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Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 ( Mark One ) ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 1934 For the fiscal year ended : December 31 , 2020 TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF FORM 10 - K For the transition period from Delaware ( State or other jurisdiction of incorporation or organization ) Title of each class Common Stock , $ 0.0001 par value to KARYOPHARM THERAPEUTICS INC . ( Exact name of registrant as specified in its charter ) Commission file number : 001-36167 26-3931704 ( I.R.S. Employer Identification No. ) 85 Wells Avenue , 2nd Floor , Newton , Massachusetts 02459 ( Address of principal executive offices ) ( zip code ) Registrant's telephone number , including area code : ( 617 ) 658-0600 Securities registered pursuant to Section 12 ( b ) of the Act : Trading Symbol ( s ) ΚΡΤΙ Securities registered pursuant to Section 12 ( g ) of the Act : None Name of each exchange on which listed Nasdaq Global Select Market No No 风 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 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 Non - accelerated filer Accelerated filer Smaller reporting company Emerging growth company 0 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 - 2of the Exchange Act ) . Yes No The aggregate market value of the registrant's voting and non - voting common stock held by non - affiliates of the registrant ( without admitting that any person whose shares are not included in such calculation is an affiliate ) computed by reference to the price at which the common stock was last sold on June 30 , 2020 was approximately $ 1.32 billion . Shares of common stock held by each executive officer and director and by each holder of 10 % or more of the outstanding common stock have been excluded in that such persons may be deemed to be affiliates . This determination of affiliate status is not necessarily a conclusive determination for other purposes . Number of shares outstanding of the registrant's Common Stock as of February 16 , 2021 : 74,634,291 . Documents incorporated by reference :