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X | UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 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 DECEMBER 31 , 2020 TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File No. 001-37917 Mammoth Energy Services , Inc. ( Exact name of registrant as specified in its charter ) Delaware ( State or other jurisdiction of incorporation or organization ) 14201 Caliber Drive , Suite 300 Oklahoma City , Oklahoma ( Address of principal executive offices ) Title of each class Common Stock ( 405 ) 608-6007 ( Registrant's telephone number , including area code ) Securities registered pursuant to Section 12 ( b ) of The Act : Trading Symbol ( s ) . TUSK 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 Act . Yes 冈 Accelerated filer Smaller reporting company Emerging growth company 32-0498321 ( I.R.S. Employer Identification No. ) Name of each exchange on which registered The Nasdaq Stock Market LLC NASDAQ Global Select Market 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 □ □ □ 73134 ( 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 . Large accelerated filer Non - accelerated filer As of February 24 , 2021 , there were 45,769,283 shares of our $ 0.01 par value common stock outstanding . No 区 DOCUMENTS INCORPORATION BY REFERENCE No " Indicate by check mark whether the registrant is a shell company ( as defined in Rule 12b - 2 of the Exchange Act ) . Yes □ No | If an emerging growth company , indicate by check mark if the registrant has elected not to use the extended transition period complying with any new or revised financial accounting standards provided pursuant to Section 13 ( a ) of the Exchange Act . □ The aggregate market value of common equity held by non - affiliates of the registrant as of June 30 , 2020 was approximately $ 15.5 million , calculated based on the closing price of the common stock on the Nasdaq Global Select Market on that date . Portions of Mammoth Energy Services , Inc.'s Proxy Statement for the 2021 Annual Meeting of Stockholders are incorporated by reference in Items 10 , 11 , 12 , 13 and 14 of Part III of this Form 10 - K .