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): February 24, 2026

CLEARSIGN TECHNOLOGIES CORPORATION

(Exact name of registrant as specified in charter)

Delaware		001-35521		26-2056298
(State or other jurisdiction of incorporation)		(Commission File Number)		(IRS Employer Identification No.)

8023 E. 63rd Place, Suite 101

Tulsa, Oklahoma 74133

(Address of Principal Executive Offices and Zip Code)

(918) 236-6461

(Registrant's telephone number, including area code)

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 (see General Instruction A.2 below).

¨	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 CFR240.14a-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 240.13(e)-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		CLIR		The Nasdaq Stock Market LLC

Indicate by check mark whether the registrant is an emerging growth company 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.

To the extent required by Item 2.02 of Form 8-K, the information set forth below in Item 7.01 of this Current Report on Form 8-K is incorporated by reference herein in its entirety.

Item 7.01

Regulation FD Disclosure.

On February 24, 2026, the Company held a conference call to discuss certain preliminary and unaudited financial information for the fourth quarter and fiscal year ended December 31, 2025 and certain corporate updates. The selected preliminary financial information are preliminary, unaudited, and are subject to change upon completion of the Company’s financial statement closing procedures. Accordingly, undue reliance should not be placed on these preliminary estimates.

The preliminary financial data has been prepared by, and is the responsibility of, the Company’s management. BPM CPA LLP (“BPM”), the Company’s independent registered public accounting firm, has not audited, reviewed, compiled or performed any procedures with respect to the accompanying preliminary financial data. Accordingly, BPM does not express an opinion or any other form of assurance with respect thereto. A copy of the transcript of this conference call is furnished as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated by reference herein.

The information set forth in this Item 7.01 of this Current Report on Form 8-K, including Exhibit 99.1 attached hereto, is being furnished and shall not be deemed “filed” for the 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 incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act except as shall be expressly set forth by specific reference in such filing.

Item 9.01

Financial Statements and Exhibits.

(d) Exhibits.

Exhibit No.		Description
99.1*		Transcript of Conference Call held on February 24, 2026.
104		Cover Page Interactive Data File (embedded within the Inline XBRL document).

* Furnished herewith.

SIGNATURE

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

Dated: February 25, 2026

	CLEARSIGN TECHNOLOGIES CORPORATION

	By:	/s/ Colin James Deller
	Name:	Colin James Deller
	Title:	Chief Executive Officer

ClearSign Technologies Corp 8-K