Amylyx Pharmaceuticals, Inc. (AMLX) Ownership
AMLX ownership summary
as of October 17, 2026- Institutions
- 92.5% of shares outstanding
- Insiders
- 7.16% of shares outstanding
- Shares outstanding
- 125.5M
- Float
- 97.3M shares available to trade
- Short interest
- 12.64% 12.7M shares short
- Days to cover
- 8.18 short interest down 6.3% vs prior month
- Institutions 92.46%
- Insiders 7.16%
- Other investors 0.38%
AMLX top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | FMR Inc | 13.33% | 16.7M | $440.6M | +97,368 (+0.6%) | June 30, 2026 |
| 2 | BlackRock Inc | 7.03% | 8.8M | $232.5M | −1,751 (−0.0%) | June 30, 2026 |
| 3 | Perceptive Advisors LLC | 6.64% | 8.3M | $219.5M | +50,000 (+0.6%) | June 30, 2026 |
| 4 | TCG Crossover Management, LLC | 4.97% | 6.2M | $164.5M | — | June 30, 2026 |
| 5 | COMMODORE CAPITAL LP | 4.50% | 5.7M | $148.8M | — | June 30, 2026 |
| 6 | Jupiter Topco LLC | 4.17% | 5.2M | $137.9M | +5.2M (0.0%) | June 30, 2026 |
| 7 | HHG PLC | 3.97% | 5.0M | $131.3M | +520,201 (+11.6%) | March 31, 2026 |
| 8 | Saturn V Capital Management LLC | 3.68% | 4.6M | $121.8M | +274,216 (+6.3%) | June 30, 2026 |
| 9 | Vanguard Capital Management, LLC | 3.37% | 4.2M | $111.3M | +82,649 (+2.0%) | June 30, 2026 |
| 10 | Morgan Stanley - Brokerage Accounts | 2.49% | 3.1M | $82.5M | +955,261 (+43.9%) | June 30, 2026 |
| 11 | Driehaus Capital Management LLC | 2.42% | 3.0M | $80.0M | +49,823 (+1.7%) | June 30, 2026 |
| 12 | First Light Asset Management, LLC | 2.41% | 3.0M | $79.6M | −167,389 (−5.2%) | June 30, 2026 |
| 13 | Franklin Templeton Inc | 2.35% | 3.0M | $77.7M | +688,656 (+30.5%) | June 30, 2026 |
| 14 | The Goldman Sachs Group Inc | 2.28% | 2.9M | $75.3M | +232,248 (+8.8%) | June 30, 2026 |
| 15 | State Street Corp | 2.07% | 2.6M | $68.6M | +240,176 (+10.2%) | June 30, 2026 |
| 16 | Geode Capital Management, LLC | 1.86% | 2.3M | $61.5M | +124,383 (+5.6%) | June 30, 2026 |
| 17 | Adage Capital Partners Gp LLC | 1.51% | 1.9M | $50.0M | −1.7M (−46.6%) | June 30, 2026 |
| 18 | JPMorgan Chase & Co | 1.48% | 1.9M | $49.1M | +1.7M (+1,067.2%) | June 30, 2026 |
| 19 | 683 Capital Management LLC | 1.22% | 1.5M | $40.3M | −120,000 (−7.3%) | March 31, 2026 |
| 20 | Siren, L.L.C. | 1.18% | 1.5M | $39.0M | +250,586 (+20.4%) | June 30, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 14 holders added 10.5M shares and 4 cut 1.9M.
AMLX top mutual fund and ETF holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | Vanguard MStar Total Stk Mkt Idx Invest | 3.02% | 3.8M | $99.8M | +617,026 (+19.4%) | August 31, 2026 |
| 2 | iShares Russell 2000 ETF | 2.15% | 2.7M | $71.0M | −17,953 (−0.7%) | September 30, 2026 |
| 3 | Fidelity Advisor Biotechnology I | 1.94% | 2.4M | $64.1M | — | August 31, 2026 |
| 4 | Fidelity Small Cap Growth | 1.69% | 2.1M | $55.7M | — | July 31, 2026 |
| 5 | Franklin Biotechnology Discv A(acc)USD | 1.37% | 1.7M | $45.2M | +323,189 (+23.2%) | August 31, 2026 |
| 6 | Fidelity Select Health Care | 1.27% | 1.6M | $42.1M | +180,000 (+12.7%) | August 31, 2026 |
| 7 | Fidelity Select Biotechnology | 1.17% | 1.5M | $38.7M | +372,942 (+34.0%) | August 31, 2026 |
| 8 | Eventide Healthcare & Life Sciences I | 1.06% | 1.3M | $34.9M | −187,450 (−12.4%) | June 30, 2026 |
| 9 | Strategic Advisers Fidelity US TtlStk | 1.04% | 1.3M | $34.5M | +173,200 (+15.2%) | August 31, 2026 |
| 10 | Fidelity Stock Selector Small Cap | 1.00% | 1.3M | $33.1M | +118 (+0.0%) | July 31, 2026 |
| 11 | Xtrackers S&P 500 Swap ETF 1C | 0.99% | 1.2M | $32.7M | −9,147 (−0.7%) | December 31, 2025 |
| 12 | Janus Henderson Hrzn Biotec E2 USD | 0.86% | 1.1M | $28.4M | +43,263 (+4.2%) | June 30, 2026 |
| 13 | Fidelity Small Cap Growth K6 | 0.84% | 1.1M | $27.7M | — | July 31, 2026 |
| 14 | Fidelity Small Cap Index | 0.80% | 1.0M | $26.5M | +8,692 (+0.9%) | July 31, 2026 |
| 15 | Fidelity Series Small Cap Opps | 0.80% | 1.0M | $26.5M | — | July 31, 2026 |
| 16 | iShares Russell 2000 Growth ETF | 0.77% | 968K | $25.5M | −1,226 (−0.1%) | September 30, 2026 |
| 17 | JPMorgan Mid Cap Growth I | 0.75% | 945K | $24.9M | +944,543 (0.0%) | August 31, 2026 |
| 18 | Franklin Biotechnology Discovery A | 0.74% | 928K | $24.4M | +175,240 (+23.3%) | August 31, 2026 |
| 19 | T. Rowe Price Health Sciences | 0.70% | 884K | $23.3M | +883,600 (0.0%) | August 31, 2026 |
| 20 | Fidelity Balanced | 0.70% | 879K | $23.2M | −680 (−0.1%) | July 31, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
AMLX insider transactions
latest 12| Date | Name | Transaction | Price | Shares | Value |
|---|---|---|---|---|---|
| 2026-01-16 | Joshua B Cohen | Sell | $13.83 | 1,974 | $27,300 |
| 2026-01-16 | Justin B Klee | Sell | $13.89 | 1,995 | $27,711 |
| 2026-01-15 | Joshua B Cohen | Sell | $13.59 | 136,193 | $1.9M |
| 2026-01-06 | James M Frates | Sell | $11.11 | 3,326 | $36,952 |
| 2026-01-06 | Joshua B Cohen | Sell | $11.09 | 7,715 | $85,559 |
| 2025-12-23 | Karen Firestone | Buy | $12.45 | 8,100 | $100,845 |
| 2025-12-01 | Camille L Bedrosian | Sell | $14.35 | 6,580 | $94,423 |
| 2025-09-30 | Camille L Bedrosian | Sell | $14.58 | 12,039 | $175,529 |
| 2025-09-30 | Gina Mazzariello | Sell | $14.58 | 8,828 | $128,712 |
| 2025-09-30 | James M Frates | Sell | $14.65 | 10,558 | $154,675 |
| 2025-09-30 | Joshua B Cohen | Sell | $14.35 | 29,933 | $429,539 |
| 2025-09-30 | Justin B Klee | Sell | $14.38 | 29,975 | $431,040 |
Reported trades by company officers, directors and other filers (including disclosures by members of Congress where EODHD lists them). "—" where the filing gives no share count.
AMLX shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns AMLX
Institutional investors own 92.5% of Amylyx Pharmaceuticals's shares and insiders 7.16%. The largest holder is FMR Inc with 13.33% of the shares (16.7M), as of June 30, 2026. Among the top 20 institutions, 14 added shares and 4 reduced their stake in the latest filings. Short interest is 12.64% of the float, or 8.18 days of average trading volume. The share count rose 105.8% since 2020.
Related: AMLX analyst forecast, AMLX key metrics. See the AMLX stock overview for the latest quote and news.
AMLX ownership FAQ
Who owns the most Amylyx Pharmaceuticals stock?
The largest shareholders of Amylyx Pharmaceuticals are FMR Inc (13.33%), BlackRock Inc (7.03%), Perceptive Advisors LLC (6.64%), TCG Crossover Management, LLC (4.97%), COMMODORE CAPITAL LP (4.50%).
What percentage of Amylyx Pharmaceuticals is owned by institutions?
Institutions hold 92.5% of Amylyx Pharmaceuticals's shares outstanding; insiders hold 7.16%.
Which funds own Amylyx Pharmaceuticals?
The largest fund holders of Amylyx Pharmaceuticals are Vanguard MStar Total Stk Mkt Idx Invest (3.02%), iShares Russell 2000 ETF (2.15%), Fidelity Advisor Biotechnology I (1.94%), Fidelity Small Cap Growth (1.69%), Franklin Biotechnology Discv A(acc)USD (1.37%).
What is Amylyx Pharmaceuticals's short interest?
12.7M shares of Amylyx Pharmaceuticals were sold short, 12.64% of the float; at the average daily volume it would take 8.18 days to cover.
Are insiders buying or selling Amylyx Pharmaceuticals?
Of the latest 12 reported insider transactions in Amylyx Pharmaceuticals (since September 30, 2025), 1 were purchases and 11 were sales.
How many shares of Amylyx Pharmaceuticals are outstanding?
Amylyx Pharmaceuticals has 125.5M shares outstanding, of which 97.3M are in the public float.