White Mountains Insurance Group Ltd

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White Mountains Insurance Group Ltd
TickerWTM
CIK #0000776867
CUSIPG9618E107
SectorFinance - Fire, Marine & Casualty Insurance
Address80 South Main St, Hanover, NH 03755
Source [EDGAR]
CIK Filing 2011 - 2026
[0000776867] 10-K
[0000776867] 10-Q
[0000776867] 13F-HR
[0000776867] 13F-NT
[0000776867] 3
[0000776867] 4
[0000776867] 5
[0000776867] 8-K
[0000776867] SC 13D
[0000776867] SC 13G
Form 13D/13G Filer Form 13D/13G Subject Filed % Owned
Vanguard Capital Management LLC White Mountains Insurance Group Ltd [2026-04-30] 0.0
Neuberger Berman Group LLC White Mountains Insurance Group Ltd [2026-02-05] 0.0
White Mountains Insurance Group Ltd Mediaalpha Inc [2023-06-30] 49.9
Fuller & Thaler Asset Management Inc White Mountains Insurance Group Ltd [2023-02-14] 5.95
Dimensional Fund Advisors LP White Mountains Insurance Group Ltd [2023-02-10] 6.2
White Mountains Insurance Group Ltd Mediaalpha Inc [2023-02-10] 39.3
River Road Asset Management LLC White Mountains Insurance Group Ltd [2023-02-08] 5.4
White Mountains Insurance Group Ltd Mediaalpha Inc [2021-02-12] 61.9
Eaton Vance Management White Mountains Insurance Group Ltd [2021-02-12] 7.02
River Road Asset Management LLC White Mountains Insurance Group Ltd [2021-02-10] 5.2
Boston Partners White Mountains Insurance Group Ltd [2019-02-14] 5.51
Wellington Management Group LLP White Mountains Insurance Group Ltd [2019-02-12] 7.05
Vanguard Group Inc White Mountains Insurance Group Ltd [2016-02-11] 5.38
Price T Rowe Associates Inc /MD/ White Mountains Insurance Group Ltd [2014-02-12] 5.2
London Co of Virginia White Mountains Insurance Group Ltd [2013-12-10] 5.19
Gillespie George J III White Mountains Insurance Group Ltd [2013-09-17] 5.2
[2013-03-18] None
Form 3/4/5 Filer 2011 - 2026
White Mountains Insurance Group Ltd
Shank Suzanne F
Tanner David Allen
Campbell Reid Tarlton
Carlson Peter M
Choksi Mary C
Chu John
Dillon Margaret
Gelston Philip A
Hicks Weston M
Seelig Robert Lawrence
Hildreth Michaela
Caffrey Liam P
Harrison Giles E
Papamichael Michael A
Rountree George Manning
Yi Steven
MediaAlpha Inc
WM Hinson Bermuda Ltd
Davis Morgan W
Palmer Jess Brian
Holiday Edith E
Bazos Frank R
Smith Lowndes Andrew
Brouillette Yves
Tolman Gary Charles
Frinquelli Angelo Michael
OneBeacon Insurance Group Ltd
Foy David Thomas
Barrette Raymond Joseph Rene
Linker David
Symetra Financial CORP
Oberting Kernan V
Waters Allan Lewis
Gillespie John Davies
Clark Howard Longstreth Jr
Byrne John Joseph
Insider Transaction (Form 3/4/5) Date Action Shares Price Value ($)
Seelig Robert Lawrence
Common Shares
2026-03-19 Gift 50 $0.00
Tanner David Allen
Common Shares
2026-03-04 Gift 225 $0.00
Hildreth Michaela
Common Shares (Restricted)
2026-02-25 Grant 600 $0.00
Caffrey Liam P
Common Shares (Restricted)
2026-02-25 Grant 1,500 $0.00
Harrison Giles E
Common Shares (restricted)
2026-02-25 Grant 775 $0.00
Papamichael Michael A
Common Shares (Restricted)
2026-02-25 Grant 500 $0.00
Seelig Robert Lawrence
Common Shares (restricted)
2026-02-25 Grant 775 $0.00
Caffrey Liam P
Common Shares
2026-01-01 Tax withheld 425 $2,078.03 883,163
Papamichael Michael A
Common Shares
2026-01-01 Tax withheld 131 $2,078.03 272,222
Seelig Robert Lawrence
Common Shares
2026-01-01 Tax withheld 398 $2,078.03 827,056
Hildreth Michaela
Common Shares
2026-01-01 Tax withheld 274 $2,078.03 569,380
Hildreth Michaela
Common Shares
2025-12-23 Gift 60 $0.00
Rountree George Manning
Common Shares
2025-12-19 Sell 5,000 $2,050.00 10,250,000
Campbell Reid Tarlton
Common Shares
2025-12-19 Sell 5,000 $0.00
Common Shares
2025-12-19 Sell 5,000 $2,050.00 10,250,000
Gelston Philip A
Common Shares
2025-12-16 Sell 165 $2,048.51 338,004
Campbell Reid Tarlton
Common Shares
2025-11-25 Gift 50 $0.00
Tanner David Allen
Common Shares
2025-11-10 Gift 4 $0.00
Shank Suzanne F
Common Shares
2025-05-22 Grant 150 $0.00
Dillon Margaret
Common Shares
2025-05-22 Grant 150 $0.00
showing 20 of 200 most recent transactions
13F Ownership Over TimeHoldersShares Held
2026-03-31 367 2,114,194
2025-12-31 352 2,259,418
2025-09-30 338 2,226,930
2025-06-30 326 2,199,299
2025-03-31 324 2,175,554
2024-12-31 325 2,145,515
2024-09-30 304 2,119,278
2024-06-30 306 2,154,257
2024-03-31 303 2,564,090
2023-12-31 295 2,392,997
2023-09-30 269 2,192,463
2023-06-30 258 2,212,717
Form 13F Holdings
Firm Period DFND Voting Shares
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Reinhart Partners LLC [2026-06-30] SOLE 40,969 44,480
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Farther Finance Advisors LLC [2026-06-30] SOLE 0 723
Avior Wealth Management LLC [2026-06-30] SOLE 0 619
BOSS Retirement Advisors LLC [2026-06-30] SOLE 0 533
Lexington Hill Partners LLC [2026-06-30] SOLE 0 520
Legacy Wealth Asset Management LLC [2026-06-30] SOLE 329 329
Brown Miller Wealth Management LLC [2026-06-30] SOLE 298 298
Wealth Enhancement Advisory Services LLC [2026-06-30] SOLE 1 289
Gamma Investing LLC [2026-06-30] DFND 249 249
Venturi Wealth Management LLC [2026-06-30] SOLE 213 213
Hudson Value Partners LLC [2026-06-30] SOLE 206 206
Folger Nolan Fleming Douglas Capital Management Inc [2026-06-30] SOLE 0 199
Alaska Retirement Management Board [2026-06-30] SOLE 119 119
Hengehold Capital Management LLC [2026-06-30] SOLE 42 111
Merit Financial Group LLC [2026-06-30] SOLE 0 107
Ballentine Partners LLC [2026-06-30] OTR 0 100
Chicago Trust Co NA [2026-06-30] SOLE 100 100
Baldwin Wealth Partners LLC/MA [2026-06-30] SOLE 100 100
Eastern Bank [2026-06-30] SOLE 100 100
Steph & Co [2026-06-30] SOLE 58 58
Davis Capital Management [2026-06-30] SOLE 37 37
Versant Capital Management Inc [2026-06-30] SOLE 24 24
Fortitude Family Office LLC [2026-06-30] SOLE 20 20
Reyes Financial Architecture Inc [2026-06-30] SOLE 20 20
LRI Investments LLC [2026-06-30] SOLE 17 17
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