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UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 FORM 10 - K ( Mark One ) [ 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 NO [ X ] [ ] TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM Delaware ( State or other jurisdiction of incorporation or organization ) OR 21925 W. Field Parkway , Suite 235 Deer Park , IL ( Address of principal executive offices ) Commission File Number 001-38738 ETON PHARMACEUTICALS , INC . ( Exact name of registrant as specified in its charter ) Title of each class Common Stock , $ 0.001 par value Large accelerated filer Non - accelerated filer ΤΟ 60010-7208 ( Zip Code ) Registrant's telephone number , including area code : ( 847 ) 787-7361 Securities registered pursuant to Section 12 ( b ) of the Act : Trading Symbol ΕΤΟΝ 37-1858472 ( I.R.S. Employer Identification No. ) [ ] [ X ] 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 [ ] Name of each exchange on which registered The Nasdaq Global Market Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or 15 ( d ) of the Act . YES [ ] NO [ X ] Indicate by check I whether the registrant : ( 1 ) has all reports required to 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 , 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 . Accelerated filer Smaller reporting company Emerging growth company [ X ] [ X ]