Castle Biosciences, Inc. (CSTL) Insider Trading
Over the last 3 months, CSTL insiders made 0 open-market buys and 42 sales, a net sale of -$4.0M (SEC Form 4). Over the last 6 months, 153 institutions increased and 129 reduced their position (13F).
Insider Activity
Sentiment
0/100
Buys (3m)
0
Sells (3m)
42
Net (3m)
-$4.0M
Insider trades by month Buys Sells
Dec
Jan
Feb
Mar
Apr
May
Context3-month price -22.6%Institutions mixed (13F)
| Date | Insider | Type | Shares | Price |
|---|---|---|---|---|
| Jun 1, 2026 | Cole G Bradleydirector | Grant | 11,766 | — |
| Jun 1, 2026 | Harrison Milesdirector | Grant | 11,766 | — |
| Jun 1, 2026 | BRADBURY DANIELdirector | Grant | 11,766 | — |
| Jun 1, 2026 | Cotton Rodneydirector | Grant | 11,766 | — |
| Jun 1, 2026 | Goldberg Ellendirector | Grant | 11,766 | — |
| Jun 1, 2026 | Olson Tiffanydirector | Grant | 11,766 | — |
| Jun 1, 2026 | Caple Kimdirector | Grant | 11,766 | — |
| May 27, 2026 | Harrison Milesdirector | Option | 13,667 | — |
| May 27, 2026 | Cotton Rodneydirector | Option | 13,667 | — |
| May 27, 2026 | Goldberg Ellendirector | Option | 13,667 | — |
| May 27, 2026 | Cole G Bradleydirector | Option | 13,667 | — |
| May 27, 2026 | BRADBURY DANIELdirector | Option | 13,667 | — |
| May 27, 2026 | Olson Tiffanydirector | Option | 13,667 | — |
| May 27, 2026 | Caple Kimdirector | Option | 13,667 | — |
| May 26, 2026 | Juvenal Tobin Wofficer: Chief Commercial Officer | Option | 11,210 | $3.38 |
| May 22, 2026 | MAETZOLD DEREK Jdirector, officer: Pres. & Chief Exec. Officer | Option | 130 | $2.39 |
| May 22, 2026 | MAETZOLD DEREK Jdirector, officer: Pres. & Chief Exec. Officer | Sell | 322 | $20.00 |
| May 22, 2026 | MAETZOLD DEREK Jdirector, officer: Pres. & Chief Exec. Officer | Sell | 273 | $20.00 |
| May 22, 2026 | MAETZOLD DEREK Jdirector, officer: Pres. & Chief Exec. Officer | Option | 420 | $2.39 |
| May 22, 2026 | MAETZOLD DEREK Jdirector, officer: Pres. & Chief Exec. Officer | Sell | 212 | $20.20 |
| May 22, 2026 | MAETZOLD DEREK Jdirector, officer: Pres. & Chief Exec. Officer | Sell | 66 | $20.00 |
| May 22, 2026 | MAETZOLD DEREK Jdirector, officer: Pres. & Chief Exec. Officer | Sell | 880 | $20.20 |
| May 22, 2026 | MAETZOLD DEREK Jdirector, officer: Pres. & Chief Exec. Officer | Sell | 130 | $20.00 |
| May 22, 2026 | MAETZOLD DEREK Jdirector, officer: Pres. & Chief Exec. Officer | Sell | 420 | $20.20 |
| May 22, 2026 | MAETZOLD DEREK Jdirector, officer: Pres. & Chief Exec. Officer | Sell | 1,035 | $20.20 |
| May 11, 2026 | MAETZOLD DEREK Jdirector, officer: Pres. & Chief Exec. Officer | Sell | 41 | $22.59 |
| May 11, 2026 | MAETZOLD DEREK Jdirector, officer: Pres. & Chief Exec. Officer | Sell | 168 | $22.59 |
| May 11, 2026 | MAETZOLD DEREK Jdirector, officer: Pres. & Chief Exec. Officer | Sell | 1,159 | $22.08 |
| May 11, 2026 | MAETZOLD DEREK Jdirector, officer: Pres. & Chief Exec. Officer | Option | 6,214 | $2.39 |
| May 11, 2026 | MAETZOLD DEREK Jdirector, officer: Pres. & Chief Exec. Officer | Sell | 906 | $22.59 |
Source: CSTL SEC Form 4 filings, latest Jun 1, 2026. For informational purposes only — not investment advice.
Institutional activity (13F)
How institutions changed their CSTL positions over the last 6 months (SEC Form 13F).
Increased
153
New positions
61
Reduced
129
Sold out
52
Largest moves
| Institution | Action | Shares | Filed |
|---|---|---|---|
| BLACKROCK, INC. | Reduced | 3.1M | Feb 12, 2026 |
| BLACKROCK, INC. | Reduced | 3.0M | May 13, 2026 |
| RTW INVESTMENTS, LP | Increased | 2.8M | May 15, 2026 |
| VANGUARD GROUP INC | Increased | 2.2M | Jan 29, 2026 |
| RTW INVESTMENTS, LP | New Position | 2.1M | Feb 17, 2026 |
| PRINCIPAL FINANCIAL GROUP INC | Increased | 1.8M | Feb 2, 2026 |
| PRINCIPAL FINANCIAL GROUP INC | Reduced | 1.8M | May 4, 2026 |
| PORTOLAN CAPITAL MANAGEMENT, LLC | Increased | 1.7M | Feb 17, 2026 |
| PORTOLAN CAPITAL MANAGEMENT, LLC | Reduced | 1.4M | May 15, 2026 |
| VANGUARD CAPITAL MANAGEMENT LLC | New Position | 1.2M | May 15, 2026 |
| DIMENSIONAL FUND ADVISORS LP | Reduced | 1.1M | Feb 12, 2026 |
| SUMMIT PARTNERS PUBLIC ASSET MANAGEMENT, LLC | Increased | 1.1M | Feb 17, 2026 |
| DIMENSIONAL FUND ADVISORS LP | Reduced | 1.0M | May 7, 2026 |
| SUMMIT PARTNERS PUBLIC ASSET MANAGEMENT, LLC | Reduced | 941K | May 15, 2026 |
| VANGUARD PORTFOLIO MANAGEMENT LLC | New Position | 862K | May 8, 2026 |
Source: SEC Form 13F filings. For informational purposes only — not investment advice.