CASTLE BIOSCIENCES INC

CSTL

Form 4 • Statement of Changes in Beneficial Ownership

SEC Accession Number: 0001628280-26-015344
Filing date: Mar 5, 2026
Earliest execution date: Mar 3, 2026

Summary

Type

Sell

Net shares

-36,974

% of shares

-7.89%

Amount (USD)

$1,030,131

Insider confidence score

37.5 out of 100

Positive

  • Tax withholding obligation

Negative

  • Large tax withholding sell (≥1% of shares)
  • Very large sell amount ($1M+)

Stock transactions

Transaction 1

Security

Common Stock

Action

Tax_withhold

Date

2026-03-03

Code

F

Net shares

-19,043.0

Price per Share

$27.57

Amount (USD)

$525,015.51

Acquired/Disposed

Disposed

Shares Owned Before

83,698.0

Shares Owned After

64,655.0

Transaction 2

Security

Common Stock

Action

Exercise

Date

2026-03-04

Code

M

Net shares

+59,097.0

Acquired/Disposed

Acquired

Shares Owned Before

64,655.0

Shares Owned After

123,752.0

Transaction 3

Security

Common Stock

Action

Tax_withhold

Date

2026-03-04

Code

F

Net shares

-17,931.0

Price per Share

$28.17

Amount (USD)

$505,116.27

Acquired/Disposed

Disposed

Shares Owned Before

123,752.0

Shares Owned After

105,821.0

Derivative Transactions

Transaction 1

Security

Restricted Stock Units

Action

Grant

Date

2026-03-03

Code

A

Net shares

+102,597.0

Acquired/Disposed

Acquired

Shares Owned Before

0.0

Shares Owned After

102,597.0

Transaction 2

Security

Restricted Stock Units

Action

Exercise

Date

2026-03-04

Code

M

Net shares

-31,110.0

Acquired/Disposed

Disposed

Shares Owned Before

93,328.0

Shares Owned After

62,218.0

Transaction 3

Security

Restricted Stock Units

Action

Exercise

Date

2026-03-04

Code

M

Net shares

-27,987.0

Acquired/Disposed

Disposed

Shares Owned Before

111,948.0

Shares Owned After

83,961.0

Filing's footnotes

1. Reflects the withholding of shares of the Issuer's common stock to satisfy tax withholding obligations in connection with the delivery of vested performance stock units reported on January 12, 2026.

2. Each Restricted Stock Unit ("RSU") represents the right to receive one share of the Issuer's Common Stock.

3. Held by The Maetzold Descendants 2020 Trust of which the Reporting Person's spouse is the trustee and the Reporting Person's spouse and their children are beneficiaries.

4. Held by Derek Maetzold 2020 Irrevocable Trust of which the Reporting Person is the trustee and his children are beneficiaries.

5. Held by The Maetzold 2018 Remainder Trust FBO Emily Carol Kirk of which the Reporting Person is the trustee and his child is the beneficiary.

6. Held by The Maetzold 2018 Remainder Trust FBO Hannah Elizabeth Maetzold of which the Reporting Person is the trustee and his child is the beneficiary.

7. Held by The Maetzold 2018 Remainder Trust FBO John Derek Maetzold of which the Reporting Person is the trustee and his child is the beneficiary.

8. Held by The Maetzold 2018 Remainder Trust FBO Peter Douglas Maetzold of which the Reporting Person is the trustee and his child is the beneficiary.

9. Held by DJM Grantor Retained Annuity Trust No. 5 of which the Reporting Person is the trustee and beneficiary.

10. Held by DJM Grantor Retained Annuity Trust No. 6 of which the Reporting Person is the trustee and the beneficiaries are The Maetzold 2018 Remainder Trust FBO John Derek Maetzold, The Maetzold 2018Remainder Trust FBO Emily Carol Kirk, The Maetzold 2018 Remainder Trust FBO Peter Douglas Maetzold and The Maetzold 2018 Remainder Trust FBO Hannah Elizabeth Maetzold.

11. Held by DJM Grantor Retained Annuity Trust No. 7 of which the Reporting Person is the trustee and beneficiary.

12. The RSU's vest in four equal annual installments beginning on March 03, 2027.

13. On March 4, 2024, the Reporting Person was granted 124,437 RSUs which vest in four equal installments beginning on March 4, 2025.

14. On March 4, 2025, the Reporting Person was granted 111,948 RSUs which vest in four equal installments beginning on March 4, 2026.

This page is for informational purposes only. While we strive for accuracy, the summary may contain inaccuracies or omissions. Please refer to the official SEC filing for authoritative information. Open the SEC filing.