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Table of Contents ( Mark One ) UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 FORM 10 - K 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 . OR TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 Quebec For the transition period from Commission file number 001-38899 to Milestone Pharmaceuticals Inc. ( Exact name of registrant as specified in its charter ) ( State or Other Jurisdiction of Incorporation or Organization ) 1111 Dr. Frederik - Phillips Boulevard , Suite 420 Montréal , Québec CA ( Address of Principal Executive Offices ) Title of each class Common Shares Not applicable ( I.R.S. Employer Identification No. ) Registrant's telephone number , including area code ( 514 ) -336-0444 Securities registered pursuant to Section 12 ( b ) of the Act : Trading Symbol ( s ) MIST H4M 2X6 ( Zip Code ) Name of each exchange on which registered The Nasdaq Stock Market LLC 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 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 , if any , every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S - T during the preceding 12 months ( or for such shorter period that the registrant was required to submit and post 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 Accelerated filer Non - 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 . Yes □ No 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 ( approximate ) of the registrant's common equity held by non - affiliates based on the closing price of a share of the registrant's common share for The Nasdaq Stock Market on June 30 , 2020 ( the last business day of the registrant's most recently completed second fiscal quarter ) was $ 93.3 million . As of March 5 , 2021 , the total number of shares outstanding of the registrant's Common Shares was 29,846,000 shares , net of treasury shares .