White Mountains Insurance GPWTM
13F holders, Q3 2025 (September 30)338holders +13
42new positions
26sold out
6famous investors
$1672.08avg. 13F price*
At the end of Q3 2025, 338 institutions reported holding White Mountains Insurance GP (WTM) in their 13F filings, up 13 from Q2 2025. 42 opened new positions and 26 sold out. The largest holders were Vanguard Group Inc. ($412.9M), Dimensional Fund Advisors LP ($262.8M) and Morgan Stanley ($232.1M). 6 famous investors held it, including Joel Greenblatt (0.1% of Gotham Asset Management's portfolio), Cliff Asness (0.0% of AQR Capital Management's portfolio) and Jim Simons / Peter Brown (0.0% of Renaissance Technologies's portfolio).
- Company
- White Mountains Insurance GP
- CUSIP
- G9618E107
- Latest filing quarter
- Q2 2026
History
Number of 13F holders
Total Exit/New Position Q2 2025 → Q3 2025
| Institutions | Total Value | |
|---|---|---|
| New Positions | 42 | $27.4M |
| Exits | 26 | $17.1M |
All 13F filers, Q2 2025 → Q3 2025: 167,377 shares bought and 129,040 shares sold, net +38,337 shares. Counts holders who added, trimmed, opened or closed a position; split-adjusted.
Ownership 338 holders
| Vanguard Group Inc. | 0.01% | Reduce -0.9% | 247,004 | $412.9M |
| Dimensional Fund Advisors LP | 0.06% | Add +0.9% | 157,217 | $262.8M |
| Morgan Stanley | 0.01% | Reduce -15.9% | 138,862 | $232.1M |
| Neuberger Berman Group LLC | 0.14% | Add +37.4% | 115,015 | $192.2M |
| BlackRock, Inc. | 0.00% | Reduce -0.5% | 112,579 | $188.2M |
| River Road Asset Management, LLC | 2.05% | Reduce -0.3% | 109,588 | $183.2M |
| Fuller & Thaler Asset Management, Inc. | 0.61% | Add +7.0% | 108,091 | $180.7M |
| Cooke & Bieler LP | 1.86% | Add +40.5% | 107,851 | $180.3M |
| Fiduciary Management Inc. | 1.60% | Add +32.0% | 94,383 | $157.8M |
| Boston Partners | 0.15% | Reduce -5.5% | 84,445 | $142.5M |
| Wallace Capital Management Inc. | 16.93% | Add +3.1% | 81,489 | $136.2M |
| London Co. of Virginia | 0.62% | Reduce -2.9% | 66,802 | $111.7M |
| State Street Corp. | 0.00% | Reduce -4.9% | 54,444 | $91.0M |
| T. Rowe Price Investment Management, Inc. | 0.05% | Reduce -24.1% | 47,772 | $79.9M |
| Geode Capital Management, LLC | 0.00% | Reduce -1.0% | 42,090 | $70.4M |
| Reinhart Partners, Llc. | 2.26% | Reduce -0.2% | 41,609 | $69.6M |
| Bank of America Corp. | 0.00% | Reduce -1.5% | 38,812 | $64.9M |
| Lord, Abbett & Co. LLC | 0.19% | Add +14.6% | 36,919 | $61.7M |
| Southeastern Asset Management Inc. | 2.70% | Add +50.0% | 31,652 | $52.9M |
| Allspring Global Investments Holdings, LLC | 0.08% | Add +7.1% | 31,698 | $52.3M |
| Raymond James Financial Inc. | 0.02% | Reduce -4.2% | 29,392 | $49.1M |
| Cannell & Spears LLC | 0.89% | Reduce -0.2% | 28,288 | $47.3M |
| Charles Schwab Investment Management Inc. | 0.01% | Add +0.2% | 24,232 | $40.5M |
| Mraz, Amerine & Associates, Inc. | 5.89% | Add +4.8% | 22,606 | $37.8M |
| Brown Advisory Inc. | 0.04% | Reduce -2.5% | 20,332 | $34.0M |
| Wellington Management Group LLP | 0.01% | Reduce -22.1% | 19,211 | $32.1M |
| Northern Trust Corp. | 0.00% | Add +2.0% | 17,757 | $29.7M |
| Envestnet Asset Management Inc. | 0.01% | Add +0.5% | 17,591 | $29.4M |
| Robeco Institutional Asset Management B.V. | 0.04% | Reduce -3.3% | 17,239 | $28.8M |
| Select Equity Group, L.P. | 0.12% | Reduce -5.2% | 16,946 | $28.3M |
| Elkhorn Partners Limited Partnership | 16.80% | Reduce -0.6% | 14,810 | $24.8M |
| WCM Investment Management, LLC | 0.05% | Add +1.1% | 13,235 | $22.2M |
| Horizon Kinetics Asset Management LLC | 0.27% | Add +19.3% | 13,084 | $21.9M |
| UBS Group AG | 0.00% | Add +141.1% | 12,085 | $20.2M |
| Speece Thorson Capital Group Inc. | 3.76% | Reduce -1.1% | 11,262 | $18.8M |
| Bank of New York Mellon Corp | 0.00% | Reduce -7.0% | 10,102 | $16.9M |
| Wells Fargo & Company | 0.00% | Reduce -2.5% | 9,352 | $15.6M |
| California Public Employees Retirement System | 0.01% | Reduce -11.2% | 9,232 | $15.4M |
| Thompson Siegel & Walmsley LLC | 0.23% | Add +4.2% | 8,652 | $14.5M |
| Victory Capital Management Inc. | 0.01% | Reduce -51.7% | 8,526 | $14.3M |
| Perpetual Ltd | 0.17% | Add +5.2% | 8,127 | $13.6M |
| GW&K Investment Management, LLC | 0.12% | Reduce -3.2% | 8,010 | $13.4M |
| Susquehanna International Group, LLP | 0.02% | Add +2455.6% | 7,360 | $12.3M |
| Hotchkis & Wiley Capital Management LLC | 0.04% | Add +3.5% | 7,106 | $11.9M |
| Gotham Asset Management | 0.05% | Add +618.6% | 6,899 | $11.5M |
| Royce & Associates LP | 0.10% | Reduce -4.6% | 6,302 | $10.5M |
| Quantinno Capital Management LP | 0.03% | Add +41.1% | 6,054 | $10.1M |
| Goldman Sachs Group Inc. | 0.00% | Reduce -14.2% | 5,911 | $9.9M |
| AQR Capital Management | 0.01% | Reduce -26.9% | 5,913 | $9.8M |
| Bradley Foster & Sargent Inc. | 0.14% | Add +0.4% | 5,546 | $9.3M |
| Phocas Financial Corp. | 1.19% | Add +2.1% | 5,505 | $9.2M |
| Sei Investments Co. | 0.01% | Add +9.8% | 5,386 | $9.0M |
| Williams Jones Wealth Management, LLC. | 0.10% | No change | 5,193 | $8.7M |
| Swiss National Bank | 0.00% | No change | 4,946 | $8.3M |
| Jane Street Group, LLC | 0.01% | Reduce -20.6% | 4,820 | $8.1M |
| JPMorgan Chase & Co. | 0.00% | Add +86.0% | 4,322 | $7.2M |
| Rhumbline Advisers | 0.01% | Reduce -1.1% | 4,232 | $7.1M |
| Legal & General Group Plc | 0.00% | Reduce -6.0% | 4,049 | $6.8M |
| Prospector Partners LLC | 0.77% | Reduce -7.2% | 3,783 | $6.3M |
| HRT Financial LP | 0.02% | Reduce -29.5% | 3,587 | $6.0M |
| Nuveen, LLC | 0.00% | No change | 3,458 | $5.8M |
| Brandywine Global Investment Management, LLC | 0.04% | Reduce -5.7% | 3,326 | $5.6M |
| Invesco Ltd. | 0.00% | Reduce -9.0% | 3,317 | $5.5M |
| Lee Danner & Bass Inc. | 0.38% | No change | 3,148 | $5.3M |
| State Board of Administration of Florida Retirement System | 0.01% | Add +20.2% | 3,142 | $5.3M |
| Creative Planning | 0.00% | Add +9.2% | 3,102 | $5.2M |
| Ameriprise Financial Inc. | 0.00% | Reduce -13.0% | 3,028 | $5.1M |
| Lighthouse Investment Partners, LLC | 0.18% | New | 2,939 | $4.9M |
| MML Investors Services, LLC | 0.01% | Add +4.3% | 2,852 | $4.8M |
| New York State Common Retirement Fund | 0.01% | No change | 2,519 | $4.2M |
| D. E. Shaw & Co. | 0.00% | Add +3.1% | 2,512 | $4.2M |
| California State Teachers Retirement System | 0.00% | Add +2.6% | 2,433 | $4.1M |
| LPL Financial LLC | 0.00% | Add +16.2% | 2,306 | $3.9M |
| American Century Companies Inc. | 0.00% | Reduce -64.8% | 2,242 | $3.7M |
| DAVENPORT & Co LLC | 0.02% | No change | 2,173 | $3.6M |
| Forum Financial Management, LP | 0.05% | No change | 2,016 | $3.4M |
| Cerity Partners LLC | 0.01% | Add +2.1% | 1,940 | $3.2M |
| T. Rowe Price Associates Inc. | 0.00% | Add +7.5% | 1,882 | $3.1M |
| Parsons Capital Management Inc. | 0.18% | Reduce -0.5% | 1,882 | $3.1M |
| Renaissance Technologies | 0.00% | New | 1,851 | $3.1M |
| Agf Management Ltd. | 0.01% | Add +33.6% | 1,780 | $3.0M |
| Royal Bank of Canada | 0.00% | Reduce -19.2% | 1,770 | $3.0M |
| Atlantic Union Bankshares Corp | 0.06% | New | 1,765 | $3.0M |
| Oppenheimer Asset Management Inc. | 0.03% | Add +15.3% | 1,572 | $2.6M |
| BNP Paribas Financial Markets | 0.00% | Add +717.0% | 1,536 | $2.6M |
| Citigroup Inc. | 0.00% | Add +9.3% | 1,489 | $2.5M |
| HighTower Advisors, LLC | 0.00% | Add +0.1% | 1,465 | $2.4M |
| Edgestream Partners, L.P. | 0.07% | Reduce -82.4% | 1,371 | $2.3M |
| Focus Partners Wealth | 0.00% | Reduce -15.2% | 1,353 | $2.3M |
| Stifel Financial Corp. | 0.00% | Reduce -2.1% | 1,316 | $2.2M |
| Main Street Financial Solutions, LLC | 0.14% | Reduce -2.5% | 1,261 | $2.1M |
| Leuthold Group, LLC | 0.22% | Add +3.5% | 1,206 | $2.0M |
| 1834 Investment Advisors Co. | 0.24% | No change | 1,176 | $2.0M |
| Truist Financial Corp. | 0.00% | Reduce -5.4% | 1,173 | $2.0M |
| Pecaut & Co. | 0.63% | No change | 1,167 | $2.0M |
| TD Asset Management Inc | 0.00% | Reduce -27.9% | 1,166 | $1.9M |
| State of New Jersey Common Pension Fund D | 0.01% | Add +10.2% | 1,155 | $1.9M |
| Treasurer of the State of North Carolina | 0.01% | Reduce -3.2% | 1,125 | $1.9M |
| Janus Henderson Group PLC | 0.00% | No change | 1,123 | $1.9M |
| Police & Firemen's Retirement System of New Jersey | 0.01% | Add +19.6% | 1,117 | $1.9M |
"% of holder's portfolio" is WTM's weight in each manager's 13F, not the share of White Mountains Insurance GP the manager owns.