Assured Guaranty Ltd. Announces Reinsurance Transactions with Ambac Assurance.

HAMILTON, Bermuda -- Assured Guaranty Ltd. (NYSE:AGO) ("Assured") has announced that its reinsurance subsidiary Assured Guaranty Re Ltd. ("AG Re") has agreed to reinsure a diversified portfolio of financial guaranty contracts totaling approximately $29 billion of net par outstanding from Ambac Assurance Corporation ("Ambac"), a subsidiary of Ambac Financial Group, Inc. (NYSE:ABK). The portfolio is consistent with AG Re's underwriting standards and will be reinsured under AG Re's existing master facultative reinsurance agreement with Ambac. In addition, AG Re has announced that effective January 1, 2008 it has agreed to provide reinsurance under the terms of Ambac's current surplus share treaty program that expires March 31, 2008. Ambac has also agreed to offer AG Re the opportunity to provide reinsurance under the terms of Ambac's surplus share treaty programs that commence April 1, 2008, 2009 and 2010, if Ambac maintains its reinsurance program in those periods.

Assured announced a $300 million common equity offering on December 12, 2007 and intends to contribute the net proceeds of the offering to AG Re. AG Re intends to use the proceeds to capitalize on large reinsurance portfolio opportunities which provide capital relief to unaffiliated monoline financial guaranty companies, as well as support the growth of Assured Guaranty Corp. ("AGC"), Assured's direct financial guaranty subsidiary. AG Re is AGC's principal financial guaranty reinsurer. Proceeds of this offering will be used in part to fund AG Re's incremental capital requirements due to the assumption of the Ambac facultative portfolio, which is contingent on raising this capital.

"We are pleased to be able to provide reinsurance capacity to Ambac, a leading financial guaranty company with a long and successful track record," stated Dominic Frederico, President and Chief Executive Officer of Assured Guaranty Ltd. "We look forward to a sustained, mutually-beneficial relationship going forward."

Robert J. Genader, Chairman and Chief Executive Officer of Ambac Financial Group, Inc. noted: "Reinsurance is a valuable, capital efficient and shareholder friendly tool for managing risk and capital in the financial guaranty industry. We value Assured's facultative reinsurance capacity, as well as their participation in our surplus share treaty agreements going forward."

Assured Guaranty Ltd. is a Bermuda-based holding company. Its operating subsidiaries provide credit enhancement products to the U.S. and international public finance, structured finance and mortgage markets. More information can be found at www.assuredguaranty.com.

Any forward-looking statements made in this press release reflect the Company's current views with respect to future events and financial performance and are made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Such statements involve risks and uncertainties that may cause actual results to differ materially from those set forth in these statements. For example, the Company's forward-looking statements, including statements regarding share repurchases, capital and accretion could be affected by many events. These events include a significant reduction in the amount of reinsurance ceded by one or more of our principal ceding companies, rating agency action such as a ratings downgrade, difficulties with the execution of the Company's business strategy, contract cancellations, developments or volatility in the world's financial and capital markets, more severe or frequent losses associated with products affecting the adequacy of the Company's loss reserves, changes in regulation or tax laws, governmental actions, natural catastrophes, the Company's dependence on customers, decreased demand or increased competition, loss of key personnel, technological developments, the effects of mergers, acquisitions and divestitures, changes in accounting policies or practices, changes in general economic conditions, other risks and uncertainties that have not been identified at this time, management's response to these factors, and other risk factors identified in the Company's filings with the Securities and Exchange Commission. Readers are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the dates on which they are made. The Company undertakes no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.