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Table of Contents П 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 Maryland ( State of Organization ) or Commission file number 1-15319 DIVERSIFIED HEALTHCARE TRUST ( Exact Name of Registrant as Specified in Its Charter ) 04-3445278 DHC DHCNI DHCNL ( IRS Employer Identification No. ) Two Newton Place , 255 Washington Street , Suite 300 , Newton , MA 02458-1634 ( Address of Principal Executive Offices ) ( Zip Code ) 617-796-8350 ( Registrant's Telephone Number , Including Area Code ) Securities registered pursuant to Section 12 ( b ) of the Act : Trading Symbol ( s ) Title Of Each Class Common Shares of Beneficial Interest 5.625 % Senior Notes due 2042 6.25 % Senior Notes due 2046 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 x 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 x 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 x No " Name Of Each Exchange On Which Registered The Nasdaq Stock Market LLC The Nasdaq Stock Market LLC The Nasdaq Stock Market LLC 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 during the preceding 12 months ( or for such shorter period that the registrant was required to submit such files ) . Yes x 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 X Accelerated filer Non - 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 . " 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 x The aggregate market value of the voting common shares of beneficial interest , $ .01 par value , or common shares , of the registrant held by non - affiliates was approximately $ 1.0 billion based on the $ 4.43 closing price per common share on The Nasdaq Stock Market LLC on June 30 , 2020. For purposes of this calculation , an aggregate of 3,014,390 common shares held directly by , or by affiliates of , the trustees and the executive officers of the registrant have been included in the number of common shares held by affiliates . Number of the registrant's common shares outstanding as of February 23 , 2021 : 238,268,478 . References in this Annual Report on Form 10 - K to the Company , DHC , we , us or our mean Diversified Healthcare Trust and its consolidated subsidiaries unless otherwise expressly stated or the context indicates otherwise . DOCUMENTS INCORPORATED BY REFERENCE Certain information required by Items 10 , 11 , 12 , 13 and 14 of Part III of this Annual Report on Form 10 - K is incorporated by reference to our definitive Proxy Statement for the 2021 Annual Meeting of Shareholders , to be filed with the Securities and Exchange Commission within 120 days after the fiscal year ended December 31 , 2020 .