# EDGAR Filing Document

**Accession Number:** 0001447362
**File Stem:** 0001628280-26-015334
**Filing Date:** 2026-3
**Character Count:** 8489
**Document Hash:** ffbdc32210d1823f2aa4c261b09c202c
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001628280-26-015334.hdr.sgml**: 20260305

**ACCESSION NUMBER**: 0001628280-26-015334

**CONFORMED SUBMISSION TYPE**: 4

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20260303

**FILED AS OF DATE**: 20260305

**DATE AS OF CHANGE**: 20260305

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Stokes Frank
- **CENTRAL INDEX KEY:** 0001782815

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-38984
- **FILM NUMBER:** 26727288

**MAIL ADDRESS:**
- **STREET 1:** C/O CASTLE BIOSCIENCES
- **STREET 2:** 820 S. FRIENDSWOOD DRIVE, SUITE 201
- **CITY:** FRIENDSWOOD
- **STATE:** TX
- **ZIP:** 77546
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** CASTLE BIOSCIENCES INC
- **CENTRAL INDEX KEY:** 0001447362
- **STANDARD INDUSTRIAL CLASSIFICATION:** SERVICES-MEDICAL LABORATORIES [8071]
- **ORGANIZATION NAME:** 08 Industrial Applications and Services
- **EIN:** 770701774
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** 1500 W. PARKWOOD AVE.
- **STREET 2:** SUITE 400
- **CITY:** FRIENDSWOOD
- **STATE:** TX
- **ZIP:** 77546
- **BUSINESS PHONE:** 866-788-9007

**MAIL ADDRESS:**
- **STREET 1:** 1500 W. PARKWOOD AVE.
- **STREET 2:** SUITE 400
- **CITY:** FRIENDSWOOD
- **STATE:** TX
- **ZIP:** 77546

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

## FORM 4

### STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

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

[x] 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**<sup>*</sup><br>Stokes Frank<br><sub>(Last) (First) (Middle)</sub><br>C/O CASTLE BIOSCIENCES, INC.<br>1500 W. PARKWOOD AVE SUITE 400<br><sub>(Street)</sub><br>FRIENDSWOOD, TX 77546<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2026-03-03 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director [ ] 10% Owner<br>[X] Officer (give title below) [ ] Other (specify below)<br>_Chief Financial Officer_ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>CASTLE BIOSCIENCES INC [ CSTL ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[X] Form filed by One Reporting Person<br>[ ] Form filed by More than One Reporting Person |

---

## Table I - Non-Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | 3. Transaction Code (V) | 3. Transaction Code (V) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | Code | V | Amount | (A) or (D) | Price | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| Common Stock | 2026-03-03 |  | S<sup>(1)</sup> |  | 5300 | D | 27.32<sup>(2)</sup> | 54183<sup>(3)</sup> | D |  |
| Common Stock | 2026-03-03 |  | S<sup>(1)</sup> |  | 1700 | D | 27.81<sup>(4)</sup> | 52483 | D |  |
| Common Stock | 2026-03-03 |  | F |  | 3611<sup>(5)</sup> | D | $27.57 | 48872 | D |  |
| Common Stock | 2026-03-04 |  | M |  | 24146 | A | <sup>(6)</sup> | 73018 | D |  |
| Common Stock | 2026-03-04 |  | F |  | 10732 | D | $28.17 | 62286 | D |  |
| Common Stock | 2026-03-04 |  | M |  | 3800 | A | $3.38 | 66086 | D |  |

---

## Table II - Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | 4. Transaction Code (V) | 4. Transaction Code (V) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 6. Date Exercisable and Expiration Date | 6. Date Exercisable and Expiration Date | 7. Title and Amount of Underlying Securities | 7. Title and Amount of Underlying Securities | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | Code | V | (A) | (D) | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| Restricted Stock Units | <sup>(6)</sup> | 2026-03-03 |  | A |  | 48367 |  | <sup>(7)</sup> | <sup>(7)</sup> | Common Stock | 48367 | $0 | 48367 | D |  |
| Restricted Stock Units | <sup>(6)</sup> | 2026-03-04 |  | M |  |  | 12186 | <sup>(8)</sup> | <sup>(8)</sup> | Common Stock | 12186 | $0 | 24372 | D |  |
| Restricted Stock Units | <sup>(6)</sup> | 2026-03-04 |  | M |  |  | 11960 | <sup>(9)</sup> | <sup>(9)</sup> | Common Stock | 11960 | $0 | 35878 | D |  |
| Stock option (right to buy) | $3.38 | 2026-03-04 |  | M |  |  | 3800 | <sup>(10)</sup> | 2029-03-12 | Common Stock | 3800 | $0 | 14912 | D |  |

---

### Footnotes:

(1) The transaction on this Form 4 was made pursuant to a Rule 10b5-1 plan adopted by Frank Stokes on November 13, 2025.

(2) This transaction was executed in multiple trades at prices ranging from $26.70 to $27.67, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

(3) Includes 1,033 shares acquired on February 27, 2026, under the Issuer's employee stock purchase plan.

(4) This transaction was executed in multiple trades at prices ranging from $27.72 to $27.97, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

(5) 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.

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

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

(8) On March 4, 2024, the Reporting Person was granted 48,744 RSUs which vest in four equal installments beginning on March 4, 2025.

(9) On March 4, 2025, the Reporting Person was granted 47,838 RSUs which vest in four equal installments beginning on March 4, 2026.

(10) The shares subject to the option are fully vested.

**Signature:** /s/ Frank Stokes, Attorney-in-fact  
**Date:** 2025-03-05

### Remarks:

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.**