XOMA Announces Closing of the Offering and Exercise of Option

BERKELEY, Calif., Dec. 18, 2013 (GLOBE NEWSWIRE) -- XOMA Corporation (Nasdaq:XOMA) announced today the closing of the offering of 10,925,000 shares of its common stock, including 1,425,000 shares of common stock that were issued upon the exercise in full of the underwriters' option to purchase additional shares, at a price to the public of $5.25 per share. The shares were sold pursuant to a prospectus supplement filed as part of a shelf registration statement previously filed with the Securities and Exchange Commission (SEC) on Form S-3. XOMA anticipates its aggregate net proceeds from the offering will be approximately $53.5 million after deducting the underwriting discount and estimated offering expenses payable by XOMA.

Credit Suisse Securities (USA) LLC and Jefferies LLC acted as joint book running managers. Cowen and Company, LLC, Piper Jaffray & Co. and RBC Capital Markets, LLC acted as co-managers. Piper Jaffray & Co. served as financial advisor to XOMA.

This press release does not constitute an offer to sell or a solicitation of an offer to buy nor shall there be any sale of these securities in any state or jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction.

About XOMA

XOMA discovers and develops innovative antibody therapeutics.

CONTACT: XOMA Corporation

         Company and Investor Contact:
         Ashleigh Barreto
         510-204-7482
         barreto@xoma.com

         Juliane Snowden
         The Oratorium Group, LLC
         jsnowden@oratoriumgroup.com

         Media Contact:
         Canale Communications
         Carolyn Hawley
         619-849-5375
         carolyn@canalecomm.com

Released December 18, 2013