As of September 29, 2026, the three largest insider holders of ATRA are Capital, Llc Ecor1 (TenPercentOwner, 1.55Mn shares), Capital Fund I Lp Adiumentum (Director, 1.21Mn shares), Innovation Ltd Panacea (TenPercentOwner, 1.01Mn shares).
| # | Insider | Position | Direct | Indirect | Total | Share of Insiders | Last Filed |
|---|---|---|---|---|---|---|---|
| 1 | Capital, Llc Ecor1 | TenPercentOwner | 0 | 1,552,000 | 1,552,000 | 30.1% | 11 May, 2026 |
| 2 | Capital Fund I Lp Adiumentum | Director, TenPercentOwner, Other | 1,209,395 | 0 | 1,209,395 | 23.4% | 16 May, 2025 |
| 3 | Innovation Ltd Panacea | TenPercentOwner | 0 | 1,011,000 | 1,011,000 | 19.6% | 11 May, 2026 |
| 4 | Group, Llc Redmile | Director | 0 | 636,852 | 636,852 | 12.3% | 24 Jul, 2026 |
| 5 | Brian N Cherry | Director | 166,486 | 0 | 166,486 | 3.2% | 04 Sep, 2026 |
| 6 | Anhco Nguyen | President And Ceo | 132,775 | 0 | 132,775 | 2.6% | 26 Aug, 2026 |
| 7 | Pascal Touchon | President And Ceo | 77,955 | 0 | 77,955 | 1.5% | 12 Jun, 2025 |
| 8 | Eric J Hyllengren | Evp, Cfo And Coo | 56,231 | 0 | 56,231 | 1.1% | 05 Mar, 2025 |
| 9 | Yanina Grant-Huerta | Chief Accounting Officer | 49,636 | 0 | 49,636 | 1.0% | 20 May, 2026 |
| 10 | William K Heiden | Director | 34,188 | 0 | 34,188 | 0.7% | 11 Jun, 2026 |
| 11 | Carol Giltner Gallagher | Director | 33,012 | 0 | 33,012 | 0.6% | 12 Jun, 2025 |
| 12 | Matthew K Fust | Director | 30,188 | 0 | 30,188 | 0.6% | 11 Jun, 2026 |
| 13 | Amar Murugan | Evp, Chief Legal Officer | 26,827 | 0 | 26,827 | 0.5% | 20 Aug, 2024 |
| 14 | Eric Dobmeier | Director | 22,533 | 0 | 22,533 | 0.4% | 14 Nov, 2023 |
| 15 | Jill Henrich | Evp, Chief Regulatory Officer | 18,679 | 0 | 18,679 | 0.4% | 05 Mar, 2025 |
| 16 | Maria Grazia Roncarolo | Director | 17,368 | 0 | 17,368 | 0.3% | 12 Jun, 2025 |
| 17 | Ameet Mallik | Director | 16,928 | 0 | 16,928 | 0.3% | 12 Jun, 2025 |
| 18 | Gregory Austin Ciongoli | Director, TenPercentOwner, Other | 12,000 | 0 | 12,000 | 0.2% | 11 Jun, 2026 |
| 19 | Jakob Dupont | Evp, Head Of Rd | 11,632 | 0 | 11,632 | 0.2% | 06 Mar, 2023 |
| 20 | Charlene A. Banard | Evp, Chief Technical Officer | 11,040 | 0 | 11,040 | 0.2% | 18 May, 2023 |
| 21 | Utpal Koppikar | Chief Financial Officer | 7,279 | 0 | 7,279 | 0.1% | 06 Mar, 2023 |
| 22 | Kristin Yarema | Chief Commercial Officer | 6,857 | 0 | 6,857 | 0.1% | 03 Mar, 2022 |
| 23 | Manher Joshi | Evp, Chief Medical Officer | 6,851 | 0 | 6,851 | 0.1% | 20 Nov, 2023 |
| 24 | Beth C Seidenberg | Director | 4,628 | 0 | 4,628 | 0.1% | 02 Jun, 2023 |
| 25 | Joe Newell | Chief Operations Officer | 4,524 | 0 | 4,524 | 0.1% | 18 Nov, 2021 |
| 26 | Roy D. Baynes | Director | 1,740 | 0 | 1,740 | 0.0% | 27 Jun, 2022 |
| 27 | Ronald C Jr Renaud | Director | 1,260 | 0 | 1,260 | 0.0% | 27 Jun, 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 |
|---|---|---|---|---|---|---|---|---|
| 04 Sep, 2026 | Brian N Cherry | Director | Acquired P | 104,166 | $9.60 | $999.99K | 166,486 | Direct |
| 17 Aug, 2026 | Anhco Nguyen | President And Ceo | Disposed S | 5,062 | $8.08 | $40.88K | 132,775 | Direct |
| 22 Jul, 2026 | Group, Llc Redmile | Director | Acquired M | 195,211 | — | — | 636,912 | Indirect |
| 22 Jul, 2026 | Group, Llc Redmile | Director | Disposed F | 60 | — | — | 636,852 | Indirect |
| 22 Jul, 2026 | Group, Llc Redmile | Director | Disposed M | 101,089 | $0.00 | $0 | 0 | Indirect |
| 22 Jul, 2026 | Group, Llc Redmile | Director | Disposed M | 38,735 | $0.00 | $0 | 0 | Indirect |
| 22 Jul, 2026 | Group, Llc Redmile | Director | Disposed M | 55,387 | $0.00 | $0 | 0 | Indirect |
| 11 Jun, 2026 | Brian N Cherry | Director | Acquired A | 24,000 | $0.00 | $0 | 62,320 | Direct |
| 09 Jun, 2026 | William K Heiden | Director | Acquired A | 12,000 | $0.00 | $0 | 34,188 | Direct |
| 09 Jun, 2026 | Gregory Austin Ciongoli | Director, TenPercentOwner, Other | Acquired A | 12,000 | $0.00 | $0 | 12,000 | Direct |
| 09 Jun, 2026 | Matthew K Fust | Director | Acquired A | 12,000 | $0.00 | $0 | 30,188 | Direct |
| 18 May, 2026 | Yanina Grant-Huerta | Chief Accounting Officer | Disposed S | 2,414 | $9.13 | $22.04K | 49,636 | Direct |
| 18 May, 2026 | Anhco Nguyen | President And Ceo | Disposed S | 5,241 | $9.13 | $47.84K | 137,837 | Direct |
| 07 May, 2026 | Innovation Ltd Panacea | TenPercentOwner | Disposed S | 313,446 | $10.10 | $3.17Mn | 1,011,000 | Indirect |
| 07 May, 2026 | Capital, Llc Ecor1 | TenPercentOwner | Acquired P | 507,407 | $9.35 | $4.74Mn | 1,552,000 | Indirect |
| 17 Mar, 2026 | Innovation Ltd Panacea | TenPercentOwner | Acquired M | 259,163 | $0.00 | $26 | 307,899 | Indirect |
| 17 Mar, 2026 | Innovation Ltd Panacea | TenPercentOwner | Disposed F | 5 | $5.23 | $26 | 307,894 | Indirect |
| 17 Mar, 2026 | Innovation Ltd Panacea | TenPercentOwner | Disposed M | 259,163 | $6.61 | $1.71Mn | 0 | Indirect |
| 09 Mar, 2026 | Yanina Grant-Huerta | Chief Accounting Officer | Acquired A | 20,300 | $0.00 | $0 | 52,050 | Direct |
| 09 Mar, 2026 | Anhco Nguyen | President And Ceo | Acquired A | 81,100 | $0.00 | $0 | 143,078 | Direct |