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WTMNYSE
WHITE MOUNTAINS INSURANCE GROUP LTD
Fire, Marine & Casualty Insurance · D0 · CIK 776867
Acquires, operates, and disposes of businesses and assets in insurance, financial services, and related sectors
red 8-K · 90d
$5.01B
Market cap
$2090.94
Last close
-0.3%
1D
+4.0%
5D
13K
Volume
Price · last 39 sessions-3.5%
May 4L $1989.54 · H $2167.41Jun 29
320
Total filings
Jun 5, 2026
Last filing
12/31
Fiscal year end
8-KReg FD DisclosureJun 5, 20268-KExecutive Change · Shareholder VoteMay 21, 20268-KMaterial Agreement · New Debt / ObligationMay 15, 202610-Q10-QMay 6, 20268-KResults of OperationsMay 6, 20268-KCompany UpdateApr 1, 2026DEF 14AFORM DEF 14AApr 1, 202610-K10-KFeb 27, 20268-KCompany UpdateFeb 26, 20268-KResults of OperationsFeb 6, 20268-KCompany UpdateJan 7, 20268-KAcquisition / Disposition · Company UpdateDec 8, 202510-Q10-QNov 6, 20258-KResults of OperationsNov 6, 20258-KMaterial AgreementOct 3, 20258-KCompany UpdateSep 3, 20258-KExecutive ChangeSep 2, 202510-Q10-QAug 7, 20258-KResults of OperationsAug 7, 20258-KCompany UpdateJul 18, 20258-KCompany UpdateJul 16, 202511-K11-KJul 7, 20258-KMaterial AgreementJul 7, 20258-KReg FD DisclosureJun 6, 20258-KShareholder VoteMay 22, 202510-Q10-QMay 7, 20258-KResults of OperationsMay 7, 20258-KCompany UpdateApr 10, 2025DEF 14ADEF 14AApr 2, 202510-K10-KFeb 28, 20258-KResults of OperationsFeb 7, 20258-KCompany UpdateJan 8, 202510-Q10-QNov 6, 20248-KResults of OperationsNov 6, 202410-Q10-QAug 7, 20248-KResults of OperationsAug 7, 20248-KReg FD DisclosureJun 7, 202411-K11-KMay 31, 20248-KShareholder VoteMay 23, 202410-Q10-QMay 9, 20248-KResults of OperationsMay 9, 20248-KExecutive ChangeApr 10, 2024DEF 14AFORM-DEF14AApr 4, 202410-K10-KFeb 26, 20248-KExecutive ChangeFeb 23, 20248-KResults of OperationsFeb 7, 20248-KCompany UpdateJan 3, 20248-KCompany UpdateDec 21, 202310-Q10-QNov 6, 20238-KResults of OperationsNov 6, 20238-KMaterial AgreementOct 20, 202310-Q10-QAug 7, 20238-KResults of OperationsAug 7, 2023SC 13DSC 13DJun 30, 202311-K11-KJun 15, 20238-KReg FD DisclosureJun 6, 20238-KShareholder VoteMay 25, 20238-KExecutive ChangeMay 25, 2023DEFA14ADEFA14AMay 10, 202310-Q10-QMay 9, 20238-KResults of OperationsMay 9, 2023DEF 14ADEF 14AApr 5, 202310-K10-KFeb 27, 20238-KExecutive ChangeFeb 23, 2023SC 13GSC 13GFeb 14, 2023SC 13GSC 13GFeb 10, 2023SC 13GSEC SCHEDULE 13GFeb 10, 2023SC 13GSC 13GFeb 8, 20238-KResults of OperationsFeb 7, 20238-KCompany UpdateDec 21, 202210-Q10-QNov 7, 20228-KResults of OperationsNov 7, 20228-KResults of OperationsAug 8, 202210-Q10-QAug 8, 20228-KAcquisition / Disposition · Company UpdateAug 5, 202211-K11-KJun 14, 20228-KReg FD DisclosureJun 10, 20228-KShareholder VoteMay 26, 20228-KCompany UpdateMay 26, 2022DEFA14ADEFA14AMay 16, 2022
Insider Activity
In the 90 days to Dec 19, 2025: 3 sold $20.8M.
| Date | Insider | Action | Shares | Price | Value |
|---|---|---|---|---|---|
| Dec 19, 2025 | Campbell Reid TarltonDirector | Sell | 5,000 | $2050.00 | $10.3M |
| Dec 19, 2025 | Rountree George ManningChief Executive Officer | Sell | 5,000 | $2050.00 | $10.3M |
| Dec 19, 2025 | Campbell Reid TarltonDirector | Sell | 5,000 | $0.00 | $0 |
| Dec 16, 2025 | Gelston Philip ADirector | Sell | 165 | $2048.51 | $338K |
Open-market buys & sells (Form 4, transaction codes P/S). Source: SEC structured insider data.
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