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
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(Print or Type Responses)
1. Name and Address of Reporting Person *
  Klein Thomas
 2. Date of Event Requiring Statement (Month/Day/Year)
03/18/2013		 3. Issuer Name and Ticker or Trading Symbol
XOMA Corp [XOMA]
(Last)
(First)
(Middle)
C/O XOMA CORPORATION, 2910 SEVENTH STREET		 4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
Chief Commercial Officer
 5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

BERKELEY, CA 94710		 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)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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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
Non-Qualified Share Option (right to buy)   (1) 03/18/2023 Common Shares 335,000 $ 3.31 D  
Restricted Stock Units   (2) 03/18/2016 Common Shares 240,000 $ 0 D  

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
Klein Thomas
C/O XOMA CORPORATION
2910 SEVENTH STREET
BERKELEY, CA 94710		       Chief Commercial Officer  

Signatures

Thomas Klein 03/20/2013
**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) Exercisable as to (a) 25% of the option shares upon the first anniversary of the date of grant, and (b) the remaining 75% of the option shares in thirty-six (36) equal and consecutive monthly installments beginning one year and one month after the date of grant.
(2) These restricted stock units are scheduled to vest in substantially equal installments annually over three years, with the first installment vesting on March 18, 2014.

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