White Mountains Insurance GPWTM
13F holders, Q2 2026 (June 30)356holders −12
33new positions
45sold out
5famous investors
$2073.78avg. 13F price*
At the end of Q2 2026, 356 institutions reported holding White Mountains Insurance GP (WTM) in their 13F filings, down 12 from Q1 2026. 33 opened new positions and 45 sold out. The largest holders were Dimensional Fund Advisors LP ($329.6M), Neuberger Berman Group LLC ($247.0M) and BlackRock, Inc. ($244.4M). 5 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 Ken Griffin (0.0% of Citadel Advisors's portfolio).
- Company
- White Mountains Insurance GP
- CUSIP
- G9618E107
- Latest filing quarter
- Q2 2026
History
Number of 13F holders
Total Exit/New Position Q1 2026 → Q2 2026
| Institutions | Total Value | |
|---|---|---|
| New Positions | 33 | $29.4M |
| Exits | 45 | $85.3M |
All 13F filers, Q1 2026 → Q2 2026: 151,392 shares bought and 183,416 shares sold, net −32,024 shares. Counts holders who added, trimmed, opened or closed a position; split-adjusted.
Ownership 356 holders
| Dimensional Fund Advisors LP | 0.06% | Add +1.5% | 158,954 | $329.6M |
| Neuberger Berman Group LLC | 0.16% | Reduce -4.5% | 119,141 | $247.0M |
| BlackRock, Inc. | 0.00% | Add +4.0% | 117,871 | $244.4M |
| River Road Asset Management, LLC | 2.68% | Reduce -3.9% | 115,880 | $240.3M |
| Vanguard Portfolio Management LLC | 0.01% | Reduce -3.1% | 111,969 | $232.2M |
| Vanguard Capital Management LLC | 0.00% | Reduce -1.5% | 107,479 | $222.8M |
| Fuller & Thaler Asset Management, Inc. | 0.58% | Reduce -2.5% | 101,892 | $211.3M |
| Cooke & Bieler LP | 2.04% | Reduce -18.8% | 85,120 | $176.5M |
| Wallace Capital Management Inc. | 18.20% | Add +1.6% | 80,067 | $166.0M |
| Fiduciary Management Inc. | 1.96% | Reduce -21.8% | 66,550 | $138.0M |
| Gendell Jeffrey L | 1.11% | Add +56.7% | 59,243 | $122.8M |
| Boston Partners | 0.10% | Reduce -3.3% | 55,569 | $115.3M |
| London Co. of Virginia | 0.64% | Reduce -5.4% | 54,025 | $112.1M |
| State Street Corp. | 0.00% | Add +2.2% | 50,257 | $104.2M |
| Geode Capital Management, LLC | 0.01% | Add +17.3% | 49,412 | $102.5M |
| Morgan Stanley | 0.01% | Reduce -21.0% | 46,866 | $97.2M |
| Reinhart Partners, Llc. | 2.11% | Add +19.0% | 44,480 | $92.3M |
| T. Rowe Price Investment Management, Inc. | 0.05% | Reduce -17.5% | 34,237 | $71.0M |
| Lord, Abbett & Co. LLC | 0.20% | Reduce -0.8% | 32,829 | $68.1M |
| American Century Companies Inc. | 0.03% | Add +274.4% | 31,108 | $64.5M |
| Norges Bank | 0.01% | — | 27,956 | $58.0M |
| Cannell & Spears LLC | 1.03% | Reduce -1.6% | 27,577 | $57.2M |
| Bank of America Corp. | 0.00% | Reduce -11.7% | 25,028 | $51.9M |
| Charles Schwab Investment Management Inc. | 0.01% | Reduce -3.0% | 23,505 | $48.7M |
| Mraz, Amerine & Associates, Inc. | 6.61% | Add +0.2% | 22,218 | $46.1M |
| Allspring Global Investments Holdings, LLC | 0.06% | Reduce -2.7% | 18,116 | $37.4M |
| Gotham Asset Management | 0.09% | Add +98.3% | 17,940 | $37.2M |
| Brown Advisory Inc. | 0.06% | Reduce -0.7% | 17,722 | $36.7M |
| Jane Street Group, LLC | 0.02% | Add +24.8% | 17,226 | $35.7M |
| Southeastern Asset Management Inc. | 1.85% | Reduce -9.3% | 17,104 | $35.5M |
| UBS Group AG | 0.01% | Add +55.1% | 16,198 | $33.6M |
| Vanguard Fiduciary Trust Co. | 0.01% | Add +0.9% | 15,319 | $31.8M |
| Raymond James Financial Inc. | 0.01% | Reduce -38.1% | 14,833 | $30.8M |
| Northern Trust Corp. | 0.00% | Reduce -6.0% | 14,571 | $30.2M |
| Wellington Management Group LLP | 0.01% | Reduce -2.4% | 14,532 | $30.1M |
| Envestnet Asset Management Inc. | 0.01% | Reduce -11.1% | 13,838 | $28.7M |
| Quantinno Capital Management LP | 0.03% | Add +29.0% | 12,624 | $26.2M |
| Elkhorn Partners Limited Partnership | 21.89% | Reduce -3.0% | 12,320 | $25.5M |
| Horizon Kinetics Asset Management LLC | 0.29% | Reduce -6.9% | 12,206 | $25.3M |
| Goldman Sachs Group Inc. | 0.00% | Reduce -23.0% | 12,151 | $25.2M |
| Boussard & Gavaudan Gestion Sas | 2.97% | — | 11,679 | $24.5M |
| Victory Capital Management Inc. | 0.01% | Reduce -4.1% | 10,684 | $22.2M |
| First Trust Advisors LP | 0.01% | Add +246.8% | 10,604 | $22.0M |
| Qube Research & Technologies Ltd | 0.02% | Add +852.1% | 9,673 | $20.1M |
| Speece Thorson Capital Group Inc. | 4.08% | Reduce -1.9% | 9,215 | $19.1M |
| Wells Fargo & Company | 0.00% | Reduce -0.8% | 8,710 | $18.1M |
| Bank of New York Mellon Corp | 0.00% | Reduce -0.4% | 8,412 | $17.4M |
| Sei Investments Co. | 0.01% | Reduce -26.9% | 8,108 | $16.8M |
| GW&K Investment Management, LLC | 0.13% | Reduce -1.1% | 7,839 | $16.3M |
| Thompson Siegel & Walmsley LLC | 0.29% | Add +6.2% | 7,656 | $15.9M |
| Arrowstreet Capital, Limited Partnership | 0.01% | Add +280.8% | 7,284 | $15.1M |
| Citadel Advisors | 0.01% | Add +174.2% | 7,136 | $14.8M |
| Hotchkis & Wiley Capital Management LLC | 0.04% | Add +12.2% | 6,788 | $14.1M |
| Royce & Associates LP | 0.11% | Add +5.0% | 6,781 | $14.1M |
| HRT Financial LP | 0.03% | Add +184.6% | 6,760 | $14.0M |
| D. E. Shaw & Co. | 0.01% | Reduce -25.7% | 6,618 | $13.7M |
| Edgestream Partners, L.P. | 0.41% | Add +110.2% | 6,578 | $13.6M |
| JPMorgan Chase & Co. | 0.00% | Add +110.8% | 5,410 | $11.5M |
| AQR Capital Management | 0.00% | Reduce -29.6% | 5,450 | $11.3M |
| California Public Employees Retirement System | 0.01% | Reduce -18.2% | 5,248 | $10.9M |
| Williams Jones Wealth Management, LLC. | 0.12% | Reduce -0.0% | 5,193 | $10.8M |
| Swiss National Bank | 0.01% | Reduce -4.2% | 4,826 | $10.0M |
| Winmill & Co. Inc. | 2.20% | New | 4,800 | $10.0M |
| Franklin Resources Inc. | 0.00% | Reduce -12.9% | 4,178 | $8.7M |
| Phocas Financial Corp. | 1.17% | Reduce -5.0% | 4,078 | $8.5M |
| Rhumbline Advisers | 0.01% | Reduce -5.7% | 3,898 | $8.1M |
| Creative Planning | 0.00% | Reduce -4.6% | 3,861 | $8.0M |
| Nuveen, LLC | 0.00% | Reduce -14.6% | 3,679 | $7.6M |
| Invesco Ltd. | 0.00% | Add +17.9% | 3,497 | $7.3M |
| Lee Danner & Bass Inc. | 0.39% | Add +1.6% | 3,253 | $6.7M |
| Ameriprise Financial Inc. | 0.00% | Reduce -0.5% | 2,852 | $5.9M |
| California State Teachers Retirement System | 0.01% | Reduce -4.4% | 2,761 | $5.7M |
| New York State Common Retirement Fund | 0.01% | Add +0.8% | 2,532 | $5.2M |
| Triad Investment Management | 5.65% | Reduce -1.7% | 2,471 | $5.1M |
| VANGUARD ASSET MANAGEMENT, Ltd | 0.00% | Add +2.9% | 2,392 | $5.0M |
| Russell Investments Group, Ltd. | 0.00% | Add +107.4% | 2,369 | $4.9M |
| State Board of Administration of Florida Retirement System | 0.01% | Add +4.0% | 2,351 | $4.9M |
| T. Rowe Price Associates Inc. | 0.00% | Add +5.6% | 2,335 | $4.8M |
| Legal & General Group Plc | 0.00% | Reduce -6.3% | 2,257 | $4.7M |
| Robeco Institutional Asset Management B.V. | 0.01% | Add +0.2% | 2,184 | $4.5M |
| Regency Capital Management Inc.\DE | 1.77% | Add +39.8% | 2,146 | $4.4M |
| DAVENPORT & Co LLC | 0.02% | No change | 2,123 | $4.4M |
| Bradley Foster & Sargent Inc. | 0.06% | Reduce -5.1% | 1,899 | $3.9M |
| Parsons Capital Management Inc. | 0.18% | Reduce -0.1% | 1,887 | $3.9M |
| Lighthouse Investment Partners, LLC | 0.12% | New | 1,868 | $3.9M |
| Cerity Partners LLC | 0.00% | Reduce -3.8% | 1,797 | $3.7M |
| Atlantic Union Bankshares Corp | 0.06% | No change | 1,765 | $3.7M |
| MML Investors Services, LLC | 0.01% | Reduce -29.2% | 1,741 | $3.6M |
| Agf Management Ltd. | 0.01% | Reduce -0.4% | 1,696 | $3.5M |
| XTX Topco Ltd | 0.04% | Add +557.6% | 1,644 | $3.4M |
| Tidal Investments LLC | 0.01% | Add +17.1% | 1,578 | $3.3M |
| Focus Partners Wealth | 0.00% | Add +37.6% | 1,553 | $3.2M |
| ExodusPoint Capital Management, LP | 0.03% | Add +136.2% | 1,443 | $3.0M |
| Oppenheimer Asset Management Inc. | 0.03% | Reduce -8.4% | 1,356 | $2.8M |
| LPL Financial LLC | 0.00% | Reduce -5.5% | 1,318 | $2.7M |
| HighTower Advisors, LLC | 0.00% | Reduce -9.1% | 1,316 | $2.7M |
| Royal Bank of Canada | 0.00% | Add +3.5% | 1,237 | $2.6M |
| Stifel Financial Corp. | 0.00% | Reduce -4.6% | 1,235 | $2.6M |
| WCM Investment Management, LLC | 0.00% | Reduce -80.0% | 1,197 | $2.5M |
| 1834 Investment Advisors Co. | 0.28% | No change | 1,176 | $2.4M |
"% of holder's portfolio" is WTM's weight in each manager's 13F, not the share of White Mountains Insurance GP the manager owns.