Westfield Capital Management’s iRhythm Holdings IRTC Stock Holding History

Westfield Capital 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	$34.4M	Buy	+288,924	New	+$33.6M	0.11%	195
2026 Q1	–	Sell	-325,063	Closed	-$57.7M	–	272
2025 Q4	$57.7M	Buy	325,063 +1,083	+0.3%	+$192K	0.24%	137
2025 Q3	$55.7M	Buy	323,980 +33,410	+11%	+$5.31M	0.23%	136
2025 Q2	$44.7M	Sell	290,570 -326,508	-53%	-$42.2M	0.19%	159
2025 Q1	$64.6M	Sell	617,078 -148,175	-19%	-$15.7M	0.31%	100
2024 Q4	$69M	Buy	765,253 +236,962	+45%	+$18.6M	0.3%	102
2024 Q3	$39.2M	Sell	528,291 -80,789	-13%	-$6.43M	0.18%	150
2024 Q2	$65.6M	Buy	609,080 +106,402	+21%	+$10.9M	0.32%	101
2024 Q1	$58.3M	Buy	+502,678	New	+$56.5M	0.31%	119

Other funds holding IRTC

BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return

RTW Investments New York $11.7B AUM 174.13% 1-Year Est. Return

Vanguard Portfolio Management Malvern, Pennsylvania $2.22T AUM

Artisan Partners Milwaukee, Wisconsin $63.1B AUM 35.51% 1-Year Est. Return

Vanguard Capital Management Malvern, Pennsylvania $4.68T AUM

Millennium Management New York $276B AUM 44.8% 1-Year Est. Return

Fidelity Investments Boston, Massachusetts $2.3T AUM 54.33% 1-Year Est. Return

UBS AM Chicago, Illinois $550B AUM 43.33% 1-Year Est. Return

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

Westfield Capital Management's IRTC Position: Q2 2026 in Review

Westfield Capital Management opened a new position in iRhythm Holdings (IRTC) in Q2 2026: 288,924 shares worth $34.4M. The stake represents 0.11% of the portfolio and ranks #195 among its holdings. This is a return to the name: Westfield Capital Management previously reported a position in IRTC as recently as Q4 2025.

Westfield Capital Management first reported a position in IRTC in Q1 2024 and has held it in 9 quarters since. The position peaked at $69M in Q4 2024. 304 funds tracked by Wall St. Rank hold IRTC as of Q2 2026.

Westfield Capital Management held 288,924 shares of iRhythm Holdings worth $34.4M as of Q2 2026.
iRhythm Holdings was a new Westfield Capital Management position in Q2 2026.
iRhythm Holdings made up 0.11% of Westfield Capital Management's portfolio in Q2 2026, its #195 holding.
Westfield Capital Management first reported a position in iRhythm Holdings in Q1 2024 and has held it in 9 quarters since.
Westfield Capital Management's iRhythm Holdings position peaked at $69M in Q4 2024.
304 funds tracked by Wall St. Rank held iRhythm Holdings as of Q2 2026.

Based on Westfield Capital Management's 13F filing for Q2 2026, filed 12 Aug 2026.