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): September 25, 2019

CLEARSIGN COMBUSTION CORPORATION

(Exact name of registrant as specified in Charter)

12870 Interurban Avenue South

Seattle, Washington 98168

(Address of Principal Executive Offices)

206-673-4848

(Issuer Telephone number)

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).

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. ¨

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

On September 25, 2019, ClearSign Combustion Corporation (the “Company”) determined to write-off certain patents included in its patent portfolio based on management’s analysis of both the cost of maintaining the patents and the likelihood that the inventions described would not have significant value in the Company’s future technology strategy.

In conjunction with the decision to write-off the patents, the Company anticipates that it will be required under generally accepted accounting principles to incur a non-cash impairment charge of an estimated $337,302 in its statement of operations for the three and nine months ended September 30, 2019. Other than expenses incurred for maintenance of the patents but not yet paid, the Company does not expect future cash expenditures relating to the write-off.

Forward-Looking Statements

This report contains “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, which are intended to be covered by the safe harbor created by such sections and other applicable laws. Where the Company expresses or implies an expectation or belief as to future events or results, such expectation or belief is expressed in good faith and believed to have a reasonable basis. However, such statements are subject to risks, uncertainties and other factors, which could cause actual results to differ materially from future results expressed, projected or implied by the forward-looking statements. Forward-looking statements often contain words such as “anticipate,” “intend,” “plan,” “will,” “would,” “estimate,” “expect,” “believe,” “target,” “indicative,” “preliminary,” or “potential.”  Forward-looking statements in this report include the Company’s estimate of the non-cash impairment charge.  The Company does not undertake any obligation to release publicly revisions to any “forward-looking statement,” including, without limitation, to reflect events or circumstances after the date of this report or to reflect the occurrence of unanticipated events, except as may be required under applicable securities laws.

SIGNATURE

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

Dated: September 27, 2019