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Siren LLC’s Rhythm Pharmaceuticals RYTM Stock Holding History

Siren LLC’s Portfolio RYTM Stock Details RYTM Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2026
Q2 		$126M Buy
1,136,275
+410,764
+57% +$37.1M 2.55% 11
2026
Q1 		$63.1M Buy
725,511
+225,536
+45% +$21.9M 1.75% 20
2025
Q4 		$53.5M Hold
499,975
– – 1.6% 21
2025
Q3 		$50.5M Buy
499,975
+90,233
+22% +$8.38M 1.98% 15
2025
Q2 		$25.9M Buy
409,742
+132,209
+48% +$8.1M 1.34% 20
2025
Q1 		$14.7M Buy
+277,533
New +$15.4M 0.83% 30

Other funds holding RYTM

RCM
RA Capital Management Boston, Massachusetts $11.5B AUM 168.77% 1-Year Est. Return
BlackRock
BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return
BBA
Baker Bros. Advisors New York $20B AUM 154.41% 1-Year Est. Return
Primecap Management
Primecap Management Pasadena, California $169B AUM 114.72% 1-Year Est. Return
Vanguard Portfolio Management
Vanguard Portfolio Management Malvern, Pennsylvania $2.22T AUM
Vanguard Capital Management
Vanguard Capital Management Malvern, Pennsylvania $4.68T AUM
JP Morgan Chase
JP Morgan Chase New York $1.81T AUM 41.13% 1-Year Est. Return
PA
Perceptive Advisors New York $6.66B AUM 360.84% 1-Year Est. Return
State Street
State Street Boston, Massachusetts $3.37T AUM 44.26% 1-Year Est. Return
T. Rowe Price Associates
T. Rowe Price Associates Baltimore, Maryland $999B AUM 46.22% 1-Year Est. Return

Siren LLC's RYTM Position: Q2 2026 in Review

Siren LLC increased its Rhythm Pharmaceuticals (RYTM) stake by 57% in Q2 2026, buying an estimated $37.1M and bringing the position to 1,136,275 shares worth $126M. The position accounts for 2.55% of the portfolio, ranked #11.

Siren LLC first reported a position in RYTM in Q1 2025 and has held it in 6 quarters since. 304 funds tracked by Wall St. Rank hold RYTM as of Q2 2026.

  • Siren LLC held 1,136,275 shares of Rhythm Pharmaceuticals worth $126M as of Q2 2026.
  • Siren LLC bought 410,764 Rhythm Pharmaceuticals shares in Q2 2026, an estimated $37.1M.
  • Rhythm Pharmaceuticals made up 2.55% of Siren LLC's portfolio in Q2 2026, its #11 holding.
  • Siren LLC first reported a position in Rhythm Pharmaceuticals in Q1 2025 and has held it in 6 quarters since.
  • 304 funds tracked by Wall St. Rank held Rhythm Pharmaceuticals as of Q2 2026.

Based on Siren LLC's 13F filing for Q2 2026, filed 13 Aug 2026.