InsiderSource
CSTL

CASTLE BIOSCIENCES INC

SEC CIK 1447362
$20.70 −40.8% · 90 days
90-day buys
$0
0 open-market
90-day sells
$865.3K
33 open-market
Net insider flow
−$865.3K
Net selling
Filings shown
55
Most recent
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At a glance

Over the last 90 days, insiders at CSTL have sold a net $865.3K of stock (0 open-market buys vs 33 sells).

Largest recent trade: Juvenal Tobin W sold $526.6K of CSTL, trimming their stake 19%.

Most active filer: Maetzold Derek J, with 45 transactions among the recent filings shown.

Insider transaction history

Form 4 filings for CSTL, newest first
View on SEC EDGAR ↗
CSTL
CASTLE BIOSCIENCES INC
Sell MAETZOLD DEREK J · Director, Pres. & Chief Exec. Officer · Open-market sale · filed 1w ago ΔOwn −22%

Maetzold Derek J sold $129.6K of CSTL, trimming their stake 22%.

−$129.6K
6,214 sh @ $21
CSTL
CASTLE BIOSCIENCES INC
Sell MAETZOLD DEREK J · Director, Pres. & Chief Exec. Officer · Open-market sale · filed 1w ago ΔOwn −3.0%

Maetzold Derek J sold $28.3K of CSTL, trimming their stake 3%.

−$28.3K
1,357 sh @ $21
CSTL
CASTLE BIOSCIENCES INC
Sell MAETZOLD DEREK J · Director, Pres. & Chief Exec. Officer · Open-market sale · filed 1w ago ΔOwn −3.0%

Maetzold Derek J sold $24K of CSTL, trimming their stake 3%.

−$24K
1,153 sh @ $21
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CSTL
CASTLE BIOSCIENCES INC
Sell MAETZOLD DEREK J · Director, Pres. & Chief Exec. Officer · Open-market sale · filed 1w ago ΔOwn −14%

Maetzold Derek J sold $5.8K of CSTL, trimming their stake 14%.

−$5.8K
278 sh @ $21
CSTL
CASTLE BIOSCIENCES INC
Sell MAETZOLD DEREK J · Director, Pres. & Chief Exec. Officer · Open-market sale · filed 3w ago ΔOwn −1.9%

Maetzold Derek J sold $8.5K of CSTL, trimming their stake 2%.

−$8.5K
420 sh @ $20
CSTL
CASTLE BIOSCIENCES INC
Sell MAETZOLD DEREK J · Director, Pres. & Chief Exec. Officer · Open-market sale · filed 3w ago ΔOwn −2.3%

Maetzold Derek J sold $20.9K of CSTL, trimming their stake 2%.

−$20.9K
1,035 sh @ $20
CSTL
CASTLE BIOSCIENCES INC
Sell MAETZOLD DEREK J · Director, Pres. & Chief Exec. Officer · Open-market sale · filed 3w ago ΔOwn −2.3%

Maetzold Derek J sold $17.8K of CSTL, trimming their stake 2%.

−$17.8K
880 sh @ $20
CSTL
CASTLE BIOSCIENCES INC
Sell MAETZOLD DEREK J · Director, Pres. & Chief Exec. Officer · Open-market sale · filed 3w ago ΔOwn −9.8%

Maetzold Derek J sold $4.3K of CSTL, trimming their stake 10%.

−$4.3K
212 sh @ $20
CSTL
CASTLE BIOSCIENCES INC
Sell MAETZOLD DEREK J · Director, Pres. & Chief Exec. Officer · Open-market sale · filed 3w ago ΔOwn −0.6%

Maetzold Derek J sold $2.6K of CSTL, trimming their stake 1%.

−$2.6K
130 sh @ $20
CSTL
CASTLE BIOSCIENCES INC
Sell MAETZOLD DEREK J · Director, Pres. & Chief Exec. Officer · Open-market sale · filed 3w ago ΔOwn −0.7%

Maetzold Derek J sold $6.4K of CSTL, trimming their stake 1%.

−$6.4K
322 sh @ $20
CSTL
CASTLE BIOSCIENCES INC
Sell MAETZOLD DEREK J · Director, Pres. & Chief Exec. Officer · Open-market sale · filed 3w ago ΔOwn −0.7%

Maetzold Derek J sold $5.5K of CSTL, trimming their stake 1%.

−$5.5K
273 sh @ $20
CSTL
CASTLE BIOSCIENCES INC
Sell MAETZOLD DEREK J · Director, Pres. & Chief Exec. Officer · Open-market sale · filed 3w ago ΔOwn −3.0%

Maetzold Derek J sold $1.3K of CSTL, trimming their stake 3%.

−$1.3K
66 sh @ $20
CSTL
CASTLE BIOSCIENCES INC
Sell MAETZOLD DEREK J · Director, Pres. & Chief Exec. Officer · Open-market sale · filed May 11, 2026 ΔOwn −19%

Maetzold Derek J sold $117.2K of CSTL, trimming their stake 19%.

−$117.2K
5,308 sh @ $22
CSTL
CASTLE BIOSCIENCES INC
Sell MAETZOLD DEREK J · Director, Pres. & Chief Exec. Officer · Open-market sale · filed May 11, 2026 ΔOwn −2.4%

Maetzold Derek J sold $25.6K of CSTL, trimming their stake 2%.

−$25.6K
1,159 sh @ $22
CSTL
CASTLE BIOSCIENCES INC
Sell MAETZOLD DEREK J · Director, Pres. & Chief Exec. Officer · Open-market sale · filed May 11, 2026 ΔOwn −2.4%

Maetzold Derek J sold $21.7K of CSTL, trimming their stake 2%.

−$21.7K
985 sh @ $22
CSTL
CASTLE BIOSCIENCES INC
Sell MAETZOLD DEREK J · Director, Pres. & Chief Exec. Officer · Open-market sale · filed May 11, 2026 ΔOwn −9.5%

Maetzold Derek J sold $5.2K of CSTL, trimming their stake 9%.

−$5.2K
237 sh @ $22
CSTL
CASTLE BIOSCIENCES INC
Sell MAETZOLD DEREK J · Director, Pres. & Chief Exec. Officer · Open-market sale · filed May 11, 2026 ΔOwn −4.0%

Maetzold Derek J sold $20.5K of CSTL, trimming their stake 4%.

−$20.5K
906 sh @ $23
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About CSTL insider activity

This page tracks every recent Form 4 filed for CASTLE BIOSCIENCES INC with the U.S. Securities and Exchange Commission. Form 4 is the disclosure that company insiders — officers, directors, and holders of more than 10% of the stock — must file within two business days of buying or selling shares.

The summary above nets open-market purchases against open-market sales over the trailing 90 days. Open-market trades (codes P and S) tend to carry the most signal because they reflect a deliberate choice to put money in or take it out, as opposed to routine grants, option exercises, or tax-withholding events. Use the badges on each row to tell them apart, and always confirm details against the original filing before drawing conclusions.

Frequently asked questions

How often is CSTL insider data updated?

Continuously. We read from SEC EDGAR, so new Form 4 filings for CASTLE BIOSCIENCES INC usually appear here within minutes of being accepted by the SEC.

What does "net insider flow" mean?

It is the total dollar value of open-market insider purchases minus open-market sales over the last 90 days. A positive number (green) means insiders bought more than they sold; a negative number (red) means the reverse.

Why do some rows show grants or option exercises instead of buys?

Insiders receive stock through compensation as well as buying it outright. Form 4 captures all of these. We label each transaction by its SEC code so you can focus on open-market activity if you prefer.

Is this investment advice?

No. InsiderSource presents public filing data for informational purposes only. Insider activity is one of many factors to consider and is never a recommendation to buy or sell.