As of September 29, 2026, Amylyx Pharmaceuticals's top three insider holders are Venture Investments Ltd Morningside (TenPercentOwner, 21.09Mn shares), Isaac Cheng (Director, 10.42Mn shares), Invest 1 B.V. Als (TenPercentOwner, 5.90Mn shares).
| # | Insider | Position | Direct | Indirect | Total | Share of Insiders | Last Filed |
|---|---|---|---|---|---|---|---|
| 1 | Isaac Cheng | Director | 6,578 | 10,415,650 | 10,422,228 | 32.0% | 10 Jan, 2022 |
| 2 | Invest 1 B.V. Als | TenPercentOwner | 5,895,280 | 0 | 5,895,280 | 18.1% | 08 Jul, 2022 |
| 3 | Venture Investments Ltd Morningside | TenPercentOwner | 4,997,302 | 0 | 4,997,302 | 15.4% | 17 Aug, 2023 |
| 4 | Joshua B Cohen | Co Chief Executive Officer | 3,613,123 | 0 | 3,613,123 | 11.1% | 14 Sep, 2026 |
| 5 | Justin B. Klee | Co Chief Executive Officer | 3,613,056 | 0 | 3,613,056 | 11.1% | 14 Sep, 2026 |
| 6 | Global Investors Lp Viking | TenPercentOwner | 0 | 1,850,940 | 1,850,940 | 5.7% | 09 Sep, 2022 |
| 7 | George M Jr Milne | Director | 812,881 | 0 | 812,881 | 2.5% | 14 Jan, 2026 |
| 8 | Camille L Bedrosian | Chief Medical Officer | 278,064 | 0 | 278,064 | 0.9% | 14 Sep, 2026 |
| 9 | Margaret Olinger | Chief Commercial Officer | 276,108 | 0 | 276,108 | 0.8% | 29 Dec, 2023 |
| 10 | James M Frates | Chief Financial Officer | 233,625 | 0 | 233,625 | 0.7% | 14 Sep, 2026 |
| 11 | Patrick D Yeramian | Chief Medical Officer | 205,605 | 0 | 205,605 | 0.6% | 11 Jan, 2024 |
| 12 | Gina Mazzariello | Chief Legal Officer | 190,838 | 0 | 190,838 | 0.6% | 14 Sep, 2026 |
| 13 | Karen Firestone | Director | 116,900 | 0 | 116,900 | 0.4% | 02 Sep, 2026 |
| 14 | Bernhardt G Zeiher | Director | 10,000 | 0 | 10,000 | 0.0% | 24 Mar, 2025 |
| 15 | Daphne Quimi | Director | 5,000 | 0 | 5,000 | 0.0% | 16 May, 2024 |
| 16 | Paul R. Fonteyne | Director | 3,947 | 0 | 3,947 | 0.0% | 10 Jan, 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 |
|---|---|---|---|---|---|---|---|---|
| 31 Aug, 2026 | Karen Firestone | Director | Acquired M | 25,000 | $1.76 | $44.00K | 91,900 | Direct |
| 31 Aug, 2026 | Karen Firestone | Director | Acquired M | 25,000 | $5.05 | $126.25K | 116,900 | Direct |
| 31 Aug, 2026 | Karen Firestone | Director | Disposed M | 25,000 | $0.00 | $0 | 0 | Direct |
| 31 Aug, 2026 | Karen Firestone | Director | Disposed M | 25,000 | $0.00 | $0 | 0 | Direct |
| 18 Aug, 2026 | Camille L Bedrosian | Chief Medical Officer | Acquired A | 22,807 | $0.00 | $0 | 288,092 | Direct |
| 18 Aug, 2026 | Justin B. Klee | Co Chief Executive Officer | Acquired A | 60,039 | $0.00 | $0 | 3,643,520 | Direct |
| 18 Aug, 2026 | James M Frates | Chief Financial Officer | Acquired A | 22,807 | $0.00 | $0 | 244,435 | Direct |
| 18 Aug, 2026 | Gina Mazzariello | Chief Legal Officer | Acquired A | 21,284 | $0.00 | $0 | 200,374 | Direct |
| 18 Aug, 2026 | Joshua B Cohen | Co Chief Executive Officer | Acquired A | 60,039 | $0.00 | $0 | 3,643,587 | Direct |
| 09 Jul, 2026 | Gina Mazzariello | Chief Legal Officer | Disposed S | 15,000 | $18.32 | $274.75K | 194,090 | Direct |
| 10 Jul, 2026 | Gina Mazzariello | Chief Legal Officer | Disposed S | 15,000 | $17.61 | $264.12K | 179,090 | Direct |
| 04 Jun, 2026 | Paul R. Fonteyne | Director | Acquired A | 24,372 | $0.00 | $0 | 24,372 | Direct |
| 04 Jun, 2026 | Daphne Quimi | Director | Acquired A | 24,372 | $0.00 | $0 | 24,372 | Direct |
| 04 Jun, 2026 | Bernhardt G Zeiher | Director | Acquired A | 24,372 | $0.00 | $0 | 24,372 | Direct |
| 04 Jun, 2026 | George M Jr Milne | Director | Acquired A | 24,372 | $0.00 | $0 | 24,372 | Direct |
| 04 Jun, 2026 | Karen Firestone | Director | Acquired A | 24,372 | $0.00 | $0 | 24,372 | Direct |
| 21 May, 2026 | Karen Firestone | Director | Acquired P | 3,800 | $13.51 | $51.34K | 66,900 | Direct |
| 05 Mar, 2026 | Gina Mazzariello | Chief Legal Officer | Acquired A | 74,660 | $0.00 | $0 | 209,090 | Direct |
| 05 Mar, 2026 | Joshua B Cohen | Co Chief Executive Officer | Acquired A | 248,865 | $0.00 | $0 | 3,583,548 | Direct |
| 05 Mar, 2026 | James M Frates | Chief Financial Officer | Acquired A | 95,990 | $0.00 | $0 | 261,628 | Direct |