Rhythm Pharmaceuticals, Inc. has 10 Schedule 13D or 13G filings on record since 2025-08-14. 4 holders' latest filing reports 5% or more of common stock, $0.001 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 |
|---|---|---|---|---|
| RA Capital Management, L.P. | 9.9% | 6,666,837 | SCHEDULE 13G/A, 2026-02-17 | 2025-12-31 |
| Primecap Management Co | 5.21% | 3,478,669 | SCHEDULE 13G/A, 2026-02-12 | 2025-12-31 |
| Perceptive Advisors LLC | 5.1% | 3,519,626 | SCHEDULE 13G/A, 2026-05-15 | 2026-03-31 |
| Vanguard Capital Management | 5.02% | 3,432,949 | SCHEDULE 13G, 2026-04-30 | 2026-03-31 |
| The Vanguard Group | 0% | 0 | SCHEDULE 13G/A, 2026-03-27 | 2026-03-13 |
Timeline
| Filed | Holder | Percent | Filing |
|---|---|---|---|
| 2025-08-14 | Primecap Management Co | 7.67% | SCHEDULE 13G/A |
| 2025-08-14 | RA Capital Management, L.P. | 8.7% | SCHEDULE 13G/A |
| 2025-10-30 | The Vanguard Group | 7.52% | SCHEDULE 13G/A |
| 2025-11-14 | Primecap Management Co | 6.42% | SCHEDULE 13G/A |
| 2026-01-30 | The Vanguard Group | 9.3% | SCHEDULE 13G/A |
| 2026-02-12 | Primecap Management Co | 5.21% | SCHEDULE 13G/A |
| 2026-02-17 | RA Capital Management, L.P. | 9.9% | SCHEDULE 13G/A |
| 2026-03-27 | The Vanguard Group | 0% | SCHEDULE 13G/A |
| 2026-04-30 | Vanguard Capital Management | 5.02% | SCHEDULE 13G |
| 2026-05-15 | Perceptive Advisors LLC | 5.1% | SCHEDULE 13G/A |
Tools for this story
Each opens in a new tab, filled in for Rhythm Pharmaceuticals, Inc.. With no account yet, you sign up free and land on the result.
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.