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Rhythm Pharmaceuticals
RYTM

Overview Fund Activity

227 hedge funds and large institutions have $3.42B invested in Rhythm Pharmaceuticals in 2025 Q1 according to their latest regulatory filings, with 45 funds opening new positions, 85 increasing their positions, 69 reducing their positions, and 20 closing their positions.

New
Increased
Maintained
Reduced
Closed
Holders
227
Holders Change
+24
Holders Change %
+11.82%
% of All Funds
3.08%
Holding in Top 10
7
Holding in Top 10 Change
-4
Holding in Top 10 Change %
-36.36%
% of All Funds
0.1%
New
45
Increased
85
Reduced
69
Closed
20
Calls
$21.5M
Puts
$3.46M
Net Calls
+$18M
Net Calls Change
-$6.98M

Top Buyers

1
Fidelity Investments
Fidelity Investments
Massachusetts
+$83.4M
2
Westfield Capital Management
Westfield Capital Management
Massachusetts
+$71M
3
T. Rowe Price Associates
T. Rowe Price Associates
Maryland
+$27.2M
4
Janus Henderson Group
Janus Henderson Group
United Kingdom
+$23.9M
5
SL
Siren LLC
Connecticut
+$14.7M

Top Sellers

1
FLSM
Frazier Life Sciences Management
California
-$63.1M
2
PA
Perceptive Advisors
New York
-$60M
3
PCH
Polar Capital Holdings
United Kingdom
-$53M
4
Primecap Management
Primecap Management
California
-$41.5M
5
BBA
Baker Bros. Advisors
New York
-$25.4M
Name Holding Trade Value Shares
Change 		Shares
Change %
BlackRock
1
BlackRock
New York
$363M -$5.08M -95,960 -1%
RCM
2
RA Capital Management
Massachusetts
$322M – – –
Primecap Management
3
Primecap Management
California
$307M -$41.5M -783,868 -12%
BBA
4
Baker Bros. Advisors
New York
$297M -$25.4M -479,766 -8%
Vanguard Group
5
Vanguard Group
Pennsylvania
$182M +$123K +2,326 +0.1%
NMC
6
NEA Management Company
Maryland
$154M – – –
PA
7
Perceptive Advisors
New York
$135M -$60M -1,132,028 -31%
State Street
8
State Street
Massachusetts
$104M +$6.88M +129,863 +7%
Janus Henderson Group
9
Janus Henderson Group
United Kingdom
$90.7M +$23.9M +435,796 +36%
Fidelity Investments
10
Fidelity Investments
Massachusetts
$89.4M +$83.4M +1,575,266 +1,393%
Goldman Sachs
11
Goldman Sachs
New York
$86.8M -$9.23M -174,298 -10%
Federated Hermes
12
Federated Hermes
Pennsylvania
$84.3M +$2.24M +42,236 +3%
DCM
13
Driehaus Capital Management
Illinois
$77.2M +$8.85M +167,047 +13%
Westfield Capital Management
14
Westfield Capital Management
Massachusetts
$71M +$71M +1,341,092 New
Geode Capital Management
15
Geode Capital Management
Massachusetts
$68.2M +$1.66M +31,369 +2%
T. Rowe Price Associates
16
T. Rowe Price Associates
Maryland
$63.5M +$27.2M +513,901 +75%
CC
17
Checkpoint Capital
California
$48.1M +$9.5M +179,258 +25%
RSCM
18
Rock Springs Capital Management
Maryland
$44.2M -$17.4M -328,530 -28%
Alkeon Capital Management
19
Alkeon Capital Management
New York
$43.3M -$18.5M -350,000 -30%
FLSM
20
Frazier Life Sciences Management
California
$36M -$63.1M -1,191,048 -64%
HRCM
21
Hood River Capital Management
Florida
$34.9M +$834K +15,740 +2%
Loomis, Sayles & Company
22
Loomis, Sayles & Company
Massachusetts
$32.1M -$674K -12,721 -2%
Northern Trust
23
Northern Trust
Illinois
$28.4M -$482K -9,108 -2%
Marshall Wace
24
Marshall Wace
United Kingdom
$28.3M -$8.35M -157,700 -23%
Morgan Stanley
25
Morgan Stanley
New York
$26.7M -$2.97M -56,038 -10%
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