White Mountains Insurance Group, Ltd. is a holding company. The Company's principal businesses are conducted through its insurance subsidiaries and other affiliates. Its segments include HG Global/BAM and Other Operations. The HG Global/BAM segment consists of the operations of HG Global Ltd. (HG Global) and Build America Mutual Assurance Company (BAM). The Other Operations segment consists of the Company and its intermediate holding companies, its investment management subsidiary, White Mountains Advisors LLC, and certain consolidated and unconsolidated private capital investments.