Press Release

Ambac Financial Group, Inc. Provides Additional Disclosures on its Web Site Related to Collateralized Debt Obligations of Asset-Backed Securities

NEW YORK, August 10, 2007 -- Ambac Financial Group, Inc. (NYSE:ABK) today announced that it has provided additional information on its web site (click here) regarding its exposure to Collateralized Debt Obligations of Asset-backed Securities ("CDOs of ABS"), including additional details of each transaction's underlying collateral composition, underlying collateral ratings, and overall transaction ratings.

In its July 25th conference call with investors, Ambac provided commentary and analysis with respect to its exposure to CDOs of ABS and its underwriting standards. A replay of the telephone conference call is available on Ambac's web site until approximately 5:00 p.m. on August 17. The replay numbers are 877-660-6853 (domestic) and 201-612-7415 (international). The account and confirmation numbers for the replay are 286 and 225610, respectively.

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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, and Fitch, Inc. Ambac Financial Group, Inc. common stock is listed on the New York Stock Exchange (ticker symbol ABK).