Headquartered in Boston, OneBeacon Insurance Group offers specialty and segmented personal and commercial insurance products sold primarily through select independent agents. The companies comprising the OneBeacon Insurance Group include International Marine Underwriters, OneBeacon Agri, OneBeacon Professional Partners, OneBeacon Specialty Property and A.G. Dewar. It is rated A excellent by A.M. Best Company. OneBeacon has more than 12 locations throughout the United States, including one Buffalo, N.Y. OneBeacon is wholly owned by White Mountains Insurance Group. White Mountains' principal businesses are conducted through its subsidiaries and affiliates in the business of property-casualty insurance and reinsurance. The company is publicly traded on the New York Stock Exchange and the Bermuda Stock Exchange under the symbol WTM.