Rhythm Pharmaceuticals, Inc.: which funds bought and sold

Institutions that bought and sold Rhythm Pharmaceuticals shares in Q2 2026, from the holdings they reported to the SEC on Form 13F for March 31, 2026 and June 30, 2026.

Between March 31, 2026 and June 30, 2026, 164 institutions that filed 13F reports for both quarters added to or opened positions in Rhythm Pharmaceuticals, and 141 cut or closed them. Together they added a net 3.1M shares, +4.3% on what they held at the start of the quarter. Active managers and hedge funds on our list were net buyers of 478K shares (+1.2%); index fund managers were net buyers of 550K shares (+3.1%). 59 opened a new position and 40 sold out entirely.

Bought, Q2 2026 164 institutions, 59 of them new holders Sold, Q2 2026 141 institutions, 40 of them sold out

Net change, all compared +3.1M shares (+4.3%)

Net change, active managers +478K shares (+1.2%), 31 bought, 35 sold

Buyers versus sellers

institutions compared, 338

164 bought 33 141 sold

Active managers and hedge funds 31 bought · 35 sold · +478K

Index fund managers 9 bought · 3 sold · +550K

Other institutions 124 bought · 103 sold · +2.1M

Biggest buyers

by change in shares held

Biggest buyers
Institution	Change in shares	Shares June 30, 2026	Value
Jpmorgan Chase & Co	+1.1M +70.7%	2.7M	$292M
Price T Rowe Associates Inc Active manager	+911K +55.1%	2.6M	$285M
Federated Hermes, Inc. Active manager	+499K +38.8%	1.8M	$198M
Capital Research Global Investors Active manager	+417K +37.4%	1.5M	$170M
Siren, L.L.C.	+411K +56.6%	1.1M	$126M
Morgan Stanley	+408K +58.0%	1.1M	$123M
Assenagon Asset Management S.A.	+373K New position	373K	$41.4M
State Street Corp Index funds	+302K +13.3%	2.6M	$286M
Pictet Asset Management Holding SA	+291K +43.6%	958K	$106M
Westfield Capital Management Co LP Active manager	+279K +14.5%	2.2M	$245M
Wellington Management Group LLP Active manager	+215K +78.5%	489K	$54.3M
Perceptive Advisors LLC Hedge fund	+213K +9.0%	2.6M	$287M
Duquesne Family Office LLC Hedge fund	+204K New position	204K	$22.6M
Invesco Ltd.	+179K +49.1%	543K	$60.3M
Goldman Sachs Group Inc	+161K +8.2%	2.1M	$236M
Squarepoint Ops LLC Hedge fund	+160K +60.8%	423K	$47M
First Turn Management, LLC	+154K New position	154K	$17.1M
Nicholas Investment Partners, LP	+139K New position	139K	$15.5M
Kennedy Capital Management LLC Active manager	+127K +193.6%	193K	$21.5M
Segall Bryant & Hamill, LLC Active manager	+122K New position	122K	$13.5M

Biggest buyers, active managers and hedge funds
Institution	Change in shares	Shares June 30, 2026	Value
Price T Rowe Associates Inc Active manager	+911K +55.1%	2.6M	$285M
Federated Hermes, Inc. Active manager	+499K +38.8%	1.8M	$198M
Capital Research Global Investors Active manager	+417K +37.4%	1.5M	$170M
Westfield Capital Management Co LP Active manager	+279K +14.5%	2.2M	$245M
Wellington Management Group LLP Active manager	+215K +78.5%	489K	$54.3M
Perceptive Advisors LLC Hedge fund	+213K +9.0%	2.6M	$287M
Duquesne Family Office LLC Hedge fund	+204K New position	204K	$22.6M
Squarepoint Ops LLC Hedge fund	+160K +60.8%	423K	$47M
Kennedy Capital Management LLC Active manager	+127K +193.6%	193K	$21.5M
Segall Bryant & Hamill, LLC Active manager	+122K New position	122K	$13.5M

Biggest sellers

by change in shares held

Biggest sellers
Institution	Change in shares	Shares June 30, 2026	Value
FMR LLC Active manager	−664K −39.3%	1.0M	$114M
Point72 Asset Management, L.P. Hedge fund	−433K −51.1%	414K	$46M
Lord, Abbett & Co. LLC	−349K Sold out	0	—
Adage Capital Partners Gp, L.L.C. Hedge fund	−329K −45.3%	397K	$44.1M
Logos Global Management LP Hedge fund	−325K −72.2%	125K	$13.9M
Driehaus Capital Management LLC Active manager	−307K −70.4%	129K	$14.4M
Bank Of America Corp	−303K −48.2%	325K	$36.1M
Primecap Management Co Active manager	−249K −7.3%	3.2M	$352M
Hood River Capital Management LLC	−240K Sold out	0	—
Renaissance Technologies LLC Hedge fund	−190K −73.5%	68K	$7.6M
Citadel Advisors LLC Hedge fund	−155K −10.9%	1.3M	$140M
Qube Research & Technologies Ltd Hedge fund	−144K −51.6%	134K	$14.9M
M&G PLC	−139K Sold out	0	—
Millennium Management LLC Hedge fund	−135K −29.9%	317K	$35.2M
UBS Group AG	−87K −37.7%	144K	$16M
Blackrock, Inc. Index funds	−80K −1.3%	6.2M	$684M
ADAR1 Capital Management, LLC Hedge fund	−75K −35.6%	136K	$15.1M
Xtx Topco Ltd	−58K −96.6%	1,996	$221,616
Universal- Beteiligungs- Und Servicegesellschaft Mbh	−54K −85.1%	9,393	$1M
First Trust Advisors LP	−53K −62.0%	32K	$3.6M

Biggest sellers, active managers and hedge funds
Institution	Change in shares	Shares June 30, 2026	Value
FMR LLC Active manager	−664K −39.3%	1.0M	$114M
Point72 Asset Management, L.P. Hedge fund	−433K −51.1%	414K	$46M
Adage Capital Partners Gp, L.L.C. Hedge fund	−329K −45.3%	397K	$44.1M
Logos Global Management LP Hedge fund	−325K −72.2%	125K	$13.9M
Driehaus Capital Management LLC Active manager	−307K −70.4%	129K	$14.4M
Primecap Management Co Active manager	−249K −7.3%	3.2M	$352M
Renaissance Technologies LLC Hedge fund	−190K −73.5%	68K	$7.6M
Citadel Advisors LLC Hedge fund	−155K −10.9%	1.3M	$140M
Qube Research & Technologies Ltd Hedge fund	−144K −51.6%	134K	$14.9M
Millennium Management LLC Hedge fund	−135K −29.9%	317K	$35.2M

New positions

largest by value

Institution	Shares	Value June 30, 2026
Assenagon Asset Management S.A.	373K	$41.4M
Duquesne Family Office LLCHedge fund	204K	$22.6M
First Turn Management, LLC	154K	$17.1M
Nicholas Investment Partners, LP	139K	$15.5M
Segall Bryant & Hamill, LLCActive manager	122K	$13.5M
Longaeva Partners L.P.	110K	$12.2M
Sphera Funds Management Ltd.	80K	$8.9M
Capital Fund Management S.A.Hedge fund	69K	$7.6M
Trexquant Investment LPHedge fund	56K	$6.2M
Canada Pension Plan Investment Board	47K	$5.3M

Sold out

largest by value

Institution	Shares	Value March 31, 2026
Lord, Abbett & Co. LLC	349K	$30.3M
Hood River Capital Management LLC	240K	$20.9M
M&G PLC	139K	$12.1M
Balyasny Asset Management L.P.Hedge fund	53K	$4.6M
Castleark Management LLC	52K	$4.5M
Harvest Investment Services, LLC	48K	$4.2M
Utah Retirement Systems	42K	$3.7M
Alyeska Investment Group, L.P.Hedge fund	33K	$2.8M
Harbor Capital Advisors, Inc.	30K	$2.6M
PDT Partners, LLCHedge fund	27K	$2.4M

Who holds the shares

13F holdings at June 30, 2026

Institutions reporting: 302
Ten largest holders: 49.3%
Index fund managers: 23.3%
Active managers and hedge funds: 50.9%

Buying and selling by type of institution, March 31, 2026 to June 30, 2026
Type	Bought	Sold	New	Sold out	Net change in shares	Net %
Active managers and hedge funds	31	35	10	7	+478K	+1.2%
Index fund managers	9	3	0	0	+550K	+3.1%
Other institutions	124	103	49	33	+2.1M	+12.9%

Active managers and hedge funds: a list we maintain of about 400 well-known stock-picking firms and hedge funds, matched by SEC registration number (CIK) and checked against the filer names each quarter. Index fund managers: the large index houses, such as BlackRock, Vanguard, State Street, Geode and Northern Trust. Every other filer (banks, brokers, wealth managers, pension funds, insurers and firms not on the list) counts as another institution. A firm that files under several SEC registrations appears once for each.

What these filings can and cannot tell you

Form 13F lists the long positions in US-listed shares held by investment managers with more than $100 million in such holdings. Managers file it up to 45 days after each quarter ends, so this page shows what funds held at the end of each quarter, not what they are doing now: a position may have changed since. Short positions, most derivatives and smaller managers are not included, and a cut can mean a fund lost clients or rebalanced rather than a view on Rhythm Pharmaceuticals.

Only managers that filed a holdings report for both quarters are compared (338 here). 10 other holders are left out: first-time or late filers, firms that changed their SEC registration, and filings that withheld positions under confidential treatment, any of which would otherwise look like a new position or a sale. Figures are as reported by each manager in the SEC's quarterly 13F data sets; option positions are excluded.

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