White Mountains Reports Adjusted Book Value Per Share of $411

HAMILTON, Bermuda - 29 April, 2010 - White Mountains Insurance Group, Ltd. (NYSE: WTM) reported an adjusted book value per share of $411 at 31 March, 2010, a decrease of 1% for the quarter, including dividends.

Ray Barrette, Chairman and CEO, commented, "It was a tough quarter. Book value per share was down 1%. Catastrophe losses, primarily from the earthquake in Chile and winter weather in Europe and the Northeastern United States, were a major drag on results. Investment results were good with our portfolio up 1.4% despite some headwinds from a strengthening dollar. With the transformation of OneBeacon into a specialty company nearly complete, a well capitalized, disciplined reinsurance business in White Mountains Re, and Esurance growing again, I like how we are positioned. Our capital position remains strong, and we repurchased about 103,000 shares in the quarter."

Adjusted comprehensive loss was $51 million for the first quarter compared to adjusted comprehensive loss of $9 million in the first quarter of last year, while net loss was $40 million compared to net income of $30 million in the first quarter of 2009.

White Mountainsis a Bermuda-domiciled financial services holding company traded on the New York Stock Exchange and the Bermuda Stock Exchange under the symbol WTM. Additional financial information and other items of interest are available at the company's website located at www.whitemountains.com. White Mountains expects to file its Form 10-Q with the Securities and Exchange Commission on or before May 10, 2010 and urges shareholders to refer to that document for more complete information concerning its financial results.

CONTACT:     

David Foy                                (203) 458-5850