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UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON , DC 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 OR TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from Commission File Number : 001-37783 FORM 10 - K Delaware ( State or other jurisdiction of incorporation or organization ) 900 North Point Parkway , Suite 200 Alpharetta , GA ( Address of principal executive offices ) Clearside Biomedical , Inc. ( Exact Name of Registrant as Specified in its Charter ) Title of each class Common Stock , par value $ 0.001 per share to 45-2437375 ( I.R.S. Employer Identification No. ) Registrant's telephone number , including area code : ( 678 ) 270-3631 Securities registered pursuant to Section 12 ( b ) of the Act : Trading Symbol ( s ) . CLSD 30005 ( Zip Code ) Name of each exchange on which registered The Nasdaq Stock Market LLC 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 No 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 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 , 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 . Large accelerated filer Non - accelerated filer Accelerated filer Smaller reporting company Emerging growth 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 the registrant is a shell company ( as defined in Rule 12b - 2 of the Exchange Act ) . Yes No The aggregate market value of Clearside Biomedical , Inc. voting and non - voting common equity held by non - affiliates as of June 30 , 2020 ( the last business day of the registrant's most recently completed second fiscal quarter ) based on the closing sale price of $ 1.88 as reported on the Nasdaq Global Market on that date was approximately $ 66,100,000 . As of March 10 , 2021 , the registrant had 57,422,475 shares of common stock , par value $ 0.001 per share , outstanding . DOCUMENTS INCORPORATED BY REFERENCE Portions of the Company's definitive proxy statement , to be filed pursuant to Regulation 14A under the Securities Exchange Act of 1934 , for its 2021 Annual Meeting of Stockholders are incorporated by reference in Part III of the Form 10 - K .