White Mountains Insurance Group Ltd
WTM- Exchange
- NYSE
- Industry
- Fire, Marine & Casualty Insurance
- SEC CIK
- 0000776867
No open-market purchases or sales by White Mountains Insurance Group Ltd insiders were filed in the last 90 days; 356 institutions reported holding it in 13F filings for Q2 2026, worth $4.57B in total; Southeastern Asset Management (Longleaf) is the only superinvestor holding it.
13F holders, Q4 2025
Institutional positions in White Mountains Insurance Group Ltd as of Dec 31, 2025. Investment managers with $100 million or more in US stocks report their long positions on Form 13F within 45 days after each quarter ends. How 13F works
- Institutional holders
- 353
- +20 vs. Q3 2025
- Shares held
- 2.25M
- −77.3K (−3.3%) vs. Q3 2025
- Total value
- $4.67B
- +$782.8M (+20.1%) vs. Q3 2025
- New holders
- 55
- 104 more added
- Sold out
- 35
- 126 more reduced
5 institutions that held it in Q3 2025 haven't filed for Q4 2025 yet. Not filing isn't selling, so they aren't counted as sold out or in the changes above.
Compare with Q3 2025: new holders, sold out and not filed yet
Holders and value by quarter
Institutions reporting WTM on Form 13F each quarter since Q1 2021, and the total value they reported. Values are as of each quarter end, so they also move with the share price.
| Quarter | Holders | Value |
|---|---|---|
| Q2 2026 | 356 | $4.57B |
| Q1 2026 | 368 | $4.86B |
| Q4 2025 | 353 | $4.67B |
| Q3 2025 | 338 | $3.89B |
| Q2 2025 | 325 | $4.17B |
| Q1 2025 | 322 | $4.44B |
| Q4 2024 | 325 | $4.43B |
| Q3 2024 | 304 | $3.78B |
| Q2 2024 | 306 | $4.14B |
| Q1 2024 | 303 | $4.06B |
| Q4 2023 | 295 | $3.42B |
| Q3 2023 | 272 | $3.40B |
| Q2 2023 | 258 | $3.13B |
| Q1 2023 | 262 | $3.09B |
| Q4 2022 | 265 | $3.20B |
| Q3 2022 | 251 | $2.98B |
| Q2 2022 | 259 | $3.32B |
| Q1 2022 | 244 | $3.09B |
| Q4 2021 | 243 | $2.71B |
| Q3 2021 | 232 | $2.86B |
| Q2 2021 | 233 | $3.11B |
| Q1 2021 | 245 | $3.02B |
Institutions, Q4 2025
Shares, value and share of portfolio for each institution holding White Mountains Insurance Group Ltd; share changes are against Q3 2025.
| Institution | Shares | Value | % of portfolio | Change in shares | Action |
|---|---|---|---|---|---|
| Vanguard Group Inc | 235,698 | $489.8M | 0.01% | −11,306−4.6% | Reduced |
| Dimensional Fund Advisors LP | 156,604 | $325.4M | 0.07% | −613−0.4% | Reduced |
| Neuberger Berman Group LLC | 129,654 | $269.4M | 0.20% | +14,639+12.7% | Added |
| River Road Asset Management, LLC | 120,880 | $251.2M | 2.76% | +11,292+10.3% | Added |
| BlackRock, Inc. | 112,289 | $233.3M | 0.00% | −290−0.3% | Reduced |
| Fuller & Thaler Asset Management, Inc. | 108,172 | $224.8M | 0.76% | +81+0.1% | Added |
| Cooke & Bieler LP | 106,579 | $221.5M | 2.31% | −1,272−1.2% | Reduced |
| Fiduciary Management Inc | 90,333 | $187.7M | 2.06% | −4,050−4.3% | Reduced |
| Morgan Stanley | 82,151 | $170.7M | 0.01% | −56,711−40.8% | Reduced |
| Wallace Capital Management Inc. | 80,347 | $167.0M | 20.10% | −1,142−1.4% | Reduced |
| Boston Partners | 76,911 | $159.7M | 0.17% | −7,534−8.9% | Reduced |
| London Co of Virginia | 58,697 | $122.0M | 0.70% | −8,105−12.1% | Reduced |
| State Street Corp | 50,663 | $105.3M | 0.00% | −3,781−6.9% | Reduced |
| T. Rowe Price Investment Management, Inc. | 44,560 | $92.6M | 0.06% | −3,212−6.7% | Reduced |
| Reinhart Partners, Inc. | 43,973 | $91.4M | 2.74% | +2,364+5.7% | Added |
| Geode Capital Management, LLC | 41,518 | $86.3M | 0.01% | −572−1.4% | Reduced |
| Lord, Abbett & Co. LLC | 33,796 | $70.2M | 0.22% | −3,123−8.5% | Reduced |
| Gendell Jeffrey L | 32,520 | $67.6M | 1.18% | +32,520 | New |
| Norges Bank | 32,184 | $66.9M | 0.01% | +32,184 | New |
| Southeastern Asset Management IncSuperinvestorSoutheastern Asset Management (Longleaf) | 31,652 | $65.8M | 2.93% | 00.0% | Unchanged |
| Bank of America Corp | 28,809 | $59.9M | 0.00% | −10,003−25.8% | Reduced |
| Spears Abacus Advisors LLC | 28,115 | $58.4M | 1.09% | −173−0.6% | Reduced |
| Raymond James Financial Inc | 23,969 | $49.8M | 0.02% | −5,423−18.5% | Reduced |
| Charles Schwab Investment Management Inc | 23,238 | $48.3M | 0.01% | −994−4.1% | Reduced |
| Mraz, Amerine & Associates, Inc. | 22,629 | $47.0M | 6.99% | +23+0.1% | Added |
| Allspring Global Investments Holdings, LLC | 20,193 | $41.2M | 0.07% | −11,505−36.3% | Reduced |
| Select Equity Group, L.P. | 19,713 | $41.0M | 0.19% | +2,767+16.3% | Added |
| Brown Advisory Inc | 18,956 | $39.4M | 0.05% | −1,376−6.8% | Reduced |
| Northern Trust Corp | 16,667 | $34.6M | 0.00% | −1,090−6.1% | Reduced |
| Wellington Management Group LLP | 15,928 | $33.1M | 0.01% | −3,283−17.1% | Reduced |
| Envestnet Asset Management Inc | 15,798 | $32.8M | 0.01% | −1,793−10.2% | Reduced |
| Elkhorn Partners Limited Partnership | 13,598 | $28.3M | 17.85% | −1,212−8.2% | Reduced |
| Horizon Kinetics Asset Management LLC | 13,121 | $27.3M | 0.37% | +37+0.3% | Added |
| WCM Investment Management, LLC | 10,682 | $22.2M | 0.05% | −2,553−19.3% | Reduced |
| Speece Thorson Capital Group Inc | 10,672 | $22.2M | 4.80% | −590−5.2% | Reduced |
| Wells Fargo & Company | 9,141 | $19.0M | 0.00% | −211−2.3% | Reduced |
| Thompson Siegel & Walmsley LLC | 8,927 | $18.6M | 0.31% | +275+3.2% | Added |
| Bank of New York Mellon Corp | 8,831 | $18.4M | 0.00% | −1,271−12.6% | Reduced |
| GW&K Investment Management, LLC | 8,621 | $17.9M | 0.15% | +611+7.6% | Added |
| D. E. Shaw & Co., Inc. | 8,593 | $17.9M | 0.01% | +6,081+242.1% | Added |
| SEI Investments Co | 7,916 | $16.5M | 0.02% | +2,530+47.0% | Added |
| UBS Asset Management Americas Inc | 7,655 | $15.9M | 0.00% | +7,648+109,257.1% | Added |
| Quantinno Capital Management LP | 7,271 | $15.1M | 0.03% | +1,217+20.1% | Added |
| Hotchkis & Wiley Capital Management LLC | 6,752 | $14.0M | 0.04% | −354−5.0% | Reduced |
| California Public Employees Retirement System | 6,716 | $14.0M | 0.01% | −2,516−27.3% | Reduced |
| Gotham Asset Management, LLC | 6,716 | $14.0M | 0.05% | −183−2.7% | Reduced |
| Victory Capital Management Inc | 6,296 | $13.1M | 0.01% | −2,230−26.2% | Reduced |
| UBS Group AG | 6,001 | $12.5M | 0.00% | −6,084−50.3% | Reduced |
| Royce & Associates LP | 5,947 | $12.4M | 0.13% | −355−5.6% | Reduced |
| Phocas Financial Corp. | 5,491 | $11.4M | 1.48% | −14−0.3% | Reduced |
| Bradley Foster & Sargent Inc | 5,456 | $11.3M | 0.17% | −90−1.6% | Reduced |
| Goldman Sachs Group Inc | 5,260 | $10.9M | 0.00% | −651−11.0% | Reduced |
| Williams Jones Wealth Management, LLC. | 5,193 | $10.8M | 0.12% | 00.0% | Unchanged |
| Swiss National Bank | 5,086 | $10.6M | 0.01% | +140+2.8% | Added |
| First Trust Advisors LP | 4,555 | $9.47M | 0.01% | +4,555 | New |
| AQR Capital Management LLC | 4,476 | $9.30M | 0.00% | −1,437−24.3% | Reduced |
| Rhumbline Advisers | 4,165 | $8.65M | 0.01% | −67−1.6% | Reduced |
| Dark Forest Capital Management LP | 3,615 | $7.51M | 0.34% | +3,615 | New |
| Cerity Partners LLC | 3,543 | $7.36M | 0.01% | +1,603+82.6% | Added |
| Nuveen, LLC | 3,475 | $7.22M | 0.00% | +17+0.5% | Added |
| Creative Planning | 3,415 | $7.10M | 0.01% | +313+10.1% | Added |
| BNP Paribas Arbitrage, SA | 3,340 | $6.94M | 0.00% | +1,804+117.4% | Added |
| Brandywine Global Investment Management, LLC | 3,226 | $6.70M | 0.04% | −100−3.0% | Reduced |
| Lee Danner & Bass Inc | 3,103 | $6.45M | 0.46% | −45−1.4% | Reduced |
| Ameriprise Financial Inc | 3,053 | $6.34M | 0.00% | +25+0.8% | Added |
| Legal & General Group Plc | 3,037 | $6.31M | 0.00% | −1,012−25.0% | Reduced |
| Invesco Ltd. | 2,995 | $6.22M | 0.00% | −322−9.7% | Reduced |
| MML Investors Services, LLC | 2,935 | $6.10M | 0.01% | +83+2.9% | Added |
| State Board of Administration of Florida Retirement System | 2,792 | $5.80M | 0.01% | −350−11.1% | Reduced |
| Triad Investment Management | 2,548 | $5.29M | 5.36% | +2,548 | New |
| New York State Common Retirement Fund | 2,513 | $5.22M | 0.01% | −6−0.2% | Reduced |
| California State Teachers Retirement System | 2,457 | $5.11M | 0.01% | +24+1.0% | Added |
| Davenport & Co LLC | 2,123 | $4.41M | 0.02% | −50−2.3% | Reduced |
| Forum Financial Management, LP | 2,016 | $4.19M | 0.05% | 00.0% | Unchanged |
| Price T Rowe Associates Inc | 1,990 | $4.14M | 0.00% | +108+5.7% | Added |
| LPL Financial LLC | 1,965 | $4.08M | 0.00% | −341−14.8% | Reduced |
| Parsons Capital Management Inc | 1,872 | $3.89M | 0.21% | −10−0.5% | Reduced |
| Citigroup Inc | 1,849 | $3.84M | 0.00% | +360+24.2% | Added |
| JPMorgan Chase & Co | 1,806 | $3.75M | 0.00% | −2,516−58.2% | Reduced |
| Atlantic Union Bankshares Corp | 1,765 | $3.67M | 0.07% | 00.0% | Unchanged |
| Jane Street Group, LLC | 1,707 | $3.55M | 0.00% | −3,113−64.6% | Reduced |
| Regency Capital Management Inc. | 1,635 | $3.40M | 1.41% | +824+101.6% | Added |
| Oppenheimer Asset Management Inc. | 1,502 | $3.12M | 0.04% | −70−4.5% | Reduced |
| Renaissance Technologies LLC | 1,501 | $3.12M | 0.00% | −350−18.9% | Reduced |
| Colony Group, LLC | 1,610 | $3.10M | 0.00% | +257+19.0% | Added |
| HighTower Advisors, LLC | 1,447 | $3.01M | 0.00% | −18−1.2% | Reduced |
| Agf Management Ltd | 1,408 | $2.93M | 0.01% | −372−20.9% | Reduced |
| Stifel Financial Corp | 1,312 | $2.73M | 0.00% | −4−0.3% | Reduced |
| Citadel Advisors LLC | 1,193 | $2.48M | 0.00% | +912+324.6% | Added |
| Aquatic Capital Management LLC | 1,180 | $2.45M | 0.07% | +415+54.2% | Added |
| Northern Oak Wealth Management Inc | 1,176 | $2.44M | 0.31% | 00.0% | Unchanged |
| Pecaut & Co. | 1,167 | $2.43M | 0.78% | 00.0% | Unchanged |
| State of New Jersey Common Pension Fund D | 1,135 | $2.36M | 0.01% | −20−1.7% | Reduced |
| Janus Henderson Group PLC | 1,123 | $2.34M | 0.00% | 00.0% | Unchanged |
| Leuthold Group, LLC | 1,117 | $2.32M | 0.25% | −89−7.4% | Reduced |
| Marshall Wace, LLP | 1,098 | $2.28M | 0.00% | +1,098 | New |
| Royal Bank of Canada | 1,097 | $2.28M | 0.00% | −673−38.0% | Reduced |
| Autumn Glory Partners, LLC | 1,080 | $2.24M | 0.79% | 00.0% | Unchanged |
| Police & Firemen's Retirement System of New Jersey | 1,070 | $2.22M | 0.02% | −47−4.2% | Reduced |
| Treasurer of the State of North Carolina | 1,034 | $2.15M | 0.01% | −91−8.1% | Reduced |