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Table of Contents UNITED STATES 冈 SECURITIES AND EXCHANGE COMMISSION Washington , DC 20549 ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 . For the fiscal year ended December 31 , 2020 Form 10 - K or TRANSITION REPORTS PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 . Delaware ( State or other jurisdiction of incorporation or organization ) NEKTAR THERAPEUTICS ( Exact name of registrant as specified in its charter ) For the transition period from to Commission File Number : 0-24006 Title of Each Class Common Stock , $ 0.0001 par value 455 Mission Bay Boulevard South San Francisco , California 94158 ( Address of principal executive offices and zip code ) 415-482-5300 ( Registrant's telephone number , including area code ) Securities registered pursuant to Section 12 ( b ) of the Act : Trading Symbol NKTR 94-3134940 ( IRS Employer Identification No. ) Name of Each Exchange on Which Registered NASDAQ Global Select Market 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 > 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 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 , 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 Non - accelerated filer Emerging growth company Accelerated filer Smaller reporting 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 Exchange Act Rule 12b - 2 ) . Yes No The approximate aggregate market value of voting stock held by non - affiliates of the registrant , based upon the last sale price of the registrant's common stock on the last business day of the registrant's most recently completed second fiscal quarter , June 30 , 2020 , as reported on The NASDAQ Global Select Market , was approximately $ 4.1 billion . This calculation excludes approximately 1,117,000 shares held by directors and executive officers of the registrant . Exclusion of these shares does not constitute a determination that each such person is an affiliate of the registrant .