Rhythm Pharmaceuticals, Inc.
Rhythm Pharmaceuticals, Inc. (RYTM) Stock Ownership
Institutional vs insider vs public ownership from 13F and float data — top holders, activity, and insider trades below.
SEC 13F · FMP · RYTM · as of Sep 30, 2025
Ownership Breakdown
275
Institutional Holders
▲ 36 vs Q2
$7.20B
Total Inst. Value
▲ $3.00B vs Q2
68.59M
Shares Outstanding
freeFloat 81.20%
71.31M
13F Shares Held
▲ 4.76M vs Q2
Institutional ownership = 13F shares ÷ total outstanding. Insider % = 100 − free float. Public % = free float − institution %. Data: FMP /symbol-positions-summary + /shares-float + SEC EDGAR.
Top Institutional Holders
RYTM largest shareholders · institutional ownership
Q3 2025 · SEC 13F
Showing top 10 holders
| Holder | Shares | % Owned | Weight | Value | Reported | Change |
|---|---|---|---|---|---|---|
BLACKROCK, INC. pharmaceutical preparations | 6.30M | 9.90% | 9.90% | $636.46B | Nov 12, 2025 | ▲ 34.7K |
RA CAPITAL MANAGEMENT, L.P. pharmaceutical preparations | 5.68M | 8.92% | 8.92% | $573.76B | Nov 14, 2025 | ▲ 120.0K |
BAKER BROS. ADVISORS LP pharmaceutical preparations | 5.60M | 8.80% | 8.80% | $566.00B | Nov 14, 2025 | — held |
VANGUARD GROUP INC pharmaceutical preparations | 5.00M | 7.85% | 7.85% | $504.59B | Nov 7, 2025 | ▲ 1.41M |
PRIMECAP MANAGEMENT CO/CA/ pharmaceutical preparations | 4.26M | 6.69% | 6.69% | $430.51B | Nov 12, 2025 | ▼ 615.2K |
NEA MANAGEMENT COMPANY, LLC pharmaceutical preparations | 2.91M | 4.57% | 4.57% | $293.88B | Nov 14, 2025 | — held |
PERCEPTIVE ADVISORS LLC pharmaceutical preparations | 2.86M | 4.48% | 4.48% | $288.39B | Nov 14, 2025 | ▲ 437.3K |
FMR LLC pharmaceutical preparations | 2.15M | 3.37% | 3.37% | $216.64B | Nov 13, 2025 | ▲ 191.7K |
STATE STREET CORP pharmaceutical preparations | 2.03M | 3.19% | 3.19% | $204.87B | Nov 14, 2025 | ▲ 121.0K |
GOLDMAN SACHS GROUP INC pharmaceutical preparations | 1.89M | 2.97% | 2.97% | $191.24B | Nov 14, 2025 | ▲ 159.9K |
Data from SEC Form 13F filings. Ownership bar normalised to largest holder. Change flags: isNew / isSoldOut / changeInSharesNumber (FMP extract-analytics/holder).
Institutional Activity
Q3 2025 vs prior quarter
Q3 2025
31
Increased
+6.65M shares2
New Positions
first time holders14
Decreased
−2.70M shares0
Sold Out
fully exitedNet shares change (top 50)
+3.95M
+6.65M / −2.70M
Net new holders
+19
2 new / 0 exited
Based on top 50 institutional holders by position size. Fields: isNew, isSoldOut, changeInSharesNumber (FMP extract-analytics/holder, limit=50).
Insider Buying vs Selling
RYTM insider trading · insider activity
Source: SEC Form 4
Insiders have been primarily selling shares recently. Selling may be driven by pre-scheduled Rule 10b5-1 plans rather than negative sentiment.
7
Buy transactions
7
Sell transactions
1.00
Buy/Sell ratio
$0M
Total disposed
Recent Insider Transactions
Showing 10 most recent · Common Stock only
| Name · Role | Date | Type | Shares | Price | Value | After Trans. | Filing |
|---|---|---|---|---|---|---|---|
German Christopher Paul Corporate Controller & CAO | May 15, 2026 | Sale | 4,643 | $92.21 | $428.1K | 0 | Form 4 ↗ |
Popovits Kimberly J director | Apr 1, 2026 | Award | 10,257 | $88.12 | $903.8K | 10.3K | Form 4 ↗ |
Popovits Kimberly J director | Apr 1, 2026 | Award | 6,808 | — | — | 6.8K | Form 4 ↗ |
Mathers Edward T director | Mar 12, 2026 | J-Other | 4,199 | — | — | 14.2K | Form 4 ↗ |
German Christopher Paul Corporate Controller & CAO | Mar 4, 2026 | Sale | 5,614 | $89.56 | $502.8K | 160 | Form 4 ↗ |
Mazabraud Yann EVP, Head of International | Mar 2, 2026 | Award | 35,000 | $94.94 | $3.32M | 35.0K | Form 4 ↗ |
Source: /insider-trading/search (FMP stable). Buy/Sell direction: acquisitionOrDisposition A=Buy, D=Sell. RSU vesting (M-Exempt) excluded from sentiment bar. All data from SEC EDGAR public filings.
About institutional & insider ownership
Rhythm Pharmaceuticals, Inc. (RYTM) is primarily owned by institutional investors, who hold approximately 100.0% of total shares outstanding. Company insiders own approximately 18.80%, while retail and public investors account for the remaining 0.00%.
The largest institutional shareholder of Rhythm Pharmaceuticals, Inc. is BLACKROCK, INC., holding approximately 6.30 million shares — equal to 9.90% of outstanding shares — as of September 30, 2025.
A total of 275 institutional investors currently hold RYTM stock, with a combined institutional value of approximately $7.20 billion as of the most recent 13F filing period.
Frequently asked questions
RYTM ownershipRhythm Pharmaceuticals, Inc. (RYTM) is primarily owned by institutional investors, who hold approximately 100.0% of shares. The largest shareholder is BLACKROCK, INC. with a 9.90% stake. Company insiders hold 18.80%. Data sourced from SEC Form 13F as of September 30, 2025.