Castle Biosciences (NASDAQ: CSTL) shares preliminary 2025 results update

Rhea-AI Filing Summary

Castle Biosciences, Inc. reported that it has shared an early look at its recent business performance. On January 11, 2026, the company issued a press release with certain preliminary performance results for the fourth quarter of 2025 and for the full year ended December 31, 2025, which is provided as Exhibit 99.1.

The company also released an investor slide presentation on the same date, attached as Exhibit 99.2, which management may use in future meetings. Both the preliminary results and the slide presentation are being furnished under Items 2.02 and 7.01, respectively, and are expressly stated as not being deemed “filed” for purposes of the Exchange Act or incorporated by reference into other filings unless specifically referenced.

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): January 11, 2026

Castle Biosciences, Inc.

(Exact name of registrant as specified in its charter)

Delaware

001-38984

77-0701774

(state or other jurisdiction of incorporation)

(Commission File Number)

(I.R.S. Employer Identification No.)

505 S. Friendswood Drive, Suite 401 Friendswood, Texas

77546

(Address of principal executive offices)

(Zip Code)

Registrant’s telephone number, including area code: (866) 788-9007

(Former name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions: 

☐    Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐    Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) 

☐    Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) 

☐    Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) 

Securities registered pursuant to Section 12(b) of the Act:

Title of each class

Trading Symbol(s)

Name of each exchange on which registered

Common Stock, $0.001 par value per share

CSTL

The Nasdaq Global Market

Indicate by check mark whether the registrant is an emerging growth company as defined in as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b–2 of the Securities Exchange Act of 1934 (§ 240.12b–2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐ 

Item 2.02    Results of Operations and Financial Condition.

On January 11, 2026, Castle Biosciences, Inc. (the “Company”) issued a press release announcing certain preliminary performance results for the fourth quarter of 2025 and for the year ended December 31, 2025. A copy of the press release is attached hereto as Exhibit 99.1 and incorporated herein by reference.

The information contained or incorporated in this Current Report on Form 8-K, including Exhibit 99.1, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed to be incorporated by reference into any filing under the Exchange Act or the Securities Act of 1933, as amended (the “Securities Act”), except as expressly set forth by specific reference in such filing to this Current Report on Form 8-K.

Item 7.01    Regulation FD Disclosure.

On January 11, 2026, the Company made available the slide presentation attached hereto as Exhibit 99.2. Information from this slide presentation may also be used by the management of the Company in future meetings regarding the Company.

The information contained or incorporated in this Item 7.01 of this Current Report on Form 8-K, including Exhibit 99.2, shall not be deemed “filed” for purposes of Section 18 of the Exchange Act or otherwise subject to the liabilities of that section, nor shall it be deemed to be incorporated by reference into any filing under the Exchange Act or the Securities Act except as expressly set forth by specific reference in such filing to this Current Report on Form 8-K.

Item 9.01    Financial Statements and Exhibits.

(d) Exhibits.

Exhibit
Number						Description
99.1						Press release issued January 11, 2026.
99.2						Slide presentation.
104						Inline XBRL for the cover page of this Current Report on Form 8-K.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

			CASTLE BIOSCIENCES, INC.
			By:			/s/ Frank Stokes
						Frank Stokes
						Chief Financial Officer
Date: January 11, 2026

FAQ

What did Castle Biosciences (CSTL) disclose in this 8-K?

Castle Biosciences disclosed that it issued a press release with certain preliminary performance results for the fourth quarter of 2025 and the year ended December 31, 2025, and made an investor slide presentation available.

Which periods do Castle Biosciences’ preliminary results cover?

The preliminary performance results cover the fourth quarter of 2025 and the full year ended December 31, 2025.

How did Castle Biosciences share its preliminary 2025 results?

The company shared its preliminary 2025 results through a press release dated January 11, 2026, which is attached as Exhibit 99.1 to the report.

What is included in Castle Biosciences’ Exhibit 99.2?

Exhibit 99.2 consists of a slide presentation that the company made available on January 11, 2026, which management may also use in future meetings about the company.

Are Castle Biosciences’ preliminary results considered filed with the SEC?

No. The company states that the information in the preliminary results press release and the slide presentation is furnished and not deemed “filed” for purposes of Section 18 of the Exchange Act.

Which items of Form 8-K did Castle Biosciences use in this report?

The company used Item 2.02 for Results of Operations and Financial Condition and Item 7.01 for Regulation FD Disclosure, and listed related exhibits under Item 9.01.