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Table of Contents SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 ( Mark One ) ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended : December 31 , 2020 Form 10 - K TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from Delaware Title of each class Common Stock ( State of Incorporation ) OR Commission File Number 001-33059 Fuel Tech , Inc. ( Exact name of registrant as specified in its charter ) to Fuel Tech , Inc. 27601 Bella Vista Parkway Warrenville , IL 60555-1617 ( 630 ) 845-4500 www.ftek.com FTEK Securities registered pursuant to Section 12 ( b ) of the Act : Trading Symbol ( s ) 20-5657551 ( I.R.S. ID ) Name of each exchange on which registered NASDAQ Securities registered pursuant to Section 12 ( g ) of the Act : NONE Indicate by check mark if the registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Act . Yes Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15 ( d ) of the Exchange Act . Yes No X No | Indicate by check mark whether the registrant : ( 1 ) has filed all reports required to be filed by Section 13 or 15 ( d ) of the Securities Exchange Act of 1934 during the preceding 12 months ( or for such shorter period that the registrant was required to file such reports ) , and ( 2 ) has been subject to such filing requirements for the past 90 days . Yes No Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S - T ( §232.405 of this chapter ) during the preceding 12 months ( or for such shorter period that the registrant was required to submit such files ) . Yes No