As of August 29, 2026, C4 Therapeutics's top three insider holders are Andrew Hirsch (President Ceo, 1.07Mn shares), Elena Prokupets (Director, 534.81K shares), Kendra Adams (Chief Financial Officer, 385.10K shares).
| # | Insider | Position | Direct | Indirect | Total | Share of Insiders | Last Filed |
|---|---|---|---|---|---|---|---|
| 1 | Andrew Hirsch | President Ceo | 1,074,934 | 0 | 1,074,934 | 28.0% | 18 Feb, 2026 |
| 2 | Elena Prokupets | Director | 0 | 534,807 | 534,807 | 14.0% | 29 Sep, 2021 |
| 3 | Kendra Adams | Chief Financial Officer | 385,098 | 0 | 385,098 | 10.0% | 18 Feb, 2026 |
| 4 | Leonard Reyno | Chief Medical Officer | 372,406 | 0 | 372,406 | 9.7% | 13 Jul, 2026 |
| 5 | Paige Mahaney | Chief Scientific Officer | 336,910 | 0 | 336,910 | 8.8% | 18 Feb, 2026 |
| 6 | Kelly Schick | Chief People Officer | 299,881 | 0 | 299,881 | 7.8% | 18 Feb, 2026 |
| 7 | Scott N Boyle | Chief Business Officer | 298,801 | 0 | 298,801 | 7.8% | 18 Feb, 2026 |
| 8 | Stewart Fisher | Chief Scientific Officer | 130,710 | 0 | 130,710 | 3.4% | 17 Sep, 2024 |
| 9 | Jolie Siegel | Chief Legal Officer | 107,939 | 0 | 107,939 | 2.8% | 18 Feb, 2025 |
| 10 | Donna Roy Grogan | Director | 74,853 | 0 | 74,853 | 2.0% | 02 Jul, 2026 |
| 11 | Kenneth Carl Anderson | Director | 71,950 | 0 | 71,950 | 1.9% | 02 Jul, 2026 |
| 12 | Mark Mossler | Chief Accounting Officer | 71,916 | 0 | 71,916 | 1.9% | 18 Feb, 2026 |
| 13 | Lauren White | Chief Financial Officer | 32,686 | 0 | 32,686 | 0.9% | 31 Aug, 2023 |
| 14 | Glenn Dubin | Director | 22,075 | 0 | 22,075 | 0.6% | 02 Apr, 2024 |
| 15 | Malcolm Salter | Director | 11,380 | 0 | 11,380 | 0.3% | 18 Jan, 2022 |
| 16 | Utpal Koppikar | Director | 5,667 | 0 | 5,667 | 0.1% | 10 Feb, 2023 |
| 17 | Alain J Cohen | Director | 928 | 0 | 928 | 0.0% | 05 Apr, 2022 |
Each row is that insider’s most recently reported position, from Form 4 filings over the last 60 months — which is why this total does not tie to the quarterly series above, where a quarter counts only the insiders who filed in it. Shares held through a fund or institutional portfolio are counted on the institutional ownership page instead.
| Date | Insider | Position | Transaction | Shares | Price | Value | Shares Held After | Ownership |
|---|---|---|---|---|---|---|---|---|
| 10 Jul, 2026 | Leonard Reyno | Chief Medical Officer | Acquired M | 15,325 | $0.00 | $0 | 379,803 | Direct |
| 10 Jul, 2026 | Leonard Reyno | Chief Medical Officer | Disposed F | 7,397 | $4.06 | $30.03K | 372,406 | Direct |
| 01 Jul, 2026 | Donna Roy Grogan | Director | Acquired A | 3,341 | $4.34 | $14.50K | 74,853 | Direct |
| 01 Jul, 2026 | Kenneth Carl Anderson | Director | Acquired A | 2,650 | $4.34 | $11.50K | 71,950 | Direct |
| 24 Jun, 2026 | Donna Roy Grogan | Director | Acquired A | 62,000 | $0.00 | $0 | 62,000 | Direct |
| 24 Jun, 2026 | Laura Bessen | Director | Acquired A | 62,000 | $0.00 | $0 | 62,000 | Direct |
| 24 Jun, 2026 | Owen Hughes | Director | Acquired A | 62,000 | $0.00 | $0 | 62,000 | Direct |
| 24 Jun, 2026 | Ronald Harold Wilfred Cooper | Director | Acquired A | 62,000 | $0.00 | $0 | 62,000 | Direct |
| 24 Jun, 2026 | Utpal Koppikar | Director | Acquired A | 62,000 | $0.00 | $0 | 62,000 | Direct |
| 24 Jun, 2026 | Steven L. Hoerter | Director | Acquired A | 62,000 | $0.00 | $0 | 62,000 | Direct |
| 24 Jun, 2026 | Kenneth Carl Anderson | Director | Acquired A | 62,000 | $0.00 | $0 | 62,000 | Direct |
| 24 Jun, 2026 | Stephen Fawell | Director | Acquired A | 62,000 | $0.00 | $0 | 62,000 | Direct |
| 01 Jun, 2026 | Kenneth Carl Anderson | Director | Acquired M | 1,070 | $2.11 | $2.26K | 69,300 | Direct |
| 01 Jun, 2026 | Kenneth Carl Anderson | Director | Disposed M | 1,070 | $0.00 | $0 | 0 | Direct |
| 01 Apr, 2026 | Donna Roy Grogan | Director | Acquired A | 5,370 | $2.70 | $14.50K | 71,512 | Direct |
| 01 Apr, 2026 | Kenneth Carl Anderson | Director | Acquired A | 4,259 | $2.70 | $11.50K | 68,230 | Direct |
| 13 Feb, 2026 | Kendra Adams | Chief Financial Officer | Acquired A | 240,000 | $0.00 | $0 | 402,342 | Direct |
| 13 Feb, 2026 | Kelly Schick | Chief People Officer | Acquired A | 200,000 | $0.00 | $0 | 308,885 | Direct |
| 13 Feb, 2026 | Kelly Schick | Chief People Officer | Acquired A | 200,000 | $0.00 | $0 | 308,885 | Direct |
| 13 Feb, 2026 | Paige Mahaney | Chief Scientific Officer | Acquired A | 240,000 | $0.00 | $0 | 339,356 | Direct |