WTM (White Mountains Insurance Group Ltd.)
Insider Trading Activity
Every open-market purchase and sale reported by WTM officers, directors and 10%+ beneficial owners on SEC Form 4, which must be filed within two business days of the transaction. Sales often reflect scheduled 10b5-1 plans or tax withholding rather than a directional view, so read counts alongside the size and the filer.
Market data may be delayed, incomplete, or inaccurate. Not a recommendation to buy, sell, or hold any security. Verify quotes with your broker before trading. See Terms §17.
| Filed | Insider | Role | Type | Shares | Value |
|---|---|---|---|---|---|
| 2026-08-31 | David Allen Tanner | Director | G | — | — |
| 2026-08-27 | Stephen Klar | Director | A | — | — |
| 2026-05-22 | REID TARLTON CAMPBELL | Director | A | — | — |
| 2026-05-22 | Peter M Carlson | Director | A | — | — |
| 2026-05-22 | MARY C CHOKSI | Director | A | — | — |
| 2026-05-22 | John Chu | Director | A | — | — |
| 2026-05-22 | Margaret Dillon | Director | A | — | — |
| 2026-05-22 | Philip A Gelston | Director | A | — | — |
| 2026-05-22 | Weston M Hicks | Director | A | — | — |
| 2026-05-22 | SUZANNE F. SHANK | Director | A | — | — |
| 2026-05-22 | David Allen Tanner | Director | A | — | — |
| 2026-03-20 | ROBERT LAWRENCE SEELIG | EVP & General Counsel | G | — | — |
| 2026-03-05 | David Allen Tanner | Director | G | — | — |
| 2026-02-27 | ROBERT LAWRENCE SEELIG | EVP & General Counsel | A | — | — |
| 2026-02-27 | Michael A Papamichael | Chief Financial Officer | A | — | — |
| 2026-02-27 | Michaela Hildreth | MD & Chief Accounting Officer | A | — | — |
| 2026-02-27 | Giles E Harrison | President | A | — | — |
| 2026-02-27 | Liam P Caffrey | Chief Executive Officer | A | — | — |
| 2026-01-05 | Michaela Hildreth | MD & Chief Accounting Officer | F | — | — |
| 2026-01-02 | Liam P Caffrey | Chief Executive Officer | F | — | — |
| 2026-01-02 | ROBERT LAWRENCE SEELIG | EVP & General Counsel | F | — | — |
| 2026-01-02 | Michael A Papamichael | Chief Financial Officer | F | — | — |
| 2025-12-23 | Michaela Hildreth | MD & Chief Accounting Officer | G | — | — |
| 2025-12-22 | REID TARLTON CAMPBELL | Director | Sell | — | — |
| 2025-12-22 | George Manning Rountree | Chief Executive Officer | Sell | — | — |
| 2025-12-22 | REID TARLTON CAMPBELL | Director | Sell | — | — |
| 2025-12-16 | Philip A Gelston | Director | Sell | — | — |
| 2025-11-26 | REID TARLTON CAMPBELL | Director | G | — | — |
| 2025-11-10 | David Allen Tanner | Director | G | — | — |
| 2025-05-27 | SUZANNE F. SHANK | Director | A | — | — |
| 2025-05-23 | REID TARLTON CAMPBELL | Director | A | — | — |
| 2025-05-23 | Peter M Carlson | Director | A | — | — |
| 2025-05-23 | MARY C CHOKSI | Director | A | — | — |
| 2025-05-23 | Margaret Dillon | Director | A | — | — |
| 2025-05-23 | Philip A Gelston | Director | A | — | — |
| 2025-05-23 | Weston M Hicks | Director | A | — | — |
| 2025-05-23 | David Allen Tanner | Director | A | — | — |
| 2025-05-23 | Steven Yi | Director | A | — | — |
| 2025-02-28 | Michaela Hildreth | MD & Chief Accounting Officer | A | — | — |
| 2025-02-28 | ROBERT LAWRENCE SEELIG | EVP & General Counsel | A | — | — |
| 2025-02-28 | Giles E Harrison | EVP & Chief Strategy Officer | A | — | — |
| 2025-02-28 | Liam P Caffrey | EVP& Chief Financial Officer | A | — | — |
| 2025-02-28 | George Manning Rountree | Chief Executive Officer | A | — | — |
| 2025-01-03 | Michaela Hildreth | MD & Chief Accounting Officer | F | — | — |
| 2025-01-03 | ROBERT LAWRENCE SEELIG | EVP & General Counsel | F | — | — |
| 2025-01-03 | Liam P Caffrey | President & CFO | F | — | — |
| 2025-01-03 | George Manning Rountree | Chief Executive Officer | F | — | — |
| 2024-12-02 | Michaela Hildreth | MD & Chief Accounting Officer | G | — | — |
| 2024-06-10 | Giles E Harrison | EVP & Chief Strategy Officer | A | — | — |
| 2024-05-24 | Weston M Hicks | Director | A | — | — |
| Insider | Role | Shares Held | Value |
|---|---|---|---|
| — | 10%+ Owner | 89,279 | — |
| — | Director | 52,825 | — |
| — | Chief Executive Officer | 46,713 | — |
| — | EVP & General Counsel | 17,861 | — |
| — | Chief Executive Officer | 13,931 | — |
| — | CEO - Sirius Int'l Ins. Group | 11,555 | — |
| — | Director | 10,694 | — |
| — | Director | 9,578 | — |
| — | Director | 8,045 | — |
| — | Director | 7,739 | — |
| — | Chief Investment Officer | 4,740 | — |
| — | Director | 4,121 | — |
| — | Chief Executive Officer | 3,658 | — |
| — | EVP and Head of M&A | 3,600 | — |
| — | Director | 2,936 | — |
| — | Director | 2,827 | — |
| — | President | 2,677 | — |
| — | Pres & CEO - Esurance | 2,620 | — |
| — | CFO - White Mountains Re Group | 2,051 | — |
| — | Director | 2,012 | — |
| — | Director | 1,993 | — |
| — | MD & Chief Accounting Officer | 1,845 | — |
| — | Managing Director | 1,782 | — |
| — | Director | 1,703 | — |
| — | Director | 1,641 | — |
Form 4 reports a change in beneficial ownership by an officer, director or 10%+ holder, and must be filed within two business days of the transaction — so this is close to real time, unlike the 45-day-lagged 13F institutional data.
Transaction codes matter more than the raw buy/sell count. Code P is an open-market purchase — an insider choosing to buy with their own money, which is the signal most research treats as informative. Code S is a sale, but sales are frequently pre-scheduled under a 10b5-1 plan or cover tax withholding on vesting equity, so a run of sales often says nothing directional. Codes A and M are grants and option exercises rather than open-market decisions.
Full filing history and per-insider positions are on the WTM quote page; the site-wide leaderboard is on the insider transactions hub.