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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 For the transition period from to Commission File Number : 1-33100 Owens Corning ( Exact name of registrant as specified in its charter ) Delaware ( State or other jurisdiction of incorporation or organization ) or One Owens Corning Parkway , Toledo , OH ( Address of principal executive offices ) Title of each class Common Stock , par value $ 0.01 per share Securities registered ( 419 ) 248-8000 ( Registrant's telephone number , including area code ) Securities registered pursuant to Section 12 ( b ) of the Act : 43-2109021 Trading Symbol OC ( I.R.S. Employer Identification No. ) 43659 ( Zip Code ) Name of each exchange on which registered New York Stock Exchange 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 p No r Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or 15 ( d ) of the Act . Yes r No þ 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 p No r 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 þ No r 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 p Accelerated filer r Non - accelerated filer r 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 . r 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 p Indicate by check mark whether the registrant is a shell company ( as defined in Rule 12b - 2 of the Act ) . Yes On June 30 , 2020 , the last business day of the registrant's most recently completed second fiscal quarter , the aggregate market value of $ 0.01 par value common stock ( the voting stock of the registrant ) held by non - affiliates ( assuming for purposes of this computation only that the registrant had no affiliates ) was approximately $ 6,023,086,936 . As of February 12 , 2021 , 104,926,383 shares of the registrant's common stock , par value $ 0.01 per share , were outstanding . DOCUMENTS INCORPORATED BY REFERENCE Portions of Owens Corning's proxy statement to be delivered to stockholders in connection with the Annual Meeting of Stockholders to be held on or about April 15 , 2021 ( the " 2021 Proxy Statement " ) are incorporated by reference into Part III hereof .