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 7, 2026 CLEARSIGN TECHNOLOGIES CORPORATION (Exact name of registrant as specified in charter) (State or other jurisdiction of incorporation) Delaware 001-35521 26-2056298 (Commission File Number) (IRS Employer Identification No.) 8023 E. 63rd Place, Suite 101 Tulsa, Oklahoma 74133 (Addr ...