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Castleark Management’s Rhythm Pharmaceuticals RYTM Stock Holding History

Castleark Management’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
Q1 		$4.55M Sell
52,279
-12,200
-19% -$1.19M 0.15% 155
2025
Q4 		$6.9M Buy
64,479
+21,940
+52% +$2.33M 0.2% 120
2025
Q3 		$4.3M Buy
+42,539
New +$3.95M 0.12% 155
2025
Q1 		– Sell
-18,390
Closed -$1.03M – 334
2024
Q4 		$1.03M Sell
18,390
-870
-5% -$48.1K 0.04% 213
2024
Q3 		$1.01M Buy
19,260
+250
+1% +$12K 0.04% 198
2024
Q2 		$781K Sell
19,010
-44,890
-70% -$1.79M 0.03% 210
2024
Q1 		$2.77M Buy
+63,900
New +$2.8M 0.12% 161

Other funds holding RYTM

RCM
RA Capital Management Boston, Massachusetts $9.44B AUM 157.3% 1-Year Est. Return
BlackRock
BlackRock New York $5.72T AUM 30.48% 1-Year Est. Return
BBA
Baker Bros. Advisors New York $17.4B AUM 131.5% 1-Year Est. Return
Primecap Management
Primecap Management Pasadena, California $127B AUM 44.11% 1-Year Est. Return
VPM
Vanguard Portfolio Management Malvern, Pennsylvania $1.91T AUM
VCM
Vanguard Capital Management Malvern, Pennsylvania $4.04T AUM
PA
Perceptive Advisors New York $5.12B AUM 314.02% 1-Year Est. Return
State Street
State Street Boston, Massachusetts $2.9T AUM 29.55% 1-Year Est. Return
Goldman Sachs
Goldman Sachs New York $871B AUM 31.28% 1-Year Est. Return
Westfield Capital Management
Westfield Capital Management Boston, Massachusetts $23.8B AUM 49.45% 1-Year Est. Return

Castleark Management's RYTM Position: Q1 2026 in Review

Castleark Management reduced its Rhythm Pharmaceuticals (RYTM) stake by 19% in Q1 2026, selling an estimated $1.19M and leaving 52,279 shares worth $4.55M. The position accounts for 0.15% of the portfolio, ranked #155.

Castleark Management first reported a position in RYTM in Q1 2024 and has held it in 7 quarters since. The position peaked at $6.9M in Q4 2025. 285 funds tracked by Wall St. Rank hold RYTM as of Q1 2026.

  • Castleark Management held 52,279 shares of Rhythm Pharmaceuticals worth $4.55M as of Q1 2026.
  • Castleark Management sold 12,200 Rhythm Pharmaceuticals shares in Q1 2026, an estimated $1.19M.
  • Rhythm Pharmaceuticals made up 0.15% of Castleark Management's portfolio in Q1 2026, its #155 holding.
  • Castleark Management first reported a position in Rhythm Pharmaceuticals in Q1 2024 and has held it in 7 quarters since.
  • Castleark Management's Rhythm Pharmaceuticals position peaked at $6.9M in Q4 2025.
  • 285 funds tracked by Wall St. Rank held Rhythm Pharmaceuticals as of Q1 2026.

Based on Castleark Management's 13F filing for Q1 2026, filed 15 May 2026.