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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1. Name and Address of Reporting Person * BAKER BROS. ADVISORS LP   2. Issuer Name and Ticker or Trading Symbol XOMA Corp [XOMA] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 667 MADISON AVENUE, 21ST FLOOR 3. Date of Earliest Transaction (Month/Day/Year) 08/19/2013 (Street) NEW YORK, NY US 10065 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 08/19/2013   A   882,323 A $ 3.62 2,829,753 I See footnote (1) (4) (5) Common Stock 08/19/2013   A   1,854,058 A $ 3.62 19,767,770 I See footnote (2) (4) (5) Common Stock 08/19/2013   A   21,410 A $ 3.62 510,449 I See footnote (3) (4) (5)

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
BAKER BROS. ADVISORS LP 667 MADISON AVENUE, 21ST FLOOR NEW YORK, NY US 10065	X	X
667, L.P. 667 MADISON AVENUE 21ST FLOOR NEW YORK, NY US 10065	X	X
Baker Brothers Life Sciences LP 667 MADISON AVENUE, 21ST FLOOR NEW YORK, NY US 10065	X	X
14159, L.P. 667 MADISION AVENUE, 21ST FLOOR NEW YORK, NY US 10065	X	X
Baker Bros. Advisors (GP) LLC 667 MADISION AVENUE 21ST FLOOR NEW YORK, NY US 10065	X	X
BAKER FELIX 667 MADISON AVENUE, 21ST FLOOR NEW YORK, NY US 10065	X	X
BAKER JULIAN 667 MADISON AVENUE, 21ST FLOOR NEW YORK, NY US 10065	X	X

Signatures

By: Baker Bros. Advisors (GP) LLC, Name: Scott L. Lessing Title: President /s/ Scott L. Lessing		08/21/2013
**Signature of Reporting Person		Date
Baker Bros. Advisors, LLC, Mgmt. Co. and Inv. Adviser to 667, L.P., pursuant to authority granted by Baker Biotech Capital, L.P., GP to 667, L.P. Name: Scott L. Lessing, Title: President /s/ Scott L. Lessing		08/21/2013
**Signature of Reporting Person		Date
Baker Bros. Advisors, LLC, Mgmt. Co. and Inv. Adviser to BAKER BROTHERS LIFE SCIENCES, L.P., pursuant to authority granted by Baker Brothers Life Sciences Capital, L.P., GP to Baker Brothers Life Sciences, L.P Name:Scott L. Lessing, Title: President /s/		08/21/2013
**Signature of Reporting Person		Date
Baker Bros. Advisors, LLC, Mgmt. Co. and Inv. Adviser to 14159, L.P., pursuant to authority granted by 14159 Capital, L.P., GP to 14159, L.P. Name: Scott L. Lessing, Title: President /s/ Scott L. Lessing		08/21/2013
**Signature of Reporting Person		Date
Name: Scott L. Lessing Title: President /s/ Scott L. Lessing		08/21/2013
**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)	As a result of their ownership interest in Baker Biotech Capital (GP), LLC, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in 2,829,753 shares of Common Stock of the Issuer beneficially owned by 667, L.P., a limited partnership of which the sole general partner is Baker Biotech Capital, L.P., a limited partnership of which the sole general partner is Baker Biotech Capital (GP), LLC, due to Baker Biotech Capital, L.P.'s right to receive an allocation of a portion of the profits from 667, L.P.
(2)	As a result of their ownership interest in Baker Brothers Life Sciences Capital (GP), LLC, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in 19,767,770 shares of Common Stock of the Issuer beneficially owned by Baker Brothers Life Sciences, L.P., a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital, L.P., a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital (GP), LLC, due to Baker Brothers Life Sciences Capital, L.P.'s right to receive an allocation of a portion of the profits from Baker Brothers Life Sciences, L.P.
(3)	As a result of their ownership interest in 14159 Capital (GP), LLC, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in 510,449 shares of Common Stock of the Issuer beneficially owned by 14159, L.P., a limited partnership of which the sole general partner is 14159 Capital L.P., a limited partnership of which the sole general partner is 14159 Capital (GP), LLC, due to 14159 Capital L.P.'s right to receive an allocation of a portion of the profits from 14159, L.P.
(4)	The aggregate indirect beneficial ownership reported on this form is 23,107,972 shares.
(5)	Baker Bros. Advisors LP (the "Adviser") serves as the Investment Adviser to 667, L.P., Baker Brothers Life Sciences, L.P. and 14159, L.P. (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 in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are principals of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds. Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.
Remarks: Kelvin Neu, a Managing Director of Baker Bros. Advisors, LLC, is a director of Xoma Corporation (the "Issuer"). By virtue of his representation on the Board of Directors of the Issuer, for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, the reporting persons are deemed directors by deputization of the Issuer.

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