Amylyx Pharmaceuticals Inc
Ownership
Ownership Structure
Who owns Amylyx Pharmaceuticals Inc (AMLX)? This page shows the largest institutions and funds, the ownership structure and the latest insider transactions. 87.2% of the shares are freely tradable; institutional investors hold 105.3%.
Largest Shareholders
Institutions
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| FMR Inc | 14.93 | 16,630,541 | +0.7 | 03/31/2026 |
| BlackRock Inc | 7.92 | 8,828,836 | -2.5 | 03/31/2026 |
| Perceptive Advisors LLC | 7.48 | 8,334,882 | +0.6 | 06/30/2026 |
| TCG Crossover Management, LLC | 5.60 | 6,243,812 | +0.0 | 06/30/2026 |
| COMMODORE CAPITAL LP | 5.07 | 5,650,000 | +0.0 | 03/31/2026 |
| HHG PLC | 4.47 | 4,986,073 | +11.6 | 03/31/2026 |
| Saturn V Capital Management LLC | 4.15 | 4,624,101 | +6.3 | 06/30/2026 |
| Vanguard Capital Management, LLC | 3.72 | 4,141,575 | +0.0 | 03/31/2026 |
| First Light Asset Management, LLC | 2.71 | 3,023,256 | -5.2 | 06/30/2026 |
Funds
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| Vanguard MStar Total Stk Mkt Idx Invest | 2.85 | 3,172,904 | +0.6 | 07/31/2026 |
Largest reported positions according to regulatory filings; stake as a percentage of shares outstanding, change versus the previous filing. Source: fundamentals data.
Insider holdings
| Person | Role | Shares | Value | As of | Type |
|---|---|---|---|---|---|
| Cohen Joshua B | Co-Chief Executive Officer | 3,613,123 | 122,484,870 $ | Sep 10, 2026 | direct |
| Klee Justin B. | Co-Chief Executive Officer | 3,613,056 | 122,482,598 $ | Sep 10, 2026 | direct |
| Bedrosian Camille L | Chief Medical Officer | 278,064 | 9,426,370 $ | Sep 10, 2026 | direct |
| Frates James M | Chief Financial Officer | 233,625 | 7,919,888 $ | Sep 10, 2026 | direct |
| Mazzariello Gina | Chief Legal Officer | 190,838 | 6,469,408 $ | Sep 10, 2026 | direct |
| Firestone Karen | Director | 116,900 | 3,962,910 $ | Aug 31, 2026 | direct |
Holdings as of each person's most recent SEC Form 4 filing — excluding options and RSUs, which are not shares yet. Holdings may have changed between two filings.
Insiders
Insider Transactions
| Date | Person | Role | Type | Shares | Price | Value |
|---|---|---|---|---|---|---|
| Sep 10, 2026 | Bedrosian Camille L | Chief Medical Officer | Sell | 2,081 | 33.09 | 68,864 |
| Sep 10, 2026 | Bedrosian Camille L | Chief Medical Officer | Sell | 7,947 | 32.21 | 256,004 |
| Sep 10, 2026 | Frates James M | Chief Financial Officer | Sell | 1,042 | 33.23 | 34,626 |
| Sep 10, 2026 | Frates James M | Chief Financial Officer | Sell | 9,768 | 32.27 | 315,195 |
| Sep 10, 2026 | Mazzariello Gina | Chief Legal Officer | Sell | 11 | 33.34 | 367 |
| Sep 10, 2026 | Mazzariello Gina | Chief Legal Officer | Sell | 9,525 | 32.46 | 309,140 |
| Sep 10, 2026 | Cohen Joshua B | Co-Chief Executive Officer | Sell | 919 | 33.15 | 30,464 |
| Sep 10, 2026 | Cohen Joshua B | Co-Chief Executive Officer | Sell | 29,545 | 32.16 | 950,040 |
| Sep 10, 2026 | Klee Justin B. | Co-Chief Executive Officer | Sell | 1,439 | 33.16 | 47,710 |
| Sep 10, 2026 | Klee Justin B. | Co-Chief Executive Officer | Sell | 29,025 | 32.13 | 932,553 |
| Aug 31, 2026 | Firestone Karen | Director | Other | 25,000 | 5.05 | 126,250 |
| Aug 18, 2026 | Frates James M | Chief Financial Officer | Other | 22,807 | 0.00 | – |
| Aug 18, 2026 | Klee Justin B. | Co-Chief Executive Officer | Other | 60,039 | 0.00 | – |
| Aug 18, 2026 | Mazzariello Gina | Chief Legal Officer | Other | 21,284 | 0.00 | – |
| Aug 18, 2026 | Bedrosian Camille L | Chief Medical Officer | Other | 22,807 | 0.00 | – |
| Aug 18, 2026 | Cohen Joshua B | Co-Chief Executive Officer | Other | 60,039 | 0.00 | – |
| Jul 10, 2026 | Mazzariello Gina | Chief Legal Officer | Sell | 15,000 | 17.61 | 264,122 |
| Jul 9, 2026 | Mazzariello Gina | Chief Legal Officer | Sell | 15,000 | 18.32 | 274,746 |
Reportable transactions by officers and major shareholders from SEC Form 4 filings. "Other" includes things like stock grants and option exercises without a buy/sell character. View all insider transactions →
Data as of: September 17, 2026 · Source: fundamental data & SEC filings (annual and quarterly reports, 10-K/10-Q)
Note: pure fact-based analysis, not investment advice and not a solicitation to buy or sell. All figures without guarantee.