X0202 4 2004-05-11 0 0000791908 XOMA LTD /DE/ XOMA 0001222786 CASTELLO JOHN L C/O XOMA, LTD. 2910 SEVENTH STREET BERKELEY CA 94710 1 1 0 0 Chairman, CEO & President Common Shares 2004-05-10 4 G 0 15000 3.89 D 45035 D Common Shares 12229 I by 401(k) Common Shares 13751 I by Trust Mr. and Mrs. Castello are gifting 5,000 shares each to their son, John L. Castello, Jr., and the Jeffrey Castello Family Education Trust for the benefit of Mr. Castello's grandson. They are also gifting 2,500 shares each to their son, Jeffrey Castello, and daughter-in-law. None of the individuals reside with Mr. Castello and Mr. Castello denies any beneficial interest in the shares upon transfer. Held indirectly under the XOMA Ltd. Deferred Savings Plan. All shares were acquired in a transaction exempt from Section 16(b). Held indirectly under The John L. and Katherine C. Castello Trust. John L. Castello 2004-05-11