White Mountains Insurance Group Ltd (WTM) · Insider trading
What White Mountains Insurance Group's directors, officers and largest holders bought and sold themselves, from the Form 4 each of them files with the SEC within two business days of a trade. Open-market purchases and sales first: those are the trades somebody chose to make at the market price.
Bought, 12 months
$0
0 insiders, 0 trades
Sold, 12 months
$20.84M
3 insiders, 0% under a plan
Net, 12 months
−$20.84M
bought less sold
Latest filing
2026-08-31
filings read to 2026-10-19
Who traded, two years
| Insider | Bought | Sold | Trades | Last trade | Holds after |
|---|---|---|---|---|---|
| Rountree George ManningDirector, Chief Executive Officer | – | $10.25M | 1 | 2025-12-19 | 13,809 |
| Campbell Reid TarltonDirector | – | $10.25M | 1 | 2025-12-19 | 10,440 |
| Gelston Philip ADirector | – | $338,004 | 1 | 2025-12-16 | 1,568 |
Open-market purchases and sales
Newest first. “Plan” marks a trade made under a 10b5-1 plan set up in advance.
| Date | Insider | Trade | Shares | Price | Value | Holds after | Filing |
|---|---|---|---|---|---|---|---|
| 2025-12-19 | Rountree George ManningDirector, Chief Executive Officer | Sale | 5,000 | 2050.00 | $10.25M | 13,809 | Form 4 |
| 2025-12-19 | Campbell Reid TarltonDirector | Sale | 5,000 | 2050.00 | $10.25M | 10,440 | Form 4/A |
| 2025-12-16 | Gelston Philip ADirector | Sale | 165 | 2048.51 | $338,004 | 1,568 | Form 4 |
Grants, exercises and other transactions
Pay, tax and paperwork rather than a choice to trade at the market price. Two years.
29 × grant or award8 × shares withheld for tax7 × gift
Show them
| Date | Insider | What | Shares | Price | Holds after | Filing |
|---|---|---|---|---|---|---|
| 2026-08-31 | Tanner David AllenDirector | Gift G | −2 | – | 2,012 | Form 4 |
| 2026-08-26 | Klar StephenDirector | Grant or award A | +113 | – | 113 | Form 4 |
| 2026-05-21 | Campbell Reid TarltonDirector | Grant or award A | +135 | – | 10,575 | Form 4 |
| 2026-05-21 | Carlson Peter MDirector | Grant or award A | +135 | – | 852 | Form 4 |
| 2026-05-21 | Choksi Mary CDirector | Grant or award A | +135 | – | 1,993 | Form 4 |
| 2026-05-21 | Chu JohnDirector | Grant or award A | +135 | – | 335 | Form 4 |
| 2026-05-21 | Dillon MargaretDirector | Grant or award A | +135 | – | 1,080 | Form 4 |
| 2026-05-21 | Gelston Philip ADirector | Grant or award A | +135 | – | 1,703 | Form 4 |
| 2026-05-21 | Hicks Weston MDirector | Grant or award A | +190 | – | 2,936 | Form 4 |
| 2026-05-21 | Shank Suzanne F.Director | Grant or award A | +135 | – | 1,006 | Form 4 |
| 2026-05-21 | Tanner David AllenDirector | Grant or award A | +135 | – | 2,014 | Form 4 |
| 2026-03-19 | Seelig Robert LawrenceEVP & General Counsel | Gift G | −50 | – | 17,857 | Form 4 |
| 2026-03-04 | Tanner David AllenDirector | Gift G | −225 | – | 1,879 | Form 4 |
| 2026-02-25 | Seelig Robert LawrenceEVP & General Counsel | Grant or award A | +775 | – | 2,500 | Form 4 |
| 2026-02-25 | Papamichael Michael AChief Financial Officer | Grant or award A | +500 | – | 1,200 | Form 4 |
| 2026-02-25 | Hildreth MichaelaMD & Chief Accounting Officer | Grant or award A | +600 | – | 1,825 | Form 4 |
| 2026-02-25 | Harrison Giles EPresident | Grant or award A | +775 | – | 2,675 | Form 4 |
| 2026-02-25 | Caffrey Liam PDirector, Chief Executive Officer | Grant or award A | +1,500 | – | 3,650 | Form 4 |
| 2026-01-01 | Hildreth MichaelaMD & Chief Accounting Officer | Shares withheld for tax F | −274 | 2078.03 | 2,491 | Form 4 |
| 2026-01-01 | Caffrey Liam PChief Executive Officer | Shares withheld for tax F | −425 | 2078.03 | 1,655 | Form 4 |
| 2026-01-01 | Seelig Robert LawrenceEVP & General Counsel | Shares withheld for tax F | −398 | 2078.03 | 17,907 | Form 4 |
| 2026-01-01 | Papamichael Michael AChief Financial Officer | Shares withheld for tax F | −131 | 2078.03 | 772 | Form 4 |
| 2025-12-23 | Hildreth MichaelaMD & Chief Accounting Officer | Gift G | −60 | – | 2,165 | Form 4 |
| 2025-11-25 | Campbell Reid TarltonDirector | Gift G | −50 | – | 15,440 | Form 4 |
| 2025-11-10 | Tanner David AllenDirector | Gift G | −4 | – | 2,104 | Form 4 |
| 2025-05-22 | Shank Suzanne F.Director | Grant or award A | +150 | – | 871 | Form 4 |
| 2025-05-22 | Campbell Reid TarltonDirector | Grant or award A | +150 | – | 15,490 | Form 4 |
| 2025-05-22 | Carlson Peter MDirector | Grant or award A | +150 | – | 717 | Form 4 |
| 2025-05-22 | Choksi Mary CDirector | Grant or award A | +150 | – | 1,858 | Form 4 |
| 2025-05-22 | Dillon MargaretDirector | Grant or award A | +150 | – | 945 | Form 4 |
| 2025-05-22 | Gelston Philip ADirector | Grant or award A | +150 | – | 1,733 | Form 4 |
| 2025-05-22 | Hicks Weston MDirector | Grant or award A | +210 | – | 2,746 | Form 4 |
| 2025-05-22 | Tanner David AllenDirector | Grant or award A | +150 | – | 2,108 | Form 4 |
| 2025-05-22 | Yi StevenDirector | Grant or award A | +150 | – | 525 | Form 4 |
| 2025-02-26 | Hildreth MichaelaMD & Chief Accounting Officer | Grant or award A | +625 | – | 1,825 | Form 4 |
| 2025-02-26 | Seelig Robert LawrenceEVP & General Counsel | Grant or award A | +825 | – | 2,725 | Form 4 |
| 2025-02-26 | Harrison Giles EEVP & Chief Strategy Officer | Grant or award A | +900 | – | 1,900 | Form 4 |
| 2025-02-26 | Caffrey Liam PEVP& Chief Financial Officer | Grant or award A | +1,025 | – | 3,400 | Form 4 |
| 2025-02-26 | Rountree George ManningDirector, Chief Executive Officer | Grant or award A | +1,625 | – | 5,425 | Form 4 |
| 2025-01-01 | Hildreth MichaelaMD & Chief Accounting Officer | Shares withheld for tax F | −323 | 1945.06 | 2,225 | Form 4 |
| 2025-01-01 | Seelig Robert LawrenceEVP & General Counsel | Shares withheld for tax F | −496 | 1945.06 | 17,305 | Form 4 |
| 2025-01-01 | Caffrey Liam PPresident & CFO | Shares withheld for tax F | −420 | 1945.06 | 830 | Form 4 |
| 2025-01-01 | Rountree George ManningDirector, Chief Executive Officer | Shares withheld for tax F | −1,067 | 1945.06 | 18,809 | Form 4 |
| 2024-11-29 | Hildreth MichaelaMD & Chief Accounting Officer | Gift G | −75 | – | 1,798 | Form 4 |
How to read it
- Buy, sale
- Code P and S on the form: shares bought or sold in the market, at the market price. The other codes are mostly pay (a grant, an option exercised) or tax (shares the company withheld), and say little about what the insider thinks of the price.
- Plan
- A sale or purchase under a Rule 10b5-1 plan, set up in advance and running on its own schedule. Since April 2023 the form has a box for it. Much executive selling is planned and says more about diversifying than about the company.
- Holds after
- The shares the insider still held after the trade, in the form the trade was in (directly, or indirectly through a trust or a fund).
- Value
- Shares times the price the form reports, which is often an average over several fills on the day.
Read from the SEC's own quarterly data sets of Forms 3, 4 and 5, and from each day's filings since the last one. A correcting amendment replaces the lines it restates. Every row links to its filing. None of this is advice: insiders sell for many reasons, and buy for fewer.