Castle Biosciences director exercises 13,667 RSUs

Castle Biosciences Inc. director Cole G. Bradley reported a compensation-related stock transaction.

Rhea-AI Filing Summary

Castle Biosciences Inc. director Cole G. Bradley reported a compensation-related stock transaction. Bradley exercised previously granted Restricted Stock Units (RSUs), receiving 13,667 shares of Common Stock at a stated price of $0.00 per share. Following this exercise, Bradley directly holds 32,976 shares of Common Stock. Each RSU represents the right to receive one share of Common Stock, with vesting tied to the earlier of a one-year anniversary of the grant date or the day before the next Annual Meeting of Stockholders.

Insider Trade Summary

13,667 shares exercised/converted

Exercise 2 txns

Insider Cole G Bradley

Role Director

Type	Security	Shares	Price	Value
Exercise	Restricted Stock Units	13,667	$0.00	$0.00
Exercise	Common Stock	13,667	$0.00	$0.00

Holdings After Transaction: Restricted Stock Units — 0 contracts (Direct); Common Stock — 32,976 shares (Direct)

Footnotes (2)

1. F1. Each Restricted Stock Unit ("RSU") represents the right to receive one share of the Issuer's Common Stock.
2. F2. The RSUs vest in full on the earlier of the (a) one-year anniversary of the date on May 22, 2026, or (b) the day immediately preceding the next Annual Meeting of Stockholders following the date of the grant.

Key Figures

RSUs exercised: 13,667 shares Exercise price: $0.00 per share Shares held after transaction: 32,976 shares +2 more

5 metrics

RSUs exercised 13,667 shares Restricted Stock Units converted to Common Stock on May 22, 2026

Exercise price $0.00 per share Stated price for RSU conversion to Common Stock

Shares held after transaction 32,976 shares Cole G. Bradley direct Common Stock holdings post-transaction

Derivative transactions 1 derivative, 1 non-derivative entry RSU derivative line plus resulting Common Stock line

Net buy/sell direction Neutral (no market buys or sells) transactionSummary shows netBuySellDirection neutral

Key Terms

Restricted Stock Units, Common Stock, derivative security, Annual Meeting of Stockholders

4 terms

Restricted Stock Units financial

"security_title: "Restricted Stock Units""

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

Common Stock financial

"security_title: "Common Stock""

Common stock represents ownership shares in a company, giving investors a stake in its success and a say in important decisions through voting rights. It is the most common type of stock traded on markets and can provide income through dividends, as well as potential for value growth. For investors, holding common stock means sharing in the company’s profits and risks.

derivative security financial

"transaction_code_description: "Exercise or conversion of derivative security""

A derivative security is a financial contract whose value comes from the price or performance of something else, such as a stock, bond, commodity, or market index. For investors it acts like an insurance policy or a wager: it can be used to protect against losses, lock in prices, or amplify gains and losses, so it can change a portfolio’s risk and potential return without owning the underlying asset directly.

Annual Meeting of Stockholders financial

"the day immediately preceding the next Annual Meeting of Stockholders"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transaction did CSTL director Cole G. Bradley report?

Director Cole G. Bradley exercised previously granted RSUs into 13,667 shares of Castle Biosciences Common Stock at a stated price of $0.00 per share. This is a compensation-related derivative exercise, not an open-market stock purchase or sale.

How many CSTL shares does Cole G. Bradley hold after this Form 4?

After the reported RSU exercise, Cole G. Bradley directly holds 32,976 shares of Castle Biosciences Common Stock. This total reflects his updated direct ownership position as of the transaction date reported in this Form 4 filing.

What are Restricted Stock Units (RSUs) in the CSTL Form 4 filing?

In this filing, each Restricted Stock Unit represents the right to receive one share of Castle Biosciences Common Stock. RSUs are a form of equity compensation that convert into shares upon meeting specified vesting conditions and are not open-market purchases.

What vesting terms apply to the CSTL RSUs reported for Cole G. Bradley?

The RSUs vest in full on the earlier of the one-year anniversary of the May 22 grant date or the day immediately preceding the next Annual Meeting of Stockholders. Once vested, the RSUs convert into an equivalent number of Common Stock shares.

Was the CSTL insider transaction a stock sale or purchase in the market?

The transaction was an exercise of derivative securities, not an open-market buy or sell. Cole G. Bradley received 13,667 Common Stock shares by converting Restricted Stock Units at a stated price of $0.00, reflecting equity compensation rather than trading activity.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 05/27/2026 - 04:20 PM EDT Learn about SEC filing dates

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Cole G Bradley

(Last) (First) (Middle)

C/O CASTLE BIOSCIENCES, INC.

1500 W. PARKWOOD AVE SUITE 400

(Street)

FRIENDSWOOD TEXAS 77546

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
CASTLE BIOSCIENCES INC [ CSTL ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/22/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	05/22/2026		M		13,667	A	(1)	32,976	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Restricted Stock Units	(1)	05/22/2026		M			13,667	(2)	(2)	Common Stock	13,667	$0	0	D

Explanation of Responses:

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

2. The RSUs vest in full on the earlier of the (a) one-year anniversary of the date on May 22, 2026, or (b) the day immediately preceding the next Annual Meeting of Stockholders following the date of the grant.

Remarks:

	/s/ Frank Stokes, Attorney-in-fact	05/27/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)