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, Q1 2026
Institutional positions in White Mountains Insurance Group Ltd as of Mar 31, 2026. 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
- 368
- +23 vs. Q4 2025
- Shares held
- 2.21M
- +232.8K (+11.8%) vs. Q4 2025
- Total value
- $4.86B
- +$748.7M (+18.2%) vs. Q4 2025
- New holders
- 49
- 120 more added
- Sold out
- 26
- 111 more reduced
8 institutions that held it in Q4 2025 haven't filed for Q1 2026 yet. Not filing isn't selling, so they aren't counted as sold out or in the changes above.
Compare with Q4 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, Q1 2026
Shares, value and share of portfolio for each institution holding White Mountains Insurance Group Ltd; share changes are against Q4 2025.
| Institution | Shares | Value | % of portfolio | Change in shares | Action |
|---|---|---|---|---|---|
| First Trust Advisors LP | 3,058 | $6.72M | 0.00% | −1,497−32.9% | Reduced |
| Edgestream Partners, L.P. | 3,130 | $6.88M | 0.23% | +2,601+491.7% | Added |
| Lee Danner & Bass Inc | 3,203 | $7.04M | 0.44% | +100+3.2% | Added |
| Marshall Wace, LLP | 3,878 | $8.52M | 0.01% | +2,780+253.2% | Added |
| Creative Planning | 4,049 | $8.90M | 0.01% | +634+18.6% | Added |
| Rhumbline Advisers | 4,132 | $9.08M | 0.01% | −33−0.8% | Reduced |
| Phocas Financial Corp. | 4,292 | $9.43M | 1.48% | −1,199−21.8% | Reduced |
| Nuveen, LLC | 4,309 | $9.47M | 0.00% | +834+24.0% | Added |
| Franklin Resources Inc | 4,798 | $10.5M | 0.00% | +4,398+1,099.5% | Added |
| Swiss National Bank | 5,036 | $11.1M | 0.01% | −50−1.0% | Reduced |
| Williams Jones Wealth Management, LLC. | 5,194 | $11.4M | 0.14% | +10.0% | Added |
| WCM Investment Management, LLC | 5,995 | $13.2M | 0.03% | −4,687−43.9% | Reduced |
| Hotchkis & Wiley Capital Management LLC | 6,048 | $13.3M | 0.04% | −704−10.4% | Reduced |
| California Public Employees Retirement System | 6,414 | $14.1M | 0.01% | −302−4.5% | Reduced |
| Royce & Associates LP | 6,460 | $14.2M | 0.14% | +513+8.6% | Added |
| BNP Paribas Arbitrage, SA | 6,623 | $14.6M | 0.01% | +3,283+98.3% | Added |
| Thompson Siegel & Walmsley LLC | 7,209 | $15.8M | 0.28% | −1,718−19.2% | Reduced |
| AQR Capital Management LLC | 7,738 | $17.0M | 0.01% | +3,262+72.9% | Added |
| UBS Asset Management Americas Inc | 7,826 | $17.2M | 0.00% | +171+2.2% | Added |
| GW&K Investment Management, LLC | 7,926 | $17.4M | 0.15% | −695−8.1% | Reduced |
| American Century Companies Inc | 8,308 | $18.3M | 0.01% | +7,413+828.3% | Added |
| Bank of New York Mellon Corp | 8,444 | $18.6M | 0.00% | −387−4.4% | Reduced |
| Wells Fargo & Company | 8,782 | $19.3M | 0.00% | −359−3.9% | Reduced |
| D. E. Shaw & Co., Inc. | 8,910 | $19.6M | 0.02% | +317+3.7% | Added |
| Gotham Asset Management, LLC | 9,047 | $19.9M | 0.06% | +2,331+34.7% | Added |
| Speece Thorson Capital Group Inc | 9,397 | $20.6M | 4.70% | −1,275−11.9% | Reduced |
| Quantinno Capital Management LP | 9,784 | $21.5M | 0.04% | +2,513+34.6% | Added |
| UBS Group AG | 10,441 | $22.9M | 0.00% | +4,440+74.0% | Added |
| Select Equity Group, L.P. | 10,560 | $23.2M | 0.12% | −9,153−46.4% | Reduced |
| Susquehanna International Group, LLP | 10,965 | $24.1M | 0.03% | +10,833+8,206.8% | Added |
| SEI Investments Co | 11,098 | $24.4M | 0.02% | +3,182+40.2% | Added |
| Victory Capital Management Inc | 11,145 | $24.5M | 0.02% | +4,849+77.0% | Added |
| Elkhorn Partners Limited Partnership | 12,700 | $27.9M | 17.76% | −898−6.6% | Reduced |
| Horizon Kinetics Asset Management LLC | 13,112 | $28.8M | 0.31% | −9−0.1% | Reduced |
| Jane Street Group, LLC | 13,808 | $30.3M | 0.03% | +12,101+708.9% | Added |
| Boussard & Gavaudan Investment Management LLP | 13,975 | $31.0M | 2.97% | +13,975 | New |
| Wellington Management Group LLP | 14,884 | $32.7M | 0.01% | −1,044−6.6% | Reduced |
| Vanguard Fiduciary Trust Co | 15,186 | $33.4M | 0.01% | +15,186 | New |
| Northern Trust Corp | 15,495 | $34.0M | 0.00% | −1,172−7.0% | Reduced |
| Envestnet Asset Management Inc | 15,563 | $34.2M | 0.01% | −235−1.5% | Reduced |
| Goldman Sachs Group Inc | 15,783 | $34.7M | 0.00% | +10,523+200.1% | Added |
| Brown Advisory Inc | 17,844 | $39.2M | 0.06% | −1,112−5.9% | Reduced |
| Allspring Global Investments Holdings, LLC | 18,612 | $40.5M | 0.07% | −1,581−7.8% | Reduced |
| Southeastern Asset Management IncSuperinvestorSoutheastern Asset Management (Longleaf) | 18,864 | $41.4M | 2.04% | −12,788−40.4% | Reduced |
| Mraz, Amerine & Associates, Inc. | 22,179 | $48.7M | 7.18% | −450−2.0% | Reduced |
| Raymond James Financial Inc | 23,951 | $52.6M | 0.02% | −18−0.1% | Reduced |
| Charles Schwab Investment Management Inc | 24,241 | $53.3M | 0.01% | +1,003+4.3% | Added |
| Spears Abacus Advisors LLC | 28,027 | $61.6M | 1.21% | −88−0.3% | Reduced |
| Bank of America Corp | 28,358 | $62.3M | 0.00% | −451−1.6% | Reduced |
| Lord, Abbett & Co. LLC | 33,110 | $72.7M | 0.24% | −686−2.0% | Reduced |
| Reinhart Partners, Inc. | 37,374 | $82.1M | 2.36% | −6,599−15.0% | Reduced |
| Gendell Jeffrey L | 37,814 | $83.1M | 1.13% | +5,294+16.3% | Added |
| T. Rowe Price Investment Management, Inc. | 41,513 | $91.2M | 0.06% | −3,047−6.8% | Reduced |
| Geode Capital Management, LLC | 42,119 | $92.6M | 0.01% | +601+1.4% | Added |
| State Street Corp | 49,158 | $108.0M | 0.00% | −1,505−3.0% | Reduced |
| London Co of Virginia | 57,131 | $125.5M | 0.77% | −1,566−2.7% | Reduced |
| Boston Partners | 57,459 | $126.2M | 0.13% | −19,452−25.3% | Reduced |
| Morgan Stanley | 59,295 | $130.3M | 0.01% | −22,856−27.8% | Reduced |
| Wallace Capital Management Inc. | 78,795 | $173.1M | 19.88% | −1,552−1.9% | Reduced |
| Fiduciary Management Inc | 85,066 | $186.9M | 2.32% | −5,267−5.8% | Reduced |
| Fuller & Thaler Asset Management, Inc. | 104,561 | $229.7M | 0.77% | −3,611−3.3% | Reduced |
| Cooke & Bieler LP | 104,857 | $230.4M | 2.61% | −1,722−1.6% | Reduced |
| Vanguard Capital Management LLC | 109,157 | $239.8M | 0.01% | +109,157 | New |
| BlackRock, Inc. | 113,328 | $249.0M | 0.00% | +1,039+0.9% | Added |
| Vanguard Portfolio Management LLC | 115,553 | $253.9M | 0.01% | +115,553 | New |
| River Road Asset Management, LLC | 120,519 | $264.8M | 3.00% | −361−0.3% | Reduced |
| Neuberger Berman Group LLC | 124,715 | $274.0M | 0.21% | −4,939−3.8% | Reduced |
| Dimensional Fund Advisors LP | 156,618 | $344.1M | 0.07% | +140.0% | Added |
| Forum Financial Management, LP | 0 | $0 | 0.00% | −2,016−100.0% | Sold out |
| Holocene Advisors, LP | 0 | $0 | 0.00% | −998−100.0% | Sold out |
| Squarepoint Ops LLC | 0 | $0 | 0.00% | −706−100.0% | Sold out |
| Jump Financial, LLC | 0 | $0 | 0.00% | −658−100.0% | Sold out |
| King Luther Capital Management Corp | 0 | $0 | 0.00% | −560−100.0% | Sold out |
| Oak Thistle LLC | 0 | $0 | 0.00% | −530−100.0% | Sold out |
| Lecap Asset Management Ltd | 0 | $0 | 0.00% | −340−100.0% | Sold out |
| Greenland Capital Management LP | 0 | $0 | 0.00% | −290−100.0% | Sold out |
| Highlander Partners, L.P. | 0 | $0 | 0.00% | −280−100.0% | Sold out |
| Envestnet Portfolio Solutions, Inc. | 0 | $0 | 0.00% | −261−100.0% | Sold out |
| Cambridge Investment Research Advisors, Inc. | 0 | $0 | 0.00% | −200−100.0% | Sold out |
| Two Sigma Securities, LLC | 0 | $0 | 0.00% | −160−100.0% | Sold out |
| Crossmark Global Holdings, Inc. | 0 | $0 | 0.00% | −137−100.0% | Sold out |
| AlphaGrep UK Ltd | 0 | $0 | 0.00% | −129−100.0% | Sold out |
| Swiss Life Asset Management Ltd | 0 | $0 | 0.00% | −117−100.0% | Sold out |
| Johnson Investment Counsel Inc | 0 | $0 | 0.00% | −115−100.0% | Sold out |
| Jefferies Financial Group Inc. | 0 | $0 | 0.00% | −112−100.0% | Sold out |
| Childress Capital Advisors, LLC | 0 | $0 | 0.00% | −99−100.0% | Sold out |
| Callan Family Office, LLC | 0 | $0 | 0.00% | −97−100.0% | Sold out |
| Caitong International Asset Management Co., Ltd | 0 | $0 | 0.00% | −61−100.0% | Sold out |
| Quarry LP | 0 | $0 | 0.00% | −26−100.0% | Sold out |
| Danske Bank A/S | 0 | $0 | 0.00% | −20−100.0% | Sold out |
| Torren Management, LLC | 0 | $0 | 0.00% | −13−100.0% | Sold out |
| SageView Advisory Group, LLC | 0 | $0 | 0.00% | −4−100.0% | Sold out |
| Quattro Advisors LLC | 0 | $0 | 0.00% | −2−100.0% | Sold out |
| Bruce G. Allen Investments, LLC | 0 | $0 | 0.00% | −1−100.0% | Sold out |
| Vanguard Group Inc | – | – | – | – | Not filed |
| Norges Bank | – | – | – | – | Not filed |
| Brandywine Global Investment Management, LLC | – | – | – | – | Not filed |
| Prospector Partners LLC | – | – | – | – | Not filed |
| Global Retirement Partners, LLC | – | – | – | – | Not filed |
| David Loasby | – | – | – | – | Not filed |