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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 TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File Number : 1-13274 Mack - Cali Realty Corporation Commission File Number : 333-57103 : Mack - Cali Realty , L.P. MACK - CALI REALTY CORPORATION Maryland ( Mack - Cali Realty Corporation ) Delaware ( Mack - Cali Realty , L.P. ) ( State or other jurisdiction of incorporation or organization ) Harborside 3 , 210 Hudson St. , Ste . 400 , Jersey City , New Jersey ( Address of principal executive offices ) ( Title of Each Class ) Mack - Cali Realty Corporation Common Stock , $ 0.01 par value Mack - Cali Realty , L.P. None MACK - CALI REALTY , L.P. ( Exact Name of Registrant as specified in its charter ) ( 732 ) 590-1010 ( Registrant's telephone number , including area code ) Securities registered pursuant to Section 12 ( b ) of the Act : Trading Symbol ( s ) Mack - Cali Realty Corporation Mack - Cali Realty , L.P. 22-3305147 ( Mack - Cali Realty Corporation ) 22-3315804 ( Mack - Cali Realty , L.P. ) ( IRS Employer Identification No. ) CLI N / A 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 . Mack - Cali Realty Corporation Mack - Cali Realty , L.P. Accelerated filer ( Name of Each Exchange on Which Registered ) Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15 ( d ) of the Exchange Act . Mack - Cali Realty Corporation Mack - Cali Realty , L.P. 07311 ( Zip code ) Non - accelerated filer New York Stock Exchange 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 . Mack - Cali Realty Corporation YES I NOI YES I NOI Mack - Cali Realty , L.P. None 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 ) . Smaller reporting company YES I NOI YES I NOI Mack - Cali Realty Corporation Mack - Cali Realty , L.P. Indicate by check mark whether the registrant is a large accelerated filer , an accelerated filer , a non - accelerated filer , or a smaller reporting company . See the definitions of " large accelerated filer , " " accelerated filer ” and “ smaller reporting company " in Rule 12b - 2 of the Exchange Act . Mack - Cali Realty Corporation : Large accelerated filer Mack - Cali Realty , L.P .: Large accelerated filer 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 . YES I NOI YES I NOI YES I NOI YES I NOI Emerging growth company 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 USC . 7262 ( b ) ) by the registered public accounting firm that prepared or issued its audit report . YES x NO o Indicate by check mark whether the registrant is a shell company ( as defined in Rule 12b - 2 of the Exchange Act . ) YES I NO I YES I NOI As of June 30 , 2020 , the aggregate market value of the voting stock held by non - affiliates of the Mack - Cali Realty Corporation was $ 1,314,998,454 . The aggregate market value was computed with reference to the closing price on the New York Stock Exchange on such date . This calculation does not reflect a determination that persons are affiliates for any other purpose . The registrant has no non - voting common stock . As of February 23 , 2021 , 90,729,044 shares of common stock , $ 0.01 par value , of Mack - Cali Realty Corporation ( " Common Stock " ) were outstanding . Mack - Cali Realty , L.P. does not have any class of common equity that is registered pursuant to Section 12 of the Exchange Act . LOCATION OF EXHIBIT INDEX : The index of exhibits is contained herein on page number 145 . DOCUMENTS INCORPORATED BY REFERENCE : Portions of the Mack - Cali Realty Corporation's definitive proxy statement for fiscal year ended December 31 , 2020 to be issued in conjunction with the registrant's annual meeting of shareholders expected to be held on June 9 , 2021 are incorporated by reference in Part III of this Form 10 - K . The definitive proxy statement will be filed by the registrant with the SEC not later than 120 days from the end of the registrant's fiscal year ended December 31 , 2020 .