As of August 29, 2026, the three largest insider holders of CTMX are Sean A. Mccarthy (Ceo, 1.08Mn shares), Sean A. Mccarthy (Ceo, 1.08Mn shares), Sean A. Mccarthy (Ceo, 987.89K shares).
| # | Insider | Position | Direct | Indirect | Total | Share of Insiders | Last Filed |
|---|---|---|---|---|---|---|---|
| 1 | Sean A. Mccarthy | Ceo | 2,066,813 | 0 | 2,066,813 | 61.9% | 19 Mar, 2026 |
| 2 | Marcia Belvin | Svp, Chief Scientific Officer | 300,760 | 0 | 300,760 | 9.0% | 19 Mar, 2026 |
| 3 | Christopher Ogden | Chief Financial Officer | 295,324 | 0 | 295,324 | 8.8% | 17 Jun, 2026 |
| 4 | Yu-Waye Chu | Chief Medical Officer | 189,446 | 0 | 189,446 | 5.7% | 19 Mar, 2026 |
| 5 | Lloyd A Rowland | General Counsel | 120,594 | 0 | 120,594 | 3.6% | 20 Mar, 2025 |
| 6 | Jeffrey B Landau | Chief Business Officer | 119,056 | 0 | 119,056 | 3.6% | 22 Aug, 2024 |
| 7 | Alejandra Carvajal | Chief Legal Officer | 100,000 | 0 | 100,000 | 3.0% | 05 Aug, 2026 |
| 8 | Amy C. Peterson | Evp, Chief Development Officer | 58,433 | 0 | 58,433 | 1.7% | 20 Mar, 2023 |
| 9 | Carlos Campoy | Chief Financial Officer | 38,224 | 0 | 38,224 | 1.1% | 20 Mar, 2023 |
| 10 | Alison L. Hannah | Chief Medical Officer | 31,898 | 0 | 31,898 | 1.0% | 21 Jul, 2022 |
| 11 | Rachael Lester | Chief Business Officer | 20,000 | 0 | 20,000 | 0.6% | 04 Feb, 2026 |
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 |
|---|---|---|---|---|---|---|---|---|
| 03 Aug, 2026 | Alejandra Carvajal | Chief Legal Officer | Acquired A | 100,000 | $0.00 | $0 | 100,000 | Direct |
| 03 Aug, 2026 | Alejandra Carvajal | Chief Legal Officer | Acquired A | 450,000 | $0.00 | $0 | 450,000 | Direct |
| 24 Jul, 2026 | Charles S. Fuchs | Director | Acquired A | 118,000 | $0.00 | $0 | 118,000 | Direct |
| 17 Jun, 2026 | Matthew P. Young | Director | Acquired A | 59,000 | $0.00 | $0 | 59,000 | Direct |
| 17 Jun, 2026 | Zhen Su | Director | Acquired A | 59,000 | $0.00 | $0 | 59,000 | Direct |
| 17 Jun, 2026 | James R Meyers | Director | Acquired A | 59,000 | $0.00 | $0 | 59,000 | Direct |
| 17 Jun, 2026 | Alan Ashworth | Director | Acquired A | 59,000 | $0.00 | $0 | 59,000 | Direct |
| 17 Jun, 2026 | Mani Mohindru | Director | Acquired A | 59,000 | $0.00 | $0 | 59,000 | Direct |
| 15 Jun, 2026 | Christopher Ogden | Chief Financial Officer | Disposed S | 1,624 | $3.05 | $4.95K | 295,324 | Direct |
| 17 Mar, 2026 | Yu-Waye Chu | Chief Medical Officer | Disposed S | 21,279 | $6.42 | $136.68K | 189,446 | Direct |
| 17 Mar, 2026 | Christopher Ogden | Chief Financial Officer | Disposed S | 19,323 | $6.42 | $124.11K | 296,948 | Direct |
| 17 Mar, 2026 | Sean A. Mccarthy | Ceo | Disposed S | 118,969 | $6.42 | $764.14K | 1,078,922 | Direct |
| 17 Mar, 2026 | Sean A. Mccarthy | Ceo | Disposed S | 118,969 | $6.42 | $764.14K | 1,078,922 | Direct |
| 17 Mar, 2026 | Sean A. Mccarthy | Ceo | Disposed S | 118,969 | $6.42 | $764.14K | 1,078,922 | Direct |
| 17 Mar, 2026 | Sean A. Mccarthy | Ceo | Disposed S | 118,969 | $6.42 | $764.14K | 1,078,922 | Direct |
| 17 Mar, 2026 | Marcia Belvin | Svp, Chief Scientific Officer | Disposed S | 31,492 | $6.42 | $202.27K | 300,760 | Direct |
| 02 Feb, 2026 | Sean A. Mccarthy | Ceo | Acquired A | 210,000 | $0.00 | $0 | 1,197,891 | Direct |
| 02 Feb, 2026 | Rachael Lester | Chief Business Officer | Acquired A | 20,000 | $0.00 | $0 | 20,000 | Direct |
| 02 Feb, 2026 | Sean A. Mccarthy | Ceo | Acquired A | 210,000 | $0.00 | $0 | 1,197,891 | Direct |
| 02 Feb, 2026 | Rachael Lester | Chief Business Officer | Acquired A | 20,000 | $0.00 | $0 | 20,000 | Direct |