Castle Biosciences
CSTL
173 hedge funds and large institutions have $608M invested in Castle Biosciences in 2025 Q3 according to their latest regulatory filings, with 37 funds opening new positions, 62 increasing their positions, 53 reducing their positions, and 15 closing their positions.
356% more call options, than puts
Call options by funds: $984K | Put options by funds: $216K
147% more first-time investments, than exits
New positions opened: 37 | Existing positions closed: 15
17% more repeat investments, than reductions
Existing positions increased: 62 | Existing positions reduced: 53
14% more funds holding
Funds holding: 152 → 173 (+21)
12% more capital invested
Capital invested by funds: $542M → $608M (+$66.5M)
0.04% less ownership
Funds ownership: 91.91% → 91.87% (-0.04%)
Top Buyers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
ACM
AIGH Capital Management
Baltimore,
Maryland
|
+$14.4M |
| 2 |
SPPAM
Summit Partners Public Asset Management
Boston,
Massachusetts
|
+$8.13M |
| 3 |
Point72 Asset Management
Stamford,
Connecticut
|
+$6.84M |
| 4 |
Connor, Clark & Lunn Investment Management (CC&L)
Vancouver,
British Columbia, Canada
|
+$4.25M |
| 5 |
Millennium Management
New York
|
+$2.98M |
Top Sellers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
Citadel Advisors
Miami,
Florida
|
-$13M |
| 2 |
Wellington Management Group
Boston,
Massachusetts
|
-$8.32M |
| 3 |
WA
Wasatch Advisors
Salt Lake City,
Utah
|
-$7.73M |
| 4 |
Schroder Investment Management Group
London,
United Kingdom
|
-$3.12M |
| 5 |
TI
Trexquant Investment
Stamford,
Connecticut
|
-$2.84M |
CSTL Hedge Fund Activity: Q3 2025 in Review
173 of the 7,619 institutional investors tracked by Wall St. Rank reported a position in Castle Biosciences (CSTL) for Q3 2025, worth a combined $608M — up 12% from $542M a quarter earlier.
Buyers outnumbered sellers: 37 funds opened new CSTL positions and 15 closed out — a net gain of 22 holders — while 62 added to existing stakes and 53 trimmed.
The largest buyer was AIGH Capital Management, opening a new position worth an estimated $14.4M. The largest seller was Citadel Advisors, cutting an estimated $13M.
- 173 institutional investors held Castle Biosciences (CSTL) as of Q3 2025, up from 152 in Q2 2025.
- Funds reported $608M of Castle Biosciences stock for Q3 2025, up 12% quarter-over-quarter.
- 37 funds opened new Castle Biosciences positions in Q3 2025 and 15 closed out, a net change of +22 holders.
- The largest Castle Biosciences buyer in Q3 2025 was AIGH Capital Management, an estimated $14.4M added.
- The largest Castle Biosciences seller in Q3 2025 was Citadel Advisors, an estimated $13M sold.
Based on aggregated 13F filings for Q3 2025.