1 unchanged sentence
Insider Trading Arrangements
−Removed: On August 12, 2025 , Frank Stokes , our Chief Financial Officer , adopted a Rule 10b5-1 trading arrangement providing for the sale from time to time of an aggregate of up to 5,388 shares of our common stock.
+Added: On March 9, 2026 , Frank Stokes , our Chief Financial Officer , adopted a Rule 10b5-1 trading arrangement providing for the sale from time to time of an aggregate of up to 29,421 shares of our common stock.
The trading arrangement is intended to satisfy the affirmative defense in Rule 10b5-1(c).
−Removed: The duration of the trading arrangement is estimated to be from November 11, 2025 until the earlier of all transaction under the trading arrangement being completed or November 30, 2025 .
−Removed: No other officers or directors, as defined in Rule 16a-1(f), adopted and/or terminated a Rule 10b5-1 trading arrangement or a non-Rule 10b5-1 trading arrangement, as defined in Regulation S-K Item 408, for the three months ended September 30, 2025.
+Added: The duration of the trading arrangement is estimated to be from June 8, 2026 until the earlier of all transaction under the trading arrangement being completed or June 30, 2026 .
+Added: No other officers or directors, as defined in Rule 16a-1(f), adopted and/or terminated a Rule 10b5-1 trading arrangement or a non-Rule 10b5-1 trading arrangement, as defined in Regulation S-K Item 408, for the three months ended March 31, 2026.
Exhibit Number Description
3.1 Amended and Restated Certificate of Incorporation of the Registrant, incorporated by reference to Exhibit 3.1 of the Registrant’s Current Report on Form 8-K filed with the SEC on May 23, 2025.
−Removed: 3.2 Amended and Restated Bylaws of the Registrant, incorporated by reference to Exhibit 3.
−Removed: 1 of the Registrant’s Current Report on Form 8-K filed with the SEC on August 8, 2025.
+Added: 3.2 Amended and Restated Bylaws of the Registrant, incorporated by reference to Exhibit 3.1 of the Registrant’s Current Report on Form 8-K filed with the SEC on August 8, 2025.
4.1 Form of Common Stock Certificate of the Registrant, incorporated by reference to Exhibit 4.1 of the Registrant’s Registration Statement on Form S-1 (File No.
333-232369), as amended, originally filed with the SEC on June 26, 2019.
−Removed: 4.2 Sixth Amended and Restated Investors’ Rights Agreement, dated July 12, 2019, by and among the Registrant and certain of its stockholders, incorporated by reference to Exhibit 4.2 of the Registrant’s Registration Statement on Form S-1 (File No.
−Removed: 333-232369), as amended, originally filed with the SEC on June 26, 2019.
−Removed: Non-Employee Director Compensation Policy, as amended effective August 5, 2025.
−Removed: Castle Biosciences, Inc.
−Removed: 2022 Inducement Plan, as amended and restated.
+Added: First Amendment to Office Lease Agreement, dated March 5, 2026, by and between the Registrant and Perimeter Gateway Portfolio LLC.
+Added: Lease Agreement, dated March 19, 2026, by and between the Registrant and Faros ACA RE LLC.
+Added: Second Amendment to Lease Agreement, dated March 19, 2026, by and between the Registrant and ACA Concourse East Unit 3 LLC.
31.1* Certification of Principal Executive Officer pursuant to Rules 13a-14(a) and 15d-14(a) of the Exchange Act.
11 unchanged sentences
** Furnished herewith
−Removed: Indicates management contract or compensatory plan.
+Added: † Certain schedules or exhibits have been omitted pursuant to Item 601(a)(5) of Regulation S-K.
+Added: A copy of any omitted schedule or exhibit will be furnished to the SEC upon request;
+Added: provided, however, that we may request confidential treatment pursuant to Rule 24b-2 of the Exchange Act for any schedule or exhibit so furnished.
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.
CASTLE BIOSCIENCES, INC.
−Removed: November 3, 2025 By:
+Added: May 6, 2026 By:
President and Chief Executive Officer
(Principal Executive Officer)
−Removed: November 3, 2025 By:
+Added: May 6, 2026 By:
/s/ Frank Stokes
2 unchanged sentences
Compared sentence by sentence after normalising whitespace, quotation marks, case and digits, so re-formatting and restated figures do not read as changed language. Wording changes appear as one removal and one addition. The current filing and the prior one are authoritative.