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( mark one ) 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 TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 001-35007 K UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 FORM 10 - K KNIGHT TRANSPORTATION Delaware ( State or other jurisdiction of incorporation or organization ) Title of each class Common Stock $ 0.01 Par Value Large Accelerated Filer Non - Accelerated Filer Knight - Swift Transportation Holdings Inc. ( Exact name of registrant as specified in its charter ) 4 X U SWIFT TRANSPORTATION KNX 20002 North 19th Avenue Phoenix , Arizona 85027 ( Address of principal executive offices and Zip Code ) ( I.R.S. Employer Identification No. ) 20-5589597 ( 602 ) 269-2000 ( Registrant's telephone number , including area code ) Securities registered pursuant to Section 12 ( b ) of the Act : Trading Symbol ( s ) 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 X 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 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 . No There were 165,649,273 shares of the registrant's common stock outstanding as of February 16 , 2021 . DOCUMENTS INCORPORATED BY REFERENCE Accelerated Filer Smaller Reporting Company Emerging Growth Company 000 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 Exchange Act ) . Yes No > As of June 30 , 2020 , the aggregate market value of our common stock held by non - affiliates was $ 5,655,678,003 , based on the closing price of our common stock as quoted on the NYSE as of such date . Portions of the registrant's definitive proxy statement for its 2021 Annual Meeting of Stockholders to be filed with the Securities and Exchange Commission ( the " SEC " ) are incorporated by reference into Part III of this report .