain from the sale of the secured property.

Prohibited Transactions. A REIT will incur a 100% tax on the net income derived from any sale or other disposition of property, other than foreclosure property, that the REIT holds primarily for sale to customers in the ordinary course of a trade or business. There is a safe harbor from such treatment, but such safe harbor only applies to properties that the REIT has held for at least four years, among other requirements. Prior to the REIT merger, GMH will engage in certain sales of property and transactions expected to be treated as sales of property for federal income tax purposes, including the military housing sale, the contribution of properties to the joint venture with Fidelity, and the sale of the disposition properties and home office. Furthermore, ACC may sell some of its properties. To the extent possible, GMH and ACC will attempt to comply with the terms of the safe harbor provisions. However, not all of the properties are expected to qualify for the safe harbor. In the absence of the safe harbor, whether a REIT holds an asset "primarily for sale to customers in the ordinary course of a trade or business" depends on the facts and circumstances in effect from time to time, including those related to a particular asset. Considering all facts and circumstances, ACC believes that none of these properties is held primarily for sale to customers and that a sale of any of these properties will not be in the ordinary course of business. However, the IRS may successfully take a contrary position and characterize some or all of these sales and deemed sales of property as prohibited transactions.

Foreclosure Property. ACC will be subject to tax at the maximum corporate rate on certain income from foreclosure property. ACC does not own any foreclosure properties and does not expect to own any foreclosure properties in the future. This would only change in the future if it were to make loans to third parties secured by real property.

Hedging Transactions. From time to time, ACC may enter into hedging transactions with respect to one or more of its assets or liabilities. Its hedging activities may include entering into interest rate swaps, caps, and floors, options to purchase such items, and futures and forward contracts. Income from certain hedging transactions, clearly identified as such, is not included in ACC's gross income for purposes of the 95% gross income test. Since the financial markets continually introduce new and innovative instruments related to risk-sharing or trading, it is not entirely clear which such instruments will generate income and which will be considered qualifying income for purposes of the gross income tests. ACC intends to structure any hedging or similar transactions so as not to jeopardize its status as a REIT.

Failure to Satisfy Gross Income Tests

If ACC fails to satisfy one or both of the gross income tests for any taxable year, it nevertheless may qualify as a REIT for that year if it qualifies for relief under certain provisions of the federal income tax laws. Those relief provisions generally will be available if:

•: its failure to meet the income tests was due to reasonable cause and not due to willful neglect; and
•: it files a description of each item of its gross income in accordance with applicable Treasury Regulations.

ACC cannot with certainty predict whether any failure to meet these tests will qualify for the relief provisions. As discussed above in "—Taxation of ACC," even if the relief provisions apply, ACC

101

would incur a 100% tax on the gross income attributable to the greater of the amounts by which ACC fails the 75% and 95% gross income tests, multiplied by a fraction intended to reflect its profitability.

Asset Tests

To maintain its qualification as a REIT, ACC also must satisfy the following asset tests at the end of each quarter of each taxable year:

•: First, at least 75% of the value of its total assets must consist of: (a) cash or cash items, including certain receivables, (b) government securities, (c) interests in real property, including leaseholds and options to acquire real property and leaseholds, (d) interests in mortgages on real property, (e) stock in other REITs, and (f) investments in stock or debt instruments during the one year period following its receipt of new capital that it raises through equity offerings or offerings of debt with at least a five-year term;
•: Second, of its investments not included in the 75% asset class, the value of its interest in any one issuer's securities may not exceed 5% of the value of its total assets;
•: Third, it may not own more than 10% of the voting power or value of any one issuer's outstanding securities;
•: Fourth, no more than 20% of the value of its total assets may consist of the securities of one or more taxable REIT subsidiaries; and
•: Fifth, no more than 25% of the value of its total assets may consist of the securities of taxable REIT subsidiaries and other non-TRS taxable subsidiaries and other assets that are not qualifying assets for purposes of the 75% asset test.

For purposes of the second and third asset tests, the term "securities" does not include stock in another REIT, equity or debt securities of a qualified REIT subsidiary or TRS, mortgage loans that constitute real estate assets, or equity interests in a partnership. For purposes of the 10% value test, the term "securities" generally does not include debt securities issued by a partnership to the extent of ACC's interest as a partner of the partnership or if at least 75% of the partnership's gross income (excluding income from prohibited transactions) is qualifying income for purposes of the 75% gross income test. In addition, "straight debt" and certain other instruments are not treated as "securities" for purposes of the 10% value test.

Failure to Satisfy the Asset Tests

ACC will monitor the status of its assets for purposes of the various asset tests and will manage its portfolio in order to comply at all times with such tests. If it fails to satisfy the asset tests at the end of a calendar quarter, it will not lose its REIT status if:

•: it satisfied the asset tests at the end of the preceding calendar quarter; and
•: the discrepancy between the value of its assets and the asset test requirements arose from changes in the market values of its assets and was not wholly or partly caused by the acquisition of one or more non-qualifying assets.

If it did not satisfy the condition described in the second item, above, it still could avoid disqualification by eliminating any discrepancy within 30 days after the close of the calendar quarter in which it arose.

If ACC fails to satisfy one or more of the asset tests for any quarter of a taxable year, it nevertheless may qualify as a REIT for such year if it qualifies for relief under certain provisions of the Code. These relief provisions generally will be available for failures of the 5% asset test and the 10%

102

asset tests if (i) the failure is due to the ownership of assets that do not exceed the lesser of 1% of its total assets or $10.0 million, and the failure is corrected within six months following the quarter in which it was discovered, or (ii) the failure is due to ownership of assets that exceed the amount in (i) above, the failure is due to reasonable cause and not due to willful neglect, ACC files a schedule with a description of each asset causing the failure in accordance with Treasury Regulations, the failure is corrected within six months following the quarter in which it was discovered, and it pays a tax consisting of the greater of $50,000 or a tax computed at the highest corporate rate on the amount of net income generated by the assets causing the failure from the date of failure until the assets are disposed of or it otherwise returns to compliance with the asset test. ACC may not qualify for the relief provisions in all circumstances.

Distribution Requirements

Each taxable year, ACC must distribute dividends, other than capital gain dividends and deemed distributions of retained capital gains, to its stockholders in an aggregate amount not less than: the sum of (a) 90% of its "REIT taxable income," computed without regard to the dividends-paid deduction or its net capital gain or loss, and (b) 90% of its after-tax net income, if any, from foreclosure property, minus the sum of certain items of non-cash income.

ACC must pay such dividends in the taxable year to which they relate, or in the following taxable year if it declares the dividend before it timely files its federal income tax return for the year and pays the dividend on or before the first regular dividend payment date after such declaration.

To the extent that ACC does not distribute all of its net capital gains or distributes at least 90%, but less than 100%, of its real estate investment trust taxable income, as adjusted, it will have to pay tax on those amounts at regular ordinary and capital gains corporate tax rates. Furthermore, if it fails to distribute during each calendar year at least the sum of (a) 85% of its ordinary income for that year, (b) 95% of its capital gain net income for that year, and (c) any undistributed taxable income from prior periods, it would have to pay a 4% nondeductible excise tax on the excess of the required dividend over the amounts actually distributed.

ACC may elect to retain and pay income tax on the net long-term capital gains it receives in a taxable year. See "—Taxation of Taxable U.S. Holders." If ACC so elects, it will be treated as having distributed any such retained amount for purposes of the 4% excise tax described above. ACC intends to make timely dividends sufficient to satisfy the annual dividend requirements and to avoid corporate income tax and the 4% excise tax.

It is possible that, from time to time, ACC may experience timing differences between the actual receipt of income and actual payment of deductible expenses and the inclusion of that income and deduction of such expenses in arriving at its REIT taxable income. For example, ACC may not deduct recognized capital losses from its "REIT taxable income." Further, it is possible that, from time to time, it may be allocated a share of net capital gains attributable to the sale of depreciated property that exceeds ACC's allocable share of cash attributable to that sale. As a result of the foregoing, ACC may have less cash than is necessary to distribute all of its taxable income and thereby avoid corporate income tax and the excise tax imposed on certain undistributed income. In such a situation, ACC may need to borrow funds or issue additional common or preferred shares or pay dividends in the form of taxable stock dividends.

Under certain circumstances, ACC may be able to correct a failure to meet the distribution requirements for a year by paying "deficiency dividends" to ACC stockholders in a later year. It may include such deficiency dividends in its deduction for dividends paid for the earlier year. Although it may be able to avoid income tax on amounts distributed as deficiency dividends, it will be required to pay interest based upon the amount of any deduction it takes for deficiency dividends.

103

Recordkeeping Requirements

ACC must maintain certain records in order to qualify as a REIT. In addition, to avoid paying a penalty, it must request on an annual basis information from ACC stockholders designed to disclose the actual ownership of the outstanding common stock. ACC has complied and intends to continue to comply with these requirements.

Accounting Period

In order to elect to be taxed as a REIT, ACC must use a calendar year accounting period. ACC uses the calendar year as its accounting period for federal income tax purposes for each and every year it intends to operate as a REIT.

Failure to Qualify as a REIT

If ACC failed to qualify as a REIT in any taxable year and no relief provision applied, it would have the following consequences. ACC would be subject to federal income tax and any applicable alternative minimum tax at rates applicable to regular C corporations on ACC's taxable income, determined without reduction for amounts distributed to stockholders. ACC would not be required to make any distributions to stockholders, and any dividends to stockholders would be taxable as ordinary income to the extent of its current and accumulated earnings and profits (which may be subject to tax at preferential rates to individual stockholders). Corporate stockholders could be eligible for a dividends-received deduction if certain conditions are satisfied. Unless ACC qualified for relief under specific statutory provisions, it would not be permitted to elect taxation as a REIT for the four taxable years following the year during which it ceased to qualify as a REIT. ACC might not be entitled to the statutory relief described in this paragraph in all circumstances.

Relief From Certain Failures of the REIT Qualification Provisions

If ACC fails to satisfy one or more of the requirements for REIT qualification (other than the income tests or the asset tests), it nevertheless may avoid termination of its REIT election in such year if the failure is due to reasonable cause and not due to willful neglect and it pays a penalty of $50,000 for each failure to satisfy the REIT qualification requirements. ACC may not qualify for this relief provision in all circumstances.

Taxation of Taxable U.S. Holders

For purposes of this discussion, the term "U.S. holder" means a beneficial owner of securities that is for U.S. federal income tax purposes:

•: a citizen or individual resident of the U.S.;
•: a corporation (or other entity treated as a corporation for U.S. federal income tax purposes) created or organized under the laws of U.S., any State thereof or the District of Columbia;
•: a trust if it (1) is subject to the primary supervision of a court within the U.S. and one or more U.S. persons have the authority to control all substantial decisions of the trust, or (2) has a valid election in effect under applicable U.S. Treasury regulations to be treated as a U.S. person; or
•: an estate the income of which is subject to U.S. federal income tax regardless of its source.

As long as ACC qualifies as a REIT, distributions made by it out of its current or accumulated earnings and profits, and not designated as capital gain dividends, will constitute dividends taxable to its

104

taxable U.S. holders as ordinary income. Individuals receiving "qualified dividends" from domestic and certain qualifying foreign subchapter C corporations may be entitled to lower rates on dividends (at rates applicable to long-term capital gains, currently at a maximum rate of 15%) provided certain holding period requirements are met. However, individuals receiving dividend distributions from ACC, a REIT, will generally not be eligible for the recent lower rates on dividends except with respect to the portion of any distribution which (a) represents dividends being passed through to ACC from a corporation in which it owns shares (but only if such dividends would be eligible for the recent lower rates on dividends if paid by the corporation to its individual stockholders), including dividends from its TRS, (b) is equal to ACC's REIT taxable income (taking into account the dividends paid deduction available to it) less any taxes paid by ACC on these items during its previous taxable year, or (c) are attributable to built-in gains realized and recognized by ACC from the disposition of properties acquired by it in certain non-recognition transactions, less any taxes paid by ACC on these items during its previous taxable year. The lower rates will apply only to the extent ACC designates a distribution as qualified dividend income in a written notice to you. Individual taxable U.S. holders should consult their own tax advisors to determine the impact of these provisions. Dividends of this kind will not be eligible for the dividends-received deduction in the case of taxable U.S. holders that are corporations. Dividends made by ACC that it properly designates as capital gain dividends will be taxable to taxable U.S. holders as gain from the sale of a capital asset held for more than one year, to the extent that they do not exceed ACC's actual net capital gain for the taxable year, without regard to the period for which a taxable U.S. holder has held its common stock. Thus, with certain limitations, capital gain dividends received by an individual taxable U.S. holder may be eligible for preferential rates of taxation. Taxable U.S. holders that are corporations may, however, be required to treat up to 20% of certain capital gain dividends as ordinary income.

The 15% reduced maximum tax rate on "qualified dividends" and certain long-term capital gains, as described above, was provided in the Jobs and Growth Tax Relief Reconciliation Act of 2003 and generally is effective for taxable years ending on or after May 6, 2003 through December 31, 2008. On May 17, 2006, President Bush signed the Tax Relief Extension Reconciliation Act of 2005, which extended this reduction until December 31, 2010. Without future legislative changes, the maximum long-term capital gains and dividend rate discussed above will increase in 2011. This recent legislation could cause stock in non-REIT corporations to be a more attractive investment to individual investors than stock in REITs and could have an adverse effect on the market price of ACC's equity securities.

To the extent that ACC pays dividends, not designated as capital gain dividends, in excess of its current and accumulated earnings and profits, these dividends will be treated first as a tax-free return of capital to each taxable U.S. holder. Thus, these dividends will reduce the adjusted basis which the taxable U.S. holder has in ACC stock for tax purposes by the amount of the dividend, but not below zero. Dividends in excess of a taxable U.S. holder's adjusted basis in its common stock will be taxable as capital gains, provided that the stock has been held as a capital asset.

Dividends authorized by ACC in October, November, or December of any year and payable to a stockholder of record on a specified date in any of these months will be treated as both paid by it and received by the stockholder on December 31 of that year, provided that ACC actually pays the dividend in January of the following calendar year. Stockholders may not include in their own income tax returns any of ACC's net operating losses or capital losses.

ACC may elect to retain, rather than distribute, all or a portion of its net long-term capital gains and pay the tax on such gains. If ACC makes such an election, it will designate amounts as undistributed capital gains in respect of your shares or beneficial interests by written notice to you which ACC will mail out to you with its annual report or at any time within 60 days after December 31 of any year. When it makes such an election, taxable U.S. holders holding common stock at the close of ACC's taxable year will be required to include, in computing their long-term capital gains for the taxable year in which the last day of ACC's taxable year falls, the amount that it designates in a written

105

notice mailed to its stockholders. It may not designate amounts in excess of its undistributed net capital gain for the taxable year. Each taxable U.S. holder required to include the designated amount in determining the holder's long-term capital gains will be deemed to have paid, in the taxable year of the inclusion, the tax paid by ACC in respect of the undistributed net capital gains. Taxable U.S. holders to whom these rules apply will be allowed a credit or a refund, as the case may be, for the tax they are deemed to have paid. Taxable U.S. holders will increase their basis in their stock by the difference between the amount of the includible gains and the tax deemed paid by the stockholder in respect of these gains.

Dividends made by ACC and gain arising from a taxable U.S. holder's sale or exchange of ACC's stock will not be treated as passive activity income. As a result, taxable U.S. holders generally will not be able to apply any passive losses against that income or gain.

When a taxable U.S. holder sells or otherwise disposes of ACC's securities, the holder will recognize gain or loss for federal income tax purposes in an amount equal to the difference between (a) the amount of cash and the fair market value of any property received on the sale or other disposition, and (b) the holder's adjusted basis in the security for tax purposes. This gain or loss will be capital gain or loss if the U.S. holder has held the security as a capital asset. The gain or loss will be long-term gain or loss if the U.S. holder has held the security for more than one year. Long-term capital gains of an individual taxable U.S. holder is generally taxed at preferential rates. The highest marginal individual income tax rate is currently 35%. The maximum tax rate on long-term capital gains applicable to individuals is 15% for sales and exchanges of assets held for more than one year and occurring after May 6, 2003 through December 31, 2010. The maximum tax rate on long-term capital gains from the sale or exchange of "section 1250 property" (i.e., generally, depreciable real property) is 25% to the extent the gain would have been treated as ordinary income if the property were "section 1245 property" (i.e., generally, depreciable personal property). ACC generally may designate whether a distribution it designates as capital gain dividends (and any retained capital gain that it is deemed to distribute) is taxable to non-corporate holders at a 15% or 25% rate. The characterization of income as capital gain or ordinary income may affect the deductibility of capital losses. A non-corporate taxpayer may deduct capital losses not offset by capital gains against its ordinary income only up to a maximum of $3,000 annually. A non-corporate taxpayer may carry unused capital losses forward indefinitely. A corporate taxpayer must pay tax on its net capital gains at corporate ordinary income rates. A corporate taxpayer may deduct capital losses only to the extent of capital gains, with unused losses carried back three years and forward five years. In general, any loss recognized by a taxable U.S. holder when the holder sells or otherwise disposes of ACC's securities that the holder has held for six months or less, after applying certain holding period rules, will be treated as a long-term capital loss, to the extent of dividends received by the holder from ACC which were required to be treated as long-term capital gains.

Information Reporting Requirements and Backup Withholding

ACC will report to holders of its debt securities and stock and to the Internal Revenue Service the amount of interest or dividends it pays during each calendar year and the amount of tax it withholds, if any. A holder may be subject to backup withholding at a rate of 28% with respect to interest or dividends unless the holder:

•: is a corporation or comes within certain other exempt categories and, when required, demonstrates this fact; or
•: provides a taxpayer identification number, certifies as to no loss of exemption from backup withholding, and otherwise complies with the applicable requirements of the backup withholding rules.

106

A holder who does not provide ACC with its correct taxpayer identification number also may be subject to penalties imposed by the Internal Revenue Service. Any amount paid as backup withholding will be creditable against the holder's income tax liability. In addition, ACC may be required to withhold a portion of capital gain dividends to any holders who fail to certify their non-foreign status to ACC. For a discussion of the backup withholding rules as applied to non-U.S. holders, see "—Taxation of Non-U.S. Holders."

Taxation of Tax-Exempt Holders

Amounts distributed as dividends by a REIT generally do not constitute unrelated business taxable income when received by a tax-exempt entity. Provided that a tax-exempt holder is not one of the types of entity described in the next paragraph, does not hold its stock as "debt financed property" within the meaning of the Code, and the stock is not otherwise used in a trade or business, the dividend income from the stock will not be unrelated business taxable income to a tax-exempt stockholder. Similarly, income from the sale of stock will not constitute unrelated business taxable income unless the tax-exempt holder has held the stock as "debt financed property" within the meaning of the Code or has used the stock in a trade or business.

Income from an investment in ACC's securities will constitute unrelated business taxable income for tax-exempt stockholders that are social clubs, voluntary employee benefit associations, supplemental unemployment benefit trusts, and qualified group legal services plans exempt from federal income taxation under the applicable subsections of Section 501(c) of the Code, unless the organization is able to properly deduct amounts set aside or placed in reserve for certain purposes so as to offset the income generated by its securities. Prospective investors of the types described in the preceding sentence should consult their own tax advisors concerning these "set aside" and reserve requirements.

Notwithstanding the foregoing, however, a portion of the dividends paid by a "pension-held REIT" will be treated as unrelated business taxable income to any trust which:

•: is described in Section 401(a) of the Code;
•: is tax-exempt under Section 501(a) of the Code; and
•: holds more than 10% (by value) of the equity interests in the REIT.

Tax-exempt pension, profit-sharing and stock bonus funds that are described in Section 401(a) of the Code are referred to below as "qualified trusts." A REIT is a "pension-held REIT" if:

•: it would not have qualified as a REIT but for the fact that Section 856(h)(3) of the Code provides that stock owned by qualified trusts will be treated, for purposes of the "not closely held" requirement, as owned by the beneficiaries of the trust (rather than by the trust itself); and
•: either (a) at least one qualified trust holds more than 25% by value of the interests in the REIT or (b) one or more qualified trusts, each of which owns more than 10% by value of the interests in the REIT, hold in the aggregate more than 50% by value of the interests in the REIT.

The percentage of any REIT dividend treated as unrelated business taxable income to a qualifying trust is equal to the ratio of (a) the gross income of the REIT from unrelated trades or businesses, determined as though the REIT were a qualified trust, less direct expenses related to this gross income, to (b) the total gross income of the REIT, less direct expenses related to the total gross income. A de minimis exception applies where this percentage is less than 5% for any year. ACC does not expect to be classified as a pension-held REIT, but this cannot be guaranteed.

107

The rules described above in "—Taxation of Taxable U.S. Holders" concerning the inclusion of ACC's designated undistributed net capital gains in the income of its stockholders will apply to tax-exempt entities. Thus, tax-exempt entities will be allowed a credit or refund of the tax deemed paid by these entities in respect of the includible gains.

Taxation of Non-U.S. Holders

The rules governing U.S. federal income taxation of nonresident alien individuals, foreign corporations, foreign partnerships and other foreign stockholders are complex. This section is only a summary of such rules. ACC urges non-U.S. holders to consult their own tax advisors to determine the impact of federal, state, and local income tax laws on ownership of common stock, including any reporting requirements.

Ordinary Dividends. Dividends, other than dividends that are treated as attributable to gain from sales or exchanges by ACC of U.S. real property interests, as discussed below, and other than dividends designated by ACC as capital gain dividends, will be treated as ordinary income to the extent that they are made out of ACC's current or accumulated earnings and profits. A withholding tax equal to 30% of the gross amount of the dividend will ordinarily apply to dividends of this kind to non-U.S. holders, unless an applicable income tax treaty reduces that tax. However, if income from an investment in ACC's stock is treated as effectively connected with the non-U.S. holder's conduct of a U.S. trade or business or is attributable to a permanent establishment that the non-U.S. holder maintains in the U.S. (if that is required by an applicable income tax treaty as a condition for subjecting the non-U.S. holder to U.S. taxation on a net income basis), tax at graduated rates will generally apply to the non-U.S. holder in the same manner as U.S. holders are taxed with respect to dividends, and the 30% branch profits tax may also apply if the stockholder is a foreign corporation. ACC expects to withhold U.S. tax at the rate of 30% on the gross amount of any dividends, other than dividends treated as attributable to gain from sales or exchanges of U.S. real property interests and capital gain dividends, paid to a non-U.S. holder, unless (a) a lower treaty rate applies and the required form evidencing eligibility for that reduced rate (ordinarily, IRS Form W-8BEN) is filed with ACC or the appropriate withholding agent or (b) the non-U.S. holder files an IRS Form W-8ECI or a successor form with ACC or the appropriate withholding agent claiming that the dividends are effectively connected with the non-U.S. holder's conduct of a U.S. trade or business.

Dividends to a non-U.S. holder that are designated by ACC at the time of dividend as capital gain dividends which are not attributable to or treated as attributable to the disposition by it of a U.S. real property interest generally will not be subject to U.S. federal income taxation, except as described below.

Return of Capital. Distributions in excess of ACC's current and accumulated earnings and profits, which are not treated as attributable to the gain from its disposition of a U.S. real property interest, will not be taxable to a non-U.S. holder to the extent that they do not exceed the adjusted basis of the non-U.S. holder's stock. Distributions of this kind will instead reduce the adjusted basis of the stock. To the extent that distributions of this kind exceed the adjusted basis of a non-U.S. holder's common stock, they will give rise to tax liability if the non-U.S. holder otherwise would have to pay tax on any gain from the sale or disposition of its common stock, as described below. If it cannot be determined at the time a distribution is made whether the distribution will be in excess of current and accumulated earnings and profits, withholding will apply to the distribution at the rate applicable to dividends. However, the non-U.S. holder may seek a refund of these amounts from the IRS if it is subsequently determined that the distribution was, in fact, in excess of ACC's current accumulated earnings and profits.

Capital Gain Dividends. For any year in which ACC qualifies as a REIT, dividends that are attributable to gain from sales or exchanges by ACC of U.S. real property interests will be taxed to a

108

non-U.S. holder under the provisions of the Foreign Investment in Real Property Tax Act of 1980, as amended. Under this statute, these dividends are taxed to a non-U.S. holder as if the gain were effectively connected with a U.S. business. Thus, non-U.S. holders will be taxed on the dividends at the normal capital gain rates applicable to U.S. holders, subject to any applicable alternative minimum tax and special alternative minimum tax in the case of non-U.S. holders that are individuals. The above rules relating to distributions attributable to gains from its sales or exchanges of U.S. real property interests (or such gains that are retained and deemed to be distributed) do not apply with respect to a non-U.S. holder that does not own more than 5% of its common stock at any time during the taxable year, provided ACC's common stock is "regularly traded" on an established securities market in the U.S. ACC is required by applicable Treasury Regulations under the Foreign Investment in Real Property Tax Act of 1980, as amended, to withhold 35% of any distribution that ACC could designate as a capital gains dividend. However, if ACC designates as a capital gain dividend a distribution made before the day it actually effects the designation, then although the distribution may be taxable to a non-U.S. holder, withholding does not apply to the distribution under this statute. Rather, ACC must effect the 35% withholding from distributions made on and after the date of the designation, until the distributions so withheld equal the amount of the prior distribution designated as a capital gain dividend. The non-U.S. holder may credit the amount withheld against its U.S. tax liability.

Sale of Common Stock. Gain recognized by a non-U.S. holder upon a sale or exchange of ACC's common stock generally will not be taxed under the Foreign Investment in Real Property Tax Act if ACC is a "domestically controlled REIT," defined generally as a REIT, less than 50% in value of whose stock is and is held directly or indirectly by foreign persons at all times during a specified testing period. ACC believes that it will be a domestically controlled REIT, and, therefore, that taxation under this statute generally will not apply to the sale of ACC's common stock; however, because its stock is publicly traded, no assurance can be given that the ACC will qualify as a domestically controlled REIT at any time in the future. Gain to which this statute does not apply will be taxable to a non-U.S. holder if investment in the common stock is treated as effectively connected with the non-U.S. holder's U.S. trade or business or is attributable to a permanent establishment that the non-U.S. holder maintains in the U.S. (if that is required by an applicable income tax treaty as a condition for subjecting the non-U.S. holders to U.S. taxation on a net income basis). In this case, the same treatment will apply to the non-U.S. holders as to U.S. holders with respect to the gain. In addition, gain to which the Foreign Investment in Real Property Tax Act does not apply will be taxable to a non-U.S. holder if the non-U.S. holder is a nonresident alien individual who was present in the U.S. for 183 days or more during the taxable year to which the gain is attributable. In this case, a 30% tax will apply to the nonresident alien individual's capital gains. A similar rule will apply to capital gain dividends to which this statute does not apply.

If ACC were not a domestically controlled REIT, tax under the Foreign Investment in Real Property Tax Act would apply to a non-U.S. holder's sale of common stock only if the selling non-U.S. holders owned more than 5% of the class of common stock sold at any time during a specified period. This period is generally the shorter of the period that the non-U.S. holder owned the common stock sold or the five-year period ending on the date when the stockholder disposed of the common stock. If tax under this statute applies to the gain on the sale of common stock, the same treatment would apply to the non-U.S. holder as to U.S. holders with respect to the gain, subject to any applicable alternative minimum tax and a special alternative minimum tax in the case of nonresident alien individuals.

Backup Withholding and Information Reporting

If you are a non-U.S. holder, you are generally exempt from backup withholding and information reporting requirements with respect to:

•: dividend payments;

109

•: the payment of the proceeds from the sale of common stock effected at a U.S. office of a broker, as long as the income associated with these payments is otherwise exempt from U.S. federal income tax; and
•: the payer or broker does not have actual knowledge or reason to know that you are a U.S. person and you have furnished to the payer or broker: (a) a valid Internal Revenue Service Form W-8BEN or an acceptable substitute form upon which you certify, under penalties of perjury, that you are a non-U.S. person, or (b) other documentation upon which it may rely to treat the payments as made to a non-U.S. person in accordance with U.S. Treasury Regulations, or (c) you otherwise establish an exemption.

Payment of the proceeds from the sale of common stock effected at a foreign office of a broker generally will not be subject to information reporting or backup withholding. However, a sale of common stock that is effected at a foreign office of a broker will be subject to information reporting and backup withholding if:

•: the proceeds are transferred to an account maintained by you in the U.S.;
•: the payment of proceeds or the confirmation of the sale is mailed to you at a U.S. address; or
•: the sale has some other specified connection with the U.S. as provided in U.S. Treasury Regulations,

unless the broker does not have actual knowledge or reason to know that you are a U.S. person and the documentation requirements described above are met or you otherwise establish an exemption.

In addition, a sale of common stock will be subject to information reporting if it is effected at a foreign office of a broker that is:

•: a U.S. person;
•: a controlled foreign corporation for U.S. tax purposes;
•: a foreign person 50% or more of whose gross income is effectively connected with the conduct of a U.S. trade or business for a specified three-year period; or
•: a foreign partnership, if at any time during its tax year: (a) one or more of its partners are "U.S. persons," as defined in U.S. Treasury Regulations, who in the aggregate hold more than 50% of the income or capital interest in the partnership, or (b) such foreign partnership is engaged in the conduct of a U.S. trade or business,

unless the broker does not have actual knowledge or reason to know that you are a U.S. person and the documentation requirements described above are met or you otherwise establish an exemption. Backup withholding will apply if the sale is subject to information reporting and the broker has actual knowledge that you are a U.S. person. You generally may obtain a refund of any amounts withheld under the backup withholding rules that exceed your income tax liability by filing a refund claim with the Internal Revenue Service.

Tax Aspects of Investments in the ACC Operating Partnership

The following discussion summarizes certain federal income tax considerations applicable to ACC's direct or indirect investment in the ACC Operating Partnership and any subsidiary partnerships or limited liability companies ACC forms or acquires, each individually referred to as a Partnership and, collectively, as Partnerships. The following discussion does not cover state or local tax laws or any federal tax laws other than income tax laws.

110

Classification as Partnerships

ACC is entitled to include in its income its distributive share of each Partnership's income and to deduct its distributive share of each Partnership's losses only if such Partnership is classified for federal income tax purposes as a partnership, rather than as a corporation or an association taxable as a corporation. An organization with at least two owners or partners will be classified as a partnership, rather than as a corporation, for federal income tax purposes if it:

•: is treated as a partnership under the Treasury Regulations relating to entity classification (the "check-the-box regulations"); and
•: is not a "publicly traded" partnership.

Under the check-the-box regulations, an unincorporated business entity with at least two owners or partners may elect to be classified either as a corporation or as a partnership. If such an entity does not make an election, it generally will be treated as a partnership for federal income tax purposes.

ACC intends that each partnership it owns an interest in will be classified as a partnership for federal income tax purposes (or else a disregarded entity where there are not at least two separate beneficial owners).

A publicly-traded partnership is a partnership whose interests are traded on an established securities market or are readily tradable on a secondary market (or a substantial equivalent). A publicly-traded partnership is generally treated as a corporation for federal income tax purposes, but will not be so treated for any taxable year for which at least 90% of the partnership's gross income consists of specified passive income, including real property rents, gains from the sale or other disposition of real property, interest, and dividends (the "90% passive income exception"). Treasury Regulations provide limited safe harbors from treatment as a publicly traded partnership. Pursuant to one of those safe harbors, known as the private placement exclusion, interests in a partnership will not be treated as readily tradable on a secondary market or the substantial equivalent thereof if (1) all interests in the partnership were issued in a transaction or transactions that were not required to be registered under the Securities Act, and (2) the partnership does not have more than 100 partners at any time during the partnership's taxable year. For the determination of the number of partners in a partnership, a person owning an interest in a partnership, grantor trust, or S corporation that owns an interest in the partnership is treated as a partner in the partnership only if (1) substantially all of the value of the owner's interest in the entity is attributable to the entity's direct or indirect interest in the partnership, and (2) a principal purpose of the use of the entity is to permit the partnership to satisfy the 100-partner limitation.

ACC expects that each partnership it owns an interest in will qualify for the private placement exclusion, one of the other safe harbors from treatment as a publicly traded partnership, and/or will satisfy the 90% passive income exception.

Income Taxation of the Partnerships and Their Partners

ACC owns 94.5% of the interests in the ACC Operating Partnership and certain subsidiary partnerships. ACC's ownership percentage is expected to decrease in connection with the partnership merger. Entities that it owns 100% of the interests in (directly or through other disregarded entities) will be treated as disregarded entities. In addition it may hold interests in partnerships or limited liability companies that are not disregarded entities (a "Partnership" or collectively, the "Partnerships").

Partners, Not the Partnerships, Subject to Tax. A Partnership is not a taxable entity for federal income tax purposes. ACC will therefore take into account its allocable share of each Partnership's income, gains, losses, deductions, and credits for each taxable year of the Partnership ending with or

111

within ACC's taxable year, even if it receives no distribution from the Partnership for that year or a distribution less than its share of taxable income. Similarly, even if ACC receives a distribution, it may not be taxable if the distribution does not exceed its adjusted tax basis in its interest in the Partnership.

Partnership Allocations. Although a partnership agreement generally will determine the allocation of income and losses among partners, allocations will be disregarded for tax purposes if they do not comply with the provisions of the federal income tax laws governing partnership allocations. If an allocation is not recognized for federal income tax purposes, the item subject to the allocation will be reallocated in accordance with the partners' interests in the Partnership, which will be determined by taking into account all of the facts and circumstances relating to the economic arrangement of the partners with respect to such item. Each Partnership's allocations of taxable income, gain, and loss are intended to comply with the requirements of the federal income tax laws governing partnership allocations.

Sale of a Partnership's Property. Generally, any gain realized by a Partnership on the sale of property held for more than one year will be long-term capital gain, except for any portion of the gain treated as depreciation or cost recovery recapture. Conversely, ACC's share of any Partnership gain from the sale of inventory or other property held primarily for sale to customers in the ordinary course of the Partnership's trade or business will be treated as income from a prohibited transaction subject to a 100% tax. Income from a prohibited transaction may have an adverse effect on its ability to satisfy the gross income tests for REIT status. See "—Requirements for Qualification." ACC does not presently intend to acquire or hold, or to allow any Partnership to acquire or hold, any property that is likely to be treated as inventory or property held primarily for sale to customers in the ordinary course of its, or the Partnership's, trade or business.

Tax Consequences of an Exchange of Units

The exchange of units for common stock or cash will be a fully-taxable transaction to the unit holder. The unit holder will generally recognize gain in an amount equal to the value of the common stock and the amount of cash received, plus the amount of liabilities of the ACC Operating Partnership allocable to the units being exchanged, less its tax basis in the units. The gain may exceed the value of the common stock and the amount of cash received. However, if ACC elects to pay cash for the units exchanged and it uses cash received from the ACC Operating Partnership for such purpose, it is possible that such payment will be treated for federal income tax purposes as an exchange by the ACC Operating Partnership of the units exchanged. In this case, the unitholder would recognize gain to the extent that the cash received, plus the amount of any of the ACC Operating Partnership's liabilities allocable to the units being exchanged, exceeds the adjusted tax basis in all of the holder's units prior to such payment.

The recognition of any loss resulting from an exchange of units is subject to a number of limitations set forth in the Code. The character of any gain or loss arising from an exchange as capital or ordinary will depend on the character of the units in the hands of the unitholder as well as the nature of the assets of the ACC Operating Partnership at the time of the exchange.

THIS SUMMARY DOES NOT ADDRESS ANY OF THE TAX CONSEQUENCES TO HOLDERS OF UNITS IN THE GMH OPERATING PARTNERSHIP WHO RECEIVE UNITS IN THE ACC OPERATING PARTNERSHIP IN EXCHANGE FOR THEIR UNITS IN THE GMH OPERATING PARTNERSHIP, INCLUDING WITHOUT LIMITATION THE CONSEQUENCES OF THE INITIAL ACQUISITION OF UNITS IN THE ACC OPERATING PARTNERSHIP AND THE CONSEQUENCES OF AN ONGOING INVESTMENT IN SUCH UNITS. HOLDERS OF UNITS IN THE GMH OPERATING PARTNERSHIP ARE URGED TO CONSULT THEIR OWN TAX ADVISORS REGARDING THE PARTICULAR TAX CONSEQUENCES APPLICABLE TO SUCH HOLDERS IN

112

CONNECTION WITH THE ACQUISITION OF AND INVESTMENT IN UNITS IN THE ACC OPERATING PARTNERSHIP.

State and Local Taxes

ACC and/or its stockholders may be subject to taxation by various states and localities, including those in which ACC or a holder transacts business, owns property or resides. The state and local tax treatment may differ from the federal income tax treatment described above. Consequently, holders should consult their own tax advisors regarding the effect of state and local tax laws upon an investment in ACC securities.

113

ACC's POLICIES WITH RESPECT TO CERTAIN ACTIVITIES

The following is a discussion of certain of ACC's investment, financing and other policies. These policies have been adopted by its board of directors and, in general, may be amended or revised from time to time by ACC's board of directors without a vote of its stockholders.

Investment Policies

Investment in Real Estate or Interests in Real Estate

ACC conducts all of its investment activities through the ACC Operating Partnership and its affiliates. Its investment objectives are to provide quarterly cash distributions and achieve long-term capital appreciation through increases in its value. It has not established a specific policy regarding the relative priority of these investment objectives.

ACC intends to pursue its investment objectives primarily through the ownership by the ACC Operating Partnership of the properties and other acquired properties and assets. It currently intends to invest primarily in developments of student housing and acquisitions of existing improved properties or properties in need of redevelopment and acquisitions of land which it believes has development potential for student housing. Future investment or development activities will not be limited to any geographic area, product type or to a specified percentage of its assets. While it may diversify in terms of property locations, size and market, it does not have any limit on the amount or percentage of its assets that may be invested in any one property or any one geographic area. It intends to engage in such future investment or development activities in a manner that is consistent with the maintenance of its status as a REIT for federal income tax purposes. In addition, it may purchase or lease income-producing commercial and other types of properties for long-term investment, expand and improve the properties it presently owns or other acquired properties, or sell such properties, in whole or in part, when circumstances warrant.

It may also participate with third parties in property ownership, through joint ventures or other types of co-ownership. These types of investments may permit ACC to own interests in larger assets without unduly restricting its diversification and, therefore, provide it with flexibility in structuring its portfolio. It will not, however, enter into a joint venture or other partnership arrangement to make an investment that would not otherwise meet its investment policies.

Equity investments in acquired properties may be subject to existing mortgage financing and other indebtedness or to new indebtedness, which may be in acquired properties incurred in connection with acquiring or refinancing these investments. Debt service on such financing or indebtedness will have a priority over any distributions with respect to its common stock. It may in the future acquire some, all or substantially all of the securities or assets of other REITs or similar entities where that investment would be consistent with its investment policies. Subject to the limitations imposed by such other REITs on the ownership of their stock and to the requirement that it satisfies the asset tests to qualify as a REIT under the Code, there are no limitations on the amount or percentage of its total assets that may be invested in any one issuer. However, it does not anticipate investing in other issuers of securities for the purpose of exercising control or acquiring any investments primarily for sale in the ordinary course of business or holding any investments with a view to making short-term profits from their sale. In any event, it does not intend that its investments in securities will require it to register as an "investment company" under the Investment Company Act of 1940, as amended, and it intends to divest securities before any registration would be required.

Investments in Real Estate Mortgages

While ACC's current portfolio consists of, and its business objectives emphasize, equity investments in real estate, it may, at the discretion of ACC's board of directors, invest in mortgages and other types of real estate interests consistent with its qualification as a REIT. It does not presently intend to invest in mortgages or deeds of trust, but may invest in participating or convertible mortgages

114

if it concludes that it may benefit from the gross revenues or any appreciation in value of the property. Investments in real estate mortgages run the risk that one or more borrowers may default under certain mortgages and that the collateral securing certain mortgages may not be sufficient to enable ACC to recoup its full investment.

Securities of or Interests in Persons Primarily Engaged in Real Estate Activities and Other Issuers

Subject to the percentage of ownership limitations and gross income tests necessary for REIT qualification, ACC may invest in securities of other REITs, other entities engaged in real estate activities or securities of other issuers, including for the purpose of exercising control over such entities.

Dispositions

ACC may dispose of any property if, based upon management's periodic review of its portfolio, ACC's board of directors determines that such action would be in the best interest of stockholders. For example, it may seek to enter into tax-efficient joint ventures in its stabilized properties with third-party investors to raise low-cost equity capital that it can reinvest in properties with higher growth potential.

Financing Policies

ACC presently intends to maintain a ratio of its consolidated total indebtedness-to-total market capitalization of 50% or less (excluding indebtedness encumbering its on-campus participating properties or properties that it subsequently develops or acquires that have similar ownership structures). For purposes of this calculation, its indebtedness does not include the indebtedness encumbering its on-campus participating properties or properties that it subsequently develops or acquires that have similar ownership structures. Total market capitalization is defined as the sum of the market value of the outstanding common stock and preferred stock (which may decrease, thereby increasing debt to total capitalization ratio), including shares of restricted stock or restricted stock units that may be issued to employees and directors under its 2004 incentive award plan, plus the aggregate value of the ACC Operating Partnership units not owned by ACC, plus the book value of its total consolidated indebtedness (excluding indebtedness encumbering its on-campus participating properties or properties that it subsequently develops or acquires that have similar ownership structures). Since this ratio is based, in part, upon market values of equity, it will fluctuate with changes in the price of its common stock; however, ACC believes that this ratio provides an appropriate indication of leverage for a company whose assets are primarily real estate. As of December 31, 2007, the ratio of debt-to-total market capitalization was approximately 36.6%. ACC's charter and bylaws do not limit the amount or percentage of indebtedness that it may incur. ACC's board of directors may from time to time modify the debt policy in light of then-current economic conditions, relative costs of debt and equity capital, market values of its properties, general conditions in the market for debt and equity securities, fluctuations in the market price of its common stock, growth and acquisition opportunities and other factors. Accordingly, ACC may increase or decrease its ratio of debt-to-total market capitalization beyond the limits described above. If these policies were changed, it could become more highly leveraged, resulting in an increased risk of default on its obligations and a related increase in debt service requirements that could adversely affect its financial condition and results of operations and its ability to pay distributions to its stockholders.

Conflict of Interest Policies

ACC has adopted certain policies that are designed to eliminate or minimize certain potential conflicts of interest. In addition, ACC's board of directors is subject to certain provisions of Maryland law, which are also designed to eliminate or minimize conflicts.

However, there can be no assurance that these policies or provisions of law will always be successful in eliminating the influence of such conflicts, and if they are not successful, decisions could be made that might fail to reflect fully the interests of all stockholders.

115

Interested Director and Officer Transactions

Pursuant to Maryland law, a contract or other transaction between ACC and a director or between ACC and any other corporation or other entity in which any of its directors is a director or has a material financial interest is not void or voidable solely on the grounds of such common directorship or interest. The common directorship or interest, the presence of such director at the meeting at which the contract or transaction is authorized, approved or ratified or the counting of the director's vote in favor thereof will not render the transaction void or voidable if:

•: the material facts relating to the common directorship or interest and as to the transaction are disclosed to ACC's board of directors or a committee of the board, and the board or committee authorizes, approves or ratifies the transaction or contract by the affirmative vote of a majority of disinterested directors, even if the disinterested directors constitute less than a quorum;
•: the material facts relating to the common directorship or interest and as to the transaction are disclosed to stockholders entitled to vote thereon, and the transaction is authorized, approved or ratified by a majority of the votes cast by the stockholders entitled to vote; or
•: the transaction or contract is fair and reasonable to ACC at the time it is authorized, ratified or approved.

Furthermore, under Maryland law (where the ACC Operating Partnership is formed), ACC, as the sole member of the general partner, has a fiduciary duty to the ACC Operating Partnership and, consequently, such transactions also are subject to the duties of care and loyalty. ACC has adopted a policy that requires that all contracts and transactions between ACC, the ACC Operating Partnership or any of its subsidiaries, on the one hand, and any of its directors or executive officers or any entity in which such director or executive officer is a director or has a material financial interest, on the other hand, must be approved by the affirmative vote of a majority of the disinterested directors. Where appropriate in the judgment of the disinterested directors, ACC's board of directors may obtain a fairness opinion or engage independent counsel to represent the interests of nonaffiliated security holders, although ACC's board of directors will have no obligation to do so.

Business Opportunities

Pursuant to Maryland law, each director is obligated to offer to ACC any business opportunity (with certain limited exceptions) that comes to him or her and that ACC reasonably could be expected to have an interest in pursuing.

Policies with Respect to Other Activities

ACC has authority to offer common stock, preferred stock or options to purchase stock in exchange for property and to repurchase or otherwise acquire its common stock or other securities in the open market or otherwise, and it may engage in such activities in the future. ACC's board of directors has no present intention of causing ACC to repurchase any common stock. It may issue preferred stock from time to time, in one or more series, as authorized by ACC's board of directors without the need for stockholder approval. It has not engaged in trading, underwriting or agency distribution or sale of securities of other issuers other than the ACC Operating Partnership and does not intend to do so. At all times, it intends to make investments in such a manner as to qualify as a REIT, unless because of circumstances or changes in the Code, or the Treasury Regulations, ACC's board of directors determines that it is no longer in its best interest to qualify as a REIT. ACC has not made any loans to third parties, although it may in the future make loans to third parties, including, without limitation, to joint ventures in which it participates. It intends to make investments in such a way that it will not be treated as an investment company under the Investment Company Act of 1940, as amended.

116

GMH's POLICIES WITH RESPECT TO CERTAIN ACTIVITIES

The following is a discussion of GMH's investment policies and its policies with respect to certain other activities, including financing matters and conflicts of interest. These policies may be amended or revised from time to time at the discretion of GMH's board of trustees, without a vote of its shareholders. Any change to any of these policies by the board, however, would be made only after a thorough review and analysis of that change, in light of then-existing business and other circumstances, and then only if, in the exercise of its business judgment, GMH's board of trustees believes that it is advisable to do so and in its and its shareholders' best interest. There can be no assurance that the investment objectives will be attained.

Investment Approval Policy

GMH has no set limitation regarding (i) the number of student housing properties or military housing projects in which it may invest, (ii) the amount or percentage of its assets that it may invest in any specific property or project that falls within its overall business strategy or (iii) the concentration of its investments in any geographic area in the U.S. or abroad. Prior to the first quarter of 2006, GMH's board of trustees adopted an investment approval policy pursuant to which the board must approve any acquisition with a total purchase price of $25.0 million or greater, and must approve any acquisition, regardless of purchase price, during a quarter in which other acquisitions completed during such quarter have exceeded an aggregate purchase price of $100.0 million. In April 2006, GMH's board of trustees amended this policy to require that all future student housing property acquisitions (including entering into joint ventures for the purpose of acquiring or developing properties), regardless of the applicable purchase price, be presented to the board for approval. In addition, GMH's board of trustees must approve the material terms of all student housing refinancings and dispositions. With regard to military housing, board approval is required prior to the execution of a final agreement on an award of a military housing privatization project, where such project requires an equity investment or equity commitment by GMH in excess of $25.0 million. GMH's policy is to acquire assets primarily for income.

Leverage Ratio Target

GMH has no restriction in its declaration of trust or bylaws regarding the amount of indebtedness it may incur. Under its current note facility with Merrill Lynch, however, it must maintain a fixed charge coverage ratio of at least 1.15 to 1.00. GMH is also, during the term of its note facility, required to maintain (i) a consolidated tangible net worth, as defined by in the trust indenture relating to the note facility, of at least $375.0 million, (ii) quarterly minimum Adjusted Management EBITDA, as defined in the trust indenture, of $3.5 million, and (iii) its federal tax status as a REIT. In addition, under the terms of the trust indenture, GMH must obtain prior written consent for certain transactions, including, but not limited to, (1) a merger or sale of all or substantially all of its assets, (2) certain amendments to transactions documents relating to GMH's military housing privatization projects to the extent such amendment would result in material adverse change (as defined in the trust indenture) or adversely affect the collateral; (3) the sale of any equity interest in the GMH Operating Partnership, other than in connection with the issuance of common shares under the equity incentive plan for GMH or similar equity compensation arrangements, and in connection with acquisitions of student housing properties; (4) entering into transactions with affiliates relating to or affecting the collateral; and (5) incurring additional indebtedness, other than indebtedness relating to (a) future property acquisitions or refinancings or equity commitments with respect to the student housing business, (b) financings or refinancings relating to the above-referenced military housing projects that are non-recourse to GMH and subject only to customary "bad acts" guarantees, (c) equity commitments related to the above-referenced military housing projects that will not become payable prior to the payment in full of obligations under outstanding notes, (d) financings for future military housing projects to the extent such debt is investment grade (at least rated Baa by Moody's Investors Service or

117

BBB by Standard & Poor's) and is non-recourse to GMH, and (e) obligations to contribute equity to military housing projects that do not exceed $15.0 million on an individual basis. GMH's debt level changes as it acquires properties or projects and refinances existing properties. The amount of total indebtedness GMH decides to incur during any particular period depends on how it structures and finances its property acquisitions and the current market cost of debt. GMH's targeted leverage ratio is in the range of 45% to 60%. Its debt level changes as it acquires properties or projects and refinances existing properties. The amount of total indebtedness GMH decides to incur during any particular period depends on how it structures and finances its property acquisitions and the current market cost of debt. The formula GMH uses to calculate its leverage ratio is as follows:

Total debt

Total market capitalization

As of December 31, 2007, GMH's leverage ratio was approximately 72%. GMH's leverage ratio has been impacted by a combination of additional borrowings and a significant decline in the price of its common shares. Neither its declaration of trust nor its bylaws requires GMH to maintain a specific leverage ratio and it may determine to exceed the maximum range of its target ratio depending on the circumstances. If it determines to exceed the maximum range of its target ratio, it may do so without shareholder approval. It is possible that its leverage ratio may exceed or fall below the target range for its leverage ratio from time to time.

Investments in Securities or Entities

GMH makes joint venture investments in entities that own military housing privatization projects as a part of its military housing business. It also may consider entering into joint ventures to acquire or develop student housing properties. It has no current intention of acquiring loans secured by properties. However, it may invest from time to time a substantial portion of its excess cash directly in fixed- and adjustable-rate mortgage-backed securities, and it may leverage these investments. There are no limitations on the amount of leverage it is permitted to incur to invest in mortgage-backed securities. It may invest in the securities of other issuers in connection with acquisitions of indirect interests in properties or projects, typically general or limited partnership or limited liability company interests in special-purpose entities owning properties or projects. It may in the future acquire some, all or substantially all of the securities or assets of other REITs or similar entities where that investment would be consistent with its investment policies and the REIT qualification requirements. There are no limitations on the amount or percentage of its total assets that may be invested in any one issuer, other than those imposed by the gross income and asset tests that it must satisfy to qualify as a REIT. However, it does not anticipate investing in other issuers of securities for the purpose of exercising control or acquiring any investments primarily for sale in the ordinary course of business or holding any investments with a view to making short-term profits from their sale. In any event, it does not intend that its investments in securities will require GMH to register as an "investment company" under the Investment Company Act of 1940, as amended, and it intends to divest securities before any registration would be required. It does not intend to engage in trading, underwriting, agency distribution or sales of securities of other issuers.

Lending Policies

GMH's board of trustees has adopted a policy that prohibits GMH from making loans to its executive officers, key employees or trustees. Other than this policy, it does not have a policy limiting its ability to make loans to other persons. It may consider offering purchase money financing in connection with the sale of properties or projects where the provision of that financing would increase the value to be received by it for the property or project sold. It may make loans to joint ventures in which it may participate. However, it does not intend to engage in significant lending activities.

118

Equity Capital Policies

GMH's board of trustees has the power, without further shareholder approval, to issue additional authorized common shares and preferred shares or otherwise raise capital, in any manner and on the terms and for the consideration it deems appropriate, including in exchange for property or other assets. Existing shareholders will have no preemptive right to additional shares issued in any offering, and any offering may cause a dilution of investment. GMH may in the future issue common shares or units of limited partnership interest in its operating partnership in connection with acquisitions.

GMH's board of trustees may authorize the issuance of preferred shares with terms and conditions that could have the effect of delaying, deterring or preventing a transaction or a change in control that might involve a premium price for holders of common shares or otherwise might be in their best interest. Additionally, preferred shares could have dividend, voting, liquidation and other rights and preferences that are senior to those of the common shares.

GMH may, under certain circumstances, upon approval by GMH's board of trustees but without obtaining shareholder approval, repurchase common shares from its shareholders. GMH's board of trustees has no present intention of causing GMH to repurchase any shares, and any action would only be taken in conformity with applicable federal and state laws and the applicable requirements for qualifying as a REIT.

In the future, GMH may institute a dividend reinvestment plan, which would allow its shareholders to acquire additional common shares by automatically reinvesting their cash dividends. Common shares would be acquired pursuant to the dividend reinvestment plan at a price equal to the then prevailing market price or a slight discount thereto, without payment of brokerage commissions or service charges. Shareholders who do not participate in the plan will continue to receive cash dividends as declared.

Review, Approval or Ratification of Transactions with Related Persons

From time to time, GMH may acquire, manage or develop properties in which its trustees or executive officers have an interest. GMH may recruit other persons with experience in the student or military housing industries to join its board or management team who have financial interests in housing properties it intends to acquire, develop or manage. In transactions of this nature, there will be conflicts between GMH's interests and the interests of the trustee or executive officer involved, and GMH does not intend to engage in these transactions without the approval of a majority of its independent disinterested trustees. GMH's declaration of trust provides that in defining or interpreting the powers and duties of the trustees, reference may be made by the trustees to the powers and duties of directors of a corporation under Maryland law. Maryland law provides that a contract or other transaction between a corporation and any of that corporation's directors and any other entity in which that director is also a director or has a material financial interest is not void or voidable solely on the grounds of the common directorship or interest, the fact that the director was present at the meeting at which the contract or transaction is approved or the fact that the director's vote was counted in favor of the contract or transaction, if:

•: the fact of the common directorship or interest is known or disclosed to the board of directors or a committee of the board of directors, and the board or that committee authorizes the contract or transaction by the affirmative vote of a majority of the disinterested directors, even if the disinterested directors constitute less than a quorum;
•: the fact of the common directorship or interest is known or disclosed to shareholders entitled to vote on the contract or transaction, and the contract or transaction is approved by a majority of the votes cast by the shareholders entitled to vote on the

119

matter, other than votes of shares owned of record or beneficially by the interested director, corporation, firm or other entity; or

•: the contract or transaction is fair and reasonable to the corporation.

Under GMH's conflicts of interest policy as contained in its Code of Business Conduct and Ethics, a conflict of interest exists when a person's private interest is not aligned or appears to be not aligned, or interferes or appears to interfere, in any way with GMH's interest. For example, the conflicts of interest policy prohibits its officers, employees and trustees from entering into agreements, transactions or business relationships, or otherwise taking actions, that involve conflicts of interest, other than such agreements, transactions or business relationships or other actions that are (i) otherwise contemplated in the prospectus relating to GMH's initial public offering, or (ii) approved in advance by GMH's audit committee. Except as otherwise permitted as described in the foregoing sentence, GMH is prohibited from, among other things, engaging in the following activities:

•: acquiring any assets or other property from, or selling any assets or other property to, any of its trustees, officers or employees, any of their immediate family members or any entity in which any of its trustees, officers or employees or any of their immediate family members has an interest of 5% or more;
•: making any loan to, or borrowing from, any of its trustees, officers or employees, any of their immediate family members or any entity in which any of its trustees, officers or employees or any of their immediate family members has an interest of 5% or more;
•: engaging in any other transaction with any of its trustees, officers or employees, any of their immediate family members or any entity in which any of its trustees, officers or employees or their immediate family members has an interest of 5% or more; or
•: permitting any of its trustees or officers to make recommendations regarding or to approve compensation decisions that will personally benefit such trustees or officers or their immediate family members whom it employs, other than customary compensation for service on GMH's board of trustees and its committees.

In accordance with this policy, all related-party transactions as would be required to be reported under Item 404(a) of Regulation S-K as promulgated by the SEC, must be approved in advance by the audit committee, or are otherwise deemed to be violations of the Code of Business Conduct and Ethics. In evaluating related-party transactions for approval, the audit committee has considered the business purpose of the transaction, whether the terms of the transactions are consistent with those that could be obtained in arms-length negotiations with unaffiliated third parties, the dollar value of the individual transaction and the aggregate dollar value of all related party transactions with the related party.

120

COMPARISON OF RIGHTS OF STOCKHOLDERS OF ACC
AND SHAREHOLDERS OF GMH

Both ACC and GMH are formed in Maryland. Upon consummation of the REIT merger, GMH shareholders will become stockholders of ACC. The rights of GMH shareholders are governed currently by the Maryland General Corporation Law and by GMH's charter and bylaws. Because GMH shareholders will become stockholders of ACC as a result of the REIT merger, their rights will continue to be governed by the Maryland General Corporation Law but will be governed by ACC's charter and bylaws.

The following is a summary of the material differences between the rights of GMH shareholders and the rights of ACC stockholders. This summary does not purport to be a complete description of the differences between the rights of GMH shareholders and ACC stockholders and is qualified in its entirety by reference to the governing corporate instruments of ACC and GMH. To obtain a copy of the charters and bylaws of ACC and GMH, see "Where You Can Find More Information."

Capitalization

ACC. The total number of authorized shares of ACC stock is 1,000,000,000, which consists of 800,000,000 shares of common stock, par value $0.01 per share, and 200,000,000 shares of preferred stock, $0.01 par value per share.

GMH. The total number of authorized GMH shares is 600,000,000, which consists of 500,000,000 common shares of beneficial interest, par value $0.001 per share, and 100,000,000 preferred shares of beneficial interest, par value $0.001 per share.

Composition of Boards

ACC. The bylaws provide that, except for any directors elected by holders of a class or series of shares other than common stock, the number of directors will be fixed by a majority of the entire board of directors, but may not be fewer than the minimum number permitted under Maryland law or more than fifteen. In establishing the number of directors, the board of directors may not alter the term of office of any director in office at that time. Pursuant to the charter, directors are elected by stockholders to serve until their successors are duly elected and qualify. Holders of shares of common stock have no right to cumulative voting in the election of directors. The bylaws provide that at each annual meeting of stockholders, a plurality of votes cast will be able to elect the directors.

GMH. The bylaws provide that, except for any trustees elected by holders of a class or series of shares other than common shares, the number of trustees will be fixed by a majority of the entire board of trustees, but may not be fewer than the minimum number permitted under Maryland law or more than fifteen. In establishing the number of trustees, GMH's board of trustees may not alter the term of office of any director in office at that time. Pursuant to the charter, trustees elected by shareholders serve until their successors are duly elected and qualified. Holders of common shares have no right to cumulative voting in the election of trustees. The bylaws provide that at each annual meeting of shareholders, a plurality of votes cast will be able to elect the trustees.

Pursuant to his employment agreement, Gary M. Holloway, Sr. has the right, so long as he is the chief executive officer of GMH, to nominate a certain number of members to GMH's board of trustees based on the following percentages of outstanding common shares owned by Mr. Holloway and his affiliates on a fully-diluted basis assuming conversion of all outstanding units of limited partnership in the GMH Operating Partnership other than units held by GMH:

•: three trustees, including himself, to the extent he owns at least 20%;

121

•: two trustees, including himself, to the extent he owns at least 10% but less than 20%; and
•: himself to the extent he owns less than 10%.

In addition, all nominations must be submitted to and approved by the members of the nominating and corporate governance committee of GMH's board of trustees, and satisfy the standards established by that committee for membership on the board. As of December 31, 2007, Gary M. Holloway, Sr. beneficially owned approximately 24% of the outstanding units of limited partnership interest in the GMH Operating Partnership. If the maximum number of units redeemable for common shares by Mr. Holloway had been redeemed at that date, Mr. Holloway would have beneficially owned 20% of GMH outstanding common shares.

Vacancies on and Removal from the Boards

ACC. Any vacancy may be filled by a majority of the remaining directors even if the remaining directors do not constitute a quorum, except (i) if the vacancy results from an increase in the number of directors constituting the board, in which case the vacancy will be filled by a majority of the entire board, (ii) if the vacancy results from a removal of a director, in which case the vacancy may also be filled by stockholders and (iii) as may be otherwise provided for in the terms of any class or series of preferred stock.

The charter provides that, except for any directors elected by holders of a class or series of shares other than common stock, a director may be removed by the stockholders only with the affirmative vote of at least a majority of the votes entitled to be cast generally in the election of directors and only for "cause." In the charter, "cause" means, with respect to any particular director, conviction of a felony or a final judgment of a court of competent jurisdiction holding that such director caused demonstrable, material harm to ACC through bad faith or active and deliberate dishonesty.

GMH. Any vacancy may be filled by a majority of the remaining trustees even if the remaining trustees do not constitute a quorum, except as may be provided by the board in setting the terms of any class or series of shares.

The charter provides that a trustee may be removed, with or without cause, upon the affirmative vote of at least two-thirds of the votes entitled to be cast in the election of trustees.

Charter and Bylaw Amendments

ACC. The charter, including its provisions on removal of directors, may be amended by the affirmative vote of the holders of at least a majority of all of the votes entitled to be cast on the matter. The bylaws may be amended only by a majority of directors. The stockholders have no right to amend or propose an amendment to the bylaws.

GMH. The provisions of the charter relating to the number and classification of trustees, removal of trustees, merger, consolidation or sale of property, or amendment of the charter may be amended by the affirmative vote of the holders of at least two-thirds of all the votes entitled to be cast on the matter. The other provisions of the charter may be amended by the affirmative vote of at least a majority of all of the votes entitled to be cast on the matter. The bylaws may be amended by a majority of the trustees, unless such authority is expressly delegated to the shareholders.

Transactions Outside the Ordinary Course of Business

Under Maryland law, a Maryland entity may not merge with or into another entity, sell all or substantially all of its assets, engage in a share exchange or engage in similar transactions outside the

122

ordinary course of its business unless the transaction or transactions are approved by the affirmative vote of the holders of not less than two-thirds of all of the votes entitled to be cast on the matter. However, a Maryland entity may provide in its charter for approval of these matters by a lesser percentage of the shares entitled to vote on the matter, but not less than a majority of all of the votes entitled to be cast on the matter.

ACC. The charter provides for approval of these matters by at least a majority of the votes entitled to be cast except if:

•: the merger will merge one of ACC's 90% or more owned subsidiaries into ACC without amending the charter (other than in limited respects and without altering the contract rights of the stock of the subsidiary (in which case only the approval of ACC's board of directors and the board of directors of the subsidiary is necessary));
•: ACC is the successor corporation in a share exchange (in which case only the approval of ACC's board of directors is necessary); or
•: ACC is the survivor in the merger and the merger does not change the terms of any class or series of its outstanding stock, or otherwise amend the charter, and the number of shares of stock of each class or series outstanding immediately before the merger does not increase by more than 20% of the number of shares of each such class or series of stock that was outstanding immediately prior to effectiveness of the merger (in which case, only the approval of ACC's board of directors is necessary).

GMH. The charter provides for approval of these matters by at least two-thirds of the votes entitled to be cast.

Advance Notice of Director Nominations and New Business

ACC. The bylaws provide for advance notice by a stockholder or stockholders wishing to have certain matters considered and voted upon at a meeting of stockholders.

With respect to an annual meeting of stockholders, nominations of persons for election to ACC's board of directors and the proposal of business to be considered by stockholders may be made only:

•: pursuant to the notice of the meeting;
•: by or at the direction of ACC's board of directors; or
•: by a stockholder who is entitled to vote at the meeting and has complied with the advance notice procedures set forth in the bylaws.

These procedures generally require the stockholder to deliver notice to the corporate secretary of ACC not less than 90 days or later than the close of business on the 120^th day prior to the first anniversary of the date of mailing of the notice for the preceding year's annual meeting. If the date of the annual meeting is advanced by more than 30 days from the date of the preceding year's meeting or if ACC did not hold an annual meeting the preceding year, notice must be delivered not earlier than the 120^th day prior to the date of mailing of the notice for that annual meeting and not later than the close of business on the later of the 90^th day prior to the date of mailing of the notice for the annual meeting or the 10^th day following the day on which disclosure of the date of mailing for the meeting is made.

123

With respect to special meetings of stockholders, only the business specified in the notice of meeting may be brought before the meeting of stockholders. Nominations of persons for election to ACC's board of directors may be made only:

•: pursuant to the notice of the meeting;
•: by or at the direction of ACC's board of directors; or
•: provided that ACC's board of directors has determined that directors will be elected at such meeting, by a stockholder who is entitled to vote at the meeting and has complied with the advance notice provisions set forth in the bylaws.

Notice must be delivered not earlier than the 120^th day prior to the date of the special meeting and not later than the close of business on the later of the 90^th day prior to the date of the special meeting or the 10^th day following the day on which disclosure of the date of the special meeting is made.

The postponement or adjournment of an annual or special meeting to a later date or time will not commence any new time periods for the giving of the notice described above. The bylaws contain detailed requirements for the contents of stockholder notices of director nominations and new business proposals.

GMH. The bylaws contain provisions similar to those described above.

Limits on Ownership and Transfer of Shares

ACC. ACC's charter has provisions that restrict the ownership of its stock. See "Description of ACC Capital Stock—Restrictions on Ownership."

GMH. The charter provides that no person, other than Gary M. Holloway Sr., certain persons related to Gary M. Holloway Sr., Steven Roth, certain persons related to Steven Roth, Vornado Realty L.P., certain persons related to Vornado Realty L.P., certain transferees or assignees of Vornado Realty L.P. or related persons and affiliates of such transferees or assignees may own, or be deemed to own by virtue of the attribution provisions of the Code, more than 7.1% in value of the outstanding shares of beneficial interest, referred to as the aggregate share ownership limit. In addition, the charter prohibits any person, other than Gary Holloway, certain persons related to Gary Holloway, Steven Roth, certain persons related to Steven Roth, Vornado Realty L.P., certain persons related to Vornado Realty L.P., certain transferees or assignees of Vornado Realty L.P. or related persons and affiliates of such transferees or assignees from acquiring or holding, directly or under applicable ownership attribution rules, common shares in excess of 7.1%, in value or in number of shares, whichever is more restrictive, of the aggregate of the outstanding common shares, referred to as the common share ownership limit. Gary M. Holloway, Sr. and certain related persons and entities are subject to ownership limitations that provide that they may not own, on an aggregate basis, or be deemed to own by virtue of the attribution provisions of the Code, more than 20% in value of the outstanding shares or more than 20%, by value or number of shares, whichever is more restrictive, of the outstanding common shares; provided that 9.9% will be substituted for 20% automatically immediately prior to any event which would cause Gary M. Holloway, Sr. or certain related persons and entities to own, or be treated as owning under the applicable attribution rules, a greater than 9.9% interest in any direct or indirect tenant of GMH's property or any property owned directly or indirectly by the GMH Operating Partnership and such tenant ownership would cause it to fail to satisfy a REIT gross income test. Steven Roth and certain related persons and entities are subject to ownership limitations that provide that they may not own on an aggregate basis, or be deemed to own by virtue of the attribution provisions of the Code, more than 8.5% in value of the outstanding shares or more than 8.5%, by value or number of shares, whichever is more restrictive, of the outstanding common shares. Vornado Realty L.P., certain related persons, certain transferees and assignees of Vornado Realty L.P. or related

124

persons and certain affiliates of such assignees and transferees are not be subject to the ownership limitations with respect to the shares except to the extent that (i) their direct, indirect or constructive ownership of shares would cause it to be treated as "closely held" within the meaning of Section 856(h) of the Code or (ii) any person treated for relevant federal income tax purposes as owning shares owned by such entity owns, directly, indirectly or under applicable constructive ownership rules, shares in excess of the ownership limitation applicable to such person.

The charter further prohibits any person from (a) beneficially or constructively owning shares that would result in GMH being "closely held" under Section 856(h) of the Code or, except in the case of Steven Roth, certain entities related to him, Vornado Realty L.P., certain persons related to Vornado Realty L.P., certain transferees and assignees of Vornado Realty L.P. or related persons and certain affiliates of such assignees and transferees, otherwise cause it to fail to qualify as a REIT or (b) transferring shares if such transfer would result in shares being owned by fewer than 100 persons. Any person who acquires or attempts or intends to acquire beneficial or constructive ownership of shares that will or may violate any of the foregoing restrictions on transferability and ownership, or any person who would have owned shares that resulted in a transfer of shares to the charitable trust, is required to give 15 days' prior written notice to GMH and provide it with such other information as it may request in order to determine the effect of such transfer on its status as a REIT. The foregoing restrictions on transferability and ownership will not apply if GMH's board of trustees determines that it is no longer in its best interests to attempt to qualify, or to continue to qualify, as a REIT.

The charter provides that a person will not be subject to the aggregate share ownership limit or the common share ownership limit if such person has provided GMH's board of trustees with such representations and evidence, and has entered into such agreements and undertakings, as are satisfactory to GMH's board of trustees, in its reasonable discretion, to establish that (i) such person is entitled to the "look-through" treatment with respect to the REIT requirement that not more than 50% of the value of shares may be owned, directly, indirectly or under applicable attribution rules, by five or fewer individuals (as defined to include certain entities), (ii) such person's direct, indirect or constructive ownership of interests in GMH direct or indirect tenants will not adversely affect its ability to qualify as a REIT, (iii) such person's direct, indirect or constructive ownership of shares will not adversely affect its ability to qualify as a REIT and (iv) such person has agreed that shares directly, indirectly or constructively owned by such person in excess of 7.1% of the common shares (as determined by reference to number or value, whichever is more restrictive) or 7.1% of the outstanding shares (as determined by reference to value) will automatically be transferred to a charitable trust as necessary to prevent ownership in excess of those levels from adversely affecting GMH ability to qualify as a REIT. The exemption described in the preceding sentence will automatically cease to apply in the event that such person is or becomes ineligible for the "look-through" treatment described in the preceding sentence and will not prevent the application of the provisions in the declaration of trust relating to ownership of shares in excess of the ownership limitations to shares owned by the person granted an exemption where another person treated under applicable attribution rules as owning shares owned by the person granted an exemption owns, directly, indirectly or under the applicable attribution rules, shares in excess of the ownership limitation applicable to such other person. GMH's board of trustees may grant other exemptions from the ownership limitations in certain circumstances.

Any transfer which, if effective, would result in the shares being owned by fewer than 100 persons will be null and void and the intended transferee will acquire no rights in such shares. In addition, if any transfer of shares or other event occurs which, if effective, would result in any person beneficially or constructively owning shares of beneficial interest in excess or in violation of the other transfer or ownership limitations described above, referred to as a prohibited owner, then that number of shares the beneficial or constructive ownership of which otherwise would cause such person to violate such limitations, rounded to the nearest whole share, will be automatically transferred to a trust, referred to as the charitable trust, for the exclusive benefit of one or more charitable beneficiaries,

125

referred to as the charitable beneficiary, and the prohibited owner will not acquire any rights in such shares. Such automatic transfer will be deemed to be effective as of the close of business on the Business Day, as defined in the declaration of trust, prior to the date of such violative transfer. Shares of beneficial interest transferred to the charitable trust will be issued and outstanding shares of beneficial interest. The prohibited owner will not benefit economically from ownership of any shares of beneficial interest held in the charitable trust, will have no rights to dividends and will not possess any rights to vote or other rights attributable to the shares held in the charitable trust. The trustee of the charitable trust, referred to as the charitable trustee, will have all voting rights and rights to dividends or other distributions with respect to shares, which rights will be exercised for the exclusive benefit of the charitable beneficiary. Any dividend or other distribution paid prior to GMH's discovery that shares have been transferred to the charitable trustee will be paid by the recipient of such dividend or distribution to the charitable trustee upon demand, and any dividend or other distribution authorized but unpaid will be paid when due to the charitable trustee. Any dividend or distribution so paid to the charitable trustee will be held in trust for the charitable beneficiary. The prohibited owner will have no voting rights with respect to shares held in the charitable trust and, subject to Maryland law, effective as of the date that such shares have been transferred to the charitable trust, the charitable trustee will have the authority, at the charitable trustee's sole discretion, (i) to rescind as void any vote cast by a prohibited owner prior to the discovery that such shares have been transferred to GMH and (ii) to recast such vote in accordance with the desires of the charitable trustee acting for the benefit of the charitable beneficiary. However, if GMH has already taken irreversible trust action, then the charitable trustee will not have the authority to rescind and recast such vote.

Within 20 days of receiving notice from GMH that shares have been transferred to the charitable trust, the charitable trustee will sell the shares held in the charitable trust to a person, designated by the charitable trustee, whose ownership of the shares will not violate the ownership limitations set forth in the declaration of trust. Upon such sale, the interest of the charitable beneficiary in the shares sold will terminate and the charitable trustee will distribute the net proceeds of the sale to the prohibited owner and to the charitable beneficiary as follows. The prohibited owner will receive the lesser of (i) the price paid by the prohibited owner for the shares or, if the prohibited owner did not give value for the shares in connection with the event causing the shares to be held in the charter, the market price of such shares on the day of the event causing the shares to be held in the charitable trust and (ii) the price per share received by the charitable trustee from the sale or other disposition of the shares held in the charitable trust. Any net sale proceeds in excess of the amount payable to the prohibited owner will be paid immediately to the charitable beneficiary. If, prior to the discovery that shares have been transferred to the charitable trust, such shares are sold by a prohibited owner, then (i) such shares will be deemed to have been sold on behalf of the charitable trust and (ii) to the extent that the prohibited owner received an amount for such shares that exceeds the amount that such prohibited owner was entitled to receive pursuant to the aforementioned requirement, such excess will be paid to the charitable trustee upon demand.

In addition, shares held in the charitable trust will be deemed to have been offered for sale to GMH, or its designee, at a price per share equal to the lesser of (i) the price per share in the transaction that resulted in such transfer to the charitable trust or, in the case of a devise or gift, the market price at the time of such devise or gift and (ii) the market price on the date GMH, or its designee, accepts such offer. GMH will have the right to accept such offer until the charitable trustee sells the shares held in the charitable trust. Upon such a sale, the interest of the charitable beneficiary in the shares sold will terminate and the charitable trustee will distribute the net proceeds of the sale to the prohibited owner.

126

Stockholder Meetings

Under the Maryland General Corporation Law, a special meeting of stockholders may be called by the President, the board of directors or any other person specified in the entity's charter or bylaws and, unless the charter or bylaws of the entity provide for a lower or higher (not to exceed a majority) threshold, a special meeting of stockholders must be called by the secretary upon the request of stockholders holding 25% of all the votes entitled to be cast at the meeting.

ACC. The bylaws provide that an annual meeting of stockholders is to be held at each year on a date and time set by ACC's board of directors. A special meeting of stockholders may be called by the chairman of ACC's board of directors or chief executive officer and will be called, subject to the advance notice provisions described above upon the written request of stockholders entitled to cast not less than a majority of the votes entitled to be cast at such meeting.

GMH. Under the bylaws, annual meetings of shareholders generally are to be held in June of each year at a date and time as determined by GMH's board of trustees. Special meetings of shareholders may be called only by a majority of the trustees then in office, the chairman of GMH's board of trustees, president or chief executive officer, and must be called upon the written request of the shareholders entitled to cast not less than a majority of all the votes entitled to be cast at such meeting.

Business Combination Act

Maryland law establishes special requirements for "business combinations" (including a merger, consolidation, share exchange or, in certain circumstances, an asset transfer or issuance or reclassification of equity securities) between a Maryland entity and any person who beneficially owns 10% or more of the voting power of the entity's shares or an affiliate of the entity who, at any time within the two-year period prior to the date in question, was the beneficial owner of 10% or more of the voting power of the then outstanding voting stock of the corporation, an interested stockholder, or an affiliate of such an interested stockholder are prohibited for five years after the most recent date on which the interested stockholder becomes an interested stockholder. Thereafter, any such business combination must be recommended by the board of directors of such entity and approved by the affirmative vote of at least (a) 80% of the votes entitled to be cast by holders of outstanding shares of voting stock of the entity and (b) two-thirds of the votes entitled to be cast by holders of voting stock of the entity other than shares held by the interested stockholder with whom (or with whose affiliate) the business combination is to be effected, unless, among other conditions, the entity's common stockholders receive a minimum price (as defined in Maryland law) for their shares and the consideration is received in cash or in the same form as previously paid by the interested stockholder for its shares. These provisions of Maryland law do not apply, however, to business combinations that are approved or exempted by the board of directors prior to the time that the interested stockholder becomes an interested stockholder. In addition, a person is not considered an interested stockholder under the statute if the board of directors approved in advance the transaction by which the person otherwise would have become an interested stockholder.

ACC. ACC has opted out of the business combination provisions through a resolution adopted by ACC's board of directors.

GMH. GMH has opted out of the business combination provisions through a resolution adopted by GMH's board of trustees.

Control Share Acquisition Act

Maryland law provides that "control shares" of a Maryland entity acquired in a "control share acquisition" have no voting rights except to the extent approved at a special meeting by the affirmative

127

vote of two-thirds of the votes entitled to be cast on the matter, excluding shares of stock in a entity in respect of which any of the following persons is entitled to exercise or direct the exercise of the voting power of shares of stock of the entity in the election of directors: (i) a person who makes or proposes to make a control share acquisition; (ii) an officer of the entity; or (iii) an employee of the entity who is also a director of the entity. "Control shares" are voting shares which, if aggregated with all other such shares previously acquired by the acquirer or in respect of which the acquirer is able to exercise or direct the exercise of voting power (except solely by virtue of a revocable proxy), would entitle the acquirer to exercise voting power in electing directors within one of the following ranges of voting power: (i) one-tenth or more but less than one-third; (ii) one-third or more but less than a majority; or (iii) a majority or more of all voting power. Control shares do not include shares the acquiring person is then entitled to vote as a result of having previously obtained stockholder approval. A "control share acquisition" means the acquisition of control shares, subject to certain exceptions.

A person who has made or proposes to make a control share acquisition, upon satisfaction of certain conditions (including an undertaking to pay expenses), may compel the board of directors to call a special meeting of stockholders to be held within 50 days of demand to consider the voting rights of the shares. If no request for a meeting is made, the entity may itself present the question at any stockholders' meeting.

If voting rights are not approved at the meeting or if the acquiring person does not deliver an acquiring person statement as required by the statute, then, subject to certain conditions and limitations, the entity may redeem any or all of the control shares (except those for which voting rights have previously been approved) for fair value determined, without regard to the absence of voting rights for the control shares, as of the date of the last control share acquisition by the acquirer or of any meeting of stockholders at which the voting rights of such shares are considered and not approved. If voting rights for control shares are approved at a stockholders' meeting and the acquirer becomes entitled to vote a majority of the shares entitled to vote, all other stockholders may exercise appraisal rights. The fair value of the shares as determined for purposes of such appraisal rights may not be less than the highest price per share paid by the acquirer in the control share acquisition.

The control share acquisition statute does not apply (a) to shares acquired in a merger, consolidation or share exchange if the entity is a party to the transaction or (b) to acquisitions approved or exempted by the charter or bylaws of the entity.

ACC. ACC has opted out of the control share provisions through a provision in its bylaws. There can be no assurance that ACC's board of directors will not amend or eliminate this provision of its bylaws in the future.

GMH. GMH has opted out of the control share provisions through a provision in its bylaws. There can be no assurance that GMH's board of trustees will not amend or eliminate this provision of the bylaws in the future.

128

DESCRIPTION OF ACC CAPITAL STOCK

General

Authorized Shares

ACC's charter provides that it may issue up to 800,000,000 shares of its common stock, $0.01 par value per share, and 200,000,000 shares of preferred stock, $0.01 par value per share. As of the date of this proxy statement/prospectus, 36,561,222 shares of common stock and no shares of preferred stock are issued and outstanding.

Authority of the Board of Directors Relating to Authorized Shares

ACC's charter authorizes its board of directors to amend the charter to increase or decrease the total number of authorized shares, or the number of shares of any class or series of capital stock that it has authority to issue, without stockholder approval. ACC's board of directors also has the authority, under the charter and without stockholder approval, to classify any unissued shares of common or preferred stock into one or more classes or series of stock and to reclassify any previously classified but unissued shares of any series of common or preferred stock. If, however, there are any laws or stock exchange rules that require ACC to obtain stockholder approval in order for it to take these actions, ACC will contact its stockholders to solicit that approval.

ACC believes that the power to issue additional shares of common stock or preferred stock and to classify or reclassify unissued shares of common or preferred stock and then issue the classified or reclassified shares provides it with increased flexibility in structuring possible future financings and acquisitions and in meeting other needs that may arise in the future. These actions can be taken without stockholder approval, unless stockholder approval is required by applicable law or the rules of any stock exchange or automated quotation system on which its securities may be listed or traded. Although ACC's board of directors has no present intention of doing so, it could issue a class or series of stock that could delay, defer or prevent a transaction or a change of control that would involve a premium price for holders of common stock or otherwise be favorable to them.

Terms and Conditions of Authorized Shares

Prior to issuance of shares of each class or series, ACC's board of directors is required by Maryland law and the charter to set, subject to the provisions of the charter regarding restrictions on transfer of stock, the terms, preferences, conversion or other rights, voting powers, restrictions, limitations as to dividends or other distributions, qualifications and terms or conditions of exchange for each class or series. As a result, ACC's board of directors could authorize the issuance of shares of common stock or preferred stock with terms and conditions that could have the effect of delaying, deferring or preventing a transaction or a change of control that would involve a premium price for holders of the common stock or otherwise be favorable to them.

Stockholder Liability

Applicable Maryland law provides that ACC stockholders will not be personally liable for its acts and obligations and that its funds and property will be the only recourse for its acts and obligations.

Common Stock

All shares of ACC common stock are duly-authorized, fully-paid and nonassessable. Subject to the preferential rights of any other class or series of stock and to the provisions of the charter regarding restrictions on transfer of stock, holders of shares of common stock are entitled to receive distributions on such stock if, as and when authorized by ACC's board of directors out of assets legally

129

available for the payment of distributions, and declared by ACC, and to share ratably in its assets legally available for distribution to its stockholders in the event of its liquidation, dissolution or winding up, after payment of or adequate provision for all of its known debts and liabilities.

Subject to the provisions of its charter regarding restrictions on transfer of stock, as described in more detail below under "—Restrictions on Transfer," each outstanding share of ACC common stock entitles the holder to one vote on all matters submitted to a vote of stockholders, including the election of directors and, except as provided with respect to any other class or series of stock, the holders of common stock will possess the exclusive voting power. There is no cumulative voting in the election of directors. Under Maryland law, the holders of a plurality of the votes cast at a meeting at which directors are to be elected is sufficient to elect a director unless a corporation's charter or bylaws provide otherwise. ACC's bylaws provide for such plurality voting in the election of directors.

Holders of shares of common stock have no preference, conversion, exchange, sinking fund, redemption or appraisal rights and have no preemptive or other rights to subscribe for any of ACC's securities. Subject to the provisions of the charter regarding the restrictions on transfer of stock, shares of common stock will have equal dividend, liquidation and other rights.

Preferred Stock

Under ACC's charter, ACC's board of directors may from time to time establish and issue one or more series of preferred stock without stockholder approval. Prior to issuance of shares of each series, ACC's board of directors is required by Maryland law and the charter to set, subject to the provisions of the charter regarding restrictions on transfer of stock, the terms, preferences, conversion or other rights, voting powers, restrictions, limitations as to dividends or other distributions, qualifications and terms or conditions of redemption for each series. As of the date of this proxy statement/prospectus, no shares of preferred stock are outstanding and ACC has no present plans to issue any preferred stock.

Restrictions on Transfer

In order for ACC to qualify as a REIT under the Code, its stock must be beneficially owned by 100 or more persons during at least 335 days of a taxable year of 12 months (other than the first year for which an election to be a REIT has been made) or during a proportionate part of a shorter taxable year. Also, not more than 50% of the value of the outstanding shares of stock may be owned, directly or indirectly, by five or fewer individuals (as defined in the Code to include certain entities such as qualified pension plans) during the last half of a taxable year (other than the first year for which an election to be a REIT has been made).

ACC's charter contains restrictions on the ownership and transfer of its stock that are intended to assist it in complying with these requirements and continuing to qualify as a REIT. The relevant sections of the charter provide that, subject to the exceptions described below, no person or entity may beneficially own, or be deemed to own by virtue of the applicable constructive ownership provisions of the Code, more than 9.8% (by value or by number of shares, whichever is more restrictive) of the outstanding shares of common stock or more than 9.8% by value of all of the outstanding shares, including both common and preferred stock. This restriction is referred to as the "ownership limit." A person or entity that becomes subject to the ownership limit by virtue of a violative transfer that results in a transfer to a trust, as set forth below, is referred to as a "purported beneficial transferee" if, had the violative transfer been effective, the person or entity would have been a record owner and beneficial owner or solely a beneficial owner of ACC stock, or is referred to as a "purported record transferee" if, had the violative transfer been effective, the person or entity would have been solely a record owner of ACC's stock.

130

The constructive ownership rules under the Code are complex and may cause stock owned actually or constructively by a group of related individuals and/or entities to be owned constructively by one individual or entity. As a result, the acquisition of less than 9.8% of stock (or the acquisition of an interest in an entity that owns, actually or constructively, ACC's stock) by an individual or entity, could, nevertheless cause that individual or entity, or another individual or entity, to own constructively in excess of 9.8% of ACC's outstanding stock and thereby subject the stock to the applicable ownership limit.

ACC's board of directors must waive the ownership limit with respect to a particular person if it:

•: determines that such ownership will not cause any individual's beneficial ownership of shares of ACC's stock to violate the ownership limit and that any exemption from the ownership limit will not jeopardize its status as a REIT; and
•: determines that such stockholder does not and will not own, actually or constructively, an interest in a tenant of ACC (or a tenant of any entity whose operations are attributed in whole or in part to it) that would cause ACC to own, actually or constructively, more than a 9.8% interest (as set forth in Section 856(d)(2)(B) of the Code) in such tenant or that any such ownership would not cause ACC to fail to qualify as a REIT under the Code.

As a condition of a waiver, ACC's board of directors may require the applicant to submit such information as ACC's board of directors may reasonably need to make the determinations regarding ACC's REIT status and additionally may require an opinion of counsel or IRS ruling satisfactory to ACC's board of directors, and/or representations or undertakings from the applicant with respect to preserving its REIT status.

In connection with the waiver of the ownership limit or at any other time, ACC's board of directors may increase the ownership limitation for some persons and decrease the ownership limit for all other persons and entities; provided, however, that the decreased ownership limit will not be effective for any person or entity whose percentage ownership in ACC's stock is in excess of such decreased ownership limit until such time as such person or entity's percentage of its stock equals or falls below the decreased ownership limit, but any further acquisition of its stock in excess of such percentage ownership of its common stock will be in violation of the ownership limit. Additionally, the new ownership limit may not allow five or fewer stockholders to beneficially own more than 50% in value of ACC's outstanding stock.

The charter provisions further prohibit:

•: any person from beneficially or constructively owning shares of ACC's stock that would result in it being "closely held" under Section 856(h) of the Code or otherwise cause it to fail to qualify as a REIT; and
•: any person from transferring shares of ACC's stock if such transfer would result in shares of its stock being beneficially owned by fewer than 100 persons (determined without reference to any rules of attribution).

Any person who acquires or attempts or intends to acquire beneficial or constructive ownership of shares of ACC's stock that will or may violate any of the foregoing restrictions on transferability and ownership will be required to give notice immediately to ACC and provide it with such other information as it may request in order to determine the effect of such transfer on its status as a REIT. The foregoing provisions on transferability and ownership will not apply if ACC's board of directors determines that it is no longer in ACC's best interests to attempt to qualify, or to continue to qualify, as a REIT.

131

Pursuant to the charter, if any purported transfer of ACC's stock or any other event would otherwise result in any person violating the ownership limits or such other limit as permitted by ACC's board of directors, then any such purported transfer will be void and of no force or effect as to that number of shares in excess of the ownership limit (rounded up to the nearest whole share). That number of shares in excess of the ownership limit will be automatically transferred to, and held by, a trust for the exclusive benefit of one or more charitable organizations selected by ACC. The automatic transfer will be effective as of the close of business on the business day prior to the date of the violative transfer or other event that results in a transfer to the trust. Any dividend or other distribution paid to the purported record transferee, prior to the discovery that the shares had been automatically transferred to a trust as described above, must be repaid to the trustee upon demand for distribution to the beneficiary of the trust. If the transfer to the trust as described above is not automatically effective, for any reason, to prevent violation of the applicable ownership limit or as otherwise permitted by ACC's board of directors, then the charter provides that the transfer of the excess shares will be void.

Shares of ACC's stock transferred to the trustee are deemed offered for sale to ACC, or its designee, at a price per share equal to the lesser of (i) the price paid by the purported record transferee for the shares (or, if the event which resulted in the transfer to the trust did not involve a purchase of such shares of its stock at market price, the last reported sales price reported on the NYSE on the trading day immediately preceding the day of the event which resulted in the transfer of such shares of ACC's stock to the trust); and (ii) the market price on the date ACC, or its designee, accepts such offer. ACC has the right to accept such offer until the trustee has sold the shares of stock held in the trust pursuant to the clauses discussed below. Upon a sale to ACC, the interest of the charitable beneficiary in the shares sold terminates and the trustee must distribute the net proceeds of the sale to the purported record transferee and any dividends or other distributions held by the trustee with respect to such stock will be paid to the charitable beneficiary.

If ACC does not buy the shares, the trustee must, within 20 days of receiving notice from ACC of the transfer of shares to the trust, sell the shares to a person or entity designated by the trustee who could own the shares without violating the ownership limits or as otherwise permitted by ACC's board of directors. After that, the trustee must distribute to the purported record transferee an amount equal to the lesser of (i) the price paid by the purported record transferee or owner for the shares (or, if the event which resulted in the transfer to the trust did not involve a purchase of such shares at market price, the last reported sales price reported on the NYSE on the trading day immediately preceding the relevant date); and (ii) the sales proceeds (net of commissions and other expenses of sale) received by the trust for the shares. The purported beneficial transferee or purported record transferee has no rights in the shares held by the trustee.

The trustee will be designated by ACC and will be unaffiliated with ACC and with any purported record transferee or purported beneficial transferee. Prior to the sale of any excess shares by the trust, the trustee will receive, in trust for the beneficiary, all dividends and other distributions paid by ACC with respect to the excess shares, and may also exercise all voting rights with respect to the excess shares.

Subject to Maryland law, effective as of the date that the shares have been transferred to the trust, the trustee will have the authority, at the trustee's sole discretion:

•: to rescind as void any vote cast by a purported record transferee prior to ACC's discovery that the shares have been transferred to the trust; and
•: to recast the vote in accordance with the desires of the trustee acting for the benefit of the beneficiary of the trust.

132

However, if ACC has already taken irreversible corporate action, then the trustee may not rescind and recast the vote.

Any beneficial owner or constructive owner of shares of ACC's stock and any person or entity (including the stockholder of record) who is holding shares of its stock for a beneficial owner must, on request, provide ACC with a completed questionnaire containing the information regarding their ownership of such shares, as set forth in the applicable Treasury Regulations. In addition, any person or entity that is a beneficial owner or constructive owner of shares of ACC's stock and any person or entity (including the stockholder of record) who is holding shares of such stock for a beneficial owner or constructive owner will, on request, be required to disclose to ACC in writing such information as it may request in order to determine the effect, if any, of such stockholder's actual and constructive ownership of shares of ACC's stock on its status as a REIT and to ensure compliance with the ownership limit, or as otherwise permitted by ACC's board of directors.

All certificates representing shares of ACC's stock bear a legend referring to the restrictions described above.

This ownership limit could delay, defer or prevent a transaction or a change of control of ACC that might involve a premium price for its stock or otherwise be in the best interest of its stockholders.

Transfer Agent and Registrar

The transfer agent and registrar for ACC's common stock is BNY Mellon Shareowner Services.

133

SELLING STOCKHOLDERS

Exchange of Units

Pursuant to the merger agreement, each unit in the GMH Operating Partnership will be entitled to receive at the closing of the REIT merger 0.07642 of a share of ACC common stock and $3.36 in cash, without interest, except, subject to certain conditions, in lieu of the receipt of ACC common stock, the holders of units in the GMH Operating Partnership may elect to receive 0.07642 of a common unit in the ACC Operating Partnership. The units issued in the partnership merger will not be exchangeable for ACC common stock until one year from the closing date of the mergers without the prior written consent of ACC.

The rights of unitholders to exchange their units for common stock were granted in the Amended and Restated Agreement of Limited Partnership of the ACC Operating Partnership, dated as of August 17, 2004, as amended. The following summary of the exchange rights of unitholders is not complete. You should read, in their entirety, the partnership agreement and the amendments that are filed as exhibits to the registration statement of which this proxy statement/prospectus is a part. To obtain a copy of these documents, see "Where You Can Find More Information."

Unitholders have the right to require ACC to acquire all or a portion of their units in exchange for, at ACC's election, cash or common stock by delivering a notice of exchange substantially in the form of Exhibit B to the partnership agreement. The general partner will promptly give the tendering holder written notice of its election, and the tendering holder may elect to withdraw its exchange request at any time prior to the acceptance of the cash or shares by such tendering holder. Without the consent of the general partner, no unitholder effecting an exchange of all or a portion of its units is entitled to tender less than 1,000 units for exchange at any one time, unless such lesser amount is all of the units then owned by the exchanging holder. The consent of the general partner is also required to effect an exchange during the period after a record date with respect to a distribution to unitholders and before the record date for a distribution to stockholders.

Upon exchange, the exchanging holder will receive either an equal number of shares of common stock or, at ACC's election, an amount of cash equal to the fair market value of such number of shares. The number of shares will be adjusted:

•: if ACC, under certain circumstances, acquires material assets, other than on behalf of the ACC Operating Partnership; or
•: for stock dividends, stock splits and subdivisions, reverse stock splits and combinations, distributions of rights, warrants or options, and distributions of evidences of indebtedness or assets relating to assets ACC does not receive pursuant to a pro rata distribution by the ACC Operating Partnership.

If ACC elects to deliver cash in lieu of all or any portion of the shares, the exchanging holder will receive shares valued at the average of the daily closing prices for the five consecutive trading days immediately preceding the date of receipt of a notice of exchange.

On the tenth day after ACC's receipt of the notice of exchange, it will deliver to the exchanging holder the number of shares of common stock to be exchanged or, at ACC's election, cash, each in an amount determined as described above. The common stock to be delivered will be duly authorized, validly issued, fully paid and nonassessable, and, if applicable, free of any pledge, lien, encumbrance or restriction, other than those provided in the charter, bylaws, the Securities Act, relevant state securities or blue sky laws and any applicable registration rights agreement with respect to such shares entered into by the exchanging holder. Notwithstanding any delay in such delivery, except as described in the next paragraph, the exchanging holder will be deemed the owner of such

134

shares for all purposes, including rights to vote or consent, and receive dividends, as of the date of the notice of exchange.

Notwithstanding any other provision of the partnership agreement, a unitholder will not be entitled to effect an exchange for cash or an exchange for common stock to the extent the ownership or right to acquire common stock pursuant to such exchange by such holder on the date of the notice of the exchange could cause such holder or any other person to violate the restrictions on ownership and transfer of common stock set forth in the charter and will have no rights under the partnership agreement to acquire common stock that would otherwise be prohibited under ACC's charter. To the extent any attempted exchange or exchange would be in violation of the provisions described in this paragraph, it will be null and void and such holder will not acquire any rights or economic interest in the cash otherwise payable upon such redemption or the common stock otherwise issuable upon such exchange.

Each unitholder will continue to own all units subject to redemption or exchange, and be treated as a limited partner with respect to such units for all purposes of the partnership agreement, until such units are transferred and paid for or exchanged. Until so exchanged, the exchanging holder will have no rights as a stockholder with respect to such holder's units.

In the partnership agreement, each unitholder agreed with ACC that all tendered units will be delivered to ACC free and clear of all liens, claims and encumbrances and should any such lien, claim and/or encumbrance exist or arise with respect to such tendered units, it will be under no obligation to acquire the same. Each unitholder also agreed that, in the event any state or local property transfer tax is payable as a result of the transfer of its tendered units, such holder will assume and pay such transfer tax.

Selling Stockholders

The shares of ACC's common stock issuable upon conversion of ACC common units that may be received in the partnership merger in lieu of ACC common stock are being registered to permit secondary public trading of the common stock by holders. Subject to the restrictions described in this proxy statement/prospectus, the selling stockholders, or their pledgees, donees, transferees or other successors in interest, may offer the underlying shares for resale from time to time. The underlying shares, as to their resale, under this proxy statement/prospectus include shares issuable upon conversion of the ACC common units, including any additional shares issuable to prevent dilution as a result of stock splits, stock dividends or similar events. In addition, subject to the restrictions described in this proxy statement/prospectus, the selling stockholders may sell, transfer or otherwise dispose of a portion of the underlying shares in transactions exempt from the registration requirements of the Securities Act. See "—Plan Of Distribution."

The following table sets forth the number of shares of common stock and units held by the selling stockholders as of March 31, 2008 and the maximum number of underlying shares that may be sold by the selling stockholders, or by any of their pledgees, donees, transferees or other successors in interest. Each unit may be exchanged for one share of common stock, subject to adjustment. In lieu of issuing common stock upon the exchange of the units, ACC may, at its option, issue cash in an amount equal to the fair market value of an equivalent number of shares of its common stock. The table is prepared based on information from the selling stockholders. Based on such information, no selling stockholder is a registered broker-dealer or an affiliate of a broker-dealer. Since the selling stockholders may sell all, some or none of their underlying shares, no estimate can be made of the aggregate number of underlying shares that are to be offered by the selling stockholders under this

135

proxy statement/prospectus or that will be owned by each selling stockholder upon completion of the transactions to which this proxy statement/prospectus relates.

Selling Stockholder	Underlying GMH Units Held	Number of ACC Units Held	Maximum Number of Underlying Shares to be Sold
Gary M. Holloway, Sr.	15,673,038	1,197,734	1,197,734
College Park Management, Inc.	1,250,000	95,525	95,525
GMH Associates, Inc.	53,291	4,072	4,072
LVWD, Ltd.	12,500	955	955
FW Military Housing LLC	2,583,334	197,418	197,418
Vornado Realty L.P.	6,666,667	509,467	509,467
Vornado CCA Gainesville, L.L.C.	671,190	51,292	51,292
Denise Hubley	84,170	6,432	6,432
James W. Kirby	29,167	2,229	2,229
Austin Repetto	29,167	2,229	2,229
Joseph Macchione	62,500	4,776	4,776
Ken Aspis	26,467	2,023	2,023
Candee Evelhoch	20,833	1,592	1,592
Don Blair	20,833	1,592	1,592
Christopher Williams	43,334	3,312	3,312
Richard C. Taylor	62,500	4,776	4,776
Bruce F. Robinson	1,010,306	77,208	77,208
John DeRiggi	251,250	19,201	19,201
Miles Orth	41,667	3,184	3,184
Joseph M. Coyle Enterprises, Inc.	422,769	32,308	32,308
Gary M Holloway, Jr.	125,000	9,553	9,553
Frank Tropea, III	418,750	32,001	32,001
Robert DiGiuseppe	85,602	6,542	6,542

Total	29,644,335	2,265,420	2,265,420

Plan of Distribution

The selling stockholders and any of their pledgees, donees, transferees and successors-in-interest may, from time to time, sell any or all of their underlying shares on any stock exchange, market or trading facility on which the shares are traded or in private transactions. The selling stockholders may use any one or more of the following methods when selling underlying shares:

•: ordinary brokerage transactions and transactions in which the broker-dealer solicits purchasers;
•: block trades in which the broker-dealer will attempt to sell the shares as agent but may position and resell a portion of the block as principal to facilitate the transaction;
•: purchases by a broker-dealer as principal and resale by the broker-dealer for its account;
•: an exchange distribution in accordance with the rules of the applicable exchange;
•: privately negotiated transactions;
•: settlement of short sales;

136

•: broker-dealers may agree with the selling stockholders to sell a specified number of such shares at a stipulated price per share;
•: a combination of any such methods of sale; and
•: any other method permitted pursuant to applicable law.

The selling stockholders may also sell underlying shares under Rule 144 under the Securities Act, if available, rather than under this proxy statement/prospectus. Broker-dealers engaged by the selling stockholders may arrange for other broker-dealers to receive commissions or discounts from the selling stockholders (or, if any broker-dealer acts as agent to the purchase of shares, from the purchaser) in amounts to be negotiated. The selling stockholders do not expect these commissions and discounts to exceed what is customary in the types of transactions involved.

The selling stockholders may from time to time pledge or grant a security interest in some or all of the units or common stock owned by them and, if they default in the performance of their secured obligations, the pledgees or secured parties may offer and sell the common stock from time to time under this prospectus, or under an amendment to this prospectus under Rule 424(b)(3) or other applicable provisions of the Securities Act, amending the list of selling stockholders to include the pledgee, transferee or other successor-in-interest as a selling stockholder under this prospectus.

The selling stockholders may also transfer the underlying shares in other circumstances, in which case the pledgees, donees, transferees or other successors in interest will be the selling beneficial owners for purposes of this prospectus.

The selling stockholders and any broker-dealers or agents that are involved in selling the underlying shares may be deemed to be "underwriters" within the meaning of the Securities Act in connection with such sales. In such event, any commissions received by such broker-dealers or agents and any profit on the resale of the shares purchased by them may be deemed to be underwriting commissions or discounts under the Securities Act. The selling stockholders have informed ACC that none of them have any agreement or understanding, directly or indirectly, with any person to distribute the underlying shares.

ACC will pay all fees and expenses incurred by it incident to the registration of the underlying shares.

SHAREHOLDER PROPOSALS

Due to the contemplated completion of the mergers, GMH does not intend to hold a 2008 annual meeting of shareholders. If however, the mergers are not completed and the GMH 2008 annual meeting is held, shareholder proposals intended to be presented at the meeting must have been received by GMH no later than January 8, 2008 in order to be included in the proxy statement and form of proxy relating to that meeting. In order to be included in the proxy statement, such proposals must have complied with the requirements as to form and substance established by the SEC for such proposals. However, if the date of the 2008 annual meeting changes by more than 30 days from the date of the 2007 annual meeting of shareholders, the deadline for shareholder proposals to be included in the proxy statement is a reasonable time before GMH begins to print and mail its proxy materials. GMH intends to inform its shareholders as promptly as practicable in the event it does so change the date of the 2008 annual meeting. A shareholder who wishes to make a proposal at the GMH 2008 annual meeting without submitting the proposal in the proxy statement and form of proxy relating to the meeting, must comply with the notice and other requirements set forth in GMH's current bylaws. Pursuant to GMH's bylaws, that notice must have been submitted in writing and delivered to the corporate secretary of GMH at the principal executive office of GMH between December 9, 2007 and 5:00 p.m., local time, on January 8, 2008.

137

LEGAL MATTERS

The material U.S. federal income tax consequences to GMH shareholders of the REIT merger, military sale distributions and special distribution as described in "Material U.S. Federal Income Tax Considerations—Material U.S. Federal Income Tax Consequences to GMH Shareholders of the REIT Merger and Distributions" have been passed on by Goodwin Procter LLP. The material U.S. federal income tax matters described in "Material U.S. Federal Income Tax Considerations—Material U.S. Federal Income Tax Considerations Applicable to Holders of ACC Common Stock" have been passed on by Locke Lord Bissell & Liddell LLP, Dallas, Texas.

EXPERTS

The consolidated financial statements of American Campus Communities, Inc. and its subsidiaries appearing in American Campus Communities, Inc.'s Annual Report (Form 10-K) for the year ended December 31, 2007 and ACC management's assessment of the effectiveness of internal control over financial reporting as of December 31, 2007 included therein, have been audited by Ernst & Young LLP, independent registered public accounting firm, as set forth in their report included therein, and incorporated herein by reference. Such financial statements and management's assessment have been incorporated herein by reference and included herein, respectively, in reliance upon such reports given on the authority of such firm as experts in accounting and auditing.

The consolidated financial statements and schedules of GMH Communities Trust for the fiscal years ended December 31, 2006 and 2007 appearing in GMH Communities Trust's Annual Report (Form 10-K/A) for the year ended December 31, 2007, and GMH management's assessment of the effectiveness of internal control over financial reporting as of December 31, 2007 included therein, have been audited by Reznick Group, P.C., independent registered public accounting firm, as set forth in their report included therein, and incorporated herein by reference. Such financial statements and management's assessment have been incorporated herein by reference and included herein, respectively, in reliance upon such reports given on the authority of such firm as experts in accounting and auditing.

The consolidated financial statements and schedules of GMH Communities Trust for the fiscal year ended December 31, 2005 appearing in GMH Communities Trust's Annual Report (Form 10-K) for the year ended December 31, 2007 have been audited by Ernst & Young LLP, independent registered public accounting firm, as set forth in their report thereon included therein, and incorporated herein by reference. Such consolidated financial statements have been incorporated herein by reference in reliance upon such report given on the authority of such firm as experts in accounting and auditing.

138

WHERE YOU CAN FIND MORE INFORMATION

ACC and GMH each file annual, quarterly and special reports, proxy statements and other information with the SEC. You may read and copy any reports, statements or other information ACC and GMH file at the SEC's Public Reference Room, 100 F Street, NE, Washington, DC 20549. Please call the SEC at 1-800-SEC-0330 for further information on the public reference rooms. ACC's and GMH's SEC filings are also available to the public from commercial document retrieval services and at the web site maintained by the SEC at "www.sec.gov." You may inspect information that ACC and GMH file with the NYSE at the offices of the NYSE at 20 Broad Street, New York, New York 10005.

ACC filed a registration statement on Form S-4 to register with the SEC any ACC common stock to be issued to GMH shareholders and unitholders in the mergers as well as the underlying shares. This proxy statement/prospectus is a part of that registration statement and constitutes a prospectus of ACC in addition to being a proxy statement of GMH for the special meeting. As allowed by SEC rules, this proxy statement/prospectus does not contain all the information you can find in the registration statement or the exhibits to the registration statement.

The SEC allows ACC and GMH to "incorporate by reference" information into this proxy statement/prospectus, which means that ACC and GMH can disclose important information to you by referring you to another document filed separately with the SEC. This proxy statement/prospectus incorporates by reference the documents set forth below that ACC and GMH have previously filed with the SEC. These documents contain important information about ACC and GMH and their finances.

ACC SEC Filings (File No. 001-32265)		Period
Annual Report on Form 10-K		Year ended December 31, 2007
Current Reports on Form 8-K		Dated February 12, 2008, February 14, 2008, February 27, 2008, March 11, 2008 and April 21, 2008
Registration Statement on Form 8-A		Dated August 4, 2004, setting forth the description of ACC common stock, including any amendments or reports filed for the purpose of updating such description

GMH SEC Filings (File No. 001-32290)		Period
Annual Report on Form 10-K		Year ended December 31, 2007, as amended by Amendment No. 1 to Form 10-K/A filed on Form 10-K/A on March 28, 2008
Current Reports on Form 8-K		Dated February 12, 2008, February 14, 2008, February 29, 2008, February 25, 2008 and March 25, 2008
Registration Statement on Form 8-A		Dated September 2, 2004, setting forth the description of GMH common shares, including any amendments or reports filed for the purpose of updating such description

The information incorporated by reference is deemed to be part of this proxy statement/prospectus. Any statement contained in a document incorporated or deemed to be incorporated by reference in this proxy statement/prospectus will be deemed modified, superseded or replaced for purposes of this proxy statement/prospectus to the extent that a statement contained in this proxy statement/prospectus or in any subsequently filed document that also is or is deemed to be incorporated by reference in this proxy statement/prospectus modifies, supersedes or replaces such statement. Any statement so modified, superseded or replaced will not be deemed, except as so modified, superseded or replaced, to constitute a part of this proxy statement/prospectus.

ACC has supplied all information contained or incorporated by reference in this proxy statement/prospectus relating to ACC, and GMH has supplied all such information relating to GMH.

139

If you are a shareholder, ACC or GMH may have sent you some of the documents incorporated by reference, but you can obtain any of them through ACC or GMH or the SEC. Documents incorporated by reference are available from ACC and GMH without charge, excluding all exhibits unless ACC and GMH have specifically incorporated by reference an exhibit in this proxy statement/prospectus. Shareholders may obtain documents incorporated by reference in this proxy statement/prospectus by requesting them in writing or by telephone from the appropriate party at the following addresses:

American Campus Communities, Inc.
805 Las Cimas Parkway, Suite 400
Austin, Texas 78746
Attention: Investor Relations
Telephone: (512) 732-1000

GMH Communities Trust
10 Campus Boulevard
Newtown Square, Pennsylvania 19073
Attention: Investor Relations
Telephone: (610) 355-8000

If you would like to request documents from ACC or GMH, please do so by June 3, 2008 to receive them before the special meeting.

You should rely only on the information contained or incorporated by reference in this proxy statement/prospectus to vote on the proposals. GMH has not authorized anyone to provide you with information that is different from what is contained in this proxy statement/prospectus. This proxy statement/prospectus is dated April , 2008. You should not assume that the information contained in this proxy statement/prospectus is accurate as of any date other than April , 2008, and neither the mailing of this proxy statement/prospectus to shareholders nor the issuance of ACC common stock in the merger will create any implication to the contrary.

140

AMERICAN CAMPUS COMMUNITIES, INC. AND SUBSIDIARIES

INDEX TO UNAUDITED PRO FORMA CONSOLIDATED FINANCIAL STATEMENTS

Unaudited Pro Forma Consolidated Financial Statements		F-1
Pro Forma Consolidated Balance Sheet (Unaudited) as of December 31, 2007		F-4
Pro Forma Consolidated Income Statement (Unaudited) for the Year Ended December 31, 2007		F-5
Notes to Pro Forma Financial Information		F-6

F-1

American Campus Communities, Inc. ("ACC") has entered into an Agreement and Plan of Merger, dated as of February 11, 2008 (the "Merger Agreement"), with GMH Communities Trust, a Maryland real estate investment trust ("GMH"), GMH Communities, Inc., a Delaware corporation and a wholly owned subsidiary of GMH, GMH Communities, LP, a Delaware limited partnership (the "GMH Operating Partnership"), American Campus Communities Operating Partnership LP, a Maryland limited partnership (the "ACC Operating Partnership"), American Campus Acquisition LLC, a Delaware limited liability company and a wholly owned subsidiary of the ACC Operating Partnership, and American Campus Acquisition Limited Partnership LP, a Delaware limited partnership and a wholly-owned subsidiary of the ACC Operating Partnership.

Each common share of GMH and each unit in the GMH Operating Partnership will be entitled to receive at the closing of the mergers contemplated by the Merger Agreement (the "Mergers") (i) 0.07642 of a share of ACC's common stock and (ii) $3.36 in cash, except, subject to certain conditions, in lieu of the receipt of ACC common stock, the holders of units in the GMH Operating Partnership may elect to receive 0.07642 of a unit in the ACC Operating Partnership.

The historical consolidated financial statements of ACC and GMH are contained in the companies' respective Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and other information filed with the Securities and Exchange Commission and incorporated by reference into this proxy statement/prospectus. The unaudited pro forma consolidated financial statements should be read in conjunction with, and are qualified in their entirety by, the notes thereto and the historical consolidated financial statements of both companies, including the respective notes thereto, which are incorporated by reference in this proxy statement/prospectus.

The accompanying unaudited pro forma consolidated balance sheet as of December 31, 2007 has been prepared to reflect the effect of the Mergers and the previous sale by GMH of approximately $96 million of assets related to its military housing division, as if such transactions had occurred on December 31, 2007. The accompanying unaudited pro forma consolidated statement of operations for the year ended December 31, 2007 has been prepared to reflect the effect of the Mergers and the previous sale by GMH of approximately $96 million of assets related to its military housing division, as if such transactions had occurred on January 1, 2007.

The unaudited pro forma consolidated financial statements also give effect to properties acquired by ACC during 2007, ACC's October 2007 offering of 3.5 million shares of its common stock, the reclassification of 10 properties owned by GMH from continuing operations to discontinued operations and the formation of a joint venture by ACC and Fidelity Real Estate Growth Fund III, L.P. ("Fidelity") with respect to 15 properties owned by GMH, but do not give effect to the results of operations of ACC or GMH subsequent to December 31, 2007, including ACC's offering of 9.2 million shares of its common stock that closed on April 23, 2008.

In the opinion of management, the pro forma consolidated financial information provides for all significant adjustments necessary to reflect the effects of the above transactions. The pro forma adjustments and the purchase price allocation, as presented, are based on estimates and certain information that is currently available to ACC's management.

The pro forma information is unaudited and is not necessarily indicative of the consolidated results that would have occurred if the transactions and adjustments reflected therein had been consummated in the period or on the date presented, or on any particular date in the future, nor does it purport to represent the financial position, results of operations or cash flows for future periods.

The Mergers have a total value of approximately $1.4 billion, including GMH's outstanding debt totaling approximately $962 million and approximately $452 million in equity value. ACC has received financing commitments totaling $200 million, which it intends to use to fund a portion of the total cash consideration to be paid in the Mergers.

F-2

The purchase price is determined as follows (in thousands, except per share data):

Outstanding GMH common shares (including the assumed conversion of partnership units prior to the Mergers)			71,314.2

Cash consideration ($3.36 per share)		$	239,615.8
Common share consideration ($2.17 per share)(1)			154,938.7
Estimated merger costs (see below)			57,400.0

Total consideration paid			451,954.5
Assumption of GMH mortgages			961,531.0

	Total purchase price	$