UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) x ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2018 OR ¨ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ______________ to _______________ Commission file number 001-35521 CLEARSIGN COMBUSTION CORPORATION (Exact name of registrant as specified in its charter) WASHINGT ...

ClearSign Combustion Corp. (NASDAQ:CLIR) Q4 2018 Results Conference Call February 20, 2019 5:00 PM ET Company Participants Lou Basenese - Vice President of Corporate Communications Rob Hoffman - Interim CEO and Chairman of the Board Jim Deller - President Brian Fike - Chief Financial Officer Operator Good afternoon. And welcome to the ClearSign Combustion Corporation's Full Year 2018 Conference Call. All participants will be in listen-only mode [Operator Instructions]. After today's presentation, there will ...