Rhythm Pharmaceuticals, Inc.
RYTM- Exchange
- Nasdaq
- Industry
- Pharmaceutical Preparations
- SEC CIK
- 0001649904
In the last 90 days, Rhythm Pharmaceuticals, Inc. insiders filed 0 open-market purchases and 6 sales; 304 institutions reported holding it in 13F filings for Q2 2026, worth $8.55B in total; Duquesne Family Office is the only superinvestor holding it.
Holders of 5% or more of RYTM
Holders whose latest Schedule 13D or 13G filing reports 5% or more of Rhythm Pharmaceuticals, Inc., largest stake first. The change is against the holder's previous filing.
| Holder | Latest form | Stake | Change | First filed | Latest filing | Filing |
|---|---|---|---|---|---|---|
| Baker Bros. Advisors LP | 13G/A | 8.90%5.60M shares | – | May 15, 20251 filing | May 15, 2025 | SEC |
| Ra Capital Management, L.P. | 13G/A | 8.70%5.56M shares | – | Aug 14, 20251 filing | Aug 14, 2025 | SEC |
| Vanguard Group Inc | 13G/A | 7.52%5.00M shares | – | Oct 30, 20251 filing | Oct 30, 2025 | SEC |
| BlackRock, Inc. | 13G/A | 6.90%4.36M shares | – | Apr 24, 20251 filing | Apr 24, 2025 | SEC |
| Perceptive Advisors LLC | 13G/A | 6.80%4.42M shares | – | May 15, 20251 filing | May 15, 2025 | SEC |
| Primecap Management Co | 13G/A | 6.42%4.26M shares | −1.25 ppfrom 7.67% | Feb 13, 20254 filings | Nov 14, 2025 | SEC |
Stakes are as of each holder's latest filing. Holders whose last filing was in the old format (before December 18, 2024) have no stake on record and are not listed, and after an acquisition or delisting holders usually stop filing.
13D and 13G filings
10 Schedule 13D and 13G filings on Rhythm Pharmaceuticals, Inc., newest first, including old-format filings without a stake.
| Filed (ET) | Filer | Form | Stake | Change | Event date | Filing |
|---|---|---|---|---|---|---|
| Nov 14, 202512:14 PM ET | Primecap Management Co | 13G/A | 6.42%4.26M shares | −1.25 ppfrom 7.67% | Sep 30, 2025 | SEC |
| Oct 30, 20253:50 PM ET | Vanguard Group Inc | 13G/A | 7.52%5.00M shares | – | Sep 30, 2025 | SEC |
| Aug 14, 20256:04 PM ET | Ra Capital Management, L.P.and 3 others | 13G/A | 8.70%5.56M shares | – | Jun 30, 2025 | SEC |
| Aug 14, 20251:28 PM ET | Primecap Management Co | 13G/A | 7.67%4.88M shares | −1.48 ppfrom 9.15% | Jun 30, 2025 | SEC |
| May 15, 20256:20 PM ET | Perceptive Advisors LLCand 3 others | 13G/A | 6.80%4.42M shares | – | Mar 31, 2025 | SEC |
| May 15, 20254:19 PM ET | Baker Bros. Advisors LPand 3 others | 13G/A | 8.90%5.60M shares | – | Mar 31, 2025 | SEC |
| May 13, 20254:27 PM ET | Primecap Management Co | 13G/A | 9.15%5.79M shares | −1.54 ppfrom 10.69% | Mar 31, 2025 | SEC |
| Apr 24, 20258:59 AM ET | BlackRock, Inc. | 13G/A | 6.90%4.36M shares | – | Mar 31, 2025 | SEC |
| Feb 13, 20256:36 PM ET | Primecap Management Co | 13G/A | 10.69%6.57M shares | – | Dec 31, 2024 | SEC |
| Feb 10, 20255:30 PM ET | Goldman Sachs Group Incand 1 other | 13G/A | 3.00%1.82M shares | –Below 5% | Dec 31, 2024 | SEC |
Form 144: proposed insider sales
Notices from officers, directors and other affiliates planning to sell Rhythm Pharmaceuticals, Inc. shares.
No Form 144 notices for Rhythm Pharmaceuticals, Inc. are on file.