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Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 FORM 10 - K ( 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 or TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from Washington ( State or other jurisdiction of incorporation or organization ) Title of each class Common Stock , par value $ 0.01 per share OMEROS CORPORATION ( Exact name of registrant as specified in its charter ) Large accelerated filer Non - accelerated filer Commission file number : 001-34475 to 201 Elliott Avenue West Seattle , Washington 98119 ( Address of principal executive offices and zip code ) 91-1663741 ( I.R.S. Employer Identification Number ) ( 206 ) 676-5000 ( Registrant's telephone number , including area code ) Securities registered pursuant to Section 12 ( b ) of the Act : Trading Symbol OMER Securities registered pursuant to Section 12 ( g ) of the Act : None 0 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 m 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 , as amended , 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 Name of each exchange on which registered The Nasdaq Stock Market LLC 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 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 0 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 . X Indicate by check mark whether the registrant is a shell company ( as defined in Rule 12b - 2 of the Exchange Act ) . Yes No > The aggregate market value of the voting and non - voting common stock held by non - affiliates of the registrant as of the last business day of the registrant's most recently completed second fiscal quarter was $ 762,308,158 . As of February 25 , 2021 , the number of outstanding shares of the registrant's common stock , par value $ 0.01 per share , was 61,933,806 . DOCUMENTS INCORPORATED BY REFERENCE Specified portions of the registrant's proxy statement with respect to the 2021 Annual Meeting of Shareholders to be held June 4 , 2021 , which is to be filed pursuant to Regulation 14A within 120 days after the end of the registrant's fiscal year ended December 31 , 2020 , are incorporated by reference into Part III of this Form 10 - K .