X0306 4 2018-03-27 0 0000791908 XOMA Corp XOMA 0001731721 DATTA DEEPSHIKHA C/O XOMA CORPORATION 2200 POWELL STREET, SUITE 310 EMERYVILLE CA 94608 0 1 0 0 Chief Business Officer Non-Qualified Share Option (right to buy) 33.41 2018-03-27 4 A 0 80000 0.0 A 2027-12-21 Common Shares 80000 80000 D The vesting of this option was amended by the Compensation Committee of the Board of Directors of the Issuer from the vesting upon achievement of certain performance based criteria to the following: shares subject to this option shall vest in equal monthly installments over three years from the grant date of December 21, 2017. Deepshikha Datta 2018-03-29