Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
TA ASSOCIATES INC
  2. Issuer Name and Ticker or Trading Symbol
IPG PHOTONICS CORP [IPGP]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director _____ 10% Owner
_____ Officer (give title below) __X__ Other (specify below)
See General Remarks
(Last)
(First)
(Middle)
JOHN HANCOCK TOWER, 200 CLARENDON ST, 56TH FLOOR
3. Date of Earliest Transaction (Month/Day/Year)
10/18/2007
(Street)

BOSTON, MA 02116
4. If Amendment, Date Original Filed(Month/Day/Year)
6. Individual or Joint/Group Filing(Check Applicable Line)
___ Form filed by One Reporting Person
_X_ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)
2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)
4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)
5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)
6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)
7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Stock 10/18/2007   S   11,203 (1) D $ 21.9646 1,470,298 (6) (11) D  
Common Stock 10/18/2007   S   5,231 (2) D $ 21.9646 686,520 (7) (11) D  
Common Stock 10/18/2007   S   4,844 (3) D $ 21.9646 635,757 (8) (11) D  
Common Stock 10/18/2007   S   189 (4) D $ 21.9646 24,812 (9) (11) D  
Common Stock 10/18/2007   S   329 (5) D $ 21.9646 43,121 (10) (11) D  

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)
2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)
5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)
6. Date Exercisable and Expiration Date
(Month/Day/Year)
7. Title and Amount of Underlying Securities
(Instr. 3 and 4)
8. Price of Derivative Security
(Instr. 5)
9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)
10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)
11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
TA ASSOCIATES INC
JOHN HANCOCK TOWER
200 CLARENDON ST, 56TH FLOOR
BOSTON, MA 02116
  X     See General Remarks
TA IX LP
JOHN HANCOCK TOWER
200 CLARENDON ST. 56TH FLOOR
BOSTON, MA 02116
      See General Remarks
TA ASSOCIATES IX LLC
JOHN HANCOCK TOWER
200 CLARENDON ST. 56TH FLOOR
BOSTON, MA 02116
      See General Remarks
TA ADVENT VIII LP
JOHN HANCOCK TOWER
200 CLARENDON ST, 56TH FLOOR
BOSTON, MA 02116
      See General Remarks
TA ASSOCIATES VIII LLC
JOHN HANCOCK TOWER
200 CLARENDON ST, 56TH FLOOR
BOSTON, MA 02116
      See General Remarks
TA / ATLANTIC & PACIFIC IV LP
JOHN HANCOCK TOWER
200 CLARENDON ST. 56TH FLOOR
BOSTON, MA 02116
      See General Remarks
TA ASSOCIATES AP IV LP
JOHN HANCOCK TOWER
200 CLARENDON ST. 56TH FLOOR
BOSTON, MA 02116
      See General Remarks
TA EXECUTIVES FUND LLC
JOHN HANCOCK TOWER
200 CLARENDON ST, 56TH FLOOR
BOSTON, MA 02116
      See General Remarks
TA INVESTORS LLC
JOHN HANCOCK TOWER
200 CLARENDON ST, 56TH FLOOR
BOSTON, MA 02116
      See General Remarks

Signatures

 TA Associates, Inc., By Thomas P. Alber, Chief Financial Officer   10/22/2007
**Signature of Reporting Person Date

 TA IX L.P., By TA Associates IX LLC, Its General Partner, By TA Associates, Inc., Its Manager, By Thomas P. Alber, Chief Financial Officer   10/22/2007
**Signature of Reporting Person Date

 TA/Advent VIII L.P., By TA Associates VIII LLC, Its General Partner, By TA Associates, Inc., Its Manager, By Thomas P. Alber, Chief Financial Officer   10/22/2007
**Signature of Reporting Person Date

 TA/Atlantic and Pacific IV L.P., By TA Associates AP IV L.P., Its General Partner, By TA Associates, Inc., Its General Partner, By Thomas P. Alber, Chief Financial Officer   10/22/2007
**Signature of Reporting Person Date

 TA Executives Fund LLC, By TA Associates, Inc., Its Manager, By Thomas P. Alber, Chief Financial Officer   10/22/2007
**Signature of Reporting Person Date

 TA Investors LLC, By TA Associates, Inc., Its Manager, By Thomas P. Alber, Chief Financial Officer   10/22/2007
**Signature of Reporting Person Date

 TA Associates IX LLC, By TA Associates, Inc., Its Manager, By Thomas P. Alber, Chief Financial Officer   10/22/2007
**Signature of Reporting Person Date

 TA Associates VIII LLC, By TA Associates, Inc., Its Manager, By Thomas P. Alber, Chief Financial Officer   10/22/2007
**Signature of Reporting Person Date

 TA Associates AP IV L.P., By TA Associates, Inc., Its General Partner, By Thomas P. Alber, Chief Financial Officer   10/22/2007
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) These securities were sold solely by TA IX L.P.
(2) These securities were sold solely by TA/Advent VIII L.P.
(3) These securities were sold solely by TA/Atlantic and Pacific IV L.P.
(4) These securities were sold solely by TA Executives Fund LLC.
(5) These securities were sold solely by TA Investors LLC.
(6) These securities are owned solely by TA IX L.P.
(7) These securities are owned solely by TA/Advent VIII L.P.
(8) These securities are owned solely by TA/Atlantic and Pacific IV L.P.
(9) These securities are owned solely by TA Executives Fund LLC.
(10) These securities are owned solely by TA Investors LLC.
(11) TA Associates, Inc. is the Manager of TA Associates IX LLC, which is the General Partner of TA IX L.P. TA Associates, Inc. is also the Manager of TA Associates VIII LLC, which is the General Partner of TA/Advent VIII L.P. TA Associates, Inc. is also the General Partner of TA Associates AP IV L.P., which is the General Partner of TA/Atlantic and Pacific IV L.P. TA Associates, Inc. is also the Manager of TA Executives Fund LLC and TA Investors LLC. TA IX L.P., TA/Advent VIII L.P., TA/Atlantic and Pacific IV L.P., TA Executives Fund LLC, and TA Investors LLC are collectively known as the "TA Funds". Each of TA Associates, Inc., TA Associates IX LLC, TA Associates VIII LLC, and TA Associates AP IV L.P. may be deemed to have a beneficial interest in shares held by the TA Funds and each disclaims beneficial ownership of such shares, except to the extent of its pecuniary interest in such shares which is subject to indeterminable future events.
 
Remarks:
The Reporting Persons have a representative on the Issuer's board of Directors. Michael Child currently serves as the Reporting Persons' representative on the board of directors and, as such, the reporting persons are deemed directors of the issuer.

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