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Table of Contents or 0 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 December 31 , 2020 TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number : 1-13105 Delaware ( State or other jurisdiction of incorporation or organization ) One CityPlace Drive Suite 300 St. Louis Missouri ( Address of principal executive offices ) Arch Resources , Inc. ( Exact name of registrant as specified in its charter ) Title of Each Class Common Stock , $ .01 par value Securities registered pursuant to Section 12 ( b ) of the Act : ARCH Registrant's telephone number , including area code : ( 314 ) 994-2700 Trading Symbol ARCH 43-0921172 ( I.R.S. Employer Identification Number ) Large accelerated filer Non - accelerated filer 63141 ( Zip code ) 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 > No 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 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 Name of Each Exchange on Which Registered New York Stock Exchange 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 Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S - K ( 229.405 of this chapter ) 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 . 0 Indicate by check mark whether the registrant is a large accelerated filer , an accelerated filer , a non - accelerated filer , 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 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 . □ 0 0 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 No The aggregate market value of the voting stock held by non - affiliates of the registrant ( excluding outstanding shares beneficially owned by directors , officers , other affiliates and treasury shares ) as of June 30 , 2020 was approximately $ 430.3 million . DOCUMENTS INCORPORATED BY REFERENCE Indicate by check mark whether the registrant has filed all documents and reports required to be filed by Section 12 , 13 or 15 ( d ) of the Securities Exchange Act of 1934 subsequent to the distribution of securities under a plan confirmed by a court . Yes > No At January 31 , 2021 there were 15,234,899 shares of the registrant's common stock outstanding . Portions of the registrant's definitive proxy statement to be filed with the Securities and Exchange Commission in connection with the 2021 annual stockholders ' meeting are incorporated by reference into Part III of this Form 10 - K .