WHITE MTNS INS GROUP LTD WTM
COM · Common Stock · CUSIP G9618E107
- SectorFinancials
- IndustryFire, Marine & Casualty Insurance
- HeadquartersHanover, NH
- Websitewhitemountains.com
- FilingsSEC EDGAR
* Summed across managers. Shares that two managers' reports both contain – a subsidiary's holdings that its parent's report includes too, or a sub-adviser's in its client's – are counted once ($8.0m this quarter). Holder counts are more reliable. Shares outstanding: 2.4m as of 2026-08-03, from the company's own SEC filing; the percentage can still exceed 100%: lent-out shares are counted by the lender and the buyer, and some reports overlap without saying so. Implied quarter-end price ≈ $2073.78. Options: 0 managers hold calls (— notional), 1 hold puts ($296.5k).
Trends to Q2 2026
Institutional holders
Managers reporting a position, each quarter
Numbers
| Quarter | Holders |
|---|---|
| Q3 2022 | 253 |
| Q4 2022 | 264 |
| Q1 2023 | 262 |
| Q2 2023 | 258 |
| Q3 2023 | 272 |
| Q4 2023 | 295 |
| Q1 2024 | 303 |
| Q2 2024 | 306 |
| Q3 2024 | 304 |
| Q4 2024 | 325 |
| Q1 2025 | 323 |
| Q2 2025 | 326 |
| Q3 2025 | 338 |
| Q4 2025 | 353 |
| Q1 2026 | 368 |
| Q2 2026 | 356 |
Buyers vs sellers
Managers adding to or starting a position, vs cutting or selling out
Numbers
| Quarter | Bought or added | Cut or sold out |
|---|---|---|
| Q3 2024 | 132 | 108 |
| Q4 2024 | 140 | 97 |
| Q1 2025 | 124 | 133 |
| Q2 2025 | 133 | 138 |
| Q3 2025 | 147 | 130 |
| Q4 2025 | 150 | 160 |
| Q1 2026 | 160 | 138 |
| Q2 2026 | 129 | 188 |
Calls vs puts
Options held, notional value, last 4 quarters. P/C = puts ÷ calls
Numbers
| Quarter | Calls | Puts | P/C |
|---|---|---|---|
| Q3 2025 | $0 | $0 | — |
| Q4 2025 | $0 | $0 | — |
| Q1 2026 | $0 | $0 | — |
| Q2 2026 | $0 | $296.5k | — |
Biggest buyers
| AMERICAN CENTURY COMPANIES INC | Added | +22.8k |
| GENDELL JEFFREY L | Added | +21.4k |
| Gotham Asset Management, LLC | Added | +8.9k |
| Qube Research & Technologies Ltd | Added | +8.7k |
| FIRST TRUST ADVISORS LP | Added | +7.5k |
| GEODE CAPITAL MANAGEMENT, LLC | Added | +7.3k |
| REINHART PARTNERS, LLC. | Added | +7.1k |
| UBS Group AG | Added | +5.8k |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP | Added | +5.4k |
| WINMILL & CO. INC | New | +4.8k |
Biggest sellers
| COOKE & BIELER LP | Reduced | -19.7k |
| FIDUCIARY MANAGEMENT INC /WI/ | Reduced | -18.5k |
| MORGAN STANLEY | Reduced | -12.4k |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | Sold out | -11.0k |
| Select Equity Group, L.P. | Sold out | -10.6k |
| RAYMOND JAMES FINANCIAL INC | Reduced | -9.1k |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC | Reduced | -7.8k |
| T. Rowe Price Investment Management, Inc. | Reduced | -7.3k |
| NEUBERGER BERMAN GROUP LLC | Reduced | -5.6k |
| BNP PARIBAS FINANCIAL MARKETS | Reduced | -5.5k |
Biggest calls
| None |
Biggest puts
| Chapman Investment Management, LLC | New | $296.5k143 shares |
Options at notional value: the value of the shares the contracts control, as filers report them, not what the options cost. Not included in the holders, shares or buying above.
Major shareholders (over 5%)
Anyone who owns more than 5% of a class of the company's shares has to say so: on Schedule 13D if they may try to influence or control the company, on 13G if they're a passive investor, and update it as the stake changes. Each holder's latest filing, from 19 Dec 2024 on; percentages are of the share class, as the holder worked them out.
| Holder | Stake |
|---|---|
| VANGUARD CAPITAL MANAGEMENT LLC 13G · institution new · filed 2026-04-30 | 5.2% |
Fell to 5% or below in the last year: Neuberger Berman Group LLC (4.9%, 2026-05-07), VANGUARD GROUP INC (0.0%, 2026-03-27; now reported by VANGUARD CAPITAL MANAGEMENT LLC), MORGAN STANLEY (3.0%, 2026-02-12)
Insider purchases and sales since 1 Apr 2026
Shares bought or sold by the company's own officers, directors and 10% owners, in the open market or privately, as they reported to the SEC on Form 4 (due within two business days of the trade). Grants, option exercises, shares withheld for tax and gifts aren't included.
Officers and directors buying vs selling
Number of people, by quarter (10% owners not included)
Numbers
| Quarter | Buying | Bought | Selling | Sold | Sold under a plan |
|---|---|---|---|---|---|
| Q4 2024 | 0 | — | 0 | — | — |
| Q1 2025 | 0 | — | 0 | — | — |
| Q2 2025 | 0 | — | 0 | — | — |
| Q3 2025 | 0 | — | 0 | — | — |
| Q4 2025 | 0 | — | 3 | $10.6m | — |
| Q1 2026 | 0 | — | 0 | — | — |
| Q2 2026 | 0 | — | 0 | — | — |
| Q3 2026 | 0 | — | 0 | — | — |
None reported since 1 Apr 2026.
Holders, Q2 2026
| Manager | Shares | Change |
|---|---|---|
| DIMENSIONAL FUND ADVISORS LP 0.06% of their portfolio | 159.0k $329.6m | Added +2.3k |
| NEUBERGER BERMAN GROUP LLC 0.16% of their portfolio | 119.1k $247.0m | Reduced -5.6k |
| BlackRock, Inc. 0.00% of their portfolio | 117.9k $244.4m | Added +4.5k |
| River Road Asset Management, LLC 2.67% of their portfolio | 115.9k $240.3m | Reduced -4.6k |
| VANGUARD PORTFOLIO MANAGEMENT LLC 0.01% of their portfolio | 112.0k $232.2m | Reduced -3.6k |
| VANGUARD CAPITAL MANAGEMENT LLC 0.00% of their portfolio | 107.5k $222.8m | Reduced -1.7k |
| FULLER & THALER ASSET MANAGEMENT, INC. 0.58% of their portfolio | 101.9k $211.3m | Reduced -2.7k |
| COOKE & BIELER LP 2.04% of their portfolio | 85.1k $176.5m | Reduced -19.7k |
| Wallace Capital Management Inc. 18.20% of their portfolio | 80.1k $166.0m | Added +1.3k |
| FIDUCIARY MANAGEMENT INC /WI/ 1.96% of their portfolio | 66.5k $138.0m | Reduced -18.5k |
| GENDELL JEFFREY L 1.11% of their portfolio | 59.2k $122.8m | Added +21.4k |
| Boston Partners 0.10% of their portfolio | 55.6k $115.3m | Reduced -1.9k |
| LONDON CO OF VIRGINIA 0.64% of their portfolio | 54.0k $112.1m | Reduced -3.1k |
| STATE STREET CORP 0.00% of their portfolio | 50.3k $104.2m | Added +1.1k |
| GEODE CAPITAL MANAGEMENT, LLC 0.01% of their portfolio | 49.4k $102.5m | Added +7.3k |
| MORGAN STANLEY 0.01% of their portfolio | 46.9k $97.2m | Reduced -12.4k |
| REINHART PARTNERS, LLC. 2.11% of their portfolio | 44.5k $92.3m | Added +7.1k |
| T. Rowe Price Investment Management, Inc. 0.05% of their portfolio | 34.2k $71.0m | Reduced -7.3k |
| LORD, ABBETT & CO. LLC 0.19% of their portfolio | 32.8k $68.1m | Reduced -281 |
| AMERICAN CENTURY COMPANIES INC 0.03% of their portfolio | 31.1k $64.5m | Added +22.8k |
| NORGES BANK 0.01% of their portfolio | 28.0k $58.0m | Not comparable |
| Cannell & Spears LLC 1.02% of their portfolio | 27.6k $57.2m | Reduced -450 |
| BANK OF AMERICA CORP /DE/ 0.00% of their portfolio | 25.0k $51.9m | Reduced -3.3k |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC 0.01% of their portfolio | 23.5k $48.7m | Reduced -736 |
| Mraz, Amerine & Associates, Inc. 6.61% of their portfolio | 22.2k $46.1m | Added +39 |
| Allspring Global Investments Holdings, LLC 0.06% of their portfolio | 18.1k $37.4m | Reduced -496 |
| Gotham Asset Management, LLC 0.09% of their portfolio | 17.9k $37.2m | Added +8.9k |
| BROWN ADVISORY INC 0.06% of their portfolio | 17.7k $36.7m | Reduced -122 |
| JANE STREET GROUP, LLC 0.02% of their portfolio | 17.2k $35.7m | Added +3.4k |
| SOUTHEASTERN ASSET MANAGEMENT INC/TN/ 1.85% of their portfolio | 17.1k $35.5m | Reduced -1.8k |
| UBS Group AG 0.01% of their portfolio | 16.2k $33.6m | Added +5.8k |
| VANGUARD FIDUCIARY TRUST CO 0.01% of their portfolio | 15.3k $31.8m | Added +133 |
| RAYMOND JAMES FINANCIAL INC 0.01% of their portfolio | 14.8k $30.8m | Reduced -9.1k |
| NORTHERN TRUST CORP 0.00% of their portfolio | 14.6k $30.2m | Reduced -924 |
| WELLINGTON MANAGEMENT GROUP LLP 0.01% of their portfolio | 14.5k $30.1m | Reduced -352 |
| ENVESTNET ASSET MANAGEMENT INC 0.01% of their portfolio | 13.8k $28.7m | Reduced -1.7k |
| Quantinno Capital Management LP 0.03% of their portfolio | 12.6k $26.2m | Added +2.8k |
| ELKHORN PARTNERS LIMITED PARTNERSHIP 21.89% of their portfolio | 12.3k $25.5m | Reduced -380 |
| HORIZON KINETICS ASSET MANAGEMENT LLC 0.29% of their portfolio | 12.2k $25.3m | Reduced -906 |
| GOLDMAN SACHS GROUP INC 0.00% of their portfolio | 12.2k $25.2m | Reduced -3.6k |
| BOUSSARD & GAVAUDAN GESTION SAS 1.24% of their portfolio | 11.7k $24.5m | First filing |
| VICTORY CAPITAL MANAGEMENT INC 0.01% of their portfolio | 10.7k $22.2m | Reduced -461 |
| FIRST TRUST ADVISORS LP 0.01% of their portfolio | 10.6k $22.0m | Added +7.5k |
| Qube Research & Technologies Ltd 0.02% of their portfolio | 9.7k $20.1m | Added +8.7k |
| SPEECE THORSON CAPITAL GROUP INC 4.08% of their portfolio | 9.2k $19.1m | Reduced -182 |
| WELLS FARGO & COMPANY/MN 0.00% of their portfolio | 8.7k $18.1m | Reduced -72 |
| Bank of New York Mellon Corp 0.00% of their portfolio | 8.4k $17.4m | Reduced -32 |
| SEI INVESTMENTS CO 0.01% of their portfolio | 8.1k $16.8m | Reduced -3.0k |
| GW&K Investment Management, LLC 0.13% of their portfolio | 7.8k $16.3m | Reduced -87 |
| THOMPSON SIEGEL & WALMSLEY LLC 0.29% of their portfolio | 7.7k $15.9m | Added +447 |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP 0.01% of their portfolio | 7.3k $15.1m | Added +5.4k |
| CITADEL ADVISORS LLC 0.01% of their portfolio | 7.1k $14.8m | Added +4.5k |
| HOTCHKIS & WILEY CAPITAL MANAGEMENT LLC 0.04% of their portfolio | 6.8k $14.1m | Added +740 |
| ROYCE & ASSOCIATES LP 0.11% of their portfolio | 6.8k $14.1m | Added +321 |
| HRT FINANCIAL LP 0.03% of their portfolio | 6.8k $14.0m | Added +4.4k |
| D. E. Shaw & Co., Inc. 0.01% of their portfolio | 6.6k $13.7m | Reduced -2.3k |
| Edgestream Partners, L.P. 0.41% of their portfolio | 6.6k $13.6m | Added +3.4k |
| AQR CAPITAL MANAGEMENT LLC 0.00% of their portfolio | 5.5k $11.3m | Reduced -2.3k |
| JPMORGAN CHASE & CO 0.00% of their portfolio | 5.4k $11.5m | Added +2.8k |
| California Public Employees Retirement System 0.01% of their portfolio | 5.2k $10.9m | Reduced -1.2k |
| Williams Jones Wealth Management, LLC. 0.12% of their portfolio | 5.2k $10.8m | Reduced -1 |
| Swiss National Bank 0.01% of their portfolio | 4.8k $10.0m | Reduced -210 |
| WINMILL & CO. INC 2.20% of their portfolio | 4.8k $10.0m | New |
| FRANKLIN RESOURCES INC 0.00% of their portfolio | 4.2k $8.7m | Reduced -620 |
| Phocas Financial Corp. 1.17% of their portfolio | 4.1k $8.5m | Reduced -214 |
| RHUMBLINE ADVISERS 0.01% of their portfolio | 3.9k $8.1m | Reduced -234 |
| Creative Planning 0.00% of their portfolio | 3.9k $8.0m | Reduced -188 |
| Nuveen, LLC 0.00% of their portfolio | 3.7k $7.6m | Reduced -630 |
| Invesco Ltd. 0.00% of their portfolio | 3.5k $7.3m | Added +530 |
| LEE DANNER & BASS INC 0.39% of their portfolio | 3.3k $6.7m | Added +50 |
| AMERIPRISE FINANCIAL INC 0.00% of their portfolio | 2.9k $5.9m | Reduced -14 |
| CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM 0.01% of their portfolio | 2.8k $5.7m | Reduced -126 |
| NEW YORK STATE COMMON RETIREMENT FUND 0.01% of their portfolio | 2.5k $5.2m | Added +19 |
| Triad Investment Management 5.65% of their portfolio | 2.5k $5.1m | Reduced -42 |
| VANGUARD ASSET MANAGEMENT, Ltd 0.00% of their portfolio | 2.4k $5.0m | Added +67 |
| Russell Investments Group, Ltd. 0.00% of their portfolio | 2.4k $4.9m | Added +1.2k |
| STATE BOARD OF ADMINISTRATION OF FLORIDA RETIREMENT SYSTEM 0.01% of their portfolio | 2.4k $4.9m | Added +90 |
| PRICE T ROWE ASSOCIATES INC /MD/ 0.00% of their portfolio | 2.3k $4.8m | Added +124 |
| Legal & General Group Plc 0.00% of their portfolio | 2.3k $4.7m | Reduced -151 |
| Robeco Institutional Asset Management B.V. 0.01% of their portfolio | 2.2k $4.5m | Added +5 |
| Regency Capital Management Inc.\DE 1.77% of their portfolio | 2.1k $4.4m | Added +611 |
| DAVENPORT & Co LLC 0.02% of their portfolio | 2.1k $4.4m | Unchanged |
| BRADLEY FOSTER & SARGENT INC/CT 0.06% of their portfolio | 1.9k $3.9m | Reduced -103 |
| PARSONS CAPITAL MANAGEMENT INC/RI 0.18% of their portfolio | 1.9k $3.9m | Reduced -1 |
| Lighthouse Investment Partners, LLC 0.12% of their portfolio | 1.9k $3.9m | New |
| Cerity Partners LLC 0.00% of their portfolio | 1.8k $3.7m | Reduced -70 |
| Atlantic Union Bankshares Corp 0.06% of their portfolio | 1.8k $3.7m | Unchanged |
| MML INVESTORS SERVICES, LLC 0.01% of their portfolio | 1.7k $3.6m | Reduced -718 |
| AGF MANAGEMENT LTD 0.01% of their portfolio | 1.7k $3.5m | Reduced -7 |
| XTX Topco Ltd 0.04% of their portfolio | 1.6k $3.4m | Added +1.4k |
| Tidal Investments LLC 0.01% of their portfolio | 1.6k $3.3m | Added +230 |
| Focus Partners Wealth 0.00% of their portfolio | 1.6k $3.2m | Added +424 |
| ExodusPoint Capital Management, LP 0.03% of their portfolio | 1.4k $3.0m | Added +832 |
| OPPENHEIMER ASSET MANAGEMENT INC. 0.03% of their portfolio | 1.4k $2.8m | Reduced -124 |
| LPL Financial LLC 0.00% of their portfolio | 1.3k $2.7m | Reduced -77 |
| HighTower Advisors, LLC 0.00% of their portfolio | 1.3k $2.7m | Reduced -131 |
| ROYAL BANK OF CANADA 0.00% of their portfolio | 1.2k $2.6m | Added +42 |
| STIFEL FINANCIAL CORP 0.00% of their portfolio | 1.2k $2.6m | Reduced -59 |
| WCM INVESTMENT MANAGEMENT, LLC 0.00% of their portfolio | 1.2k $2.5m | Reduced -4.8k |
| 1834 INVESTMENT ADVISORS CO 0.28% of their portfolio | 1.2k $2.4m | Unchanged |