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OneBeacon Appoints Dennis Crosby to Lead New Excess and Surplus Business

"We are pleased to welcome Dennis to OneBeacon," said Kevin Rehnberg, Executive Vice President of Specialty Lines. "His specific experience, leadership talents and successful track record will be instrumental in building our newest specialty business."

Added OneBeacon CEO Mike Miller, "I am pleased to have Dennis join our leadership team and look forward to working with him once again. Going forward, we will continue to look for opportunities to grow the value of our company by adding to our specialty capabilities."

Crosby will join OneBeacon immediately and brings nearly 30 years of industry experience. Most recently, he was President and CEO of ACE Westchester and Chairman of ACE Commercial Risk Services, where he was accountable for wholesale distribution of specialized property and casualty products within the excess and surplus lines marketplace. Prior to his six years at ACE, he spent 23 years with St. Paul Travelers in a variety of senior roles including commercial middle market, insurance operations and public sector services. Crosby holds a bachelor's degree in business administration from Appalachian State University.

About OneBeacon: OneBeacon Insurance Group, Ltd. is a Bermuda-domiciled holding company that is publicly traded on the New York Stock Exchange under the symbol "OB". OneBeacon Insurance Group's underwriting companies offer a range of specialty insurance products sold through select independent agents, regional and national brokers, and wholesalers. The company's businesses include OneBeacon Professional Insurance, International Marine Underwriters, Entertainment Brokers International Insurance Services, Specialty Accident and Health, OneBeacon Government Risks, OneBeacon Energy Group, A.W.G. Dewar (tuition refund), collector cars and boats written through Hagerty Insurance Agency, Technology, Financial Services, OneBeacon Specialty Property, Property and Inland Marine, and AutoOne.

As one of the oldest property and casualty insurers in the United States, OneBeacon traces its roots to 1831 and the Potomac Fire Insurance Company. Today, OneBeacon's specialty insurance businesses are national in scope.

Safe Harbor Statement under the Private Securities Litigation Reform Act of 1995

This press release may contain "forward-looking statements" within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. All statements, other than statements of historical facts, included or referenced in this release which address activities, events or developments which we expect or anticipate will or may occur in the future are forward-looking statements. The words "will," "believe," "intend," "expect," "anticipate," "project," "estimate," "predict" and similar expressions are also intended to identify forward-looking statements. These forward-looking statements include, among others, statements with respect to OneBeacon's:

    --  change in book value per share or return on equity;
    --  business strategy;
    --  financial and operating targets or plans;
    --  incurred loss and loss adjustment expenses and the adequacy of its loss
        and loss adjustment expense reserves and related reinsurance;
    --  projections of revenues, income (or loss), earnings (or loss) per share,
        dividends, market share or other financial forecasts;
    --  expansion and growth of our business and operations; and
    --  future capital expenditures.

These statements are based on certain assumptions and analyses made by OneBeacon in light of its experience and perception of historical trends, current conditions and expected future developments, as well as other factors believed to be appropriate in the circumstances. However, whether actual results and developments will conform to our expectations and predictions is subject to a number of risks and uncertainties that could cause actual results to differ materially from expectations, including:

    --  claims arising from catastrophic events, such as hurricanes, windstorms,
        earthquakes, floods, fires, explosions, terrorist attacks or severe
        winter weather;
    --  recorded loss and loss adjustment expense reserves subsequently proving
        to have been inadequate;
    --  the continued availability and cost of reinsurance coverage;
    --  the continued availability of capital and financing;
    --  general economic, market or business conditions;
    --  business opportunities (or lack thereof) that may be presented to it and
        pursued;
    --  competitive forces, including the conduct of other property and casualty
        insurers and agents;
    --  changes in domestic or foreign laws or regulations, or their
        interpretation, applicable to OneBeacon, its competitors, its agents or
        its customers;
    --  an economic downturn or other economic conditions adversely affecting
        its financial position including stock market volatility;
    --  actions taken by ratings agencies from time to time, such as financial
        strength or credit ratings downgrades or placing ratings on negative
        watch;
    --  the risks that are described from time to time in OneBeacon's filings
        with the Securities and Exchange Commission, including but not limited
        to OneBeacon's Annual Report on the Form 10-K for the fiscal year ended
        December 31, 2009 filed February 26, 2010.

Consequently, all of the forward-looking statements made in this press release are qualified by these cautionary statements, and there can be no assurance that the actual results or developments anticipated by OneBeacon will be realized or, even if substantially realized, that they will have the expected consequences to, or effects on, OneBeacon or its business or operations. OneBeacon assumes no obligation to update publicly any such forward-looking statements, whether as a result of new information, future events or otherwise.

Web Site: www.onebeacon.com

SOURCE OneBeacon Insurance Group, Ltd.