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, Q3 2025
Institutional positions in White Mountains Insurance Group Ltd as of Sep 30, 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
- 338
- +17 vs. Q2 2025
- Shares held
- 2.33M
- +39.1K (+1.7%) vs. Q2 2025
- Total value
- $3.89B
- −$216.4M (−5.3%) vs. Q2 2025
- New holders
- 44
- 105 more added
- Sold out
- 27
- 103 more reduced
4 institutions that held it in Q2 2025 haven't filed for Q3 2025 yet. Not filing isn't selling, so they aren't counted as sold out or in the changes above.
Compare with Q2 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, Q3 2025
Shares, value and share of portfolio for each institution holding White Mountains Insurance Group Ltd; share changes are against Q2 2025.
| Institution | Shares | Value | % of portfolio | Change in shares | Action |
|---|---|---|---|---|---|
| Vanguard Group Inc | 247,004 | $412.9M | 0.01% | −2,166−0.9% | Reduced |
| Dimensional Fund Advisors LP | 157,217 | $262.8M | 0.06% | +1,464+0.9% | Added |
| Morgan Stanley | 138,862 | $232.1M | 0.01% | −26,202−15.9% | Reduced |
| Neuberger Berman Group LLC | 115,015 | $192.2M | 0.14% | +31,316+37.4% | Added |
| BlackRock, Inc. | 112,579 | $188.2M | 0.00% | −579−0.5% | Reduced |
| River Road Asset Management, LLC | 109,588 | $183.2M | 2.05% | −304−0.3% | Reduced |
| Fuller & Thaler Asset Management, Inc. | 108,091 | $180.7M | 0.61% | +7,107+7.0% | Added |
| Cooke & Bieler LP | 107,851 | $180.3M | 1.86% | +31,070+40.5% | Added |
| Fiduciary Management Inc | 94,383 | $157.8M | 1.60% | +22,905+32.0% | Added |
| Boston Partners | 84,445 | $142.5M | 0.15% | −4,949−5.5% | Reduced |
| Wallace Capital Management Inc. | 81,489 | $136.2M | 16.93% | +2,453+3.1% | Added |
| London Co of Virginia | 66,802 | $111.7M | 0.62% | −1,968−2.9% | Reduced |
| State Street Corp | 54,444 | $91.0M | 0.00% | −2,797−4.9% | Reduced |
| T. Rowe Price Investment Management, Inc. | 47,772 | $79.9M | 0.05% | −15,169−24.1% | Reduced |
| Geode Capital Management, LLC | 42,090 | $70.4M | 0.00% | −439−1.0% | Reduced |
| Reinhart Partners, Inc. | 41,609 | $69.6M | 2.26% | −85−0.2% | Reduced |
| Bank of America Corp | 38,812 | $64.9M | 0.00% | −597−1.5% | Reduced |
| Lord, Abbett & Co. LLC | 36,919 | $61.7M | 0.18% | +4,692+14.6% | Added |
| Southeastern Asset Management IncSuperinvestorSoutheastern Asset Management (Longleaf) | 31,652 | $52.9M | 2.70% | +10,558+50.1% | Added |
| Allspring Global Investments Holdings, LLC | 31,698 | $52.3M | 0.08% | +2,113+7.1% | Added |
| Raymond James Financial Inc | 29,392 | $49.1M | 0.02% | −1,285−4.2% | Reduced |
| Spears Abacus Advisors LLC | 28,288 | $47.3M | 0.89% | −59−0.2% | Reduced |
| Charles Schwab Investment Management Inc | 24,232 | $40.5M | 0.01% | +49+0.2% | Added |
| Mraz, Amerine & Associates, Inc. | 22,606 | $37.8M | 5.89% | +1,030+4.8% | Added |
| Brown Advisory Inc | 20,332 | $34.0M | 0.04% | −522−2.5% | Reduced |
| Wellington Management Group LLP | 19,211 | $32.1M | 0.01% | −5,440−22.1% | Reduced |
| Northern Trust Corp | 17,757 | $29.7M | 0.00% | +352+2.0% | Added |
| Envestnet Asset Management Inc | 17,591 | $29.4M | 0.01% | +80+0.5% | Added |
| Robeco Institutional Asset Management B.V. | 17,239 | $28.8M | 0.04% | −583−3.3% | Reduced |
| Select Equity Group, L.P. | 16,946 | $28.3M | 0.12% | −926−5.2% | Reduced |
| Elkhorn Partners Limited Partnership | 14,810 | $24.8M | 16.80% | −90−0.6% | Reduced |
| WCM Investment Management, LLC | 13,235 | $22.2M | 0.05% | +138+1.1% | Added |
| Horizon Kinetics Asset Management LLC | 13,084 | $21.9M | 0.27% | +2,113+19.3% | Added |
| UBS Group AG | 12,085 | $20.2M | 0.00% | +7,073+141.1% | Added |
| Speece Thorson Capital Group Inc | 11,262 | $18.8M | 3.76% | −121−1.1% | Reduced |
| Bank of New York Mellon Corp | 10,102 | $16.9M | 0.00% | −758−7.0% | Reduced |
| Wells Fargo & Company | 9,352 | $15.6M | 0.00% | −235−2.5% | Reduced |
| California Public Employees Retirement System | 9,232 | $15.4M | 0.01% | −1,162−11.2% | Reduced |
| Thompson Siegel & Walmsley LLC | 8,652 | $14.5M | 0.23% | +347+4.2% | Added |
| Victory Capital Management Inc | 8,526 | $14.3M | 0.01% | −9,114−51.7% | Reduced |
| Perpetual Ltd | 8,127 | $13.6M | 0.17% | +400+5.2% | Added |
| GW&K Investment Management, LLC | 8,010 | $13.4M | 0.12% | −262−3.2% | Reduced |
| Susquehanna International Group, LLP | 7,360 | $12.3M | 0.02% | +7,072+2,455.6% | Added |
| Hotchkis & Wiley Capital Management LLC | 7,106 | $11.9M | 0.04% | +237+3.5% | Added |
| Gotham Asset Management, LLC | 6,899 | $11.5M | 0.05% | +5,939+618.6% | Added |
| Royce & Associates LP | 6,302 | $10.5M | 0.11% | −301−4.6% | Reduced |
| Quantinno Capital Management LP | 6,054 | $10.1M | 0.03% | +1,764+41.1% | Added |
| Goldman Sachs Group Inc | 5,911 | $9.88M | 0.00% | −974−14.1% | Reduced |
| AQR Capital Management LLC | 5,913 | $9.84M | 0.01% | −2,171−26.9% | Reduced |
| Bradley Foster & Sargent Inc | 5,546 | $9.27M | 0.14% | +24+0.4% | Added |
| Phocas Financial Corp. | 5,505 | $9.20M | 1.19% | +113+2.1% | Added |
| SEI Investments Co | 5,386 | $9.00M | 0.01% | +481+9.8% | Added |
| Williams Jones Wealth Management, LLC. | 5,193 | $8.68M | 0.10% | 00.0% | Unchanged |
| Swiss National Bank | 4,946 | $8.27M | 0.00% | 00.0% | Unchanged |
| Jane Street Group, LLC | 4,820 | $8.06M | 0.01% | −1,251−20.6% | Reduced |
| JPMorgan Chase & Co | 4,322 | $7.22M | 0.00% | +1,999+86.1% | Added |
| Rhumbline Advisers | 4,232 | $7.07M | 0.01% | −48−1.1% | Reduced |
| Legal & General Group Plc | 4,049 | $6.77M | 0.00% | −260−6.0% | Reduced |
| Prospector Partners LLC | 3,783 | $6.32M | 0.76% | −293−7.2% | Reduced |
| HRT Financial LP | 3,587 | $6.00M | 0.02% | −1,500−29.5% | Reduced |
| Nuveen, LLC | 3,458 | $5.78M | 0.00% | 00.0% | Unchanged |
| Brandywine Global Investment Management, LLC | 3,326 | $5.56M | 0.04% | −200−5.7% | Reduced |
| Invesco Ltd. | 3,317 | $5.54M | 0.00% | −329−9.0% | Reduced |
| Lee Danner & Bass Inc | 3,148 | $5.26M | 0.38% | 00.0% | Unchanged |
| State Board of Administration of Florida Retirement System | 3,142 | $5.25M | 0.01% | +529+20.2% | Added |
| Creative Planning | 3,102 | $5.18M | 0.00% | +260+9.1% | Added |
| Ameriprise Financial Inc | 3,028 | $5.06M | 0.00% | −454−13.0% | Reduced |
| Lighthouse Investment Partners, LLC | 2,939 | $4.91M | 0.18% | +2,939 | New |
| MML Investors Services, LLC | 2,852 | $4.77M | 0.01% | +118+4.3% | Added |
| New York State Common Retirement Fund | 2,519 | $4.21M | 0.01% | 00.0% | Unchanged |
| D. E. Shaw & Co., Inc. | 2,512 | $4.20M | 0.00% | +76+3.1% | Added |
| California State Teachers Retirement System | 2,433 | $4.07M | 0.00% | +61+2.6% | Added |
| LPL Financial LLC | 2,306 | $3.85M | 0.00% | +321+16.2% | Added |
| American Century Companies Inc | 2,242 | $3.75M | 0.00% | −4,123−64.8% | Reduced |
| Davenport & Co LLC | 2,173 | $3.63M | 0.02% | 00.0% | Unchanged |
| Forum Financial Management, LP | 2,016 | $3.37M | 0.05% | 00.0% | Unchanged |
| Cerity Partners LLC | 1,940 | $3.24M | 0.01% | +40+2.1% | Added |
| Price T Rowe Associates Inc | 1,882 | $3.15M | 0.00% | +131+7.5% | Added |
| Parsons Capital Management Inc | 1,882 | $3.15M | 0.18% | −10−0.5% | Reduced |
| Renaissance Technologies LLC | 1,851 | $3.09M | 0.00% | +1,851 | New |
| Agf Management Ltd | 1,780 | $2.98M | 0.01% | +448+33.6% | Added |
| Royal Bank of Canada | 1,770 | $2.96M | 0.00% | −420−19.2% | Reduced |
| Atlantic Union Bankshares Corp | 1,765 | $2.95M | 0.06% | +1,765 | New |
| Oppenheimer Asset Management Inc. | 1,572 | $2.63M | 0.03% | +209+15.3% | Added |
| BNP Paribas Arbitrage, SA | 1,536 | $2.57M | 0.00% | +1,348+717.0% | Added |
| Citigroup Inc | 1,489 | $2.49M | 0.00% | +127+9.3% | Added |
| HighTower Advisors, LLC | 1,465 | $2.45M | 0.00% | +1+0.1% | Added |
| Edgestream Partners, L.P. | 1,371 | $2.29M | 0.07% | −6,438−82.4% | Reduced |
| Colony Group, LLC | 1,353 | $2.26M | 0.00% | −243−15.2% | Reduced |
| Stifel Financial Corp | 1,316 | $2.20M | 0.00% | −28−2.1% | Reduced |
| Main Street Financial Solutions, LLC | 1,261 | $2.11M | 0.14% | −32−2.5% | Reduced |
| Leuthold Group, LLC | 1,206 | $2.02M | 0.22% | +41+3.5% | Added |
| Northern Oak Wealth Management Inc | 1,176 | $1.97M | 0.24% | 00.0% | Unchanged |
| Truist Financial Corp | 1,173 | $1.96M | 0.00% | −67−5.4% | Reduced |
| Pecaut & Co. | 1,167 | $1.95M | 0.63% | 00.0% | Unchanged |
| TD Asset Management Inc | 1,166 | $1.95M | 0.00% | −452−27.9% | Reduced |
| State of New Jersey Common Pension Fund D | 1,155 | $1.93M | 0.01% | +107+10.2% | Added |
| Treasurer of the State of North Carolina | 1,125 | $1.88M | 0.01% | −37−3.2% | Reduced |
| Janus Henderson Group PLC | 1,123 | $1.88M | 0.00% | 00.0% | Unchanged |
| Police & Firemen's Retirement System of New Jersey | 1,117 | $1.87M | 0.02% | +183+19.6% | Added |