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Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON , D.C. 20549 FORM 20 - F ( Mark One ) ☐ ☑ ☐ ☐ REGISTRATION STATEMENT PURSUANT TO SECTION 12 ( b ) OR ( g ) OF THE SECURITIES EXCHANGE ACT OF 1934 OR ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31 , 2020 OR TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from OR to SHELL COMPANY REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of event requiring this shell company report Commission file number 001-38097 Securities registered or to be registered pursuant to Section 12 ( b ) of the Act : ARGENX SE ( Exact name of registrant as specified in its charter and translation of Registrant's name into English ) The Netherlands ( Jurisdiction of incorporation or organization ) Willemstraat 5 4811 AH , Breda , the Netherlands ( Address of principal executive offices ) Tim Van Hauwermeiren argenx BV Industriepark Zwijnaarde 7 , Building C 9052 Zwijnaarde ( Ghent ) Belgium +32 9 310 34 00 TVanHauwermeiren@argenx.com ( Name , telephone , e - mail and / or facsimile number and address of company contact person ) Title of each class : American Depositary Shares , each representing one ordinary share with a nominal value of € 0.10 per share Ordinary shares with a nominal value of € 0.10 per share * Trading Symbol : ARGX * Not for trading , but only in connection with the registration of the American Depositary Shares . Name of each exchange on which registered : Nasdaq Global Select Market Nasdaq Global Select Market * Securities registered or to be registered pursuant to Section 12 ( g ) of the Act : None . Securities for which there is a reporting obligation pursuant to Section 15 ( d ) of the Act : None . Indicate the number of outstanding shares of each of the issuer's classes of capital or common stock as of the close of the period covered by the annual report : As of December 31 , 2020 47,571,283 ordinary shares were outstanding , including ordinary shares represented by American Depositary Shares . Indicate by check mark if the registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Act . If this report is an annual or transition report , indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or 15 ( d ) of the Securities Exchange Act of 1934 . Yes X No 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 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 X No Indicate by check mark whether the registrant is a large accelerated filer , an accelerated filer , a non - accelerated filer , or an emerging growth company . See the definitions of " large accelerated filer , " " accelerated filer , " and " emerging growth company " in Rule 12b - 2 of the Exchange Act . Large accelerated filer X Accelerated filer Non - accelerated filer Emerging growth company If an emerging growth company that prepares its financial statements in accordance with U.S. GAAP , 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 . X † The term " new or revised financial accounting standard " refers to any update issued by the Financial Accounting Standards Board to its Accounting Standards Codification after April 5 , 2012 . Indicate by check mark which basis of accounting the registrant has used to prepare the financial statements included in this filing : U.S. GAAP International Financial Reporting Standards as issued by the International Accounting Standards Board X If " Other " has been checked in response to the previous question , indicate by check mark which financial statement item the registrant has elected to follow . Other If this is an annual report , indicate by check mark whether the registrant is a shell company ( as defined in Rule 12b - 2 of the Exchange Act ) . Item 17 Item 18 Yes No X