Edgar Filing: XOMA Corp

Ownership Submission

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
INITIAL STATEMENT OF 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

OMB APPROVAL

OMB Number:

3235-0104

Expires:

January 31, 2005

Estimated average burden hours per response...

0.5

(Print or Type Responses)

1. Name and Address of Reporting Person ^*

Â BAKER BROS ADVISORS LLC

2. Date of Event Requiring Statement (Month/Day/Year)
04/12/2012

3. Issuer Name and Ticker or Trading Symbol
XOMA Corp [XOMA]

(Last)

(First)

(Middle)

667 MADISON AVENUE 21ST FLOOR

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

_____ Director	__X__ 10% Owner
_____ Officer (give title below)	_____ Other (specify below)

5. If Amendment, Date Original Filed(Month/Day/Year)

(Street)

NEW YORK,Â NYÂ US 10065

6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person

(City)

(State)

(Zip)

Table I - Non-Derivative Securities Beneficially Owned

1.Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock	0	I ⁽¹⁾ ⁽²⁾ ⁽³⁾ ⁽⁴⁾	See footnotes ⁽¹⁾ ⁽²⁾ ⁽³⁾ ⁽⁴⁾

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.			SEC 1473 (7-02)
	Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Warrants	Â ⁽⁵⁾	Â ⁽⁶⁾	Common Stock	0 ⁽¹⁾	$ 1.76	I	See footnote ⁽²⁾ ⁽³⁾ ⁽⁴⁾ ⁽¹⁾

Reporting Owners

Reporting Owner Name / Address	Relationships
Reporting Owner Name / Address	Director	10% Owner	Officer	Other
BAKER BROS ADVISORS LLC 667 MADISON AVENUE 21ST FLOOR NEW YORK,Â NYÂ US 10065	Â	Â X	Â	Â

Signatures

BAKER BROS. ADVISORS, LLC, Name: Scott L. Lessing, Title: President /s/ Scott L. Lessing		04/23/2012
^**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 5(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)	Baker Bros. Advisors, LLC ("the Adviser") serves as the Investment Adviser to Baker Brothers Life Sciences, L.P. (direct holder of 13,606,093 shares and 6,608,225 shares underlying warrants), 14159, L.P. (direct holder of 360,231 shares and 174,738 shares underlying warrants), and 667, L.P. (direct holder of 1,585,591 shares and 792,796 shares underlying warrants)("the Funds"). In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest.
(2)	On April 12, 2012 the Adviser, the Funds, and the general partners of the Funds entered into an amended and restated management agreement which gave the Adviser complete and unlimited discretion and authority with respect to the Funds' investments and voting power over investments. The general partners of the Funds relinquished all discretion and authority with respect to the Funds' investments and voting power over investments.
(3)	Julian C. Baker and Felix J. Baker each may be deemed to control the Adviser and to indirectly beneficially own the shares beneficially owned by it. Julian C. Baker and Felix J. Baker disclaim beneficial ownership of these securities, except to the extent of their pecuniary interest therein and this report shall not be deemed an admission that Felix J. Baker or Julian C. Baker is the beneficial owner of the above referenced securities for purposes of Section 16 or for any other purpose.
(4)	The securities over which the Adviser is reporting have already been reported by Felix J. Baker and Julian C. Baker in their own Forms 3 and 4. In the future the Adviser may jointly file Section 16 reports with Julian C. Baker and Felix J. Baker.
(5)	Exercisable immediately
(6)	Expiration date is five years from the date of issuance.
Â Remarks: .

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, See Instruction 6 for procedure.

Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.