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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 For the fiscal year ended December 31 , 2020 FORM 10 - K Transition Report Pursuant to Section 13 or 15 ( d ) of the Securities Exchange Act of 1934 For the transition period from : Title of each class Common Stock , $ 0.18 par value OR Delaware ( State or other jurisdiction of incorporation or organization ) Commission File Number 001-35610 to ATOSSA THERAPEUTICS , INC . ( Exact name of registrant as specified in its charter ) 107 Spring Street Seattle , WA 98104 ( Address of principal executive offices ) Registrant's telephone number , including area code : ( 206 ) 325-6068 Securities registered pursuant to Section 12 ( b ) of the Act : Trading symbol ( s ) ATOS 26-4753208 ( I.R.S. Employer Identification No. ) Name of each exchange on which registered The Nasdaq Capital 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 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 1 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