Castle Biosciences grants 11,766 RSUs to director

Olson Tiffany reported acquisition or exercise transactions in this Form 4 filing.

Rhea-AI Filing Summary

Olson Tiffany reported acquisition or exercise transactions in this Form 4 filing.

Castle Biosciences director Tiffany Olson received a grant of 11,766 Restricted Stock Units as equity compensation. Each RSU represents the right to receive one share of Castle Biosciences common stock at no purchase price.

The RSUs vest in full on the earlier of the one-year anniversary of May 28, 2027, or the day immediately before the company’s next Annual Meeting of Stockholders following the grant date. After this award, Olson holds 11,766 RSUs directly, and the filing shows no additional option or derivative positions.

Insights

Equity Compensation Analyst

Routine equity grant of 11,766 RSUs to a Castle Biosciences director.

Director Tiffany Olson was granted 11,766 Restricted Stock Units, each representing one share of common stock at a zero exercise price. This is characterized as a grant or award, a standard form of non-cash board compensation aligned with shareholder interests.

The RSUs vest fully on the earlier of the one-year anniversary of May 28, 2027 or the day immediately before the next Annual Meeting of Stockholders after the grant. No additional derivative holdings are listed, so this award defines Olson’s visible equity-based position in this filing.

Insider Trade Summary

Grant/Award: 11,766 shares

Grant/Award 1 txn

Insider Olson Tiffany

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

RSUs granted: 11,766 units Underlying common shares: 11,766 shares Exercise price: $0.00 per share +1 more

4 metrics

RSUs granted 11,766 units Restricted Stock Units granted to director Tiffany Olson

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

Exercise price $0.00 per share RSU grant/award acquisition price

Post-grant RSU holdings 11,766 units Total RSUs held following the transaction

Key Terms

Restricted Stock Units, RSU, Annual Meeting of Stockholders, Common Stock

4 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 regulatory

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

Common Stock financial

"represents the 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.

FAQ

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

What insider transaction did Castle Biosciences (CSTL) report for Tiffany Olson?

Castle Biosciences reported that director Tiffany Olson received a grant of 11,766 Restricted Stock Units. These RSUs are a form of equity compensation and give her the right to receive an equal number of Castle Biosciences common shares upon vesting.

How many RSUs did Tiffany Olson receive in the latest CSTL Form 4 filing?

Tiffany Olson received 11,766 Restricted Stock Units from Castle Biosciences. Each RSU converts into one share of common stock at no cash cost, providing equity-based compensation rather than a cash salary component for her service as a director.

When do Tiffany Olson’s RSUs from Castle Biosciences vest?

The RSUs vest in full on the earlier of the one-year anniversary of May 28, 2027, or the day immediately before Castle Biosciences’ next Annual Meeting of Stockholders after the grant, creating a single cliff-vesting schedule for all 11,766 units.

Is Tiffany Olson’s Castle Biosciences RSU grant a purchase or a sale of CSTL stock?

The filing shows an acquisition by grant or award, not a market purchase or sale. Olson did not pay a purchase price for the 11,766 RSUs, and there is no open-market buying or selling activity disclosed in this Form 4.

How many Castle Biosciences RSUs does Tiffany Olson hold after this transaction?

After the grant, Tiffany Olson holds 11,766 Restricted Stock Units directly, according to the Form 4. There are no additional option or derivative positions listed, so this amount reflects her reported RSU balance in the filing.

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

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

Olson Tiffany

(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)