Amylyx Pharmaceuticals's three largest insider shareholders as of September 09, 2026 are Venture Investments Ltd Morningside (TenPercentOwner, 21.09Mn shares), Venture Investments Ltd Morningside (TenPercentOwner, 21.09Mn shares), Venture Investments Ltd Morningside (TenPercentOwner, 21.09Mn 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 | 15.3% | 17 Aug, 2023 |
| 4 | Joshua B Cohen | Co Chief Executive Officer | 3,643,587 | 0 | 3,643,587 | 11.2% | 20 Aug, 2026 |
| 5 | Justin B. Klee | Co Chief Executive Officer | 3,643,520 | 0 | 3,643,520 | 11.2% | 20 Aug, 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 | 288,092 | 0 | 288,092 | 0.9% | 20 Aug, 2026 |
| 9 | Margaret Olinger | Chief Commercial Officer | 276,108 | 0 | 276,108 | 0.8% | 29 Dec, 2023 |
| 10 | James M Frates | Chief Financial Officer | 244,435 | 0 | 244,435 | 0.7% | 20 Aug, 2026 |
| 11 | Patrick D Yeramian | Chief Medical Officer | 205,605 | 0 | 205,605 | 0.6% | 11 Jan, 2024 |
| 12 | Gina Mazzariello | Chief Legal Officer | 200,374 | 0 | 200,374 | 0.6% | 20 Aug, 2026 |
| 13 | Karen Firestone | Director | 116,900 | 0 | 116,900 | 0.4% | 02 Sep, 2026 |
| 14 | Daphne Quimi | Director | 5,000 | 0 | 5,000 | 0.0% | 16 May, 2024 |
| 15 | 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 |
|---|---|---|---|---|---|---|---|---|
| 18 Aug, 2026 | Camille L Bedrosian | Chief Medical Officer | Acquired A | 22,807 | $0.00 | $0 | 288,092 | Direct |
| 18 Aug, 2026 | Joshua B Cohen | Co Chief Executive Officer | Acquired A | 60,039 | $0.00 | $0 | 3,643,587 | Direct |
| 18 Aug, 2026 | James M Frates | Chief Financial Officer | Acquired A | 22,807 | $0.00 | $0 | 244,435 | 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 | Gina Mazzariello | Chief Legal Officer | Acquired A | 21,284 | $0.00 | $0 | 200,374 | 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 | George M Jr Milne | 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 | 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 | Justin B. Klee | Co Chief Executive Officer | Acquired A | 248,865 | $0.00 | $0 | 3,583,481 | 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 |
| 05 Mar, 2026 | Justin B. Klee | Co Chief Executive Officer | Acquired A | 373,295 | $0.00 | $0 | 373,295 | Direct |
| 05 Mar, 2026 | Gina Mazzariello | Chief Legal Officer | Acquired A | 111,990 | $0.00 | $0 | 111,990 | Direct |
| 05 Mar, 2026 | Joshua B Cohen | Co Chief Executive Officer | Acquired A | 373,295 | $0.00 | $0 | 373,295 | Direct |
| 05 Mar, 2026 | James M Frates | Chief Financial Officer | Acquired A | 143,985 | $0.00 | $0 | 143,985 | Direct |