OneBeacon Declares Third Quarter Dividend

HAMILTON, Bermuda, Aug. 27 /PRNewswire-FirstCall/ -- At its regular
meeting held on August 26, 2008, the OneBeacon Insurance Group, Ltd.
(NYSE: OB) Board of Directors declared a $0.21 per share quarterly dividend,
payable in cash on September 24, 2008, to holders of record of Common Shares
as of the close of business on September 15, 2008.
About OneBeacon:
OneBeacon Insurance Group, Ltd.'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's:
-- growth in adjusted 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, 2007 filed February 29, 2008.

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.
SOURCE OneBeacon Insurance Group, Ltd.

Investor Relations: Todd Mills, +1-781-332-7442, ir@onebeacon.com, or Media:
Carmen Duarte, +1-781-332-7268, cduarte@onebeacon.com, both of OneBeacon
Insurance Group, Ltd.