UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) x QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ______ to______. Commission file number: 001-33059 FUEL TECH, INC. (Exact name of registrant as specified in its charter) (State or other jurisdiction of incorporation of organization) Delaware 20-5657551 For the quarterly period ended June 30, 2019 or ¨ TRANSITION REPORT PURSUANT TO SECTION 13 OR ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) x QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2019 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: 001-33059 If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended ...

Table of Contents SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 ______________________________ (Mark One) ý 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 001-33059 ______________________________ Fuel Tech, Inc. (Exact name of registrant as specified in its charter) ...