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( Mark One ) 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 Or TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ( Commission File Number ) 001-39317 ON SEMICONDUCTOR CORPORATION ( Exact name of registrant as specified in its charter ) Delaware ( State or other jurisdiction of incorporation or organization ) Securities Registered Pursuant to Section 12 ( b ) of the Act : Title of each class 5005 E. McDowell Road Phoenix , AZ 85008 ( 602 ) 244-6600 ( Address , zip code and telephone number , including area code , of principal executive offices ) Common Stock , par value $ 0.01 per share Preferred Stock , Series B Junior Participating , Purchase Rights to Trading Symbol ( s ) ON N / A Securities Registered Pursuant to Section 12 ( g ) of the Act : None 36-3840979 ( I.R.S. Employer Identification No. ) No ® 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 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 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 Accelerated filer Non - accelerated filer 1 Name of each exchange on which registered The Nasdaq Stock Market LLC The Nasdaq Stock Market LLC Smaller reporting company Emerging growth company 000 If 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 . Yes > No □ Indicate by check mark whether the registrant is a shell company ( as defined in Rule 12b - 2 of the Exchange Act ) . Yes No The aggregate market value of the voting and non - voting common equity held by non - affiliates of the registrant was $ 7,783,044,394 as of July 3 , 2020 , based on the closing sales price of such stock on the Nasdaq Global Select Market . Shares held by executive officers , directors and persons owning directly or indirectly more than 10 % of the outstanding common stock ( as applicable ) have been excluded from the preceding number because such persons may be deemed to be affiliates of the registrant . The number of shares of the registrant's common stock outstanding at February 10 , 2021 was 411,881,071 . Documents Incorporated by Reference Portions of the registrant's Definitive Proxy Statement relating to its 2021 Annual Meeting of Stockholders , which is expected to be filed pursuant to Regulation 14A within 120 days after the registrant's fiscal year ended December 31 , 2020 , are incorporated by reference into Part III of this Form 10 - K .