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Castleark Management’s iRhythm Holdings IRTC Stock Holding History

Castleark Management’s Portfolio IRTC Stock Details IRTC Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2026
Q2 		– Sell
-27,193
Closed -$3.21M – 331
2026
Q1 		$3.21M Sell
27,193
-23,000
-46% -$3.32M 0.11% 179
2025
Q4 		$8.91M Sell
50,193
-8,200
-14% -$1.45M 0.26% 78
2025
Q3 		$10M Buy
58,393
+10,213
+21% +$1.62M 0.28% 63
2025
Q2 		$7.42M Sell
48,180
-110
-0.2% -$14.2K 0.22% 77
2025
Q1 		$5.05M Buy
+48,290
New +$5.11M 0.18% 120
2022
Q4 		– Sell
-36,100
Closed -$4.52M – 303
2022
Q3 		$4.52M Sell
36,100
-3,710
-9% -$536K 0.25% 100
2022
Q2 		$4.3M Sell
39,810
-11,380
-22% -$1.51M 0.23% 109
2022
Q1 		$8.06M Buy
+51,190
New +$6.57M 0.35% 66
2020
Q4 		– Sell
-25,493
Closed -$6.07M – 348
2020
Q3 		$6.07M Buy
+25,493
New +$4.51M 0.24% 115

Other funds holding IRTC

BlackRock
BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return
RI
RTW Investments New York $11.7B AUM 174.13% 1-Year Est. Return
Vanguard Portfolio Management
Vanguard Portfolio Management Malvern, Pennsylvania $2.22T AUM
Artisan Partners
Artisan Partners Milwaukee, Wisconsin $63.1B AUM 35.51% 1-Year Est. Return
Vanguard Capital Management
Vanguard Capital Management Malvern, Pennsylvania $4.68T AUM
Millennium Management
Millennium Management New York $276B AUM 44.8% 1-Year Est. Return
Fidelity Investments
Fidelity Investments Boston, Massachusetts $2.3T AUM 54.33% 1-Year Est. Return
UBS AM
UBS AM Chicago, Illinois $550B AUM 43.33% 1-Year Est. Return
Geode Capital Management
Geode Capital Management Boston, Massachusetts $1.88T AUM 44.46% 1-Year Est. Return
EAM
Eventide Asset Management Boston, Massachusetts $7.48B AUM 104.76% 1-Year Est. Return

Castleark Management's IRTC Position: Q2 2026 in Review

Castleark Management sold out of iRhythm Holdings (IRTC) in Q2 2026, closing a stake of 27,193 shares — an estimated $3.21M sold.

Castleark Management first reported a position in IRTC in Q3 2020 and held it in 9 quarters. The position peaked at $10M in Q3 2025. 304 funds tracked by Wall St. Rank hold IRTC as of Q2 2026.

  • Castleark Management reported no remaining iRhythm Holdings position as of Q2 2026 after selling out during the quarter.
  • Castleark Management sold 27,193 iRhythm Holdings shares in Q2 2026, an estimated $3.21M.
  • Castleark Management first reported a position in iRhythm Holdings in Q3 2020 and held it in 9 quarters.
  • Castleark Management's iRhythm Holdings position peaked at $10M in Q3 2025.
  • 304 funds tracked by Wall St. Rank held iRhythm Holdings as of Q2 2026.

Based on Castleark Management's 13F filing for Q2 2026, filed 14 Aug 2026.