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UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON , DC 20549 FORM 10 - K ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For The Fiscal Year Ended March 31 , 2021 or □ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Delaware ( State or other jurisdiction of incorporation or organization ) 7171 Southwest Parkway , ( Address of principal executive offices ) Commission File Number : 001-35159 THERMON GROUP HOLDINGS , INC . ( Exact name of registrant as specified in its charter ) . Building 300 , Suite 200 , Austin , Texas ( 512 ) 690-0600 ( Registrant's telephone number , including area code ) Securities registered pursuant to Section 12 ( b ) of the Act : Title of each class Common Stock , $ 0.001 par value per share Trading Symbol ( s ) Large accelerated filer Non - accelerated filer THR 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 x No 27-2228185 ( I.R.S. Employer Identification No. ) Name of each exchange on which registered New York Stock Exchange Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 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 O O 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 ) . x Yes " No 78735 ( Zip Code ) Indicate by check mark whether the registrant is a large accelerated filer , an accelerated filer , a non - accelerated filer , a smaller reporting company , or an emerging growth company . See the definitions of " large accelerated filer , " " accelerated filer , " " smaller reporting company , " and " emerging growth company " in Rule 12b - 2 of the Exchange Act . Accelerated filer Smaller reporting company Emerging growth company As of May 26 , 2021 , the registrant had 33,245,749 shares of common stock , par value $ 0.001 per share , outstanding . DOCUMENTS INCORPORATED BY REFERENCE 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 . X 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 . X Indicate by check mark whether the registrant is a shell company ( as defined in Rule 12b - 2 of the Exchange Act ) . Yes x No The aggregate market value of the registrant's common equity held by non - affiliates as of September 30 , 2020 was $ 367,767,182 based on the closing price of $ 11.23 as reported on the New York Stock Exchange . Solely for the purposes of this calculation , directors and officers of the registrant are deemed to be affiliates .