Amylyx Pharmaceuticals
Developing avexitide-led therapies for endocrine and neurodegenerative diseases.
$34.85
After-hours close+0.12 (+0.35%)
At close$34.73(−6.59%)
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Breakdown13F · Form 4
Institutions 105.29%Insiders 8.01%
A 13F quarter can total more than the shares outstanding — sub-advisers file the same block twice, and a filer's own share count can be a quarter stale. No split is drawn from it.
Shares outstanding 111.19M · Float 82.38M · 74.1% free float
Institutions13F, as of Jun 30, 2026
223 holders · 117.07M shares · 53 new positions · 125 increased · 60 reduced · 15 closed
| Holder | Shares | % outstanding | Chg q/q | Filed |
|---|---|---|---|---|
| FMR LLC | 16.73M | 15.04% | +97.4K | Aug 13, 2026 |
| BlackRock, Inc. | 8.83M | 7.94% | −1.8K | Aug 7, 2026 |
| Perceptive Advisors LLC | 8.33M | 7.50% | +50.0K | Aug 14, 2026 |
| TCG Crossover Management, LLC | 6.24M | 5.62% | 0 | Aug 14, 2026 |
| Commodore Capital LP | 5.65M | 5.08% | 0 | Aug 14, 2026 |
| Jupiter Topco LLC | 5.24M | 4.71% | +5.24Mnew | Aug 14, 2026 |
| Saturn V Capital Management LLC | 4.62M | 4.16% | +274.2K | Aug 14, 2026 |
| Vanguard Capital Management LLC | 4.22M | 3.80% | +82.6K | Aug 13, 2026 |
Beneficial owners13D/G · 5% or more, as filed
| Holder | % of class | Shares | Form | Filed |
|---|---|---|---|---|
| FMR LLC | 15.00% | 16.47M | 13G | Feb 5, 2026 ↗ |
| Perceptive Advisors LLC | 7.50% | 8.28M | 13G | May 15, 2026 ↗ |
| BlackRock, Inc. | 7.10% | 7.78M | 13G | Jan 21, 2026 ↗ |
| TCG Crossover GP II, LLC | 5.70% | 6.24M | 13G | Feb 17, 2026 ↗ |
| Commodore Capital LP | 5.10% | 5.65M | 13G | Nov 17, 2025 ↗ |
InsidersForm 4
| Insider | Role | Shares | % outstanding | Filed |
|---|---|---|---|---|
| Joshua B. Cohen | director, officer: Co-Chief Executive Officer | 3.64M | 3.28% | Aug 20, 2026 |
| Justin B. Klee | director, officer: Co-Chief Executive Officer | 3.64M | 3.28% | Aug 20, 2026 |
| George M. Jr Milne | director | 812.9K | 0.73% | Jan 14, 2026 |
| Camille L. Bedrosian | officer: Chief Medical Officer | 288.1K | 0.26% | Aug 20, 2026 |
| James M. Frates | officer: Chief Financial Officer | 244.4K | 0.22% | Aug 20, 2026 |
| Gina Mazzariello | officer: Chief Legal Officer | 200.4K | 0.18% | Aug 20, 2026 |
| Karen Firestone | director | 66.9K | 0.06% | May 26, 2026 |
| Bernhardt G. Zeiher | director | 10.0K | 0.01% | Mar 24, 2025 |
3 ten-percent owners hold 9.60M shares by Form 4, outside the officers-and-directors figure above · 6 people have not refiled in the last 18 months (6.43M shares), so they are not in the figure above
Latest trades
| Date | Insider | Type | Shares | Avg price | Owned after |
|---|---|---|---|---|---|
| Jul 10, 2026 | Gina Mazzarielloofficer: Chief Legal Officer | Sale | 15,000 | $17.61 | 179,090 |
| Jul 9, 2026 | Gina Mazzarielloofficer: Chief Legal Officer | Sale | 15,000 | $18.32 | 194,090 |
| May 21, 2026 | Karen Firestonedirector | Purchase | 3,800 | $13.51 | 66,900 |
| Mar 2, 2026 | Gina Mazzarielloofficer: Chief Legal Officer | Sale | 6,844 | $14.52 | 134,430 |
| Mar 2, 2026 | James M. Fratesofficer: Chief Financial Officer | Sale | 7,909 | $14.52 | 165,638 |
| Mar 2, 2026 | Camille L. Bedrosianofficer: Chief Medical Officer | Sale | 6,461 | $14.58 | 169,295 |
| Mar 2, 2026 | Joshua B. Cohendirector, officer: Co-Chief Executive Officer | Sale | 29,282 | $14.48 | 3,334,683 |
| Mar 2, 2026 | Justin B. Kleedirector, officer: Co-Chief Executive Officer | Sale | 29,282 | $14.47 | 3,334,616 |
| Feb 23, 2026 | Gina Mazzarielloofficer: Chief Legal Officer | Sale | 3,419 | $14.14 | 141,274 |
| Feb 2, 2026 | Justin B. Kleedirector, officer: Co-Chief Executive Officer | Sale | 15,500 | $14.69 | 3,363,898 |
CongressHouse and Senate disclosures
Not reported.