Press Release

Ambac Financial Group, Inc. Declares Quarterly Dividend

NEW YORK, May 2, 2006 -- Ambac Financial Group, Inc. (NYSE:ABK) today announced that its Board of Directors declared a regular quarterly cash dividend of $0.15 per share of common stock. The dividend is payable on June 7, 2006 to stockholders of record on May 15, 2006.

* * * * * * *

Ambac Financial Group, Inc., headquartered in New York City, is a holding company whose affiliates provide financial guarantees and financial services to clients in both the public and private sectors around the world. Ambac’s principal operating subsidiary, Ambac Assurance Corporation, a leading guarantor of public finance and structured finance obligations, has earned triple-A ratings, the highest ratings available from Moody’s Investors Service, Inc., Standard & Poor’s Ratings Services, Fitch, Inc. and Rating and Investment Information, Inc. Ambac Financial Group, Inc. common stock is listed on the New York Stock Exchange (ticker symbol ABK).