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Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON , D.C. 20549 FORM 10 - Q ( Mark One ) × QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31 , 2021 OR TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number : 001-36304 Phio Pharmaceuticals Corp. Delaware ( Exact name of registrant as specified in its charter ) ( State of incorporation ) Title of each class 45-3215903 ( I.R.S. Employer Identification No. ) 257 Simarano Drive , Suite 101 , Marlborough , MA 01752 ( Address of principal executive office ) ( Zip code ) Registrant's telephone number : ( 508 ) 767-3861 Securities registered pursuant to Section 12 ( b ) of the Act : Common Stock , par value , $ 0.0001 per share Trading Symbol ( s ) PHIO Name of each exchange on which registered The Nasdaq Capital Market 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 time 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 . 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 7 ( a ) ( 2 ) ( B ) of the Securities Act . ■ Indicate by checkmark whether the registrant is a shell company ( as defined in Rule 12b - 2 of the Exchange Act ) . Yes ☐ No ☑ As of May 6 , 2021 , Phio Pharmaceuticals Corp. had 13,534,389 shares of common stock , $ 0.0001 par value , outstanding . ☑