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Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON , D.C. 20549 FORM 10 - K X ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Fiscal Year Ended December 31 , 2020 OR U TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File No. 001-35456 ALLISON TRANSMISSION HOLDINGS , INC . ( Exact Name of Registrant as Specified in Its Charter ) Delaware ( State of Incorporation ) Large accelerated filer Non - accelerated filer Allison Transmission . One Allison Way Indianapolis , IN 46222 ( Address of Principal Executive Offices and Zip Code ) Title of each class Common Stock , $ 0.01 par value 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 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 No No | □ □ 26-0414014 ( I.R.S. Employer Identification Number ) ( 317 ) 242-5000 ( Registrant's Telephone Number , Including Area Code ) Securities registered pursuant to Section 12 ( b ) of the Act : Trading Symbol ( s ) ALSN Indicate by check mark whether the registrant has submitted electronically every Interactive Data File requ 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 Name of each exchange on which registered New York Stock Exchange 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 oo 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 . 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 . No 区 Indicate by check mark whether the registrant is a shell company ( as defined in Rule 12b - 2 of the Exchange Act ) . Yes The aggregate market value of the voting and non - voting stock held by non - affiliates was approximately $ 4,136 million as of June 30 , 2020 . As of February 4 , 2021 , there were 111,944,955 shares of Common Stock outstanding . Documents Incorporated by Reference Portions of the Registrant's definitive Proxy Statement for its 2021 annual meeting of stockholders will be incorporated by reference in Part III of this Annual Report on Form 10 - K .