RHYTHM PHARMACEUTICALS INC RYTM
COM · Common Stock · CUSIP 76243J105
Company in Boston, United States
- SectorHealth care
- IndustryPharmaceutical Preparations
- HeadquartersBoston, MA
- Founded2008
- Websiterhythmtx.com
- FilingsSEC EDGAR
* Summed across managers. Shares that two managers' reports both contain – a subsidiary's holdings that its parent's report includes too, or a sub-adviser's in its client's – are counted once ($6.0m this quarter). Holder counts are more reliable. Shares outstanding: 66.4m as of 2025-08-01, from the company's own SEC filing; the percentage can still exceed 100%: lent-out shares are counted by the lender and the buyer, and some reports overlap without saying so. Implied quarter-end price ≈ $63.19. Options: 9 managers hold calls ($13.8m notional), 9 hold puts ($36.7m).
Trends to Q2 2025
Institutional holders
Managers reporting a position, each quarter
Numbers
| Quarter | Holders |
|---|---|
| Q3 2022 | 101 |
| Q4 2022 | 116 |
| Q1 2023 | 127 |
| Q2 2023 | 117 |
| Q3 2023 | 145 |
| Q4 2023 | 170 |
| Q1 2024 | 169 |
| Q2 2024 | 167 |
| Q3 2024 | 178 |
| Q4 2024 | 205 |
| Q1 2025 | 230 |
| Q2 2025 | 229 |
Buyers vs sellers
Managers adding to or starting a position, vs cutting or selling out
Numbers
| Quarter | Bought or added | Cut or sold out |
|---|---|---|
| Q3 2023 | 87 | 51 |
| Q4 2023 | 80 | 82 |
| Q1 2024 | 88 | 79 |
| Q2 2024 | 84 | 79 |
| Q3 2024 | 88 | 74 |
| Q4 2024 | 105 | 77 |
| Q1 2025 | 129 | 87 |
| Q2 2025 | 124 | 107 |
Calls vs puts
Options held, notional value, last 4 quarters. P/C = puts ÷ calls
Numbers
| Quarter | Calls | Puts | P/C |
|---|---|---|---|
| Q3 2024 | $46.0m | $4.7m | 0.10 |
| Q4 2024 | $26.8m | $1.8m | 0.07 |
| Q1 2025 | $21.5m | $3.5m | 0.16 |
| Q2 2025 | $13.8m | $36.7m | 2.66 |
Biggest buyers
| Polar Capital Holdings Plc | Added | +750.9k |
| JPMORGAN CHASE & CO | Added | +639.9k |
| Woodline Partners LP | New | +514.4k |
| ROYAL BANK OF CANADA | Added | +392.3k |
| ADAGE CAPITAL PARTNERS GP, L.L.C. | New | +341.0k |
| Clearbridge Investments, LLC | New | +312.4k |
| RENAISSANCE TECHNOLOGIES LLC | Added | +300.8k |
| WESTFIELD CAPITAL MANAGEMENT CO LP | Added | +288.4k |
| FMR LLC | Added | +265.1k |
| BARCLAYS PLC | Added | +250.0k |
Biggest sellers
| PRIMECAP MANAGEMENT CO/CA/ | Reduced | -909.3k |
| Frazier Life Sciences Management, L.P. | Sold out | -678.8k |
| BlackRock, Inc. | Reduced | -587.2k |
| RA CAPITAL MANAGEMENT, L.P. | Reduced | -523.1k |
| Balyasny Asset Management L.P. | Reduced | -301.6k |
| JANUS HENDERSON GROUP PLC | Reduced | -243.4k |
| Invesco Ltd. | Reduced | -193.0k |
| Driehaus Capital Management LLC | Reduced | -188.1k |
| MARSHALL WACE, LLP | Reduced | -158.9k |
| Cormorant Asset Management, LP | Sold out | -150.0k |
Biggest calls
| JANE STREET GROUP, LLC | Reduced | $4.4m69.6k shares |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | Reduced | $3.8m60.2k shares |
| Caption Management, LLC | Reduced | $2.2m35.0k shares |
| NOMURA HOLDINGS INC | Reduced | $1.4m22.8k shares |
| CITADEL ADVISORS LLC | Reduced | $1.1m17.4k shares |
| SIMPLEX TRADING, LLC | Added | $499.0k7.9k shares |
| SIG BROKERAGE, LP | Unchanged | $315.9k5.0k shares |
| GROUP ONE TRADING LLC | Reduced | $19.0k300 shares |
| CONCOURSE FINANCIAL GROUP SECURITIES, INC. | Unchanged | $00 shares |
Biggest puts
| Sofinnova Investments, Inc. | New | $14.2m225.0k shares |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | Added | $8.4m133.5k shares |
| Caption Management, LLC | New | $7.9m125.0k shares |
| JANE STREET GROUP, LLC | New | $3.3m52.7k shares |
| CITADEL ADVISORS LLC | Added | $1.8m28.3k shares |
| MILLENNIUM MANAGEMENT LLC | Reduced | $631.9k10.0k shares |
| SIMPLEX TRADING, LLC | Added | $385.0k6.1k shares |
| GROUP ONE TRADING LLC | New | $6.3k100 shares |
| CONCOURSE FINANCIAL GROUP SECURITIES, INC. | Unchanged | $00 shares |
Options at notional value: the value of the shares the contracts control, as filers report them, not what the options cost. Not included in the holders, shares or buying above.
Major shareholders (over 5%)
Anyone who owns more than 5% of a class of the company's shares has to say so: on Schedule 13D if they may try to influence or control the company, on 13G if they're a passive investor, and update it as the stake changes. Each holder's latest filing, from 19 Dec 2024 on; percentages are of the share class, as the holder worked them out.
| Holder | Stake |
|---|---|
| RA CAPITAL MANAGEMENT, L.P. 13G · passive investor +1.2 pts · filed 2026-02-17 | 9.9% |
| BAKER BROS. ADVISORS LP 13G · institution filed 2025-05-15 | 8.9% |
| BlackRock, Inc. 13G · institution filed 2025-04-24 | 6.9% |
| PRIMECAP MANAGEMENT CO/CA/ 13G · institution -1.2 pts · filed 2026-02-12 | 5.2% |
| JPMORGAN CHASE & CO 13G · institution new · filed 2026-10-13 | 5.1% |
| PERCEPTIVE ADVISORS LLC 13G · passive investor -1.7 pts · filed 2026-05-15 | 5.1% |
| VANGUARD CAPITAL MANAGEMENT LLC 13G · institution new · filed 2026-04-30 | 5.0% |
Fell to 5% or below in the last year: VANGUARD GROUP INC (0.0%, 2026-03-27; now reported by VANGUARD CAPITAL MANAGEMENT LLC)
Insider purchases and sales in Q2 2025
Shares bought or sold by the company's own officers, directors and 10% owners, in the open market or privately, as they reported to the SEC on Form 4 (due within two business days of the trade). Grants, option exercises, shares withheld for tax and gifts aren't included.
Officers and directors buying vs selling
Number of people, by quarter (10% owners not included)
Numbers
| Quarter | Buying | Bought | Selling | Sold | Sold under a plan |
|---|---|---|---|---|---|
| Q3 2023 | 0 | — | 2 | $503.1k | $503.1k |
| Q4 2023 | 0 | — | 3 | $4.0m | $2.2m |
| Q1 2024 | 0 | — | 6 | $5.4m | $147.7k |
| Q2 2024 | 0 | — | 2 | $168.6k | $153.3k |
| Q3 2024 | 0 | — | 4 | $9.4m | $9.4m |
| Q4 2024 | 0 | — | 3 | $5.9m | $5.9m |
| Q1 2025 | 0 | — | 7 | $6.3m | $5.7m |
| Q2 2025 | 0 | — | 6 | $12.4m | $12.4m |
| Date | Insider | Trade | Value |
|---|---|---|---|
| 2025-06-10 | German Christopher Paul Corporate Controller & CAO | Sold plan | $139.0k2.1k shares |
| 2025-06-06 | Cramer Pamela J. Chief Human Resources Officer | Sold plan | $478.5k7.0k shares |
| 2025-06-03 | MCGIRR DAVID W J Director | Sold plan | $4.3m65.4k shares |
| 2025-06-03 | Meeker David P President and CEO, director | Sold plan | $2.8m43.6k shares |
| 2025-05-30 | Smith Hunter C Chief Financial Officer | Sold plan | $1.4m23.4k shares |
| 2025-04-29 | Cramer Pamela J. Chief Human Resources Officer | Sold plan | $457.6k7.0k shares |
| 2025-04-29 | Mazabraud Yann EVP, Head of International | Sold plan | $439.0k6.7k shares |
| 2025-04-08 | Cramer Pamela J. Chief Human Resources Officer | Sold plan | $1.2m20.8k shares |
| 2025-04-08 | Mazabraud Yann EVP, Head of International | Sold plan | $1.1m17.8k shares |
Their holding: how much the trade added to or took from the insider's holding (direct, or the trust or fund named). The same trade is sometimes reported by more than one insider, such as a fund and the director who represents it; totals count it once. A value is left blank where the reported price is far from the market price (usually a typo).
Holders, Q2 2025
| Manager | Shares | Change |
|---|---|---|
| BlackRock, Inc. 0.01% of their portfolio | 6.3m $396.0m | Reduced -587.2k |
| BAKER BROS. ADVISORS LP 3.44% of their portfolio | 5.6m $354.1m | Unchanged |
| RA CAPITAL MANAGEMENT, L.P. 5.92% of their portfolio | 5.6m $351.4m | Reduced -523.1k |
| PRIMECAP MANAGEMENT CO/CA/ 0.24% of their portfolio | 4.9m $308.2m | Reduced -909.3k |
| VANGUARD GROUP INC 0.00% of their portfolio | 3.6m $226.8m | Added +144.2k |
| NEA Management Company, LLC 13.84% of their portfolio | 2.9m $183.9m | Unchanged |
| PERCEPTIVE ADVISORS LLC 5.73% of their portfolio | 2.4m $152.8m | Reduced -130.1k |
| FMR LLC 0.01% of their portfolio | 2.0m $123.4m | Added +265.1k |
| STATE STREET CORP 0.00% of their portfolio | 1.9m $120.5m | Reduced -63.1k |
| GOLDMAN SACHS GROUP INC 0.02% of their portfolio | 1.7m $109.6m | Added +95.8k |
| FEDERATED HERMES, INC. 0.20% of their portfolio | 1.7m $106.6m | Added +94.6k |
| WESTFIELD CAPITAL MANAGEMENT CO LP 0.43% of their portfolio | 1.6m $103.0m | Added +288.4k |
| JANUS HENDERSON GROUP PLC 0.04% of their portfolio | 1.4m $89.3m | Reduced -243.4k |
| PRICE T ROWE ASSOCIATES INC /MD/ 0.01% of their portfolio | 1.3m $84.8m | Added +142.3k |
| GEODE CAPITAL MANAGEMENT, LLC 0.01% of their portfolio | 1.3m $82.9m | Added +24.1k |
| Driehaus Capital Management LLC 0.64% of their portfolio | 1.3m $80.2m | Reduced -188.1k |
| Polar Capital Holdings Plc 0.41% of their portfolio | 1.3m $79.0m | Added +750.9k |
| Checkpoint Capital L.P. 31.21% of their portfolio | 1.1m $67.0m | Added +152.8k |
| ALKEON CAPITAL MANAGEMENT LLC 0.31% of their portfolio | 1.0m $64.3m | Added +200.0k |
| Rock Springs Capital Management LP 3.39% of their portfolio | 861.2k $54.4m | Added +27.0k |
| JPMORGAN CHASE & CO 0.00% of their portfolio | 783.6k $49.5m | Added +639.9k |
| LOOMIS SAYLES & CO L P 0.05% of their portfolio | 591.5k $37.4m | Reduced -14.3k |
| Sofinnova Investments, Inc. 2.52% of their portfolio | 586.0k $37.0m | Added +139.2k |
| FRANKLIN RESOURCES INC 0.01% of their portfolio | 543.8k $34.4m | Added +217.6k |
| Hood River Capital Management LLC 0.48% of their portfolio | 543.7k $34.4m | Reduced -115.7k |
| MORGAN STANLEY 0.00% of their portfolio | 524.5k $33.1m | Added +20.4k |
| Woodline Partners LP 0.17% of their portfolio | 514.4k $32.5m | New |
| NORTHERN TRUST CORP 0.00% of their portfolio | 510.2k $32.2m | Reduced -26.0k |
| Opaleye Management Inc. 6.07% of their portfolio | 475.0k $30.0m | Reduced -15.0k |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC 0.01% of their portfolio | 461.4k $29.2m | Added +16.0k |
| Pictet Asset Management Holding SA 0.03% of their portfolio | 416.1k $26.3m | Added +156.8k |
| Siren, L.L.C. 1.34% of their portfolio | 409.7k $25.9m | Added +132.2k |
| SILVERARC CAPITAL MANAGEMENT, LLC 5.18% of their portfolio | 400.8k $25.3m | Added +63.2k |
| ROYAL BANK OF CANADA 0.00% of their portfolio | 392.5k $24.8m | Added +392.3k |
| MARSHALL WACE, LLP 0.03% of their portfolio | 376.2k $23.8m | Reduced -158.9k |
| BARCLAYS PLC 0.01% of their portfolio | 351.2k $22.2m | Added +250.0k |
| ADAGE CAPITAL PARTNERS GP, L.L.C. 0.04% of their portfolio | 341.0k $21.5m | New |
| VOLORIDGE INVESTMENT MANAGEMENT, LLC 0.08% of their portfolio | 338.8k $21.4m | Reduced -84.1k |
| RENAISSANCE TECHNOLOGIES LLC 0.03% of their portfolio | 314.9k $19.9m | Added +300.8k |
| Candriam S.C.A. 0.11% of their portfolio | 312.5k $19.7m | Added +21.0k |
| Clearbridge Investments, LLC 0.02% of their portfolio | 312.4k $19.7m | New |
| COMERICA BANK 0.07% of their portfolio | 301.7k $19.1m | Added +56.9k |
| UBS Group AG 0.00% of their portfolio | 252.6k $16.0m | Reduced -19.5k |
| ORBIMED ADVISORS LLC 0.39% of their portfolio | 248.5k $15.7m | Reduced -131.5k |
| VOYA INVESTMENT MANAGEMENT LLC 0.02% of their portfolio | 244.0k $15.4m | Added +72.3k |
| Qube Research & Technologies Ltd 0.02% of their portfolio | 240.3k $15.2m | Added +24.2k |
| Assenagon Asset Management S.A. 0.02% of their portfolio | 238.0k $15.0m | Added +215.8k |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC 0.00% of their portfolio | 227.6k $14.4m | Added +101.8k |
| BANK OF AMERICA CORP /DE/ 0.00% of their portfolio | 222.2k $14.0m | Added +110.4k |
| NORGES BANK 0.00% of their portfolio | 207.4k $13.1m | Reduced -16.1k |
| LORD, ABBETT & CO. LLC 0.04% of their portfolio | 204.3k $12.9m | Added +68.9k |
| MILLENNIUM MANAGEMENT LLC 0.01% of their portfolio | 198.1k $12.5m | Reduced -19.3k |
| Bank of New York Mellon Corp 0.00% of their portfolio | 184.1k $11.6m | Added +37.5k |
| STEMPOINT CAPITAL LP 3.60% of their portfolio | 176.8k $11.2m | Added +142.9k |
| Artisan Partners Limited Partnership 0.02% of their portfolio | 174.5k $11.0m | New |
| AMERIPRISE FINANCIAL INC 0.00% of their portfolio | 173.1k $10.9m | Added +74.8k |
| Point72 Asset Management, L.P. 0.03% of their portfolio | 170.8k $10.8m | Added +107.0k |
| Russell Investments Group, Ltd. 0.01% of their portfolio | 131.0k $8.3m | Added +16.2k |
| Logos Global Management LP 1.10% of their portfolio | 130.0k $8.2m | New |
| Nuveen, LLC 0.00% of their portfolio | 121.9k $7.7m | Reduced -25.4k |
| Integral Health Asset Management, LLC 0.71% of their portfolio | 120.0k $7.6m | New |
| PANAGORA ASSET MANAGEMENT INC 0.03% of their portfolio | 119.5k $7.5m | Reduced -21.7k |
| Connor, Clark & Lunn Investment Management Ltd. 0.03% of their portfolio | 115.1k $7.3m | Added +64.6k |
| BNP PARIBAS FINANCIAL MARKETS 0.01% of their portfolio | 102.2k $6.5m | Added +16.2k |
| LAZARD ASSET MANAGEMENT LLC 0.01% of their portfolio | 99.4k $6.3m | Reduced -3.8k |
| PDT Partners, LLC 0.35% of their portfolio | 97.6k $6.2m | Reduced -4.6k |
| Universal- Beteiligungs- und Servicegesellschaft mbH 0.01% of their portfolio | 95.5k $6.0m | Added +2.4k |
| Swiss National Bank 0.00% of their portfolio | 90.6k $5.7m | Added +1.3k |
| RHUMBLINE ADVISERS 0.00% of their portfolio | 87.5k $5.5m | Added +1.8k |
| HARBOR CAPITAL ADVISORS, INC. 0.23% of their portfolio | 86.5k $5.5m | Added +9.2k |
| NEUBERGER BERMAN GROUP LLC 0.00% of their portfolio | 86.1k $5.4m | Added +18.2k |
| Schonfeld Strategic Advisors LLC 0.04% of their portfolio | 78.0k $4.9m | Added +20.8k |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP 0.01% of their portfolio | 77.3k $4.9m | Reduced -5.7k |
| FIRST TRUST ADVISORS LP 0.00% of their portfolio | 73.7k $4.7m | Reduced -16.1k |
| Cinctive Capital Management LP 0.25% of their portfolio | 70.9k $4.5m | Added +66.6k |
| Invesco Ltd. 0.00% of their portfolio | 68.9k $4.4m | Reduced -193.0k |
| MANUFACTURERS LIFE INSURANCE COMPANY, THE 0.00% of their portfolio | 68.1k $4.3m | Added +3.7k |
| Aberdeen Group plc 0.01% of their portfolio | 67.7k $4.3m | Reduced -40.5k |
| Cubist Systematic Strategies, LLC 0.04% of their portfolio | 64.6k $4.1m | Reduced -109.2k |
| ALLIANCEBERNSTEIN L.P. 0.00% of their portfolio | 61.5k $3.9m | Unchanged |
| ALGERT GLOBAL LLC 0.08% of their portfolio | 60.2k $3.8m | Reduced -1.2k |
| NEW YORK STATE COMMON RETIREMENT FUND 0.00% of their portfolio | 58.6k $3.7m | Added +41.8k |
| KENNEDY CAPITAL MANAGEMENT LLC 0.09% of their portfolio | 57.2k $3.6m | Added +2.3k |
| TD Asset Management Inc 0.00% of their portfolio | 56.0k $3.5m | Added +5.8k |
| Balyasny Asset Management L.P. 0.01% of their portfolio | 54.1k $3.4m | Reduced -301.6k |
| Legal & General Group Plc 0.00% of their portfolio | 52.7k $3.3m | Added +1.5k |
| AXIOM INVESTORS LLC /DE 0.03% of their portfolio | 52.5k $3.3m | New |
| Rafferty Asset Management, LLC 0.01% of their portfolio | 51.6k $3.3m | Reduced -6.1k |
| Hennion & Walsh Asset Management, Inc. 0.13% of their portfolio | 51.1k $3.2m | Reduced -38.5k |
| SAMSARA BIOCAPITAL, LLC 0.65% of their portfolio | 50.5k $3.2m | Reduced -87.6k |
| Nan Fung Group Holdings Ltd 4.89% of their portfolio | 49.1k $3.1m | Unchanged |
| AQR CAPITAL MANAGEMENT LLC 0.00% of their portfolio | 49.0k $3.1m | Added +9.7k |
| SILVERCREST ASSET MANAGEMENT GROUP LLC 0.02% of their portfolio | 48.8k $3.1m | New |
| ADAR1 Capital Management, LLC 0.47% of their portfolio | 45.4k $2.9m | Added +8.5k |
| CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM 0.00% of their portfolio | 42.9k $2.7m | Added +196 |
| WELLS FARGO & COMPANY/MN 0.00% of their portfolio | 42.4k $2.7m | Reduced -28.3k |
| Granahan Investment Management, LLC 0.11% of their portfolio | 41.2k $2.6m | New |
| DEUTSCHE BANK AG\ 0.00% of their portfolio | 36.8k $2.3m | Reduced -7.0k |
| STATE OF WISCONSIN INVESTMENT BOARD 0.01% of their portfolio | 35.7k $2.3m | Added +2.7k |
| DARK FOREST CAPITAL MANAGEMENT LP 0.09% of their portfolio | 34.8k $2.2m | Added +9.4k |