White Mountains Insurance Group, Ltd.
White Mountains Insurance Group, Ltd. (NYSE: WTM) operates as a diversified financial services holding company engaged in making opportunistic and value-oriented acquisitions of businesses and assets in the insurance, financial services and related sectors. The company's website is www.whitemountains.com. From the company’s description.
Margins and return on equity change in ; everything else in percent. Fewer shares and less debt are shown plainly, not as bad news — it depends what you make of buybacks. Dotted labels explain each measure. is shown separately from the annual figures.
What White Mountains Insurance Group, Ltd. does
In the company’s own words
White Mountains Insurance Group, Ltd. (NYSE: WTM) operates as a diversified financial services holding company engaged in making opportunistic and value-oriented acquisitions of businesses and assets in the insurance, financial services and related sectors. The company's website is www.whitemountains.com.
White Mountains conducts its business through five primary reportable segments. The Ark/WM Outrigger segment comprises specialty property and casualty insurance and reinsurance operations, with Ark offering niche insurance and reinsurance products including property, specialty, marine and energy, casualty, and accident and health coverages. Ark operates through Lloyd's of London syndicates in the United Kingdom and through Group Ark Insurance Limited in Bermuda. WM Outrigger Re provides collateralized reinsurance capacity to Ark's catastrophe portfolio. For the year ended December 31, 2025, Ark generated gross written premiums of $2,557 million across its five major lines of business.
The HG Global segment provides municipal bond guarantee reinsurance through first-loss reinsurance protection to Build America Mutual Assurance Company, the first and only mutual municipal bond insurance company in the United States. The Kudu segment provides capital solutions for asset and wealth management firms. The Distinguished segment operates specialty insurance distribution through its subsidiary WM Phoenix Parent, L.P. and its subsidiaries operating under the Distinguished Programs brand.
White Mountains's Other Operations segment includes the company's holding companies, investment management subsidiary White Mountains Advisors LLC, and various other consolidated and unconsolidated entities including interests in Bamboo Ide8 Insurance Services LLC, MediaAlpha Inc., PassportCard/DavidShield, BroadStreet Partners Inc., and Elementum Holdings LP. In December 2025, White Mountains completed the sale of a controlling financial interest in Bamboo.
As of December 31, 2025, White Mountains reported total assets of approximately $6,146 million related to Ark and $1,237 million related to HG Global. The company maintains a diversified portfolio of insurance and reinsurance businesses with geographic operations spanning the United Kingdom, Bermuda, and the United States, serving institutional and retail customers through established distribution channels including brokers, managing general agents, and reinsurance intermediaries.
Company details
- Sector
- Financials
- Industry (SIC)
- Property & Casualty Insurance
- Headquarters
- HANOVER, NH
- Fiscal year end
- December
- CIK
- 776867
- SIC
- 6331
Financial performance, year by year
Fiscal 2013–2025 · USDThe full income statement, balance sheet and cash flow for each of these years — every figure traceable to its filing — is on the Financials tab with a free account.
Who owns White Mountains Insurance Group, Ltd. — and what changed
Funds as of 2026Q2 · superinvestors as of 2026-06-30
Largest fund holders · White Mountains Insurance Group, Ltd.’s weight in each
Fund ownership is a floor, not a census — pensions, insurers and people holding shares directly are not visible here.
Fund ownership counts N-PORT filers only, so it is a floor rather than a census — pensions, insurers and direct holders are not visible here, and the remainder is not “held by individuals”.
Every fund and institutional holder, quarter by quarter, is on the Ownership tab with a free account.
Recent filings
All filings →Each filing opens into its own statements and disclosures here.
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