MAETZOLD DEREK J (Pres. & Chief Exec. Officer) sold 68.2% of their position (4.17K shares) of CASTLE BIOSCIENCES INC on the open market

Open‑market sale worth $84.1K — a major position exit. Review remaining holdings and any 10b5‑1 plan disclosures.

S · 14 sales

MAETZOLD DEREK J

Filed: 5/22/2026ACC: 0001628280-26-037724

InsiderMAETZOLD DEREK JCIK 1239501

→

IssuerCASTLE BIOSCIENCES INCCIK 1447362

DirectorOfficer10% Owner· Pres. & Chief Exec. Officer

Since Jul 2019

-4.17K

Net shares

Net seller

$84.1K

Total sold

Open market trades

0B · 14S

Total transactions

550.00 acquired · 4.72K disposed

Non-Derivative Transactions16

Common Stock

Direct

M · Option Exercise

+130.00

Price / share

$2.39

Trade value

$310.70

% of position

0.6%

5/20/2026

21.48K→21.61K

Common Stock

Direct

S · Sale

−130.00

Price / share

$20.00

Trade value

$2.60K

% of position

0.6%

5/20/2026

21.61K→21.48K

Common Stock

Indirect

S · Sale

−322.00

Price / share

$20.00

Trade value

$6.44K

% of position

0.7%

5/20/2026

46.14K→45.82K

Common Stock

Indirect

S · Sale

−273.00

Price / share

$20.00

Trade value

$5.46K

% of position

0.7%

5/20/2026

39.21K→38.94K

Common Stock

Indirect

S · Sale

−66.00

Price / share

$20.00

Trade value

$1.32K

% of position

3.0%

5/20/2026

2.22K→2.16K

Common Stock

Indirect

S · Sale

−66.00

Price / share

$20.00

Trade value

$1.32K

% of position

3.0%

5/20/2026

2.22K→2.16K

Common Stock

Indirect

S · Sale

−66.00

Price / share

$20.00

Trade value

$1.32K

% of position

3.0%

5/20/2026

2.22K→2.16K

Common Stock

Indirect

S · Sale

−66.00

Price / share

$20.00

Trade value

$1.32K

% of position

3.0%

5/20/2026

2.22K→2.16K

Common Stock

Direct

M · Option Exercise

+420.00

Price / share

$2.39

Trade value

$1K

% of position

2.0%

5/21/2026

21.48K→21.90K

Common Stock

Direct

S · Sale

−420.00

Price / share

$20.20

Trade value

$8.48K

% of position

1.9%

5/21/2026

21.90K→21.48K

Common Stock

Indirect

S · Sale

−1.03K

Price / share

$20.20

Trade value

$20.90K

% of position

2.3%

5/21/2026

45.82K→44.78K

Common Stock

Indirect

S · Sale

−880.00

Price / share

$20.20

Trade value

$17.77K

% of position

2.3%

5/21/2026

38.94K→38.06K

Common Stock

Indirect

S · Sale

−212.00

Price / share

$20.20

Trade value

$4.28K

% of position

9.8%

5/21/2026

2.16K→1.95K

Common Stock

Indirect

S · Sale

−212.00

Price / share

$20.20

Trade value

$4.28K

% of position

9.8%

5/21/2026

2.16K→1.95K

Common Stock

Indirect

S · Sale

−212.00

Price / share

$20.20

Trade value

$4.28K

% of position

9.8%

5/21/2026

2.16K→1.95K

Common Stock

Indirect

S · Sale

−212.00

Price / share

$20.20

Trade value

$4.28K

% of position

9.8%

5/21/2026

2.16K→1.95K

Total

Net shares

−3.62K

Net value

-$82.75K

Security	Date	Type	Shares	Price / Share	Trade Value	% of Position	Held Before	Held After
Common Stock Direct	5/20/2026	M · Option Exercise	+130.00	$2.39	$310.70	0.6%	21.48K	21.61K
Common Stock Direct	5/20/2026	S · Sale	−130.00	$20.00	$2.60K	0.6%	21.61K	21.48K
Common Stock Indirect	5/20/2026	S · Sale	−322.00	$20.00	$6.44K	0.7%	46.14K	45.82K
Common Stock Indirect	5/20/2026	S · Sale	−273.00	$20.00	$5.46K	0.7%	39.21K	38.94K
Common Stock Indirect	5/20/2026	S · Sale	−66.00	$20.00	$1.32K	3.0%	2.22K	2.16K
Common Stock Indirect	5/20/2026	S · Sale	−66.00	$20.00	$1.32K	3.0%	2.22K	2.16K
Common Stock Indirect	5/20/2026	S · Sale	−66.00	$20.00	$1.32K	3.0%	2.22K	2.16K
Common Stock Indirect	5/20/2026	S · Sale	−66.00	$20.00	$1.32K	3.0%	2.22K	2.16K
Common Stock Direct	5/21/2026	M · Option Exercise	+420.00	$2.39	$1K	2.0%	21.48K	21.90K
Common Stock Direct	5/21/2026	S · Sale	−420.00	$20.20	$8.48K	1.9%	21.90K	21.48K
Common Stock Indirect	5/21/2026	S · Sale	−1.03K	$20.20	$20.90K	2.3%	45.82K	44.78K
Common Stock Indirect	5/21/2026	S · Sale	−880.00	$20.20	$17.77K	2.3%	38.94K	38.06K
Common Stock Indirect	5/21/2026	S · Sale	−212.00	$20.20	$4.28K	9.8%	2.16K	1.95K
Common Stock Indirect	5/21/2026	S · Sale	−212.00	$20.20	$4.28K	9.8%	2.16K	1.95K
Common Stock Indirect	5/21/2026	S · Sale	−212.00	$20.20	$4.28K	9.8%	2.16K	1.95K
Common Stock Indirect	5/21/2026	S · Sale	−212.00	$20.20	$4.28K	9.8%	2.16K	1.95K
Total			−3.62K		-$82.75K

Derivative Transactions2

Stock option (right to buy)

Direct

M · Option Exercise

Converts to

Common Stock

130.00 shares

−130.00

Strike price

2.39

Held after

624.00

Exercisable

—

5/20/2026

Stock option (right to buy)

Direct

M · Option Exercise

Converts to

Common Stock

420.00 shares

−420.00

Strike price

2.39

Held after

204.00

Exercisable

—

5/21/2026

Security	Converts To	Date	Type	Shares	Strike Price	Exercisable	Held After
Stock option (right to buy) Direct	Common Stock130.00 shares	5/20/2026	M · Option Exercise	−130.00	2.39	—	624.00
Stock option (right to buy) Direct	Common Stock420.00 shares	5/21/2026	M · Option Exercise	−420.00	2.39	—	204.00

Non-Derivative Holdings (Post-Transaction)3

Common Stock

Indirect

Shares owned44.32K

Common Stock

Indirect

Shares owned18.72K

Common Stock

Indirect

Shares owned85.96K

Total

149K indirect149K

Security Title	Shares Owned	Ownership Type
Common Stock	44.32K	Indirect
Common Stock	18.72K	Indirect
Common Stock	85.96K	Indirect
Total	149K	149K indirect

Derivative Holdings (Post-Transaction)0

No derivative holdings reported