RTW Investments’s Castle Biosciences CSTL Stock Holding History

RTW Investments’s Portfolio CSTL Stock Details CSTL Fund Activity

Bought

Maintained

Sold

Quarter	Market Value	Status	Shares	Change in Stake	Trade Value	Portfolio Weight	Portfolio Position
2026 Q1	$67.7M	Buy	2,758,335 +643,098	+30%	+$21.1M	0.67%	38
2025 Q4	$82.3M	Buy	+2,115,237	New	+$68.2M	0.82%	35
2023 Q2	–	Sell	-258,498	Closed	-$5.87M	–	64
2023 Q1	$5.87M	Sell	258,498 -258,497	-50%	-$6.32M	0.12%	49
2022 Q4	$12.2M	Hold	516,995	–	–	0.25%	44
2022 Q3	$13.5M	Sell	516,995 -396,794	-43%	-$11.1M	0.31%	46
2022 Q2	$20.1M	Buy	913,789 +417,114	+84%	+$9.69M	0.52%	42
2022 Q1	$22.3M	Sell	496,675 -102,334	-17%	-$4.23M	0.46%	49
2021 Q4	$25.7M	Hold	599,009	–	–	0.38%	59
2021 Q3	$39.8M	Sell	599,009 -200,000	-25%	-$14.1M	0.6%	47
2021 Q2	$58.6M	Hold	799,009	–	–	0.88%	31
2021 Q1	$54.7M	Hold	799,009	–	–	0.85%	34
2020 Q4	$53.7M	Buy	799,009 +55,367	+7%	+$3M	0.9%	34
2020 Q3	$38.3M	Sell	743,642 -59,868	-7%	-$2.66M	0.92%	33
2020 Q2	$30.3M	Buy	803,510 +105,392	+15%	+$3.6M	0.85%	34
2020 Q1	$20.8M	Buy	698,118 +67,046	+11%	+$2.02M	0.9%	34
2019 Q4	$21.7M	Sell	631,072 -113,973	-15%	-$2.79M	0.82%	31
2019 Q3	$13.5M	Buy	+745,045	New	+$16.5M	0.8%	30

Other funds holding CSTL

BlackRock New York $5.72T AUM 30.48% 1-Year Est. Return

Principal Financial Group Des Moines, Iowa $187B AUM 18.48% 1-Year Est. Return

PCM

Portolan Capital Management Boston, Massachusetts $1.88B AUM 115.74% 1-Year Est. Return

VCM

Vanguard Capital Management Malvern, Pennsylvania $4.04T AUM

Dimensional Fund Advisors Austin, Texas $481B AUM 30.42% 1-Year Est. Return

SPPAM

Summit Partners Public Asset Management Boston, Massachusetts $3.72B AUM 162.29% 1-Year Est. Return

VPM

Vanguard Portfolio Management Malvern, Pennsylvania $1.91T AUM

Allianz Asset Management Munich, Germany $95.4B AUM 38.74% 1-Year Est. Return

State Street Boston, Massachusetts $2.9T AUM 29.55% 1-Year Est. Return

Geode Capital Management Boston, Massachusetts $1.61T AUM 30.72% 1-Year Est. Return

RTW Investments's CSTL Position: Q1 2026 in Review

RTW Investments increased its Castle Biosciences (CSTL) stake by 30% in Q1 2026, buying an estimated $21.1M and bringing the position to 2,758,335 shares worth $67.7M. The position accounts for 0.67% of the portfolio, ranked #38.

RTW Investments first reported a position in CSTL in Q3 2019 and has held it in 17 quarters since. The position peaked at $82.3M in Q4 2025. 186 funds tracked by Wall St. Rank hold CSTL as of Q1 2026.

RTW Investments held 2,758,335 shares of Castle Biosciences worth $67.7M as of Q1 2026.
RTW Investments bought 643,098 Castle Biosciences shares in Q1 2026, an estimated $21.1M.
Castle Biosciences made up 0.67% of RTW Investments's portfolio in Q1 2026, its #38 holding.
RTW Investments first reported a position in Castle Biosciences in Q3 2019 and has held it in 17 quarters since.
RTW Investments's Castle Biosciences position peaked at $82.3M in Q4 2025.
186 funds tracked by Wall St. Rank held Castle Biosciences as of Q1 2026.

Based on RTW Investments's 13F filing for Q1 2026, filed 15 May 2026.