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Cubist Systematic Strategies’s iRhythm Holdings IRTC Stock Holding History

Cubist Systematic Strategies’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
2025
Q3 		$15.3M Sell
89,220
-21,507
-19% -$3.42M 0.07% 372
2025
Q2 		$17M Buy
110,727
+67,010
+153% +$8.66M 0.08% 353
2025
Q1 		$4.58M Buy
+43,717
New +$4.63M 0.03% 930
2024
Q4 		– Sell
-88,863
Closed -$6.98M – 3256
2024
Q3 		$6.6M Buy
+88,863
New +$7.08M 0.04% 674
2024
Q2 		– Sell
-19,030
Closed -$2.21M – 3482
2024
Q1 		$2.21M Buy
19,030
+3,741
+24% +$421K 0.01% 1573
2023
Q4 		$1.64M Buy
+15,289
New +$1.33M 0.01% 1671
2023
Q1 		– Sell
-7,039
Closed -$659K – 4150
2022
Q4 		$659K Sell
7,039
-13,557
-66% -$1.48M ﹤0.01% 2824
2022
Q3 		$2.58M Buy
20,596
+12,586
+157% +$1.82M 0.01% 1742
2022
Q2 		$865K Buy
8,010
+797
+11% +$106K 0.01% 2590
2022
Q1 		$1.14M Sell
7,213
-3,981
-36% -$511K 0.01% 1933
2021
Q4 		$1.32M Sell
11,194
-19,150
-63% -$1.76M 0.01% 1701
2021
Q3 		$1.78M Sell
30,344
-99,523
-77% -$5.27M 0.02% 1103
2021
Q2 		$8.62M Buy
129,867
+63,993
+97% +$5.07M 0.1% 273
2021
Q1 		$9.15M Buy
65,874
+62,323
+1,755% +$11.2M 0.12% 192
2020
Q4 		$842K Sell
3,551
-18,520
-84% -$4.22M 0.01% 1485
2020
Q3 		$5.25M Buy
22,071
+285
+1% +$50.4K 0.08% 386
2020
Q2 		$2.52M Buy
21,786
+7,469
+52% +$823K 0.04% 653
2020
Q1 		$1.17M Sell
14,317
-6,072
-30% -$504K 0.03% 739
2019
Q4 		$1.39M Buy
20,389
+4,453
+28% +$302K 0.03% 957
2019
Q3 		$1.18M Sell
15,936
-5,010
-24% -$388K 0.02% 900
2019
Q2 		$1.66M Sell
20,946
-8,136
-28% -$593K 0.03% 770
2019
Q1 		$2.18M Buy
29,082
+25,948
+828% +$2.22M 0.07% 404
2018
Q4 		$218K Buy
3,134
+564
+22% +$42.8K 0.01% 1479
2018
Q3 		$243K Buy
2,570
+1,327
+107% +$116K 0.01% 1293
2018
Q2 		$101K Buy
+1,243
New +$86.9K 0.01% 1533
2017
Q4 		– Sell
-621
Closed -$32K – 1994
2017
Q3 		$32K Buy
+621
New +$28.1K ﹤0.01% 1754

Other funds holding IRTC

Vanguard Group
Vanguard Group Malvern, Pennsylvania $6.9T AUM 27.45% 1-Year Est. Return
BlackRock
BlackRock New York $5.72T AUM 30.48% 1-Year Est. Return
Artisan Partners
Artisan Partners Milwaukee, Wisconsin $62.3B AUM 26.25% 1-Year Est. Return
Sands Capital Management
Sands Capital Management Arlington, Virginia $25.5B AUM 26.46% 1-Year Est. Return
Capital Research Global Investors
Capital Research Global Investors Los Angeles, California $645B AUM 30.41% 1-Year Est. Return
State Street
State Street Boston, Massachusetts $2.9T AUM 29.55% 1-Year Est. Return
Geode Capital Management
Geode Capital Management Boston, Massachusetts $1.61T AUM 30.72% 1-Year Est. Return
William Blair & Company
William Blair & Company Chicago, Illinois $34.9B AUM 18.88% 1-Year Est. Return
EAM
Eventide Asset Management Boston, Massachusetts $6.05B AUM 76.64% 1-Year Est. Return
Fidelity Investments
Fidelity Investments Boston, Massachusetts $1.9T AUM 41.92% 1-Year Est. Return

Cubist Systematic Strategies's IRTC Position: Q3 2025 in Review

Cubist Systematic Strategies reduced its iRhythm Holdings (IRTC) stake by 19% in Q3 2025, selling an estimated $3.42M and leaving 89,220 shares worth $15.3M. The position accounts for 0.07% of the portfolio, ranked #372.

Cubist Systematic Strategies first reported a position in IRTC in Q3 2017 and has held it in 26 quarters since. The position peaked at $17M in Q2 2025. 337 funds tracked by Wall St. Rank hold IRTC as of Q3 2025.

  • Cubist Systematic Strategies held 89,220 shares of iRhythm Holdings worth $15.3M as of Q3 2025.
  • Cubist Systematic Strategies sold 21,507 iRhythm Holdings shares in Q3 2025, an estimated $3.42M.
  • iRhythm Holdings made up 0.07% of Cubist Systematic Strategies's portfolio in Q3 2025, its #372 holding.
  • Cubist Systematic Strategies first reported a position in iRhythm Holdings in Q3 2017 and has held it in 26 quarters since.
  • Cubist Systematic Strategies's iRhythm Holdings position peaked at $17M in Q2 2025.
  • 337 funds tracked by Wall St. Rank held iRhythm Holdings as of Q3 2025.

Based on Cubist Systematic Strategies's 13F filing for Q3 2025, filed 14 Nov 2025.