As of November 6, 2026, 5 holders' latest Schedule 13D or 13G filings report owning 5% or more of Amylyx Pharmaceuticals, Inc. The largest reported stake is Fmr LLC's, at 15%. 16 filings are on record since July 17, 2025 (Schedule 13G/A, February 5, 2026).
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Key facts
- · Reporting person: Perceptive Advisors LLC · Sole voting: 0 · Shared voting: 8,284,882 · Sole dispositive: 0 · Shared dispositive: 8,284,882 · SCHEDULE 13G/A, 2026-05-15
- · Reporting person: The Vanguard Group · Sole voting: 0 · Shared voting: 0 · Sole dispositive: 0 · Shared dispositive: 0 · SCHEDULE 13G/A, 2026-03-26
- · Reporting person: TCG Crossover GP II, LLC · Sole voting: 0 · Shared voting: 6,243,812 · Sole dispositive: 0 · Shared dispositive: 6,243,812 · SCHEDULE 13G/A, 2026-02-17
- · Reporting person: Adage Capital Management, L.P. · Sole voting: 0 · Shared voting: 2,777,055 · Sole dispositive: 0 · Shared dispositive: 2,777,055 · SCHEDULE 13G/A, 2026-02-12
- · Holder: Fmr LLC · Percent: 15% · SCHEDULE 13G/A
Amylyx Pharmaceuticals, Inc. has 16 Schedule 13D or 13G filings on record since 2025-07-17. 5 holders' latest filing reports 5% or more of common stock, $0.0001 par value per share. Each figure below is the holder's own, as filed, with the filing linked.
Holders
| Holder | Percent | Shares | Latest | Event date |
|---|---|---|---|---|
| Fmr LLC | 15% | 16,468,419 | SCHEDULE 13G/A, 2026-02-05 | 2025-12-31 |
| Perceptive Advisors LLC | 7.5% | 8,284,882 | SCHEDULE 13G/A, 2026-05-15 | 2026-03-31 |
| BlackRock, Inc. | 7.1% | 7,783,648 | SCHEDULE 13G/A, 2026-01-21 | 2025-12-31 |
| TCG Crossover GP II, LLC | 5.7% | 6,243,812 | SCHEDULE 13G/A, 2026-02-17 | 2025-12-31 |
| Commodore Capital LP | 5.1% | 5,650,000 | SCHEDULE 13G, 2025-11-17 | 2025-11-10 |
| Point72 Asset Management, L.P. | 2.6% | 2,801,636 | SCHEDULE 13G/A, 2025-11-14 | 2025-09-30 |
| Adage Capital Management, L.P. | 2.53% | 2,777,055 | SCHEDULE 13G/A, 2026-02-12 | 2025-12-31 |
| The Vanguard Group | 0% | 0 | SCHEDULE 13G/A, 2026-03-26 | 2026-03-13 |
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More on Amylyx Pharmaceuticals, Inc. and the records around it.
Amylyx Pharmaceuticals, Inc. elsewhere on the record
Companies that share a holder
- TCG Crossover GP II, LLC also filed stake reports on 21 other companies: ALX Oncology Holdings Inc. (Aug 2026), First Tracks Biotherapeutics, Inc. (Aug 2026), Fulcrum Therapeutics, Inc. (Aug 2026)
- Commodore Capital LP also filed stake reports on 40 other companies: Sagimet Biosciences Inc. (Oct 2026), Surrozen, Inc./DE (Oct 2026), JATT III Acquisition Corp (Sep 2026)
- Perceptive Advisors LLC also filed stake reports on 57 other companies: Nautilus Biotechnology, Inc. (Nov 2026), Athira Pharma, Inc. (Oct 2026), IRulya Therapeutics Inc. (Oct 2026)
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Voting and dispositive power, as filed
| Reporting person | Sole voting | Shared voting | Sole dispositive | Shared dispositive | Filing |
|---|---|---|---|---|---|
| Perceptive Advisors LLC | 0 | 8,284,882 | 0 | 8,284,882 | SCHEDULE 13G/A, 2026-05-15 |
| Joseph Edelman | 0 | 8,284,882 | 0 | 8,284,882 | SCHEDULE 13G/A, 2026-05-15 |
| Perceptive Life Sciences Master Fund, Ltd. | 0 | 8,284,882 | 0 | 8,284,882 | SCHEDULE 13G/A, 2026-05-15 |
| TCG Crossover GP II, LLC | 0 | 6,243,812 | 0 | 6,243,812 | SCHEDULE 13G/A, 2026-02-17 |
| TCG Crossover Fund II, L.P. | 0 | 6,243,812 | 0 | 6,243,812 | SCHEDULE 13G/A, 2026-02-17 |
| Chen Yu | 0 | 6,243,812 | 0 | 6,243,812 | SCHEDULE 13G/A, 2026-02-17 |
| Adage Capital Management, L.P. | 0 | 2,777,055 | 0 | 2,777,055 | SCHEDULE 13G/A, 2026-02-12 |
| Robert Atchinson | 0 | 2,777,055 | 0 | 2,777,055 | SCHEDULE 13G/A, 2026-02-12 |
| Phillip Gross | 0 | 2,777,055 | 0 | 2,777,055 | SCHEDULE 13G/A, 2026-02-12 |
| The Vanguard Group | 0 | 0 | 0 | 0 | SCHEDULE 13G/A, 2026-03-26 |
The latest filing identifies Amylyx Pharmaceuticals, Inc. by CUSIP 03237H101 and gives its principal executive office as 43 Thorndike St., Cambridge, MA 02141 (SCHEDULE 13G/A, 2026-05-15).
Timeline
| Filed | Holder | Percent | Filing |
|---|---|---|---|
| 2025-07-17 | BlackRock, Inc. | 5.5% | SCHEDULE 13G |
| 2025-07-29 | The Vanguard Group | 5.04% | SCHEDULE 13G |
| 2025-08-12 | Adage Capital Management, L.P. | 9.87% | SCHEDULE 13G/A |
| 2025-10-07 | Fmr LLC | 10.7% | SCHEDULE 13G |
| 2025-10-30 | The Vanguard Group | 4.94% | SCHEDULE 13G/A |
| 2025-11-13 | Adage Capital Management, L.P. | 6.39% | SCHEDULE 13G/A |
| 2025-11-14 | Point72 Asset Management, L.P. | 2.6% | SCHEDULE 13G/A |
| 2025-11-14 | Perceptive Advisors LLC | 8.2% | SCHEDULE 13G/A |
| 2025-11-17 | Commodore Capital LP | 5.1% | SCHEDULE 13G |
| 2026-01-21 | BlackRock, Inc. | 7.1% | SCHEDULE 13G/A |
| 2026-01-30 | The Vanguard Group | 5.28% | SCHEDULE 13G |
| 2026-02-05 | Fmr LLC | 15% | SCHEDULE 13G/A |
| 2026-02-12 | Adage Capital Management, L.P. | 2.53% | SCHEDULE 13G/A |
| 2026-02-17 | TCG Crossover GP II, LLC | 5.7% | SCHEDULE 13G/A |
| 2026-03-26 | The Vanguard Group | 0% | SCHEDULE 13G/A |
| 2026-05-15 | Perceptive Advisors LLC | 7.5% | SCHEDULE 13G/A |
Questions about who owns Amylyx Pharmaceuticals, Inc.
Who owns Amylyx Pharmaceuticals, Inc.?
On this page, 5 holders' latest ownership filings report 5% or more of Amylyx Pharmaceuticals, Inc.: Fmr LLC (15%, Schedule 13G/A, filed 2026-02-05), Perceptive Advisors LLC (7.5%, Schedule 13G/A, filed 2026-05-15), BlackRock, Inc. (7.1%, Schedule 13G/A, filed 2026-01-21), TCG Crossover GP II, LLC (5.7%, Schedule 13G/A, filed 2026-02-17) and Commodore Capital LP (5.1%, Schedule 13G, filed 2025-11-17).
Who are the largest shareholders of Amylyx Pharmaceuticals, Inc.?
By the share each holder's latest filing reports, the largest holders of Amylyx Pharmaceuticals, Inc. on this page are Fmr LLC (15%), Perceptive Advisors LLC (7.5%) and BlackRock, Inc. (7.1%).
When did Fmr LLC buy into Amylyx Pharmaceuticals, Inc.?
The filings give report dates, not purchase dates. The earliest filing from Fmr LLC on this page is the Schedule 13G, filed 2025-10-07, reporting 10.7%; its latest, Schedule 13G/A filed 2026-02-05, reports 15%.
Is this an audit or a full list?
Neither. The ownership list on this page covers only Schedule 13D and 13G filings, which holders make once they own 5% or more of a class of shares (an amendment can report a stake that has since fallen below 5%); 16 such filings are shown here. It is not an audit and not a full cap table: holders who never reached 5% are not listed, and a stake can change after its latest filing.
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Where this comes from
Anyone who comes to own more than 5% of a class of a listed company's voting shares has to tell the SEC. A holder who may seek to change or influence the company files Schedule 13D, and has to say in Item 4, "Purpose of Transaction", what it intends to do. A holder with no such intent, such as many index and passive funds, may file the shorter Schedule 13G. Both are amended when the stake changes, including when it falls below 5%.
Every row here is one of those filings, linked to the filing itself. Percentages and share counts are exactly as the holder filed them, for the holder the filing names; an amendment showing a lower figure is shown as filed. Item 4 text is quoted word for word. Where a 13D's Item 4 contains a sentence stating a definite intent to influence the company, that sentence is marked and quoted; the page does not describe the holder or its motives beyond the words it filed. Nothing here is investment advice.