White Mountains Insurance Group, Ltd. is an insurance holding company. The Company's segments include OneBeacon, HG Global/BAM and Other Operations. Its principal businesses are conducted through its insurance, reinsurance and insurance services subsidiaries and affiliates. Its OneBeacon segment consists of OneBeacon Insurance Group, Ltd., which owns a family of property and casualty insurance companies (collectively, OneBeacon). OneBeacon is a specialty property and casualty insurance writer that offers a range of insurance products in the United States primarily through independent agencies, regional and national brokers, wholesalers and managing general agencies. The HG Global/BAM segment consists of HG Global Ltd. (HG Global) and Build America Mutual Assurance Company (BAM). BAM provides insurance on municipal bonds issued to support the United States public purposes, such as schools. Its Other Operations segment consists of the Company and its intermediate holding companies.