Couch Braunsdorf: Pressroom: ONEBEACON APPOINTS COUCH BRAUNSDORF INSURANCE

Managing General Underwriter will handle lawyers professional liability business for
OneBeacon Professional Partners

BOSTON (June 20, 2007) – OneBeacon Insurance announced today that it has signed an agreement with Couch Braunsdorf Insurance to manage its lawyers professional liability business in New Jersey, New York and Pennsylvania for firms with 20 attorneys or fewer.

Couch Braunsdorf will represent OneBeacon Professional Partners, which offers lawyers professional liability coverage on both a primary and excess basis for firms with one to 150 attorneys.
Based in Liberty Corner, New Jersey, Couch Braunsdorf is a full-service brokerage/ agency with a consistent track record of growth and profitability.
“Couch Braunsdorf has served the legal community for more than 75 years, offering the finest in insurance products and services to the practicing attorney,” said George Rawding, head of Couch Braunsdorf’s Professional Liability unit. “OneBeacon presents an exciting new opportunity for us and the practicing bar, and we look forward to a long and rewarding relationship.”

“This relationship joins two companies with similar values,” said Kim Pihlstrom, head of OneBeacon Professional Partners’ Lawyers Professional Liability group. “The unique nature of Couch Braunsdorf’s business, coupled with its niche expertise, complements and diversifies our current book.”
OneBeacon Professional Partners is a division of OneBeacon Insurance Group that specializes in directors and officers liability; managed care organizations errors and omissions; medical malpractice; healthcare provider excess of loss insurance and HMO reinsurance; media liability; lawyers professional liability; miscellaneous professional liability.
OneBeacon Insurance Group’s operating subsidiaries offer a range of specialty and segmented commercial and personal insurance products sold primarily through select independent agents. 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 products are available countrywide, and commercial and personal lines are offered in select geographic territories.
OneBeacon’s U.S. headquarters is in Canton, Massachusetts. The company is publicly traded on the New York Stock Exchange under the symbol “OB”.

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:

growth 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, earthquakes, floods or terrorist attacks;
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 reinsurers;
changes in domestic or foreign laws or regulations, or their interpretation, applicable to OneBeacon, its competitors or its clients;
an economic downturn or other economic conditions adversely affecting its financial position;
other factors, most of which are beyond OneBeacon’s control; and 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 Form 10-K for the fiscal year ended December 31, 2006 filed February 28, 2007.

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.