THOMAS SINNICKSON GAYNER
CIK 1159015 · Chief Executive Officer · last filed 2026-05-19
THOMAS SINNICKSON GAYNER is a Chief Executive Officer who has filed 163 SEC Form 4 insider transactions across 8 companies since 2007. The most recent filing shows the insider had shares withheld for taxes covering $888.2K of MKL on May 19, 2026. Across all open-market trades the lifetime net is +$15.9M, making them a net buyer over the disclosed history. Current disclosed insider exposure totals $113.4M across reported positions.
"Disclosed insider exposure" sums this person's most-recently-reported share counts across each company they're an insider in, multiplied by the current underlying price. It is not net worth — it misses retail holdings, private investments, real estate, index funds, and any company where the person isn't an SEC-reporting insider. For informational purposes only.
$113.36M
8
163
$15.86M
Holdings By Company
| Symbol | Role | Shares | Price | Disclosed Exposure | Lifetime OM Net | Filings | Latest Filed |
|---|---|---|---|---|---|---|---|
| MKL | Chief Executive Officer | 56,682 | $1846.00 | $104.64M | -$2.99M | 51 | 2026-05-19 |
| KO | Director | 5,200 | $82.62 | $429.6K | $0 | 4 | 2026-04-03 |
| GHC | Director | 5,900 | $1174.18 | $6.93M | $365.3K | 6 | 2024-09-13 |
| CABO | Director | 29,120 | $47.00 | $1.37M | $18.48M | 25 | 2023-03-13 |
| Enovis CORP (CFXA) Delisted | Director | 65,060 | $177.71 | $11.56M | $0 | 15 | 2022-01-04 |
| Enovis CORP (CFX) Delisted | Director | 49,447 | $117.18 | $5.79M | $0 | 50 | 2019-01-03 |
| Cable One, Inc. (CABOw) Delisted | Director | 5,300 | — | — | $0 | 1 | 2015-07-01 |
| MARKEL GROUP INC. (MKV) Delisted | Pres. & Chief Investment Off. | 31,959 | — | — | $0 | 11 | 2011-12-05 |
Recent Filings
163 filings| Filed | Symbol | Action | Net Shares | Net $ | Link |
|---|---|---|---|---|---|
| 2026-05-19 | MKL | Tax (F) | −481 | -$888.2K | EDGAR |
| 2026-04-03 | KO | Grant (A) | — | $0 | EDGAR |
| 2026-02-26 | MKL | Grant (A) | +4,483 | $0 | EDGAR |
| 2025-12-03 | MKL | Tax (F) | −36 | -$75.5K | EDGAR |
| 2025-04-03 | KO | Grant (A) | — | $0 | EDGAR |
| 2025-02-20 | MKL | Grant (A) | +3,349 | $0 | EDGAR |
| 2025-02-07 | MKL | Buy (P) | +100 | $200.8K | EDGAR |
| 2024-12-09 | MKL | Tax (F) | −45 | -$79.2K | EDGAR |
| 2024-11-05 | MKL | Buy (P) | +100 | $155.0K | EDGAR |
| 2024-09-13 | GHC | Buy (P) | +100 | $74.3K | EDGAR |