OneBeacon raises $600 Million in IPO

November 10, 2006

OneBeacon Insurance Group Ltd., a property casualty unit of Bermuda-based reinsurer White Mountains Insurance Group Ltd, has raised an estimated $600 million in its initial public offering.

OneBeacon's 24 million class A common share offering sold for $25 per share.

The shares will be listed on the New York Stock Exchange and will trade under the symbol "OB" beginning Nov. 9, 2006. The subsidiary of White Mountains Insurance Group, Ltd. will receive all of the proceeds of the offering.

The underwriters have the option to purchase up to an additional 3.6 million shares from the selling shareholder at the initial public offering price less the underwriting discount. White Mountains will remain the company's majority owner.

Lehman Brothers Inc. has acted as the sole book-running manager of this offering and Banc of America Securities LLC has acted as joint lead manager.