As of April 17, 2026, the three largest insider holders of CTMX are Sean A. Mccarthy (Ceo, 1.08Mn shares), Sean A. Mccarthy (Ceo, 987.89K shares), Marcia Belvin (Svp, Chief Scientific Officer, 300.76K shares).
| Holder | Position | Shares (Direct) | Shares (Indirect) | Report Date |
|---|---|---|---|---|
| Sean A. Mccarthy | Ceo | 1,078,922 | 0 | 19 Mar, 2026 |
| Sean A. Mccarthy | Ceo | 987,891 | 0 | 10 Nov, 2025 |
| Marcia Belvin | Svp, Chief Scientific Officer | 300,760 | 0 | 19 Mar, 2026 |
| Christopher Ogden | Chief Financial Officer | 296,948 | 0 | 19 Mar, 2026 |
| Yu-Waye Chu | Chief Medical Officer | 189,446 | 0 | 19 Mar, 2026 |
| Jeffrey B Landau | Chief Business Officer | 119,056 | 0 | 22 Aug, 2024 |
| Amy C. Peterson | Evp, Chief Development Officer | 58,433 | 0 | 20 Mar, 2023 |
| Carlos Campoy | Chief Financial Officer | 38,224 | 0 | 20 Mar, 2023 |
| Alison L. Hannah | Chief Medical Officer | 31,898 | 0 | 21 Jul, 2022 |
| Rachael Lester | Chief Business Officer | 20,000 | 0 | 04 Feb, 2026 |
| Elaine V Jones | - | 5,142 | 0 | 31 Mar, 2023 |
* Please note that the shares above only reflect shares from the fund portfolio and the institutional portfolio. Shares from the personal portfolio are excluded from this Institutional Ownership Page. See these insiders' latest transactions here on Insider Page.
| Transaction Date | Insider Name | Security Class | Transaction Type | Shares Traded | Price | Shares Remaining | Ownership | Code |
|---|---|---|---|---|---|---|---|---|
| 17 Mar, 2026 | Sean A. Mccarthy | Common Stock | D | 118,969 | $6.42 | 1,078,922 | D | S |
| 17 Mar, 2026 | Yu-Waye Chu | Common Stock | D | 21,279 | $6.42 | 189,446 | D | S |
| 17 Mar, 2026 | Marcia Belvin | Common Stock | D | 31,492 | $6.42 | 300,760 | D | S |
| 17 Mar, 2026 | Christopher Ogden | Common Stock | D | 19,323 | $6.42 | 296,948 | D | S |
| 02 Feb, 2026 | Marcia Belvin | Common Stock | A | 60,000 | $0.00 | 332,252 | D | A |
| 02 Feb, 2026 | Yu-Waye Chu | Common Stock | A | 75,000 | $0.00 | 210,725 | D | A |
| 02 Feb, 2026 | Rachael Lester | Common Stock | A | 20,000 | $0.00 | 20,000 | D | A |
| 02 Feb, 2026 | Sean A. Mccarthy | Common Stock | A | 210,000 | $0.00 | 1,197,891 | D | A |
| 02 Feb, 2026 | Christopher Ogden | Common Stock | A | 90,000 | $0.00 | 316,271 | D | A |
| 02 Feb, 2026 | Christopher Ogden | Stock Option (Right to Buy) | A | 325,000 | $0.00 | 325,000 | D | A |
| 02 Feb, 2026 | Rachael Lester | Stock Option (Right to Buy) | A | 50,000 | $0.00 | 50,000 | D | A |
| 02 Feb, 2026 | Yu-Waye Chu | Stock Option (Right to Buy) | A | 300,000 | $0.00 | 300,000 | D | A |
| 02 Feb, 2026 | Marcia Belvin | Stock Option (Right to Buy) | A | 250,000 | $0.00 | 250,000 | D | A |
| 02 Feb, 2026 | Rachael Lester | Performance Stock Units (PSUs) | A | 50,000 | $0.00 | 50,000 | D | A |
| 02 Feb, 2026 | Sean A. Mccarthy | Stock Option (Right to Buy) | A | 980,000 | $0.00 | 980,000 | D | A |
| 06 Nov, 2025 | Sean A. Mccarthy | Class A Common Stock | D | 101,793 | $4.54 | 987,891 | D | S |
| 20 Oct, 2025 | Rachael Lester | Stock Option (Right to Buy) | A | 650,000 | $0.00 | 650,000 | D | A |
| 26 Sep, 2025 | Sean A. Mccarthy | Stock Option (Right to Buy) | A | 570,000 | $0.00 | 570,000 | D | A |
| 26 Sep, 2025 | Yu-Waye Chu | Stock Option (Right to Buy) | A | 87,500 | $0.00 | 87,500 | D | A |
| 26 Sep, 2025 | Marcia Belvin | Stock Option (Right to Buy) | A | 36,300 | $0.00 | 36,300 | D | A |