White Mountains Insurance GPWTM
13F holders, Q4 2025 (December 31)353holders +15
45new positions
35sold out
6famous investors
$2077.59avg. 13F price*
At the end of Q4 2025, 353 institutions reported holding White Mountains Insurance GP (WTM) in their 13F filings, up 15 from Q3 2025. 45 opened new positions and 35 sold out. The largest holders were Vanguard Group Inc. ($489.8M), Dimensional Fund Advisors LP ($325.4M) and Neuberger Berman Group LLC ($269.4M). 6 famous investors held it, including Joel Greenblatt (0.1% of Gotham Asset Management's portfolio), David E. Shaw (0.0% of D. E. Shaw & Co.'s portfolio) and Cliff Asness (0.0% of AQR Capital Management's portfolio).
- Company
- White Mountains Insurance GP
- CUSIP
- G9618E107
- Latest filing quarter
- Q2 2026
History
Number of 13F holders
Total Exit/New Position Q3 2025 → Q4 2025
| Institutions | Total Value | |
|---|---|---|
| New Positions | 45 | $100.5M |
| Exits | 35 | $29.4M |
All 13F filers, Q3 2025 → Q4 2025: 109,501 shares bought and 222,242 shares sold, net −112,741 shares. Counts holders who added, trimmed, opened or closed a position; split-adjusted.
Ownership 353 holders
| Vanguard Group Inc. | 0.01% | Reduce -4.6% | 235,698 | $489.8M |
| Dimensional Fund Advisors LP | 0.07% | Reduce -0.4% | 156,604 | $325.4M |
| Neuberger Berman Group LLC | 0.20% | Add +12.7% | 129,654 | $269.4M |
| River Road Asset Management, LLC | 2.76% | Add +10.3% | 120,880 | $251.2M |
| BlackRock, Inc. | 0.00% | Reduce -0.3% | 112,289 | $233.3M |
| Fuller & Thaler Asset Management, Inc. | 0.76% | Add +0.1% | 108,172 | $224.8M |
| Cooke & Bieler LP | 2.31% | Reduce -1.2% | 106,579 | $221.5M |
| Fiduciary Management Inc. | 2.06% | Reduce -4.3% | 90,333 | $187.7M |
| Morgan Stanley | 0.01% | Reduce -40.8% | 82,151 | $170.7M |
| Wallace Capital Management Inc. | 20.10% | Reduce -1.4% | 80,347 | $167.0M |
| Boston Partners | 0.17% | Reduce -8.9% | 76,911 | $159.7M |
| London Co. of Virginia | 0.70% | Reduce -12.1% | 58,697 | $122.0M |
| State Street Corp. | 0.00% | Reduce -6.9% | 50,663 | $105.3M |
| T. Rowe Price Investment Management, Inc. | 0.06% | Reduce -6.7% | 44,560 | $92.6M |
| Reinhart Partners, Llc. | 2.74% | Add +5.7% | 43,973 | $91.4M |
| Geode Capital Management, LLC | 0.01% | Reduce -1.4% | 41,518 | $86.3M |
| Lord, Abbett & Co. LLC | 0.23% | Reduce -8.5% | 33,796 | $70.2M |
| Gendell Jeffrey L | 1.18% | New | 32,520 | $67.6M |
| Norges Bank | 0.01% | — | 32,184 | $66.9M |
| Southeastern Asset Management Inc. | 2.93% | No change | 31,652 | $65.8M |
| Bank of America Corp. | 0.00% | Reduce -25.8% | 28,809 | $59.9M |
| Cannell & Spears LLC | 1.10% | Reduce -0.6% | 28,115 | $58.4M |
| Raymond James Financial Inc. | 0.02% | Reduce -18.4% | 23,969 | $49.8M |
| Charles Schwab Investment Management Inc. | 0.01% | Reduce -4.1% | 23,238 | $48.3M |
| Mraz, Amerine & Associates, Inc. | 6.99% | Add +0.1% | 22,629 | $47.0M |
| Allspring Global Investments Holdings, LLC | 0.07% | Reduce -36.3% | 20,193 | $41.2M |
| Select Equity Group, L.P. | 0.19% | Add +16.3% | 19,713 | $41.0M |
| Brown Advisory Inc. | 0.06% | Reduce -6.8% | 18,956 | $39.4M |
| Northern Trust Corp. | 0.00% | Reduce -6.1% | 16,667 | $34.6M |
| Wellington Management Group LLP | 0.01% | Reduce -17.1% | 15,928 | $33.1M |
| Envestnet Asset Management Inc. | 0.01% | Reduce -10.2% | 15,798 | $32.8M |
| Elkhorn Partners Limited Partnership | 17.85% | Reduce -8.2% | 13,598 | $28.3M |
| Horizon Kinetics Asset Management LLC | 0.37% | Add +0.3% | 13,121 | $27.3M |
| WCM Investment Management, LLC | 0.05% | Reduce -19.3% | 10,682 | $22.2M |
| Speece Thorson Capital Group Inc. | 4.80% | Reduce -5.2% | 10,672 | $22.2M |
| Wells Fargo & Company | 0.00% | Reduce -2.3% | 9,141 | $19.0M |
| Thompson Siegel & Walmsley LLC | 0.31% | Add +3.2% | 8,927 | $18.6M |
| Bank of New York Mellon Corp | 0.00% | Reduce -12.6% | 8,831 | $18.4M |
| GW&K Investment Management, LLC | 0.15% | Add +7.6% | 8,621 | $17.9M |
| D. E. Shaw & Co. | 0.01% | Add +242.1% | 8,593 | $17.9M |
| Sei Investments Co. | 0.02% | Add +47.0% | 7,916 | $16.5M |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC | 0.00% | Add +109257.1% | 7,655 | $15.9M |
| Quantinno Capital Management LP | 0.03% | Add +20.1% | 7,271 | $15.1M |
| Hotchkis & Wiley Capital Management LLC | 0.04% | Reduce -5.0% | 6,752 | $14.0M |
| Gotham Asset Management | 0.05% | Reduce -2.6% | 6,716 | $14.0M |
| California Public Employees Retirement System | 0.01% | Reduce -27.3% | 6,716 | $14.0M |
| Victory Capital Management Inc. | 0.01% | Reduce -26.2% | 6,296 | $13.1M |
| UBS Group AG | 0.00% | Reduce -50.3% | 6,001 | $12.5M |
| Royce & Associates LP | 0.13% | Reduce -5.6% | 5,947 | $12.4M |
| Phocas Financial Corp. | 1.48% | Reduce -0.3% | 5,491 | $11.4M |
| Bradley Foster & Sargent Inc. | 0.17% | Reduce -1.6% | 5,456 | $11.3M |
| Goldman Sachs Group Inc. | 0.00% | Reduce -11.0% | 5,260 | $10.9M |
| Williams Jones Wealth Management, LLC. | 0.12% | No change | 5,193 | $10.8M |
| Swiss National Bank | 0.01% | Add +2.8% | 5,086 | $10.6M |
| First Trust Advisors LP | 0.01% | New | 4,555 | $9.5M |
| AQR Capital Management | 0.00% | Reduce -24.3% | 4,476 | $9.3M |
| Rhumbline Advisers | 0.01% | Reduce -1.6% | 4,165 | $8.7M |
| Dark Forest Capital Management LP | 0.34% | New | 3,615 | $7.5M |
| Cerity Partners LLC | 0.01% | Add +82.6% | 3,543 | $7.4M |
| Nuveen, LLC | 0.00% | Add +0.5% | 3,475 | $7.2M |
| Creative Planning | 0.01% | Add +10.1% | 3,415 | $7.1M |
| BNP Paribas Financial Markets | 0.00% | Add +117.5% | 3,340 | $6.9M |
| Brandywine Global Investment Management, LLC | 0.05% | Reduce -3.0% | 3,226 | $6.7M |
| Lee Danner & Bass Inc. | 0.46% | Reduce -1.4% | 3,103 | $6.4M |
| Ameriprise Financial Inc. | 0.00% | Add +0.8% | 3,053 | $6.3M |
| Legal & General Group Plc | 0.00% | Reduce -25.0% | 3,037 | $6.3M |
| Invesco Ltd. | 0.00% | Reduce -9.7% | 2,995 | $6.2M |
| MML Investors Services, LLC | 0.01% | Add +2.9% | 2,935 | $6.1M |
| State Board of Administration of Florida Retirement System | 0.01% | Reduce -11.1% | 2,792 | $5.8M |
| Triad Investment Management | 5.36% | — | 2,548 | $5.3M |
| New York State Common Retirement Fund | 0.01% | Reduce -0.2% | 2,513 | $5.2M |
| California State Teachers Retirement System | 0.01% | Add +1.0% | 2,457 | $5.1M |
| DAVENPORT & Co LLC | 0.02% | Reduce -2.3% | 2,123 | $4.4M |
| Forum Financial Management, LP | 0.05% | No change | 2,016 | $4.2M |
| T. Rowe Price Associates Inc. | 0.00% | Add +5.7% | 1,990 | $4.1M |
| LPL Financial LLC | 0.00% | Reduce -14.8% | 1,965 | $4.1M |
| Parsons Capital Management Inc. | 0.21% | Reduce -0.5% | 1,872 | $3.9M |
| Citigroup Inc. | 0.00% | Add +24.2% | 1,849 | $3.8M |
| JPMorgan Chase & Co. | 0.00% | Reduce -58.2% | 1,806 | $3.8M |
| Atlantic Union Bankshares Corp | 0.07% | No change | 1,765 | $3.7M |
| Jane Street Group, LLC | 0.00% | Reduce -64.6% | 1,707 | $3.5M |
| Regency Capital Management Inc.\DE | 1.41% | Add +101.6% | 1,635 | $3.4M |
| Oppenheimer Asset Management Inc. | 0.04% | Reduce -4.5% | 1,502 | $3.1M |
| Renaissance Technologies | 0.00% | Reduce -18.9% | 1,501 | $3.1M |
| Focus Partners Wealth | 0.00% | Add +19.0% | 1,610 | $3.1M |
| HighTower Advisors, LLC | 0.00% | Reduce -1.2% | 1,447 | $3.0M |
| Agf Management Ltd. | 0.01% | Reduce -20.9% | 1,408 | $2.9M |
| Stifel Financial Corp. | 0.00% | Reduce -0.3% | 1,312 | $2.7M |
| Citadel Advisors | 0.00% | Add +324.6% | 1,193 | $2.5M |
| Aquatic Capital Management LLC | 0.07% | Add +54.3% | 1,180 | $2.5M |
| 1834 Investment Advisors Co. | 0.31% | No change | 1,176 | $2.4M |
| Pecaut & Co. | 0.78% | No change | 1,167 | $2.4M |
| State of New Jersey Common Pension Fund D | 0.01% | Reduce -1.7% | 1,135 | $2.4M |
| Janus Henderson Group PLC | 0.00% | No change | 1,123 | $2.3M |
| Leuthold Group, LLC | 0.25% | Reduce -7.4% | 1,117 | $2.3M |
| Marshall Wace, LLP | 0.00% | New | 1,098 | $2.3M |
| Royal Bank of Canada | 0.00% | Reduce -38.0% | 1,097 | $2.3M |
| Autumn Glory Partners, LLC | 0.79% | No change | 1,080 | $2.2M |
| Police & Firemen's Retirement System of New Jersey | 0.02% | Reduce -4.2% | 1,070 | $2.2M |
| Treasurer of the State of North Carolina | 0.01% | Reduce -8.1% | 1,034 | $2.1M |
"% of holder's portfolio" is WTM's weight in each manager's 13F, not the share of White Mountains Insurance GP the manager owns.