X0306 4 2013-08-14 0 0000791908 XOMA Corp XOMA 0001222790 SCANNON PATRICK J MD PHD C/O XOMA CORPORATION 2910 SEVENTH STREET BERKELEY CA 94710 1 1 0 0 Exec. VP & CSO Common Shares 2013-08-14 4 M 0 16265 0 A 33713 D Common Shares 2013-08-14 4 S 0 6002 3.8612 D 27711 D Common Shares 20339 I by 401(k) Common Shares 750 I by Daughter Common Shares 4053 I by Trust Restricted Stock Units 0 2013-08-14 4 M 0 16265 0 D 2015-08-14 Common Shares 16265 32528 D Non discretionary open market sale of shares to satisfy the minimum amount of taxes required to be withheld in connection with the vesting of Restricted Stock Units pursuant to the award. This transaction was executed in multiple trades ranging at prices from $3.86 to $3.94.The price reported reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the Issuer or a security holder of the Issuer full information regarding the number of shares and prices at which the transactions were effected. These restricted stock units are scheduled to vest in substantially equal installments annually over three years, with the first installment vesting on August 14, 2013. By: Fred Kurland For: Patrick J. Scannon 2013-08-16