AMBAC FINANCIAL GROUP, INC. BOARD OF DIRECTORS NAMES ROBERT J. GENADER CHIEF EXECUTIVE OFFICER

NEW YORK, January 27, 2004--Ambac Financial Group, Inc. (NYSE: ABK) (Ambac) announced that the Board of Directors has named Robert J. Genader Chief Executive Officer, as successor to Phillip B. Lassiter. Mr. Lassiter, who announced his intention to retire as CEO in May 2003, will continue to serve as non-executive Chairman of the Board. Mr. Genader, a 19-year veteran of Ambac, previously held the titles of President and Chief Operating Officer and is a member of the Board of Directors. He directed the team responsible for Citibank's 1985 acquisition of Ambac; and, after the acquisition headed up several departments including sales, marketing, reinsurance and technology. After going public in 1991, Mr. Genader assumed responsibility for the formation, development and global expansion of the company's Specialized Finance Group. Mr. Genader was named Vice Chairman in January 1998 before being named President and Chief Operating Officer in January 2001.

Mr. Lassiter commented, "It has been an honor and privilege to have headed the Ambac family for the past thirteen years. I am unabashedly proud of what our people and organization have accomplished. More importantly, our future is exceedingly bright and I know that Bob Genader and his highly capable leadership team will scale new heights of success in the years ahead. I look forward to continuing to assist the new team in any practical way I can in my role as Chairman."

Mr. Genader commented, "Ambac, under the skillful leadership of Phil Lassiter, has grown from solely a U.S. municipal finance guarantor to a global provider of financial guarantees and related services for a wide array of structured and municipal fixed income products. Over Phil's 13 years at the helm of Ambac he has served all constituents - Ambac's shareholders, employees, customers and the financial guarantee industry with the utmost integrity, professionalism and dedication. On behalf of all of Ambac, I thank Phil for his significant contributions and his outstanding leadership. I am honored to have the opportunity to lead Ambac and look forward to building on the record of success achieved to date."

Forward-Looking Statements

This release contains statements about our future results that may be considered "forward-looking statements" under the Private Securities Litigation Reform Act of 1995. These statements are based on current expectations and the current economic environment. We caution you that these statements are not guarantees of future performance. They involve a number of risks and uncertainties that are difficult to predict. Our actual results could differ materially from those expressed or implied in the forward-looking statements. Among the factors that could cause actual results to differ materially are (1) changes in the economic, credit, or interest rate environment in the United States and abroad; (2) the level of activity within the national and worldwide debt markets; (3) competitive conditions and pricing levels; (4) legislative and regulatory developments; (5) changes in tax laws; (6) the policies and actions of the United States and other governments; and (7) other risks and uncertainties that have not been identified at this time. We undertake no obligation to publicly correct or update any forward-looking statement if we later become aware that it is not likely to be achieved, except as required by law.

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).