Comparable stake leader
RA CAPITAL MANAGEMENT, L.P.
SEC ownership of RHYTHM PHARMACEUTICALS, INC.
Top holders, 13D/G large-stake signals, insider positions, and transaction flow tied to CIK 0001649904.
Disclosed value leader
RA CAPITAL MANAGEMENT, L.P.
Comparable rows
50/50
Latest evidence
31 Mar 2026
- Public ticker
- RYTM on Nasdaq
- Parsed ownership sources
-
13D/G and 13F
Source: Parsed SEC ownership filingsUse: Compare filing families carefully
- Largest SEC-reported holder
-
RA CAPITAL MANAGEMENT, L.P.
Ranking: Comparable ownership first, then disclosed value
- Comparable ownership rows
-
50 of 50
Meaning: Rows with safely comparable ownership %
- Latest 13D/G holder
-
RA CAPITAL MANAGEMENT, L.P.
Source: Latest parsed Schedule 13D/G stake
- Latest parsed ownership date
-
31 Mar 2026
Freshness: Most recent filing date in this holder set
- Issuer CIK
- 0001649904
- Issuer location
- Boston, MA
Ownership snapshot
CIK-linked ownership evidence from parsed SEC filings.
3 signals
Issuer
Names, identifiers, and filing context for this profile.
2 identity fields
Ownership snapshot
Top shareholders of RHYTHM PHARMACEUTICALS, INC. (13F + 13D/G + 3/4/5)
Grouped by holder across the latest SEC ownership disclosures. Start with comparable ownership when available, then verify the linked 13F, 13D/G, or 3/4/5 evidence.
Comparable stake leader
RA CAPITAL MANAGEMENT, L.P.
Disclosed value leader
RA CAPITAL MANAGEMENT, L.P.
Comparable rows
50/50
Latest evidence
31 Mar 2026
13D/G
13F
Lead comparable stake: 9.9%
13D/G row: RA CAPITAL MANAGEMENT, L.P.
Showing 1-8 of 50 holder rows.
Quick read
RA CAPITAL MANAGEMENT, L.P. leads the comparable SEC ownership view at 9.9%.
50 of 50 rows have a safely comparable ownership percentage. Use this as a filing-backed starting point, then open the detailed table for source links, reporting role, position value, share count, and filing date.
Open SEC evidence
Opens RA CAPITAL MANAGEMENT, L.P.'s linked filing trail.
Comparable ownership
Top 5
RA CAPITAL MANAGEMENT, L.P.
9.9%
BAKER BROS. ADVISORS LP
8.9%
BlackRock, Inc.
6.9%
PRIMECAP MANAGEMENT CO/CA/
5.2%
PERCEPTIVE ADVISORS LLC
5.1%
Ownership % is shown only when SEC disclosures are safely comparable across share classes.
Detailed SEC evidence table Showing 1-8 of 50 holder rows
| Holder | Evidence | Ownership % | Position | 12M Net Δ | As of |
|---|---|---|---|---|---|
| RA CAPITAL MANAGEMENT, L.P. |
13D/G
13F
Company
|
9.9%
|
$662,816,935
6,666,837 shares
|
+$109,906,623 | 31 Dec 2025 |
| BAKER BROS. ADVISORS LP |
13F
13D/G
Company
|
8.9%
from 13D/G
|
$487,421,887
5,604,483 shares
|
— | 31 Mar 2026 |
| BlackRock, Inc. |
13F
13D/G
Company
|
6.9%
from 13D/G
|
$542,445,023
6,237,151 shares
|
— | 31 Mar 2026 |
| PRIMECAP MANAGEMENT CO/CA/ |
13D/G
13F
Company
|
5.2%
|
$345,849,272
3,478,669 shares
|
-$77,964,170 | 31 Dec 2025 |
| PERCEPTIVE ADVISORS LLC |
13D/G
13F
Company
|
5.1%
|
$303,708,528
3,519,626 shares
|
-$77,990,196 | 31 Mar 2026 |
| VANGUARD CAPITAL MANAGEMENT LLC |
13D/G
13F
Vanguard Capital Management · Company
|
5%
|
$298,563,575
3,432,949 shares
|
$0 | 31 Mar 2026 |
| GOLDMAN SACHS GROUP INC |
13F
13D/G
Company · THE GOLDMAN SACHS GROUP, INC.
|
3%
from 13D/G
|
$170,933,621
1,965,432 shares
|
— | 31 Mar 2026 |
| VANGUARD PORTFOLIO MANAGEMENT LLC |
13F
Company
|
4.4%
|
$264,451,244
3,040,718 shares
|
— | 31 Mar 2026 |
How to read this table
Rows are grouped by holder and ranked first by SEC-reported ownership % when it is safely comparable, then by disclosed holdings value. — indicates unavailable or non-comparable values; "mixed-class rows" means the latest filing spans non-comparable classes.
Forms 3/4/5 flow
Insider trading overview
Net insider flow leans to selling over the last 12 months. Net value: -$18,303,972.
Buys
$0
Insiders: 0
Sells
$18,303,972
Insiders: 5
Net
-$18,303,972
Shares: -180,017
Window
Last 12 months
4 rolling buckets
Buy value
Sell value
Shares: 0
Shares: 180,017
| Window (months) | Buy shares | Sell shares | Buy value | Sell value | Net value |
|---|---|---|---|---|---|
| 0-3 | 0 | 41,643 | $0 | $4,140,027 | -$4,140,027 |
| 3-6 | 0 | 20,639 | $0 | $2,017,179 | -$2,017,179 |
| 6-9 | 0 | 36,194 | $0 | $3,690,170 | -$3,690,170 |
| 9-12 | 0 | 81,541 | $0 | $8,456,596 | -$8,456,596 |
Reporting owners
Insider holders from Forms 3/4/5
Showing 1-18 of 18 reporting-owner rows connected to RHYTHM PHARMACEUTICALS, INC.. Open a relationship link for the CIK-to-CIK filing trail.
Rows
18
Largest Forms 3/4/5 holder
David P. Meeker
Net 12M change
-$18,303,972
Latest report
01 Jul 2026
| Name | Relationship | Holdings Value | Past Year Net Change | Change % | Valuation | Report Date |
|---|---|---|---|---|---|---|
| David P. Meeker | President and CEO, Director | $29,698,128 | Mixed | 11 Feb 2026 | ||
| Hunter C. Smith | Chief Financial Officer | $11,535,524 | -$4,921,757 | -30% | Mixed | 18 May 2026 |
| Yann Mazabraud | EVP, Head of International | $7,532,851 | Mixed | 01 Apr 2026 | ||
| Pamela J. Cramer | Chief Human Resources Officer | $3,775,890 | -$2,987,426 | -44% | Mixed | 11 Feb 2026 |
| Jennifer Kayden Lee | EVP, Head of North America | $3,040,334 | Mixed | 11 Feb 2026 | ||
| Joseph Shulman | Chief Technical Officer | $2,775,638 | -$5,609,472 | -67% | Mixed | 11 Feb 2026 |
| Alastair Garfield | Chief Scientific Officer | $2,399,657 | Mixed | 01 Jul 2026 | ||
| Mathers Edward T. | Director | $2,198,720 | Mixed | 12 Mar 2026 | ||
| Jennifer L. Good | Director | $1,018,592 | Mixed | 23 Jun 2026 | ||
| Stuart A. Arbuckle | Director | $1,018,592 | Mixed | 23 Jun 2026 | ||
| David W. J. Mcgirr | Director | $1,018,592 | Mixed | 23 Jun 2026 | ||
| Christophe Jean | Director | $1,018,592 | Mixed | 23 Jun 2026 | ||
| Lynn A. Tetrault | Director | $1,018,592 | -$3,711,896 | -78% | Mixed | 23 Jun 2026 |
| Linda Shapiro Manning | Chief Medical Officer | $563,250 | Mixed | 09 Feb 2022 | ||
| Camille L. Bedrosian | Director | $421,260 | Mixed | 24 Jun 2025 | ||
| William T. Roberts | Chief Accounting Officer | $279,459 | Mixed | 29 Mar 2023 | ||
| Christopher Paul German | Corporate Controller & CAO | $120,201 | -$1,073,421 | -90% | Mixed | 15 May 2026 |
| Kimberly J. Popovits | Director | Mixed | 01 Apr 2026 |
Recent insider transactions for RHYTHM PHARMACEUTICALS, INC.
Showing up to 300 recent insider transactions from the last 12 months.
| Insider | Symbol | Class | Transaction | % | SEC-reported value | SEC-reported price | Shares | Shares owned | Date | Ownership |
|---|---|---|---|---|---|---|---|---|---|---|
| Alastair Garfield | RYTM | Common Stock | Tax liability | -17.6% | -2,150 | 10,058 | 01 Jul 2026 | Direct | ||
| Alastair Garfield | RYTM | Common Stock | Options Exercise | 57.3% | 4,445 | 12,208 | 01 Jul 2026 | Direct | ||
| Alastair Garfield | RYTM | Restricted Stock Units | Options Exercise | -33.3% | -4,445 | 8,888 | 01 Jul 2026 | Direct | ||
| Christophe Jean | RYTM | Restricted Stock Units | Award | 2,324 | 2,324 | 24 Jun 2026 | Direct | |||
| Christophe Jean | RYTM | Stock Option (right to buy) | Award | 3,691 | 3,691 | 24 Jun 2026 | Direct | |||
| David W. J. Mcgirr | RYTM | Restricted Stock Units | Award | 2,324 | 2,324 | 24 Jun 2026 | Direct | |||
| David W. J. Mcgirr | RYTM | Stock Option (right to buy) | Award | 3,691 | 3,691 | 24 Jun 2026 | Direct | |||
| Lynn A. Tetrault | RYTM | Restricted Stock Units | Award | 2,324 | 2,324 | 24 Jun 2026 | Direct | |||
| Lynn A. Tetrault | RYTM | Stock Option (right to buy) | Award | 3,691 | 3,691 | 24 Jun 2026 | Direct | |||
| Stuart A. Arbuckle | RYTM | Restricted Stock Units | Award | 2,324 | 2,324 | 24 Jun 2026 | Direct | |||
| Stuart A. Arbuckle | RYTM | Stock Option (right to buy) | Award | 3,691 | 3,691 | 24 Jun 2026 | Direct | |||
| Jennifer L. Good | RYTM | Restricted Stock Units | Award | 2,324 | 2,324 | 24 Jun 2026 | Direct | |||
| Jennifer L. Good | RYTM | Stock Option (right to buy) | Award | 3,691 | 3,691 | 24 Jun 2026 | Direct | |||
| Christophe Jean | RYTM | Common Stock | Options Exercise | 67.3% | 4,712 | 11,712 | 23 Jun 2026 | Direct | ||
| Christophe Jean | RYTM | Restricted Stock Units | Options Exercise | -100% | -4,712 | 0 | 23 Jun 2026 | Direct | ||
| David W. J. Mcgirr | RYTM | Common Stock | Options Exercise | 67.3% | 4,712 | 11,712 | 23 Jun 2026 | Direct | ||
| David W. J. Mcgirr | RYTM | Restricted Stock Units | Options Exercise | -100% | -4,712 | 0 | 23 Jun 2026 | Direct | ||
| Lynn A. Tetrault | RYTM | Common Stock | Options Exercise | 67.3% | 4,712 | 11,712 | 23 Jun 2026 | Direct | ||
| Lynn A. Tetrault | RYTM | Restricted Stock Units | Options Exercise | -100% | -4,712 | 0 | 23 Jun 2026 | Direct | ||
| Stuart A. Arbuckle | RYTM | Common Stock | Options Exercise | 67.3% | 4,712 | 11,712 | 23 Jun 2026 | Direct | ||
| Stuart A. Arbuckle | RYTM | Restricted Stock Units | Options Exercise | -100% | -4,712 | 0 | 23 Jun 2026 | Direct | ||
| Jennifer L. Good | RYTM | Common Stock | Options Exercise | 67.3% | 4,712 | 11,712 | 23 Jun 2026 | Direct | ||
| Jennifer L. Good | RYTM | Restricted Stock Units | Options Exercise | -100% | -4,712 | 0 | 23 Jun 2026 | Direct | ||
| Lynn A. Tetrault | RYTM | Common Stock | Sale | -84.1% | $3,711,896 | $100.32 | -37,000 | 7,000 | 22 Jun 2026 | Direct |
| Lynn A. Tetrault | RYTM | Common Stock | Options Exercise | 528.6% | 37,000 | 44,000 | 22 Jun 2026 | Direct | ||
| Lynn A. Tetrault | RYTM | Stock Option (right to buy) | Options Exercise | -100% | -37,000 | 0 | 22 Jun 2026 | Direct | ||
| Hunter C. Smith | RYTM | Common Stock | Options Exercise | 2.57% | 3,000 | 119,611 | 18 May 2026 | Direct | ||
| Hunter C. Smith | RYTM | Stock Options (Right to Buy) | Options Exercise | -3.66% | -3,000 | 79,000 | 18 May 2026 | Direct | ||
| Christopher Paul German | RYTM | Common Stock | Sale | -100% | $428,131 | $92.21 | -4,643 | 0 | 15 May 2026 | Direct |
| Christopher Paul German | RYTM | Common Stock | Options Exercise | 2210% | 4,442 | 4,643 | 15 May 2026 | Direct | ||
| Christopher Paul German | RYTM | Stock Options (Right to Buy) | Options Exercise | -65.6% | -4,442 | 2,325 | 15 May 2026 | Direct | ||
| Yann Mazabraud | RYTM | Common Stock | Options Exercise | 24.2% | 12,875 | 66,030 | 01 Apr 2026 | Direct | ||
| Yann Mazabraud | RYTM | Restricted Stock Units | Options Exercise | -72% | -12,875 | 5,000 | 01 Apr 2026 | Direct | ||
| Kimberly J. Popovits | RYTM | Stock Options (Right to Buy) | Award | 10,257 | 10,257 | 01 Apr 2026 | Direct | |||
| Kimberly J. Popovits | RYTM | Restricted Stock Units | Award | 6,808 | 6,808 | 01 Apr 2026 | Direct | |||
| Mathers Edward T. | RYTM | Common Stock | Other | 42.1% | 4,199 | 14,168 | 12 Mar 2026 | See Note 2 | ||
| Christopher Paul German | RYTM | Common Stock | Sale | -97.2% | $502,790 | $89.56 | -5,614 | 160 | 04 Mar 2026 | Direct |
| Christopher Paul German | RYTM | Common Stock | Options Exercise | 35.3% | 1,500 | 5,753 | 04 Mar 2026 | Direct | ||
| Christopher Paul German | RYTM | Stock Options (Right to Buy) | Options Exercise | -28.7% | -1,500 | 3,731 | 04 Mar 2026 | Direct | ||
| Yann Mazabraud | RYTM | Stock Options (Right to Buy) | Award | 35,000 | 35,000 | 02 Mar 2026 | Direct | |||
| Mathers Edward T. | RYTM | Common Stock | Other | 72.7% | 4,198 | 9,969 | 02 Mar 2026 | See Note 2 | ||
| Hunter C. Smith | RYTM | Common Stock | Options Exercise | 5.52% | 6,099 | 116,611 | 02 Mar 2026 | Direct | ||
| Hunter C. Smith | RYTM | Stock Options (Right to Buy) | Options Exercise | -6.26% | -6,099 | 91,401 | 02 Mar 2026 | Direct | ||
| Christopher Paul German | RYTM | Common Stock | Tax liability | -7.44% | -342 | 4,253 | 01 Mar 2026 | Direct | ||
| Christopher Paul German | RYTM | Common Stock | Options Exercise | 33.8% | 1,162 | 4,595 | 01 Mar 2026 | Direct | ||
| Christopher Paul German | RYTM | Restricted Stock Units | Options Exercise | -50% | -1,162 | 1,162 | 01 Mar 2026 | Direct | ||
| Hunter C. Smith | RYTM | Common Stock | Sale | -3.82% | $444,004 | $101.26 | -4,385 | 110,512 | 19 Feb 2026 | Direct |
| Hunter C. Smith | RYTM | Common Stock | Sale | -3.01% | $361,810 | $101.38 | -3,569 | 114,897 | 17 Feb 2026 | Direct |
| Yann Mazabraud | RYTM | Common Stock | Options Exercise | 23.2% | 10,000 | 53,155 | 14 Feb 2026 | Direct | ||
| Yann Mazabraud | RYTM | Restricted Stock Units | Options Exercise | -25% | -10,000 | 30,000 | 14 Feb 2026 | Direct |
* marks a reported price that did not pass the local price check.