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 |
|---|---|---|---|---|---|
| California Public Employees Retirement System | 9,232 | $15.4M | 0.01% | −1,162−11.2% | Reduced |
| Wells Fargo & Company | 9,352 | $15.6M | 0.00% | −235−2.5% | Reduced |
| Bank of New York Mellon Corp | 10,102 | $16.9M | 0.00% | −758−7.0% | Reduced |
| Speece Thorson Capital Group Inc | 11,262 | $18.8M | 3.76% | −121−1.1% | Reduced |
| UBS Group AG | 12,085 | $20.2M | 0.00% | +7,073+141.1% | Added |
| Horizon Kinetics Asset Management LLC | 13,084 | $21.9M | 0.27% | +2,113+19.3% | Added |
| WCM Investment Management, LLC | 13,235 | $22.2M | 0.05% | +138+1.1% | Added |
| Elkhorn Partners Limited Partnership | 14,810 | $24.8M | 16.80% | −90−0.6% | Reduced |
| Select Equity Group, L.P. | 16,946 | $28.3M | 0.12% | −926−5.2% | Reduced |
| Robeco Institutional Asset Management B.V. | 17,239 | $28.8M | 0.04% | −583−3.3% | Reduced |
| Envestnet Asset Management Inc | 17,591 | $29.4M | 0.01% | +80+0.5% | Added |
| Northern Trust Corp | 17,757 | $29.7M | 0.00% | +352+2.0% | Added |
| Wellington Management Group LLP | 19,211 | $32.1M | 0.01% | −5,440−22.1% | Reduced |
| Brown Advisory Inc | 20,332 | $34.0M | 0.04% | −522−2.5% | Reduced |
| Mraz, Amerine & Associates, Inc. | 22,606 | $37.8M | 5.89% | +1,030+4.8% | Added |
| Charles Schwab Investment Management Inc | 24,232 | $40.5M | 0.01% | +49+0.2% | Added |
| Spears Abacus Advisors LLC | 28,288 | $47.3M | 0.89% | −59−0.2% | Reduced |
| Raymond James Financial Inc | 29,392 | $49.1M | 0.02% | −1,285−4.2% | Reduced |
| Allspring Global Investments Holdings, LLC | 31,698 | $52.3M | 0.08% | +2,113+7.1% | Added |
| Southeastern Asset Management IncSuperinvestorSoutheastern Asset Management (Longleaf) | 31,652 | $52.9M | 2.70% | +10,558+50.1% | Added |
| Lord, Abbett & Co. LLC | 36,919 | $61.7M | 0.18% | +4,692+14.6% | Added |
| Bank of America Corp | 38,812 | $64.9M | 0.00% | −597−1.5% | Reduced |
| Reinhart Partners, Inc. | 41,609 | $69.6M | 2.26% | −85−0.2% | Reduced |
| Geode Capital Management, LLC | 42,090 | $70.4M | 0.00% | −439−1.0% | Reduced |
| T. Rowe Price Investment Management, Inc. | 47,772 | $79.9M | 0.05% | −15,169−24.1% | Reduced |
| State Street Corp | 54,444 | $91.0M | 0.00% | −2,797−4.9% | Reduced |
| London Co of Virginia | 66,802 | $111.7M | 0.62% | −1,968−2.9% | Reduced |
| Wallace Capital Management Inc. | 81,489 | $136.2M | 16.93% | +2,453+3.1% | Added |
| Boston Partners | 84,445 | $142.5M | 0.15% | −4,949−5.5% | Reduced |
| Fiduciary Management Inc | 94,383 | $157.8M | 1.60% | +22,905+32.0% | Added |
| Cooke & Bieler LP | 107,851 | $180.3M | 1.86% | +31,070+40.5% | Added |
| Fuller & Thaler Asset Management, Inc. | 108,091 | $180.7M | 0.61% | +7,107+7.0% | Added |
| River Road Asset Management, LLC | 109,588 | $183.2M | 2.05% | −304−0.3% | Reduced |
| BlackRock, Inc. | 112,579 | $188.2M | 0.00% | −579−0.5% | Reduced |
| Neuberger Berman Group LLC | 115,015 | $192.2M | 0.14% | +31,316+37.4% | Added |
| Morgan Stanley | 138,862 | $232.1M | 0.01% | −26,202−15.9% | Reduced |
| Dimensional Fund Advisors LP | 157,217 | $262.8M | 0.06% | +1,464+0.9% | Added |
| Vanguard Group Inc | 247,004 | $412.9M | 0.01% | −2,166−0.9% | Reduced |
| First Trust Advisors LP | 0 | $0 | 0.00% | −5,672−100.0% | Sold out |
| Verition Fund Management LLC | 0 | $0 | 0.00% | −571−100.0% | Sold out |
| Quadrature Capital Ltd | 0 | $0 | 0.00% | −548−100.0% | Sold out |
| Mitsubishi UFJ Trust & Banking Corp | 0 | $0 | 0.00% | −477−100.0% | Sold out |
| First Manhattan Co | 0 | $0 | 0.00% | −401−100.0% | Sold out |
| Petrus Trust Company, LTA | 0 | $0 | 0.00% | −238−100.0% | Sold out |
| Algert Global LLC | 0 | $0 | 0.00% | −233−100.0% | Sold out |
| Yorktown Management & Research Co Inc | 0 | $0 | 0.00% | −220−100.0% | Sold out |
| Nebula Research & Development LLC | 0 | $0 | 0.00% | −201−100.0% | Sold out |
| Martingale Asset Management L P | 0 | $0 | 0.00% | −191−100.0% | Sold out |
| Johnson Investment Counsel Inc | 0 | $0 | 0.00% | −185−100.0% | Sold out |
| Isthmus Partners, LLC | 0 | $0 | 0.00% | −164−100.0% | Sold out |
| Crossmark Global Holdings, Inc. | 0 | $0 | 0.00% | −158−100.0% | Sold out |
| Integrated Wealth Concepts LLC | 0 | $0 | 0.00% | −140−100.0% | Sold out |
| M&T Bank Corp | 0 | $0 | 0.00% | −125−100.0% | Sold out |
| Vident Advisory, LLC | 0 | $0 | 0.00% | −120−100.0% | Sold out |
| Opal Wealth Advisors, LLC | 0 | $0 | 0.00% | −38−100.0% | Sold out |
| BNP PARIBAS ASSET MANAGEMENT Holding S.A. | 0 | $0 | 0.00% | −22−100.0% | Sold out |
| Sierra Ocean, LLC | 0 | $0 | 0.00% | −12−100.0% | Sold out |
| Geneos Wealth Management Inc. | 0 | $0 | 0.00% | −11−100.0% | Sold out |
| Acadian Asset Management LLC | 0 | $0 | 0.00% | −10−100.0% | Sold out |
| Skopos Labs, Inc. | 0 | $0 | 0.00% | −4−100.0% | Sold out |
| Whipplewood Advisors, LLC | 0 | $0 | 0.00% | −3−100.0% | Sold out |
| Twin Peaks Wealth Advisors, LLC | 0 | $0 | 0.00% | −1−100.0% | Sold out |
| IFP Advisors, Inc | 0 | $0 | 0.00% | −1−100.0% | Sold out |
| Larson Financial Group LLC | 0 | $0 | 0.00% | −1−100.0% | Sold out |
| Stephens Consulting, LLC | 0 | $0 | 0.00% | −1−100.0% | Sold out |
| Norges Bank | – | – | – | – | Not filed |
| Atria Wealth Solutions, Inc. | – | – | – | – | Not filed |
| Avantax Advisory Services, Inc. | – | – | – | – | Not filed |
| First Horizon Advisors, Inc. | – | – | – | – | Not filed |