Castle Biosciences director granted 11,766 RSUs

Harrison Miles reported acquisition or exercise transactions in this Form 4 filing.

Rhea-AI Filing Summary

Harrison Miles reported acquisition or exercise transactions in this Form 4 filing.

CASTLE BIOSCIENCES INC director Miles Harrison received a grant of Restricted Stock Units. On May 28, 2026, he was awarded 11,766 RSUs, each representing the right to receive one share of the company’s common stock. These RSUs vest in full on the earlier of May 28, 2027, or the day immediately before the next Annual Meeting of Stockholders following the grant date. Following this award, his reported derivative holdings from this grant total 11,766 RSUs held directly.

Insights

Equity compensation analyst

Director received routine RSU equity compensation with time-based vesting.

Director Miles Harrison was granted 11,766 Restricted Stock Units, each convertible into one share of CASTLE BIOSCIENCES INC common stock. The transaction is coded as a grant or award, indicating compensation rather than an open-market trade.

The RSUs vest in full on the earlier of May 28, 2027 or immediately before the next Annual Meeting of Stockholders following the grant date. As a time-based vesting award, this filing mainly documents ongoing director compensation rather than signaling a change in market sentiment.

Insider Trade Summary

Grant/Award: 11,766 shares

Grant/Award 1 txn

Insider Harrison Miles

Role Director

Type	Security	Shares	Price	Value
Grant/Award	Restricted Stock Units	11,766	$0.00	$0.00

Holdings After Transaction: Restricted Stock Units — 11,766 contracts (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 28, 2027, or (b) the day immediately preceding the next Annual Meeting of Stockholders following the date of the grant.

Key Figures

RSU grant size: 11,766 Restricted Stock Units Underlying common shares: 11,766 shares Exercise price: $0.0000 per share +2 more

5 metrics

RSU grant size 11,766 Restricted Stock Units Grant to director Miles Harrison on May 28, 2026

Underlying common shares 11,766 shares Each RSU represents one share of common stock

Exercise price $0.0000 per share Conversion or exercise price for RSUs

Post-transaction RSUs held 11,766 units Total derivative holdings from this grant after transaction

Vesting date trigger May 28, 2027 Earlier of this date or immediately before next Annual Meeting

Key Terms

Restricted Stock Units, RSU, Annual Meeting of Stockholders, Common Stock, +1 more

5 terms

Restricted Stock Units financial

"Each Restricted Stock Unit ("RSU") represents the right to receive one share"

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.

RSU financial

"Each Restricted Stock Unit ("RSU") represents the right to receive one share"

Restricted stock units (RSUs) are a form of company shares given to employees as part of their compensation, usually with certain restrictions or conditions, such as remaining with the company for a set period. When these restrictions lift, employees receive actual shares that they can sell or hold. For investors, RSUs can impact a company's stock supply and reflect the company's commitment to attracting and retaining talent.

Annual Meeting of Stockholders financial

"the day immediately preceding the next Annual Meeting of Stockholders following the date of the grant"

Common Stock financial

"right to receive one share of the Issuer's 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.

Grant, award, or other acquisition financial

"transaction code description: Grant, award, or other acquisition"

FAQ

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

What did CASTLE BIOSCIENCES INC (CSTL) director Miles Harrison report on this Form 4?

Miles Harrison reported receiving 11,766 Restricted Stock Units as equity compensation. Each unit represents one share of CASTLE BIOSCIENCES INC common stock, granted at no exercise price, and increases his directly held derivative equity-based position in the company.

How many Restricted Stock Units did Miles Harrison receive from CASTLE BIOSCIENCES INC (CSTL)?

He received 11,766 Restricted Stock Units. Each RSU entitles him to receive one share of CASTLE BIOSCIENCES INC common stock upon vesting, so the grant corresponds to 11,766 underlying common shares if and when the vesting conditions are satisfied.

When do Miles Harrison’s CASTLE BIOSCIENCES INC (CSTL) RSUs vest?

The RSUs vest in full on the earlier of May 28, 2027 or the day immediately preceding the next Annual Meeting of Stockholders after the grant date. This time-based vesting schedule ties the award to roughly one year of board service or until the next shareholder meeting.

Does this CASTLE BIOSCIENCES INC (CSTL) Form 4 show a stock purchase or sale?

No open-market purchase or sale is shown. The Form 4 reports an acquisition coded as a grant or award of 11,766 Restricted Stock Units, reflecting equity compensation rather than a discretionary buy or sell transaction in CASTLE BIOSCIENCES INC shares.

How many CASTLE BIOSCIENCES INC (CSTL) RSUs does Miles Harrison hold after this transaction?

Following this grant, the filing shows 11,766 derivative securities related to Restricted Stock Units. These RSUs are held directly and each represents the right to receive one share of CASTLE BIOSCIENCES INC common stock upon satisfaction of the vesting conditions.

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

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Accepted by SEC EDGAR 06/01/2026 - 04:48 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^*

Harrison Miles

(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)
05/28/2026

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

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)	05/28/2026		A		11,766		(2)	(2)	Common Stock	11,766	$0	11,766	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 28, 2027, 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	06/01/2026
	** 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)