Page 1

ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31 , 2020 United States SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 FORM 10 - K or TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File Number : 001-37822 Delaware ( State of incorporation ) Advanced Emissions Solutions , Inc. ( Name of registrant as specified in its charter ) Class Common stock , par value $ 0.001 per share 27-5472457 ( IRS Employer Identification No. ) 8051 E. Maplewood Ave , Suite 210 , Greenwood Village , CO , 80111 ( Address of principal executive offices ) ( Zip Code ) Large accelerated filer Non - accelerated filer ( Registrant's telephone number , including area code ) : ( 720 ) 598-3500 Securities registered under Section 12 ( b ) of the Act : Trading Symbol ADES X Name of each exchange on which registered NASDAQ Global Market Indicate by check mark if the registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Act . Yes x No Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or 15 ( d ) of the Act . Yes 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 . x Yes No Securities registered under Section 12 ( g ) of the Act : None Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site , if any , every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S - T during the preceding 12 months ( or for such shorter period that the registrant was required to submit and post such files ) . x Yes " No Indicate by check mark if disclosure of delinquent filers in response to Item 405 of Regulation S - K is not contained herein , and will not be contained , to the best of registrant's knowledge , in definitive proxy or information statements incorporated by reference in Part III of this Form 10 - K or any amendment to this Form 10 - K . Indicate by check mark whether the registrant is a large accelerated filer , an accelerated filer , a non - accelerated filer or a smaller reporting company . See definition of " large accelerated filer , " " accelerated filer " and " smaller reporting company " in Rule 12b - 2 of the Exchange Act . Accelerated filer Smaller Reporting Company Emerging growth company X U 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 . Indicate by check mark whether the registrant has filed a report on and attestation to its management's assessment of the effectiveness of its internal control over financial reporting under Section 404 ( b ) of the Sarbanes - Oxley Act ( 15 U.S.C. 7262 ( b ) ) by the registered public accounting firm that prepared or issued its audit report . Indicate by check mark whether the registrant is a shell company ( as defined in Rule 12b - 2 of the Act . ) Yes x No The aggregate market value of the voting stock held by non - affiliates of the registrant was approximately $ 86.1 million based on the last reported bid price of the Common Stock on the NASDAQ Global Market on June 30 , 2020. The number of shares outstanding of the registrant's Common Stock , par value $ 0.001 per share , as of March 1 , 2021 was 18,518,846 .