WHITE MOUNTAINS INSURANCE GROUP LTD — All Filings
1,000 total filings on record
Public companies registered with the SEC are required to file periodic reports, disclosures, and notices throughout the year. The most important are the 10-K (annual report), 10-Q (quarterly report), and 8-K (material event notice). Use the filters below to narrow by form type.
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UPLOAD
| Form | Description | Accession Number | Filed | Period |
|---|---|---|---|---|
| SCHEDULE 13G/A | — | 0000102909-26-002687 | Mar 27, 2026 | — |
| 4 | STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES | 0000776867-26-000025 | Mar 20, 2026 | Mar 19, 2026 |
| 4 | STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES | 0000776867-26-000023 | Mar 5, 2026 | Mar 4, 2026 |
| 4 | STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES | 0000776867-26-000021 | Feb 27, 2026 | Feb 25, 2026 |
| 4 | STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES | 0000776867-26-000020 | Feb 27, 2026 | Feb 25, 2026 |
| 4 | STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES | 0000776867-26-000019 | Feb 27, 2026 | Feb 25, 2026 |
| 4 | STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES | 0000776867-26-000018 | Feb 27, 2026 | Feb 25, 2026 |
| 4 | STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES | 0000776867-26-000017 | Feb 27, 2026 | Feb 25, 2026 |
| 10-K | 10-K | 0001628280-26-012603 | Feb 27, 2026 | Dec 31, 2025 |
| 8-K | 8-K | 0001628280-26-012417 | Feb 26, 2026 | — |
| 13F-HR | — | 0001104659-26-014432 | Feb 12, 2026 | Dec 31, 2025 |
| SCHEDULE 13G/A | — | 0000895421-26-000047 | Feb 12, 2026 | — |
| 8-K | 8-K | 0001628280-26-005947 | Feb 6, 2026 | — |
| SCHEDULE 13G | — | 0001465109-26-000005 | Feb 5, 2026 | — |
| 8-K | 8-K | 0001628280-26-001102 | Jan 7, 2026 | — |
| 4 | STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES | 0000776867-26-000010 | Jan 5, 2026 | Jan 1, 2026 |
| 4 | STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES | 0000776867-26-000009 | Jan 2, 2026 | Jan 1, 2026 |
| 3 | INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES | 0000776867-26-000008 | Jan 2, 2026 | Jan 1, 2026 |
| 4 | STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES | 0000776867-26-000007 | Jan 2, 2026 | Jan 1, 2026 |
| 4 | STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES | 0000776867-26-000006 | Jan 2, 2026 | Jan 1, 2026 |
| SC TO-I/A | SC TO-I/A | 0001104659-25-124380 | Dec 29, 2025 | — |
| 4 | STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES | 0000776867-25-000034 | Dec 23, 2025 | — |
| 4/A | AMENDED STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES | 0000776867-25-000032 | Dec 22, 2025 | Dec 19, 2025 |
| 4 | STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES | 0000776867-25-000030 | Dec 22, 2025 | Dec 19, 2025 |
| 4 | STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES | 0000776867-25-000029 | Dec 22, 2025 | Dec 19, 2025 |
| SC TO-I/A | SC TO-I/A | 0001104659-25-123514 | Dec 22, 2025 | — |
| 4 | STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES | 0000776867-25-000025 | Dec 16, 2025 | — |
| 8-K | 8-K | 0001628280-25-055702 | Dec 8, 2025 | Dec 5, 2025 |
| 4 | STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES | 0000776867-25-000021 | Nov 26, 2025 | Nov 25, 2025 |
| SC TO-I | SC TO-I | 0001104659-25-114719 | Nov 21, 2025 | — |
| 13F-HR | — | 0001104659-25-110906 | Nov 13, 2025 | Sep 30, 2025 |
| 4 | STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES | 0001318960-25-000008 | Nov 10, 2025 | — |
| SCHEDULE 13G/A | — | 0000895421-25-000548 | Nov 7, 2025 | — |
| 10-Q | 10-Q | 0001628280-25-049910 | Nov 6, 2025 | Sep 30, 2025 |
| 8-K | 8-K | 0001628280-25-049888 | Nov 6, 2025 | — |
| 8-K | 8-K | 0001628280-25-044062 | Oct 3, 2025 | Oct 2, 2025 |
| 8-K | 8-K | 0000776867-25-000016 | Sep 3, 2025 | Sep 2, 2025 |
| 8-K | 8-K | 0000776867-25-000015 | Sep 2, 2025 | — |
| N-PX | — | 0001104659-25-084020 | Aug 27, 2025 | Jun 30, 2025 |
| 13F-HR | — | 0001104659-25-076169 | Aug 11, 2025 | Jun 30, 2025 |
| SCHEDULE 13D/A | — | 0000950157-25-000649 | Aug 8, 2025 | — |
| 10-Q | 10-Q | 0000776867-25-000014 | Aug 7, 2025 | Jun 30, 2025 |
| 8-K | 8-K | 0000776867-25-000013 | Aug 7, 2025 | — |
| SCHEDULE 13G/A | — | 0000895421-25-000491 | Aug 7, 2025 | — |
| 8-K | 8-K | 0000776867-25-000012 | Jul 18, 2025 | — |
| 8-K | 8-K | 0000776867-25-000011 | Jul 16, 2025 | — |
| 11-K | 11-K | 0000776867-25-000010 | Jul 7, 2025 | Dec 31, 2024 |
| 8-K | 8-K | 0000776867-25-000009 | Jul 7, 2025 | Jul 4, 2025 |
| 8-K | 8-K | 0000776867-25-000008 | Jun 6, 2025 | — |
| 4 | STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES | 0001062993-25-010325 | May 27, 2025 | May 22, 2025 |