CSTL

CASTLE BIOSCIENCES INC

NasdaqHealthcareServices-Medical Laboratories

Insider activity for last month from 08/04 to 09/04. Counts use processed Form 4 rows. Purchase and sale metrics use codes P and S; totals remain unknown when any matching value is missing. Rows without a usable transaction date cannot be assigned to a rolling period and are excluded.

Latest filingSep 03, 2026Most recent Form 4
Total buying$00 buys
Total selling$267M16 sells
Net open-market-$267M4 insiders
Open-market mix
Buy vs sell distribution by transaction count
16 transactions
0 buys0%·100%16 sells

Insider activity report

Monthly open-market purchase and sale counts
Buys Sells
1580-8-15transactionsAug 2026 sells: 14 transactions · $253M14AugSep 2026 sells: 2 transactions · $13.8M2Sep

Transaction codes

By Form 4 transaction code in selected period
20transactions
  • S · Open-market sells · dominant16 · 80%
  • M · Option exercise4 · 20%

Activity by reported role

A joint filing can contribute to multiple roles
30transactions
  • Chief executive officer · dominant10 · 33%
  • PRES10 · 33%
  • COO7 · 23%
  • CCO2 · 7%
  • Chief financial officer1 · 3%

Distinct insiders active

Reporting-owner CIKs by month · peak Aug 2026 (4)
Aug 2026Sep 2026
5distinct insiders in 2 months

Reported Holdings After

Separated by insider, security, and ownership type
Oelschlager Kristen MCommon Stock · Indirect · The Fritz Shorter Trust
85.0k72.6kAug 24, 2026 · 85,033 shares owned afterAug 25, 2026 · 72,649 shares owned afterAug 25, 2026 · 77,872 shares owned afterAug 24, 2026Aug 25, 2026
77,872Aug 25, 2026
Maetzold Derek JCommon Stock · Direct
33.9k21.5kAug 28, 2026 · 22,435 shares owned afterAug 28, 2026 · 33,907 shares owned afterAug 28, 2026 · 21,479 shares owned afterAug 28, 2026Aug 28, 2026
21,479Aug 28, 2026
Oelschlager Kristen MCommon Stock · Direct
17.5k13.4kSep 01, 2026 · 17,508 shares owned afterSep 01, 2026 · 13,556 shares owned afterSep 01, 2026 · 13,356 shares owned afterSep 01, 2026Sep 01, 2026
13,356Sep 01, 2026
Juvenal Tobin WCommon Stock · Direct
76.0k66.9kAug 17, 2026 · 75,964 shares owned afterAug 25, 2026 · 66,914 shares owned afterAug 17, 2026Aug 25, 2026
66,914Aug 25, 2026
Maetzold Derek JCommon Stock · Indirect · By The Maetzold 2018 Remainder Trust FBO Emily Carol Kirk
11.3k11.3kAug 28, 2026 · 11,256 shares owned afterAug 28, 2026 · 11,277 shares owned afterAug 28, 2026Aug 28, 2026
11,277Aug 28, 2026
Maetzold Derek JCommon Stock · Indirect · By Derek Maetzold 2020 Irrevocable Trust
15.2k15.0kAug 28, 2026 · 14,995 shares owned afterAug 28, 2026 · 15,172 shares owned afterAug 28, 2026Aug 28, 2026
15,172Aug 28, 2026
Maetzold Derek JCommon Stock · Indirect · By The Maetzold Descendants 2020 Trust
17.9k17.6kAug 28, 2026 · 17,641 shares owned afterAug 28, 2026 · 17,850 shares owned afterAug 28, 2026Aug 28, 2026
17,850Aug 28, 2026
Stokes FrankCommon Stock · Direct
35.2k35.2kAug 14, 2026 · 35,177 shares owned afterAug 14, 2026Aug 14, 2026
35,177Aug 14, 2026

These are reported post-transaction holdings, not company-wide ownership percentages. Securities, indirect vehicles, and amendments are kept separate.

Filing activity heatmap
Each cell is one day · intensity = transactions · buys green, sells red
0 active days
Aug 04Sep 04
LessMore

Filing detail checks

Secondary metrics for the selected period
Largest buy-
Largest sale$74.1M
10b5-1 detected16
Amended rows0

CSTL transaction history

Filters apply within this company and selected period by default
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TickerInsiderRoleTypeSharesValueCodeSignals90d returnFiledTrans date

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CASTLE BIOSCIENCES INC Insider Activity FAQ

SEC Form 4 context

Who recently reported transactions at CASTLE BIOSCIENCES INC?

Oelschlager Kristen M, MAETZOLD DEREK J, Juvenal Tobin W, Stokes Frank.

When was the latest reported open-market purchase?

No code-P purchase is available for this period.

When was the latest reported open-market sale?

Oelschlager Kristen M reported a sale on Sep 01, 2026 valued at $680k. Read the SEC filing.

What is the recent purchase and sale balance?

Net open-market selling in the selected period was $2,674,769.45. Sales can occur for many non-investment reasons.

Where can I see the original SEC filing?

Every transaction row and latest-activity fact links to its original SEC filing.

What do these Form 4 transaction codes mean?

P and S generally describe open-market or private purchases and sales. A, D, F, M, X, G, J, and V describe awards, issuer dispositions, tax withholding, exercises, gifts, other transactions, and voluntary early reports; review each filing and its footnotes for context.