Ambac Confirms Stock Repurchase Program; Announces Q&A Conference Call.

Business Editors

NEW YORK--(BUSINESS WIRE)--Sept. 20, 2001

Ambac Financial Group, Inc. (NYSE:ABK) (Ambac) today confirmed its stock repurchase program, previously announced.

Under this stock repurchase program, the Board of Directors has authorized Ambac to repurchase up to nine million shares of common stock, of which approximately one million remains available for repurchase. Shares will be repurchased in the open market, through block purchases or otherwise, at times and prices considered appropriate by the company. As of June 30, 2001, Ambac had approximately 106 million shares outstanding.

Ambac's Chairman and CEO Phillip B. Lassiter stated, "I remain upbeat about Ambac's current and future prospects. I am confident that New York City, our financial markets and our Country as a whole will successfully recover from this terrible tragedy and be stronger than ever."

Ambac affirms that it does not anticipate any material losses as a result of the World Trade Center tragedy. To answer any questions that investors may have, Mr. Lassiter will host a Q&A conference call tomorrow, September 21, 2001, at 11:00 a.m. EST.

The conference call numbers are 888-404-4612 (domestic) and 706-634-0913 (international). Beginning at 2 p.m. on September 21, and running through September 28, the conference call will be available in replay. The replay numbers are 800-642-1687 (domestic) and 706-645-9291 (international). The passcode for the replay is 1905680.

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.

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, is a leading guarantor of municipal and structured finance obligations. It 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).