CSTL
Castle Biosciences Inc
34.90$
-6.0%
vs. previous close
Closing price · As of: Nov 2, 2026
Ownership
Ownership Structure
Who owns Castle Biosciences Inc (CSTL)? This page shows the largest institutions and funds, the ownership structure and the latest insider transactions. 89.0% of the shares are freely tradable; institutional investors hold 93.0%.
Institutional ownership
?Share of the stock held by institutional investors (funds, banks, insurers) according to regulatory filings.
93.0%
Insiders
?Share of the stock held by the executives, founders and major shareholders of the company itself.
2.7%
Float
?Share of stock freely tradable on the market — not locked up in the hands of founders, insiders, or major shareholders.
89.0%
Short % of float
?Shares sold short as a percentage of the freely tradable float — high values signal many bets on falling prices.
6.7%
Shares Outstanding
?Total number of shares issued. Price times share count gives market cap.
31Mio.
Largest Shareholders
Institutions
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| BlackRock Inc | 10.78 | 3,291,963 | +10.4 | 06/30/2026 |
| RTW INVESTMENTS, LLC | 9.09 | 2,778,335 | +0.7 | 06/30/2026 |
| Principal Financial Group Inc | 5.65 | 1,726,648 | -2.4 | 06/30/2026 |
| Vanguard Capital Management, LLC | 4.01 | 1,226,497 | +4.2 | 06/30/2026 |
| Acadian Asset Management LLC | 3.01 | 918,668 | +89.6 | 06/30/2026 |
| Allianz Asset Management AG | 2.88 | 879,258 | +8.4 | 06/30/2026 |
| Vanguard Portfolio Management, LLC | 2.75 | 840,785 | -2.4 | 06/30/2026 |
| Summit Partners Public Asset Management, LLC | 2.70 | 824,872 | -12.3 | 06/30/2026 |
| State Street Corp | 2.69 | 822,079 | +6.9 | 06/30/2026 |
Funds
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| Vanguard MStar Total Stk Mkt Idx Invest | 2.84 | 866,498 | +1.6 | 09/30/2026 |
Largest reported positions according to regulatory filings; stake as a percentage of shares outstanding, change versus the previous filing. Source: fundamentals data.
Insider holdings
| Person | Role | Shares | Value | As of | Type |
|---|---|---|---|---|---|
| Oelschlager Kristen M | Chief Operating Officer | 86,005 | 3,001,575 $ | Aug 25, 2026 | both |
| Juvenal Tobin W | Chief Commercial Officer | 38,853 | 1,355,970 $ | Oct 28, 2026 | direct |
| Stokes Frank | Chief Financial Officer | 35,177 | 1,227,677 $ | Aug 14, 2026 | direct |
| Maetzold Derek J | Pres. & Chief Exec. Officer | 32,694 | 1,141,021 $ | Aug 28, 2026 | both |
Holdings as of each person's most recent SEC Form 4 filing — excluding options and RSUs, which are not shares yet. Holdings may have changed between two filings.
Insiders
Insider Transactions
| Date | Person | Role | Type | Shares | Price | Value |
|---|---|---|---|---|---|---|
| Oct 28, 2026 | Juvenal Tobin W | Chief Commercial Officer | Sell | 5,341 | 36.62 | 195,582 |
| Oct 28, 2026 | Juvenal Tobin W | Chief Commercial Officer | Sell | 1,237 | 35.58 | 44,009 |
| Oct 26, 2026 | Juvenal Tobin W | Chief Commercial Officer | Sell | 3,288 | 33.08 | 108,767 |
| Oct 19, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Sell | 2,718 | 31.91 | 86,731 |
| Oct 19, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Sell | 3,198 | 31.91 | 102,048 |
| Oct 19, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Sell | 8,580 | 31.91 | 273,788 |
| Oct 12, 2026 | Juvenal Tobin W | Chief Commercial Officer | Sell | 3,288 | 33.64 | 110,608 |
| Oct 5, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Sell | 2,718 | 35.57 | 96,668 |
| Oct 5, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Sell | 3,198 | 35.57 | 113,740 |
| Oct 5, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Sell | 8,580 | 35.57 | 305,156 |
| Oct 5, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Other | 8,165 | 2.39 | 19,514 |
| Oct 1, 2026 | Oelschlager Kristen M | Chief Operating Officer | Sell | 1,346 | 36.38 | 48,967 |
| Oct 1, 2026 | Oelschlager Kristen M | Chief Operating Officer | Sell | 2,807 | 35.75 | 100,350 |
| Oct 1, 2026 | Oelschlager Kristen M | Chief Operating Officer | Other | 4,153 | 3.38 | 14,037 |
| Sep 30, 2026 | Juvenal Tobin W | Chief Commercial Officer | Sell | 1,034 | 34.20 | 35,363 |
| Sep 29, 2026 | Juvenal Tobin W | Chief Commercial Officer | Sell | 5,543 | 35.50 | 196,765 |
| Sep 21, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Sell | 2,718 | 35.33 | 96,038 |
| Sep 21, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Sell | 3,198 | 35.33 | 112,998 |
| Sep 21, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Sell | 8,580 | 35.33 | 303,166 |
| Sep 21, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Other | 8,580 | 2.39 | 20,506 |
| Sep 15, 2026 | Juvenal Tobin W | Chief Commercial Officer | Sell | 3,294 | 35.14 | 115,758 |
| Sep 14, 2026 | Juvenal Tobin W | Chief Commercial Officer | Sell | 3,306 | 32.32 | 106,863 |
| Sep 11, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Sell | 71 | 32.78 | 2,327 |
| Sep 11, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Sell | 83 | 32.78 | 2,721 |
| Sep 11, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Sell | 223 | 32.78 | 7,310 |
| Sep 11, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Sell | 2,656 | 32.00 | 84,992 |
| Sep 11, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Sell | 3,124 | 32.00 | 99,968 |
| Sep 11, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Sell | 8,361 | 32.00 | 267,552 |
| Sep 11, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Other | 8,584 | 2.39 | 20,516 |
| Sep 1, 2026 | Oelschlager Kristen M | Chief Operating Officer | Sell | 200 | 34.02 | 6,804 |
| Sep 1, 2026 | Oelschlager Kristen M | Chief Operating Officer | Sell | 3,952 | 33.36 | 131,839 |
| Sep 1, 2026 | Oelschlager Kristen M | Chief Operating Officer | Other | 4,152 | 3.38 | 14,034 |
| Aug 31, 2026 | Juvenal Tobin W | Chief Commercial Officer | Sell | 1,730 | 32.81 | 56,761 |
| Aug 28, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Sell | 21 | 33.88 | 711 |
| Aug 28, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Sell | 177 | 33.88 | 5,997 |
| Aug 28, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Sell | 209 | 33.88 | 7,081 |
| Aug 28, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Sell | 956 | 33.88 | 32,389 |
| Aug 28, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Sell | 257 | 33.14 | 8,517 |
| Aug 28, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Sell | 2,129 | 33.14 | 70,555 |
| Aug 28, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Sell | 2,505 | 33.14 | 83,016 |
| Aug 28, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Sell | 11,472 | 33.14 | 380,182 |
| Aug 28, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Other | 12,428 | 2.39 | 29,703 |
| Aug 25, 2026 | Juvenal Tobin W | Chief Commercial Officer | Sell | 9,050 | 35.04 | 317,112 |
| Aug 25, 2026 | Oelschlager Kristen M | Chief Operating Officer | Sell | 5,223 | 34.64 | 180,920 |
| Aug 25, 2026 | Oelschlager Kristen M | Chief Operating Officer | Sell | 7,161 | 34.26 | 245,357 |
| Aug 24, 2026 | Oelschlager Kristen M | Chief Operating Officer | Sell | 12,218 | 33.69 | 411,588 |
| Aug 17, 2026 | Juvenal Tobin W | Chief Commercial Officer | Sell | 1,730 | 29.59 | 51,191 |
| Aug 14, 2026 | Stokes Frank | Chief Financial Officer | Sell | 24,908 | 29.77 | 741,511 |
| Aug 14, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Sell | 278 | 30.02 | 8,346 |
| Aug 14, 2026 | Maetzold Derek J | Pres. & Chief Exec. Officer | Sell | 2,306 | 30.02 | 69,226 |
Reportable transactions by officers and major shareholders from SEC Form 4 filings. "Other" includes things like stock grants and option exercises without a buy/sell character. View all insider transactions →
Data as of: November 2, 2026 · Source: fundamental data & SEC filings (annual and quarterly reports, 10-K/10-Q)
Note: pure fact-based analysis, not investment advice and not a solicitation to buy or sell. All figures without guarantee.