As of November 6, 2026, 3 holders' latest Schedule 13D or 13G filings report owning 5% or more of Disc Medicine, Inc. The largest reported stake is Fmr LLC's, at 12.8%. 10 filings are on record since August 7, 2025 (Schedule 13G/A, August 6, 2026).
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Key facts
- · Reporting person: Ai Dmi LLC · Sole voting: 2,943,410 · Shared voting: 0 · Sole dispositive: 2,943,410 · Shared dispositive: 0 · SCHEDULE 13D/A, 2026-10-26
- · Reporting person: Fmr LLC · Sole voting: 4,875,263 · Shared voting: 0 · Sole dispositive: 4,875,473 · Shared dispositive: 0 · SCHEDULE 13G/A, 2026-08-06
- · Reporting person: RA Capital Management, L.P. · Sole voting: 0 · Shared voting: 2,228,924 · Sole dispositive: 0 · Shared dispositive: 2,228,924 · SCHEDULE 13G, 2026-01-07
- · Reporting person: Atlas Venture Fund X, L.P. · Sole voting: 0 · Shared voting: 813,167 · Sole dispositive: 0 · Shared dispositive: 813,167 · SCHEDULE 13D/A, 2025-12-17
- · Holder: Fmr LLC · Percent: 14.1% · SCHEDULE 13G/A
Disc Medicine, Inc. has 10 Schedule 13D or 13G filings on record since 2025-08-07. 3 holders' latest filing reports 5% or more of common stock, par value $0.0001 per share. Each figure below is the holder's own, as filed, with the filing linked.
Layoffs on record: 1 filing or notice, latest 2026-02-27 (layoff filings and notices).
Holders
| Holder | Percent | Shares | Latest | Event date |
|---|---|---|---|---|
| Fmr LLC | 12.8% | 4,875,473 | SCHEDULE 13G/A, 2026-08-06 | 2026-06-30 |
| Ai Dmi LLC | 6.6% | 2,943,410 | SCHEDULE 13D/A, 2026-10-26 | 2026-10-22 |
| RA Capital Management, L.P. | 5.9% | 2,228,924 | SCHEDULE 13G, 2026-01-07 | 2025-12-30 |
| Wellington Management Group LLP | 4.1% | 1,432,090 | SCHEDULE 13G/A, 2025-08-12 | 2025-06-30 |
| Frazier Life Sciences Public Fund, L.P. | 3% | 1,026,489 | SCHEDULE 13G/A, 2025-08-14 | 2025-06-30 |
| Atlas Venture Fund X, L.P. | 2.2% | 813,167 | SCHEDULE 13D/A, 2025-12-17 | 2025-12-12 |
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More on Disc Medicine, Inc. and the records around it.
Disc Medicine, Inc. elsewhere on the record
- Layoff notices Feb 2026
- Who owns it
Companies that share a holder
- Atlas Venture Fund X, L.P. also filed stake reports on 5 other companies: Kymera Therapeutics, Inc. (Aug 2026), Obsidian Therapeutics, Inc. (Aug 2026), Q32 Bio Inc. (May 2026)
- Frazier Life Sciences Public Fund, L.P. also filed stake reports on 25 other companies: PHATHOM PHARMACEUTICALS, INC. (Nov 2026), Q32 Bio Inc. (Oct 2026), ACLARIS THERAPEUTICS, INC. (Sep 2026)
- RA Capital Management, L.P. also filed stake reports on 100 other companies: Climb Bio, Inc. (Nov 2026), Bambusa Therapeutics, Inc. (Nov 2026), SOLID BIOSCIENCES INC. (Nov 2026)
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What the Full Report on Disc Medicine, Inc. covers
The Short Answer
Which Company This Is
What They Do, And How The Money Works
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The Money: Funding, Valuation, Runway
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Warning Bells
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Voting and dispositive power, as filed
| Reporting person | Sole voting | Shared voting | Sole dispositive | Shared dispositive | Filing |
|---|---|---|---|---|---|
| Fmr LLC | 4,875,263 | 0 | 4,875,473 | 0 | SCHEDULE 13G/A, 2026-08-06 |
| Abigail P. Johnson | 0 | 0 | 4,875,473 | 0 | SCHEDULE 13G/A, 2026-08-06 |
| Ai Dmi LLC | 2,943,410 | 0 | 2,943,410 | 0 | SCHEDULE 13D/A, 2026-10-26 |
| Access Industries Holdings LLC | 0 | 2,943,410 | 0 | 2,943,410 | SCHEDULE 13D/A, 2026-10-26 |
| Access Industries Management, LLC | 0 | 2,943,410 | 0 | 2,943,410 | SCHEDULE 13D/A, 2026-10-26 |
| Len Blavatnik | 0 | 2,943,410 | 0 | 2,943,410 | SCHEDULE 13D/A, 2026-10-26 |
| RA Capital Management, L.P. | 0 | 2,228,924 | 0 | 2,228,924 | SCHEDULE 13G, 2026-01-07 |
| Peter Kolchinsky | 0 | 2,228,924 | 0 | 2,228,924 | SCHEDULE 13G, 2026-01-07 |
| Rajeev Shah | 0 | 2,228,924 | 0 | 2,228,924 | SCHEDULE 13G, 2026-01-07 |
| RA Capital Healthcare Fund, L.P. | 0 | 2,228,924 | 0 | 2,228,924 | SCHEDULE 13G, 2026-01-07 |
| Atlas Venture Fund X, L.P. | 0 | 813,167 | 0 | 813,167 | SCHEDULE 13D/A, 2025-12-17 |
| Atlas Venture Associates X, L.P. | 0 | 813,167 | 0 | 813,167 | SCHEDULE 13D/A, 2025-12-17 |
| Atlas Venture Associates X, LLC | 0 | 813,167 | 0 | 813,167 | SCHEDULE 13D/A, 2025-12-17 |
| Atlas Venture Fund XII, L.P. | 0 | 14,013 | 0 | 14,013 | SCHEDULE 13D/A, 2025-12-17 |
| Atlas Venture Associates XII, L.P. | 0 | 14,013 | 0 | 14,013 | SCHEDULE 13D/A, 2025-12-17 |
| Atlas Venture Associates XII, LLC | 0 | 14,013 | 0 | 14,013 | SCHEDULE 13D/A, 2025-12-17 |
| Atlas Venture Opportunity Fund I, L.P. | 0 | 349,210 | 0 | 349,210 | SCHEDULE 13D/A, 2025-12-17 |
| Atlas Venture Associates Opportunity I, L.P. | 0 | 349,210 | 0 | 349,210 | SCHEDULE 13D/A, 2025-12-17 |
| Atlas Venture Associates Opportunity I, LLC | 0 | 349,210 | 0 | 349,210 | SCHEDULE 13D/A, 2025-12-17 |
| Atlas Venture Opportunity Fund II, L.P. | 0 | 337,485 | 0 | 337,485 | SCHEDULE 13D/A, 2025-12-17 |
| Atlas Venture Associates Opportunity II, LP | 0 | 337,485 | 0 | 337,485 | SCHEDULE 13D/A, 2025-12-17 |
| Atlas Venture Associates Opportunity II, LLC | 0 | 337,485 | 0 | 337,485 | SCHEDULE 13D/A, 2025-12-17 |
The latest filing identifies Disc Medicine, Inc. by CUSIP 254604101 and gives its principal executive office as 321 Arsenal Street, Suite 101, Watertown, MA 02472 (SCHEDULE 13D/A, 2026-10-26).
What the percentages are based on
Row 11 of each Reporting Person's cover page to this Schedule 13G sets forth the percentages of shares of common stock of the Issuer beneficially owned by such Reporting Person and is incorporated by reference.RA Capital Management, L.P., SCHEDULE 13G, 2026-01-07
Timeline
| Filed | Holder | Percent | Filing |
|---|---|---|---|
| 2025-08-07 | Fmr LLC | 12.2% | SCHEDULE 13G/A |
| 2025-08-12 | Wellington Management Group LLP | 4.1% | SCHEDULE 13G/A |
| 2025-08-14 | Frazier Life Sciences Public Fund, L.P. | 3% | SCHEDULE 13G/A |
| 2025-08-15 | Atlas Venture Fund X, L.P. | 3.1% | SCHEDULE 13D/A |
| 2025-10-22 | Ai Dmi LLC | 8% | SCHEDULE 13D/A |
| 2025-11-05 | Fmr LLC | 14.1% | SCHEDULE 13G/A |
| 2025-12-17 | Atlas Venture Fund X, L.P. | 2.2% | SCHEDULE 13D/A |
| 2026-01-07 | RA Capital Management, L.P. | 5.9% | SCHEDULE 13G |
| 2026-08-06 | Fmr LLC | 12.8% | SCHEDULE 13G/A |
| 2026-10-26 | Ai Dmi LLC | 6.6% | SCHEDULE 13D/A |
Questions about who owns Disc Medicine, Inc.
Who owns Disc Medicine, Inc.?
On this page, 3 holders' latest ownership filings report 5% or more of Disc Medicine, Inc.: Fmr LLC (12.8%, Schedule 13G/A, filed 2026-08-06), Ai Dmi LLC (6.6%, Schedule 13D/A, filed 2026-10-26) and RA Capital Management, L.P. (5.9%, Schedule 13G, filed 2026-01-07).
Who are the largest shareholders of Disc Medicine, Inc.?
By the share each holder's latest filing reports, the largest holders of Disc Medicine, Inc. on this page are Fmr LLC (12.8%), Ai Dmi LLC (6.6%) and RA Capital Management, L.P. (5.9%).
When did Fmr LLC buy into Disc Medicine, Inc.?
The filings give report dates, not purchase dates. The earliest filing from Fmr LLC on this page is the Schedule 13G/A, filed 2025-08-07, reporting 12.2%; its latest, Schedule 13G/A filed 2026-08-06, reports 12.8%. That earliest filing is itself an amendment, which updates an earlier report.
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%); 10 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.