Castle Biosciences
CSTL
152 hedge funds and large institutions have $542M invested in Castle Biosciences in 2025 Q2 according to their latest regulatory filings, with 16 funds opening new positions, 69 increasing their positions, 45 reducing their positions, and 42 closing their positions.
450% more call options, than puts
Call options by funds: $22K | Put options by funds: $4K
53% more repeat investments, than reductions
Existing positions increased: 69 | Existing positions reduced: 45
1.17% more ownership
Funds ownership: 90.74% → 91.91% (+1.2%)
5% more capital invested
Capital invested by funds: $516M → $542M (+$25.5M)
16% less funds holding
Funds holding: 180 → 152 (-28)
62% less first-time investments, than exits
New positions opened: 16 | Existing positions closed: 42
100% less funds holding in top 10
Funds holding in top 10: 2 → 0 (-2)
Top Buyers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
Citadel Advisors
Miami,
Florida
|
+$11.7M |
| 2 |
B
Braidwell
Stamford,
Connecticut
|
+$8.47M |
| 3 |
N
Nuveen
Charlotte,
North Carolina
|
+$7.43M |
| 4 |
Principal Financial Group
Des Moines,
Iowa
|
+$6.13M |
| 5 |
UBS Group
Zurich,
Switzerland
|
+$5.83M |
Top Sellers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
PWAM
Park West Asset Management
San Francisco,
California
|
-$11.1M |
| 2 |
Wellington Management Group
Boston,
Massachusetts
|
-$7.8M |
| 3 |
BG
Bellevue Group
Kuesnacht,
Switzerland
|
-$6.03M |
| 4 |
CSS
Cubist Systematic Strategies
Stamford,
Connecticut
|
-$4.76M |
| 5 |
Point72 Asset Management
Stamford,
Connecticut
|
-$4.73M |
CSTL Hedge Fund Activity: Q2 2025 in Review
152 of the 7,595 institutional investors tracked by Wall St. Rank reported a position in Castle Biosciences (CSTL) for Q2 2025, worth a combined $542M — up 4.9% from $516M a quarter earlier.
Sellers outnumbered buyers: 42 funds closed out of CSTL and 16 opened new positions — a net loss of 26 holders — while 45 trimmed existing stakes and 69 added.
The largest buyer was Citadel Advisors, adding an estimated $11.7M. The largest seller was Park West Asset Management, exiting entirely with an estimated $11.1M sold.
- 152 institutional investors held Castle Biosciences (CSTL) as of Q2 2025, down from 180 in Q1 2025.
- Funds reported $542M of Castle Biosciences stock for Q2 2025, up 4.9% quarter-over-quarter.
- 16 funds opened new Castle Biosciences positions in Q2 2025 and 42 closed out, a net change of -26 holders.
- The largest Castle Biosciences buyer in Q2 2025 was Citadel Advisors, an estimated $11.7M added.
- The largest Castle Biosciences seller in Q2 2025 was Park West Asset Management, an estimated $11.1M sold.
Based on aggregated 13F filings for Q2 2025.