Castle Biosciences Inc
$33.42-0.1%
+$50.9M
Net Activity
+3.03% total shares
Institutions Holding
179
Popularity Rank
#3283
Avg Weight
0.03%
Total Value
$696.4M
Market Cap
$968.7M
179 institutions currently hold CSTL, with 104 net buyers and 88 net sellers this quarter.
Institutional Moves (Q2 2026)
Neutral
Based on recent trading activity
Net Selling Institutions
88
Net Buying Institutions
104
Top 5 by Value
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Across its top 20 institutional holders, CSTL's holder base skews toward low-concentration, high-turnover investors on average (avg. concentration score 7/100, avg. turnover score 50/100).
CSTL ranks #3283 out of 37503 tracked stocks by institutional interest — one of the most closely watched names in our coverage.
179 institutions disclose a position in CSTL, but none treat it as a major bet — even AIGH Capital Management LLC, its most concentrated holder, allocates just 0.8% of its own portfolio to it.
Mackenzie Financial CORP has added to its CSTL position for two straight quarters, increasing it by $17.5M to reach $18.9M today.
Portolan Capital Management, LLC has trimmed its CSTL position for two straight quarters, cutting it by $59.4M while still holding $7.8M.
CSTL is down 0.1% today, but institutions show net buying of $50.9M this quarter — a divergence between today's price move and the underlying institutional flow.
CSTL reported a net loss of $19.4M over the trailing twelve months.
+$154.8M
Total Buy Value
$115.8M
Total Sell Value
104
Net Buyers
88
Net Sellers
CSTL
Q2 2026
Top 5 Institutional Movers
-$25.3M
+$17.1M
+$15.4M
+$10.0M
CSTL does not currently have enough recent insider (Form 4) trading activity to compute a convergence signal against its 13F institutional flows.
13F data as of 2026-06-30 quarterly filings. Note: many large institutions file close to the 45-day post-quarter deadline, so early-quarter flow figures can shift substantially as more filings arrive.
8
Filings (90d)
$6.87M
Total Est. Value
242K shares
Planned Shares
| Filer | Filing Date | Est. Value |
|---|---|---|
| Tobin Juvenal | 2026-08-25 | $788K |
| Kristen M. Oelschlager | 2026-08-24 | $841K |
| Derek Maetzold | 2026-08-14 | $764K |
| FRANKLIN M. STOKES | 2026-08-14 | $741K |
| Tobin Juvenal | 2026-07-31 | $630K |
| Derek Maetzold | 2026-07-31 | $1.89M |
| Derek Maetzold | 2026-07-01 | $589K |
| Oelschlager Kristen M | 2026-06-16 | $618K |
Form 144 is a planned sale notice, not an executed transaction. Form 144 Tracker。
No Schedule 13D/13G filings for this ticker
1
Filings (14d)
Castle Biosciences (CSTL) issued a press release on July 30, 2026, announcing its financial results for the second quarter ended June 30, 2026, and attached that release as Exhibit 99.1 to this 8-K. That said, the excerpt we're looking at doesn't actually contain any of the numbers — the actual revenue or profit figures are in the attached press release, not in the filing text itself.
View Full Filing (SEC EDGAR)14843C105
The most-added stocks by 13F institutions this quarter
Institutions Holding
6,242
Total reported value
$2.2T
3229 13F institutions increased their position this quarter
Institutions Holding
5,990
Total reported value
$3.6T
3033 13F institutions increased their position this quarter
Institutions Holding
6,153
Total reported value
$1.8T
2971 13F institutions increased their position this quarter
The most widely held stocks tracked across all 13F institutions
Institutions Holding
4,763
Total reported value
$1.2T
Held by 4763 institutions — one of the most-tracked stocks on AlphaSMO
Institutions Holding
4,691
Total reported value
$473.3B
Held by 4691 institutions — one of the most-tracked stocks on AlphaSMO
Institutions Holding
4,637
Total reported value
$985.7B
Held by 4637 institutions — one of the most-tracked stocks on AlphaSMO
Access CSTL's institutional ownership data programmatically:
REST API
curl https://alphasmo.com/api/v1/market/stock/CSTLCLI
npx alphasmo stocks get CSTL