OneBeacon Plans Expanded Coverage and Auto Rate Decreases up to 28 Percent in Massachusetts

CANTON, Mass., Nov. 27, 2007 -- OneBeacon Insurance Group has announced expanded auto insurance coverages along with price reductions of up to 28 percent for its Massachusetts customers under managed competition. Nearly 70 percent of OneBeacon's Massachusetts customers will see price reductions for auto coverage beginning April 1, 2008, pending regulatory approval.

OneBeacon's Massachusetts auto product will incorporate many of the elements of the company's premier OneChoice Auto product, which is available in other states. Replacement cost coverage, identity theft resolution services and accident forgiveness are just a few of the planned features; and all will complement OneChoice Homeowners in providing local consumers with comprehensive protection for today's needs. Later in the year, the company expects to file for state approval of OneChoice CustomPac, its flagship package solution that bundles auto, home and ancillary coverages under a single policy featuring a common renewal date and single bill. OneBeacon anticipates that CustomPac may be Massachusetts' first package offering.

Beginning in April, the company intends to offer its popular OneChoice Auto Security Plus endorsement to Massachusetts automobile policyholders. This additional coverage features:

  -- Guaranteed original equipment manufactured parts for newer cars
  -- Expanded substitute transportation coverage
  -- Roadside assistance
  -- Auto loan/lease coverage
  -- Auto theft reward coverage
  -- Accidental air bag deployment coverage

"We are excited about bringing our hallmark products to local customers as we transition to the commonwealth's new approach to auto insurance. Beginning in April, we can finally provide our local customers with access to our innovative solutions at a competitive price," said Dick Connors, president of OneBeacon's New England personal lines operations. "OneBeacon has a rich heritage of protecting Massachusetts drivers, so we're thrilled about the opportunities this presents."

The transition will provide all OneBeacon Massachusetts automobile policyholders with identity theft resolution services, including unlimited one-on-one access to a highly experienced fraud specialist whenever they're concerned about the safety of their personal information. The company also will file for approval of its OneChoice Auto Security Rewards program, which features accident forgiveness, collision deductible savings and new-car replacement cost coverage.

Added Connors, "Our goal is to deliver comprehensive, competitive personal insurance protection in partnership with the commonwealth's leading independent agencies. This is a historic occasion for the Massachusetts insurance marketplace and OneBeacon is committed to facilitating a seamless transition for our partners and customers."

About One Beacon: 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 OneBeacon's Form
     10K 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.