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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, Q4 2025

Institutional positions in White Mountains Insurance Group Ltd as of Dec 31, 2025. 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
353
+20 vs. Q3 2025
Shares held
2.25M
−77.3K (−3.3%) vs. Q3 2025
Total value
$4.67B
+$782.8M (+20.1%) vs. Q3 2025
New holders
55
104 more added
Sold out
35
126 more reduced

5 institutions that held it in Q3 2025 haven't filed for Q4 2025 yet. Not filing isn't selling, so they aren't counted as sold out or in the changes above.

Compare with Q3 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.

Institutional holdersQ4 2025: 353 institutions
Q1 2021: 245 institutionsQ2 2021: 233 institutionsQ3 2021: 232 institutionsQ4 2021: 243 institutionsQ1 2022: 244 institutionsQ2 2022: 259 institutionsQ3 2022: 251 institutionsQ4 2022: 265 institutionsQ1 2023: 262 institutionsQ2 2023: 258 institutionsQ3 2023: 272 institutionsQ4 2023: 295 institutionsQ1 2024: 303 institutionsQ2 2024: 306 institutionsQ3 2024: 304 institutionsQ4 2024: 325 institutionsQ1 2025: 322 institutionsQ2 2025: 325 institutionsQ3 2025: 338 institutionsQ4 2025: 353 institutionsQ1 2026: 368 institutionsQ2 2026: 356 institutions
Value heldQ4 2025: $4.67B
Q1 2021: $3.02BQ2 2021: $3.11BQ3 2021: $2.86BQ4 2021: $2.71BQ1 2022: $3.09BQ2 2022: $3.32BQ3 2022: $2.98BQ4 2022: $3.20BQ1 2023: $3.09BQ2 2023: $3.13BQ3 2023: $3.40BQ4 2023: $3.42BQ1 2024: $4.06BQ2 2024: $4.14BQ3 2024: $3.78BQ4 2024: $4.43BQ1 2025: $4.44BQ2 2025: $4.17BQ3 2025: $3.89BQ4 2025: $4.67BQ1 2026: $4.86BQ2 2026: $4.57B
Institutions holding WTM and their total value by quarter
QuarterHoldersValue
Q2 2026356$4.57B
Q1 2026368$4.86B
Q4 2025353$4.67B
Q3 2025338$3.89B
Q2 2025325$4.17B
Q1 2025322$4.44B
Q4 2024325$4.43B
Q3 2024304$3.78B
Q2 2024306$4.14B
Q1 2024303$4.06B
Q4 2023295$3.42B
Q3 2023272$3.40B
Q2 2023258$3.13B
Q1 2023262$3.09B
Q4 2022265$3.20B
Q3 2022251$2.98B
Q2 2022259$3.32B
Q1 2022244$3.09B
Q4 2021243$2.71B
Q3 2021232$2.86B
Q2 2021233$3.11B
Q1 2021245$3.02B

Institutions, Q4 2025

Shares, value and share of portfolio for each institution holding White Mountains Insurance Group Ltd; share changes are against Q3 2025.

Institutions holding WTM in Q4 2025
InstitutionSharesValue% of portfolioChange in sharesAction
State of Alaska, Department of Revenue119$247.0K0.00%+2+1.7%Added
Merit Financial Group, LLC121$251.5K0.00%+1+0.8%Added
NewEdge Wealth, LLC122$253.5K0.00%+5+4.3%Added
Xponance, Inc.123$255.6K0.00%+3+2.5%Added
US Bancorp124$257.7K0.00%+1+0.8%Added
CIBC Asset Management Inc124$257.7K0.00%+124New
Columbia Asset Management125$259.8K0.05%00.0%Unchanged
Pinnacle Associates Ltd127$263.9K0.00%00.0%Unchanged
Amalgamated Bank127$264.0K0.00%+2+1.6%Added
Quadrant Capital Group LLC128$266.0K0.01%−5−3.8%Reduced
AlphaGrep UK Ltd129$268.1K0.09%+129New
HB Wealth Management, LLC130$270.1K0.00%+4+3.2%Added
Susquehanna International Group, LLP132$274.3K0.00%−7,228−98.2%Reduced
HRT Financial LP133$276.0K0.00%−3,454−96.3%Reduced
Utah Retirement Systems134$278.5K0.00%00.0%Unchanged
State of Wyoming134$278.5K0.03%+58+76.3%Added
Crossmark Global Holdings, Inc.137$284.7K0.00%+137New
State of Wisconsin Investment Board138$286.8K0.00%−111−44.6%Reduced
Syon Capital LLC140$290.9K0.01%+140New
Chapman Investment Management, LLC143$297.2K0.22%00.0%Unchanged
Evergreen Capital Management LLC143$297.2K0.01%−3−2.1%Reduced
TCG Advisory Services, LLC146$303.4K0.01%−14−8.8%Reduced
Sterling Capital Management LLC146$303.4K0.00%−8−5.2%Reduced
Douglass Winthrop Advisors, LLC150$311.7K0.01%00.0%Unchanged
Moneta Group Investment Advisors LLC150$311.7K0.00%00.0%Unchanged
Change Path, LLC150$311.7K0.01%00.0%Unchanged
Connable Office Inc152$315.9K0.03%+23+17.8%Added
Evelyn Partners Asset Management Ltd154$320.0K0.08%00.0%Unchanged
Zacks Investment Management157$326.3K0.00%00.0%Unchanged
Two Sigma Securities, LLC160$332.5K0.05%−34−17.5%Reduced
M&T Bank Corp166$345.0K0.00%+166New
Kestra Advisory Services, LLC171$356.2K0.00%+22+14.8%Added
Keybank National Association176$365.7K0.00%+9+5.4%Added
Frank, Rimerman Advisors LLC178$369.9K0.02%+1+0.6%Added
Savant Capital, LLC180$374.0K0.00%−3−1.6%Reduced
Bank of Nova Scotia189$392.7K0.00%−13−6.4%Reduced
Riverwater Partners LLC190$394.8K0.15%00.0%Unchanged
Ritholtz Wealth Management195$405.2K0.01%−13−6.3%Reduced
GWM Advisors LLC196$407.3K0.00%+26+15.3%Added
Folger Nolan Fleming Douglas Capital Management, Inc199$413.5K0.04%00.0%Unchanged
GAMMA Investing LLC199$413.5K0.02%+16+8.7%Added
Ensign Peak Advisors, Inc200$415.6K0.00%−300−60.0%Reduced
Evercore Wealth Management, LLC200$415.6K0.01%00.0%Unchanged
Sage Investment Counsel LLC200$415.6K0.46%00.0%Unchanged
Cambridge Investment Research Advisors, Inc.200$416.0K0.00%+200New
Toroso Investments, LLC204$423.9K0.00%−404−66.4%Reduced
We Are One Seven, LLC204$423.9K0.01%+17+9.1%Added
Hudson Value Partners, LLC206$428.2K0.13%00.0%Unchanged
Bryn Mawr Trust Co209$434.3K0.01%00.0%Unchanged
Atria Investments LLC209$434.4K0.00%+22+11.8%Added
Private Advisor Group, LLC213$442.6K0.00%+2+0.9%Added
Principal Securities, Inc.216$448.9K0.01%+6+2.9%Added
Venturi Wealth Management, LLC221$459.2K0.02%+7+3.3%Added
Mount Yale Investment Advisors, LLC223$463.4K0.02%+66+42.0%Added
Wealth Enhancement Advisory Services, LLC227$464.7K0.00%+17+8.1%Added
Hengehold Capital Management LLC227$471.7K0.04%−167−42.4%Reduced
David Loasby230$474.0K0.03%+17+8.0%Added
Athena Investment Management229$475.9K0.24%00.0%Unchanged
XTX Topco Ltd229$475.9K0.01%+229New
Wedbush Securities Inc229$476.0K0.01%+5+2.2%Added
Deutsche Bank AG237$492.5K0.00%+3+1.3%Added
Shotwell Rutter Baer Inc242$502.0K0.30%−28−10.4%Reduced
Voya Investment Management LLC243$505.0K0.00%+35+16.8%Added
JustInvest LLC253$525.7K0.01%+13+5.4%Added
Envestnet Portfolio Solutions, Inc.261$542.4K0.00%+7+2.8%Added
Commonwealth Equity Services, LLC271$563.4K0.00%−29−9.7%Reduced
Essex Savings Bank275$571.5K0.12%−9−3.2%Reduced
Cresset Asset Management, LLC279$579.8K0.00%−5−1.8%Reduced
Highlander Partners, L.P.280$581.8K0.21%00.0%Unchanged
SRS Capital Advisors, Inc.281$584.8K0.02%−227−44.7%Reduced
Greenland Capital Management LP290$602.6K0.09%+290New
Brown Miller Wealth Management, LLC298$620.2K0.17%00.0%Unchanged
Rockefeller Capital Management L.P.300$623.5K0.00%+80+36.4%Added
Legacy Wealth Asset Management, LLC313$650.4K0.16%+5+1.6%Added
Vestmark Advisory Solutions, Inc.321$667.0K0.01%+164+104.5%Added
Lummis Asset Management, LP325$675.4K0.42%00.0%Unchanged
Bryant Woods Investment Advisors, LLC340$706.5K0.27%00.0%Unchanged
Lecap Asset Management Ltd340$706.5K0.28%+340New
American Capital Advisory, LLC342$710.7K0.31%−15−4.2%Reduced
Public Employees Retirement Association of Colorado353$734.0K0.00%00.0%Unchanged
Glenmede Trust Co NA354$735.6K0.00%+354New
Roundview Capital LLC358$744.1K0.05%−15−4.0%Reduced
Universal- Beteiligungs- und Servicegesellschaft mbH359$746.0K0.00%+67+22.9%Added
Quadrature Capital Ltd360$748.1K0.01%+360New
RSM US Wealth Management LLC364$756.6K0.01%−32−8.1%Reduced
Cetera Investment Advisers364$756.7K0.00%00.0%Unchanged
Klingenstein Fields & Co LP380$789.7K0.03%00.0%Unchanged
Midwest Professional Planners, LTD.388$806.3K0.19%−234−37.6%Reduced
Global Retirement Partners, LLC388$806.3K0.01%+45+13.1%Added
Russell Investments Group, Ltd.397$825.5K0.00%+46+13.1%Added
Franklin Resources Inc400$831.2K0.00%+4+1.0%Added
Pictet Asset Management Holding SA400$831.2K0.00%+50+14.3%Added
Mariner, LLC402$835.4K0.00%+188+87.9%Added
Advisor Group Holdings, Inc.410$852.0K0.00%−3−0.7%Reduced
Bank of Montreal431$895.6K0.00%−1−0.2%Reduced
Resona Asset Management Co.,Ltd.443$920.6K0.00%−9−2.0%Reduced
Legacy Advisors, LLC450$935.1K0.10%00.0%Unchanged
Pathstone Holdings, LLC455$945.5K0.00%+63+16.1%Added
Parker Investment Management, LLC475$987.1K0.14%−25−5.0%Reduced
Sanctuary Advisors, LLC475$987.2K0.01%−20−4.0%Reduced