WHITE MOUNTAINS INSURANCE GROUP LTD
Ticker: WTMFinancialsProperty & Casualty InsuranceThe business
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.
- Sector
- Financials
- Industry
- Property & Casualty Insurance
- HQ
- HANOVER, NH
- FY end
- 12-31
- CIK
- 776867
- SIC
- 6331
Ownership
Who holds WHITE MOUNTAINS INSURANCE GROUP LTD — across funds, superinvestors and bonds · N-PORT 2026Q2 · 13F 2026-06-30
Top fund holders
| Fund | % of fund | Value |
|---|---|---|
| VANGUARD TOTAL STOCK MARKET INDEX FUND VTI · VANGUARD INDEX FUNDS | 0.01% | $154.79M |
| VANGUARD SMALL-CAP INDEX FUND VB · VANGUARD INDEX FUNDS | 0.06% | $111.89M |
| VANGUARD SELECTED VALUE FUND VASVX · VANGUARD WHITEHALL FUNDS | 1.33% | $87.58M |
| VANGUARD SMALL-CAP VALUE INDEX FUND VBR · VANGUARD INDEX FUNDS | 0.10% | $70.87M |
| VANGUARD EXTENDED MARKET INDEX FUND VXF · VANGUARD INDEX FUNDS | 0.06% | $58.09M |
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”.
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