The public view is the crawlable proof. The same sourced dataset is available through REST and MCP for agents, research scripts, and back-office tools.
| Date | Insider | Role | Action | Shares | Price | Value |
|---|---|---|---|---|---|---|
| Jun 15, 2026 | Besca Mark | Director | Other(J) | 81 | $1,668.65 | $135K |
| Jun 15, 2026 | Housel Morgan E. | Director | Other(J) | 66 | $1,668.65 | $110K |
| Jun 15, 2026 | Leopold Diane | Director | Other(J) | 66 | $1,668.65 | $110K |
| Jun 15, 2026 | Michael Jonathan E | Director | Other(J) | 66 | $1,668.65 | $110K |
| Jun 15, 2026 | Morrison Harold Lawrence Jr. | Director | Other(J) | 33 | $1,668.65 | $55K |
| Jun 15, 2026 | Cunningham Lawrence A | Director | Other(J) | 33 | $1,668.65 | $55K |
| Jun 15, 2026 | Puckett A. Lynne | Director | Other(J) | 66 | $1,668.65 | $110K |
| Jun 15, 2026 | Oreilly Michael | Director | Other(J) | 90 | $1,668.65 | $150K |
| May 22, 2026 | Harris Greta J | Director | Sell(S) | 35 | $1,846.12 | $65K |
| May 22, 2026 | Harris Greta J | Director | Sell(S) | 14 | $1,847.36 | $26K |
| May 22, 2026 | Harris Greta J | Director | Sell(S) | 27 | $1,848.83 | $50K |
| May 20, 2026 | Besca Mark | Director | Grant(A) | 89 | — | $0 |
| May 20, 2026 | Cunningham Lawrence A | Director | Grant(A) | 89 | — | $0 |
| May 20, 2026 | Housel Morgan E. | Director | Grant(A) | 89 | — | $0 |
| May 20, 2026 | Harris Greta J | Director | Grant(A) | 89 | — | $0 |
| May 20, 2026 | Leopold Diane | Director | Grant(A) | 89 | — | $0 |
| May 20, 2026 | Michael Jonathan E | Director | Grant(A) | 89 | — | $0 |
| May 20, 2026 | Oreilly Michael | Director | Grant(A) | 89 | — | $0 |
| May 20, 2026 | Morrison Harold Lawrence Jr. | Director | Grant(A) | 89 | — | $0 |
| May 20, 2026 | Puckett A. Lynne | Director | Grant(A) | 89 | — | $0 |
| May 15, 2026 | Costanzo Brian J. | Chief Financial Officer | Tax withholding(F) | 13 | $1,844.00 | $24K |
| May 15, 2026 | Costanzo Brian J. | Chief Financial Officer | Other(J) | 30 | $1,659.60 | $50K |
| May 15, 2026 | Gayner Thomas Sinnickson | Chief Executive Officer, Director | Tax withholding(F) | 482 | $1,844.00 | $888K |
| May 15, 2026 | Grinnan Richard Randolph | SVP, Chief Legal Officer & Sec | Tax withholding(F) | 116 | $1,844.00 | $215K |
| May 15, 2026 | Crowley Andrew G. | EVP & Pres., Markel Ventures | Tax withholding(F) | 75 | $1,844.00 | $138K |
| May 15, 2026 | Crowley Andrew G. | EVP & Pres., Markel Ventures | Other(J) | 60 | $1,659.60 | $100K |
| May 7, 2026 | Leopold Diane | Director | Buy(P) | 50 | $1,789.19 | $89K |
| May 6, 2026 | Leopold Diane | Director | Buy(P) | 100 | $1,792.61 | $179K |
| May 1, 2026 | Puckett A. Lynne | Director | Buy(P) | 57 | $1,795.53 | $102K |
| Mar 31, 2026 | Costanzo Brian J. | Chief Financial Officer | Other(J) | 2 | $1,626.96 | $3K |
| Mar 31, 2026 | Crowley Andrew G. | EVP & Pres., Markel Ventures | Other(J) | 9 | $1,626.96 | $15K |
| Feb 26, 2026 | Wilson Simon | EVP and CEO, Markel Insurance | Sell(S) | 100 | $2,079.48 | $208K |
| Feb 24, 2026 | Gayner Thomas Sinnickson | Chief Executive Officer, Director | Grant(A) | 4K | — | $0 |
| Feb 24, 2026 | Grinnan Richard Randolph | SVP, Chief Legal Officer & Sec | Grant(A) | 801 | — | $0 |
| Feb 24, 2026 | Costanzo Brian J. | Chief Financial Officer | Grant(A) | 655 | — | $0 |
| Feb 24, 2026 | Crowley Andrew G. | EVP & Pres., Markel Ventures | Grant(A) | 830 | — | $0 |
| Feb 24, 2026 | Grandis Meade P. | CAO and Controller | Grant(A) | 70 | — | $0 |
| Feb 24, 2026 | Wilson Simon | EVP and CEO, Markel Insurance | Grant(A) | 868 | — | $0 |
| Feb 17, 2026 | Wilson Simon | CEO, Markel Insurance | Tax withholding(F) | 47 | $2,084.46 | $98K |
| Dec 31, 2025 | Costanzo Brian J. | Chief Financial Officer | Other(J) | 2 | $1,602.62 | $3K |
| Dec 11, 2025 | Markel Steven A | Director | Sell(S) | 40 | $2,112.03 | $84K |
| Dec 11, 2025 | Markel Steven A | Director | Sell(S) | 120 | $2,114.99 | $254K |
| Dec 11, 2025 | Markel Steven A | Director | Sell(S) | 100 | $2,116.18 | $212K |
| Dec 11, 2025 | Markel Steven A | Director | Sell(S) | 201 | $2,117.37 | $426K |
| Dec 11, 2025 | Markel Steven A | Director | Sell(S) | 24 | $2,118.37 | $51K |
| Dec 11, 2025 | Markel Steven A | Director | Sell(S) | 51 | $2,120.65 | $108K |
| Dec 11, 2025 | Markel Steven A | Director | Sell(S) | 173 | $2,121.69 | $367K |
| Dec 11, 2025 | Markel Steven A | Director | Sell(S) | 10 | $2,123.05 | $21K |
| Dec 11, 2025 | Markel Steven A | Director | Sell(S) | 32 | $2,125.00 | $68K |
| Dec 11, 2025 | Markel Steven A | Director | Sell(S) | 75 | $2,126.00 | $159K |
| Dec 11, 2025 | Markel Steven A | Director | Sell(S) | 190 | $2,127.26 | $404K |
| Dec 11, 2025 | Markel Steven A | Director | Sell(S) | 10 | $2,128.00 | $21K |
| Dec 11, 2025 | Markel Steven A | Director | Sell(S) | 120 | $2,129.98 | $256K |
| Dec 11, 2025 | Markel Steven A | Director | Sell(S) | 70 | $2,108.27 | $148K |
| Dec 11, 2025 | Markel Steven A | Director | Sell(S) | 64 | $2,100.00 | $134K |
| Dec 11, 2025 | Markel Steven A | Director | Sell(S) | 50 | $2,103.55 | $105K |
| Dec 2, 2025 | Gayner Thomas Sinnickson | Chief Executive Officer, Director | Tax withholding(F) | 37 | $2,060.83 | $75K |
| Dec 2, 2025 | Grinnan Richard Randolph | SVP, Chief Legal Officer & Sec | Tax withholding(F) | 138 | $2,060.83 | $284K |
| Dec 2, 2025 | Heaton Michael R | EVP & Chief Operating Officer | Tax withholding(F) | 217 | $2,060.83 | $448K |
| Dec 2, 2025 | Costanzo Brian J. | Chief Financial Officer | Tax withholding(F) | 22 | $2,060.83 | $45K |
| Dec 2, 2025 | Crowley Andrew G. | President, Markel Ventures | Tax withholding(F) | 65 | $2,060.83 | $133K |
| Dec 2, 2025 | Wilson Simon | CEO, Markel Insurance | Tax withholding(F) | 94 | $2,060.83 | $194K |
| Nov 28, 2025 | Markel Steven A | Director | Sell(S) | 100 | $2,100.00 | $210K |
| Nov 26, 2025 | Markel Steven A | Director | Sell(S) | 70 | $2,100.00 | $147K |
| Nov 25, 2025 | Wilson Simon | CEO, Markel Insurance | Sell(S) | 75 | $2,072.94 | $155K |
| Nov 17, 2025 | Markel Steven A | Director | Gift(G) | 500 | — | $0 |
| Sep 30, 2025 | Costanzo Brian J. | Chief Financial Officer | Other(J) | 2 | $1,624.66 | $3K |
| Aug 25, 2025 | Grandis Meade P. | CAO and Controller | Sell(S) | 75 | $1,983.78 | $149K |
| Jul 15, 2025 | Crowley Andrew G. | President, Markel Ventures | Other(J) | 6 | $1,779.25 | $10K |
| Jun 30, 2025 | Costanzo Brian J. | Chief Financial Officer | Other(J) | 2 | $1,580.87 | $3K |
| Jun 13, 2025 | Crowley Andrew G. | President, Markel Ventures | Other(J) | 9 | $1,735.89 | $15K |
| Jun 13, 2025 | Oreilly Michael | Director | Other(J) | 81 | $1,735.89 | $140K |
| Jun 13, 2025 | Puckett A. Lynne | Director | Other(J) | 63 | $1,735.89 | $110K |
| Jun 13, 2025 | Leopold Diane | Director | Other(J) | 63 | $1,735.89 | $110K |
| Jun 13, 2025 | Housel Morgan E. | Director | Other(J) | 63 | $1,735.89 | $110K |
| Jun 13, 2025 | Cunningham Lawrence A | Director | Other(J) | 63 | $1,735.89 | $110K |
| Jun 13, 2025 | Morrison Harold Lawrence Jr. | Director | Other(J) | 32 | $1,735.89 | $55K |
| Jun 13, 2025 | Michael Jonathan E | Director | Other(J) | 63 | $1,735.89 | $110K |
| May 23, 2025 | Harris Greta J | Director | Sell(S) | 90 | $1,861.44 | $168K |
| May 22, 2025 | Cunningham Lawrence A | Director | Buy(P) | 10 | $1,854.80 | $19K |
| May 22, 2025 | Cunningham Lawrence A | Director | Buy(P) | 15 | $1,849.00 | $28K |
| May 21, 2025 | Cunningham Lawrence A | Director | Grant(A) | 88 | — | $0 |
| May 21, 2025 | Michael Jonathan E | Director | Grant(A) | 88 | — | $0 |
| May 21, 2025 | Puckett A. Lynne | Director | Grant(A) | 88 | — | $0 |
| May 21, 2025 | Oreilly Michael | Director | Grant(A) | 88 | — | $0 |
| May 21, 2025 | Morrison Harold Lawrence Jr. | Director | Grant(A) | 88 | — | $0 |
| May 21, 2025 | Leopold Diane | Director | Grant(A) | 88 | — | $0 |
| May 21, 2025 | Housel Morgan E. | Director | Grant(A) | 88 | — | $0 |
| May 21, 2025 | Besca Mark | Director | Grant(A) | 88 | — | $0 |
| May 21, 2025 | Harris Greta J | Director | Grant(A) | 88 | — | $0 |
| May 19, 2025 | Grandis Meade P. | CAO and Controller | Sell(S) | 400 | $1,911.65 | $765K |
| May 19, 2025 | Markel Steven A | Director | Gift(G) | 300 | — | $0 |
| May 15, 2025 | Crowley Andrew G. | President, Markel Ventures | Other(J) | 3 | $1,710.30 | $5K |
| May 15, 2025 | Wilson Simon | CEO, Markel Insurance | Other(J) | 0 | $1,710.30 | $633 |
| May 15, 2025 | Heaton Michael R | EVP & Chief Operating Officer | Other(J) | 88 | $1,710.30 | $150K |
| May 5, 2025 | Grandis Meade P. | CAO and Controller | Sell(S) | 400 | $1,877.44 | $751K |
| Apr 15, 2025 | Crowley Andrew G. | President, Markel Ventures | Other(J) | 9 | $1,602.95 | $14K |
| Apr 15, 2025 | Michael Jonathan E | Director | Other(J) | 11 | $1,602.95 | $18K |
| Apr 15, 2025 | Wilson Simon | CEO, Markel Insurance | Other(J) | 0 | $1,602.95 | $641 |
| Mar 31, 2025 | Costanzo Brian J. | Chief Financial Officer | Other(J) | 2 | $1,459.76 | $3K |
Insider transactions sourced from SEC EDGAR Form 4 filings, normalized within minutes of acceptance. "Buy"/"Sell" mark open-market transactions (codes P/S), the tradeable signal. Awards, option exercises and tax-withholding are shown with their raw code. All data is public domain.
Coverage: Form 4 filings indexed 2021-03-29 → 2026-07-14. Earlier history is backfilling; this window widens as it deepens.
Programmatic access via the Arkolith API & MCP server (insider.transactions, insider.company).