White Mountains Insurance Group (NYSE:WTM) Ltd. is a Bermuda‐based insurance holding company that specializes in property and casualty insurance, reinsurance, and run‐off management. Since its founding in 1986, the company has built a diversified platform of underwriting operations and investment activities. White Mountains pursues niche and specialty opportunities across global insurance markets, leveraging disciplined risk selection and capital management to deliver tailored solutions for cedents and policyholders alike.
The company’s core operating businesses include White Mountains Re, which provides customized treaty and facultative reinsurance solutions, and Sirius Group, a multiline insurance platform offering property, casualty, and specialty coverages. In addition, White Mountains manages run‐off portfolios through dedicated entities that acquire and resolve legacy liabilities. Its investment arm oversees a portfolio of public and private assets, ranging from fixed income and equities to alternative investments, supporting the long‐term funding of its underwriting businesses.
White Mountains serves clients across North America, Europe, and Asia-Pacific, adapting its product offerings to local regulatory regimes and market dynamics. Its global footprint allows the company to balance regional exposures and to capitalize on dislocations in specialty lines and reinsurance capacity. The firm maintains strategic relationships with brokers and cedents, emphasizing transparency, service quality, and financial strength in its solutions.
Under the leadership of Chairman and Chief Executive Officer Rodney O. Martin Jr., White Mountains has grown through a combination of strategic acquisitions, capital partnerships, and operational innovation. The executive team brings extensive experience in insurance, underwriting, investment management, and financial risk oversight. Over its history, the company has completed multiple spin‐offs and portfolio transactions to refine its focus on high‐return, low‐correlation insurance activities, positioning it for sustained long‐term performance in dynamic markets.
