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UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 ( Mark one ) ANNUAL REPORT UNDER SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31 , 2020 TRANSITION REPORT UNDER 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 ) FORM 10 - K 708 Quince Orchard Road Gaithersburg , Maryland ( Address of principal executive offices ) OPGEN , INC . ( Exact name of registrant as specified in its charter ) Commission file number 001-37367 Securities registered or to be registered pursuant to Section 12 ( b ) of the Act : Title of each class Common Stock to ( 240 ) 813-1260 ( Registrant's telephone number , including area code ) | X ■ Trading Symbols OPGN Securities registered or to be registered pursuant to Section 12 ( g ) of the Act : None . 06-1614015 ( I.R.S. Employer Identification No. ) 20878 ( Zip Code ) Name of each exchange on which registered Nasdaq Capital Market NO " NO 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 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 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 registrant is a shell company ( as defined in Rule 12b - 2 of the Act ) . YES NO The aggregate market value of the voting common stock held by non - affiliates of the registrant as of June 30 , 2020 , was $ 35,998,374 ( based upon the last reported sale price of $ 2.04 per share on June 30 , 2020 , on The Nasdaq Capital Market . As of March 26 , 2021 , 38,266,482 shares of common stock of the registrant were outstanding . DOCUMENTS INCORPORATED BY REFERENCE Portions of the registrant's definitive Proxy Statement to be filed with respect to its 2021 Annual Meeting of Stockholders are incorporated herein by reference in Part III of this Annual Report on Form 10 - K to the extent stated herein . The proxy statement will be filed with the Securities and Exchange Commission within 120 days after the registrant's fiscal year ended December 31 , 2020 .