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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 to Sage Therapeutics , Inc. ( Exact Name of Registrant as Specified in its Charter ) Delaware ( State or Other Jurisdiction of Incorporation or Organization ) 215 First Street Cambridge , Massachusetts ( Address of Principal Executive Offices ) Commission file number : 001-36544 ( 617 ) 299-8380 Telephone Number , Including Area Code ) ( Registrant's Securities registered pursuant to Section 12 ( b ) of the Act : Title of each class Common Stock , par value $ 0.0001 per share 27-4486580 ( I.R.S. Employer Identification No. ) Trading Symbol ( s ) SAGE Securities registered pursuant to Section 12 ( g ) of the Act : None 02142 ( Zip Code ) Name of each exchange on which registered The Nasdaq Global Market 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 Exchange 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 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 . 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 . No 冈 Indicate by check mark whether the registrant is a shell company ( as defined in Rule 12b - 2 of the Exchange Act ) . Yes □ The aggregate market value of the registrant's voting and non - voting common stock held by non - affiliates of the registrant ( without admitting that any person whose shares are not included in such calculation is an affiliate ) as of June 30 , 2020 was approximately $ 2,120,561,372 , computed by reference to the closing price of the registrant's common stock on the Nasdaq Global Market reported for such date . As of February 17 , 2021 , there were 58,381,933 shares of common stock , $ 0.0001 par value per share , outstanding . DOCUMENTS INCORPORATED BY REFERENCE Part III of this Annual Report on Form 10 - K incorporates by reference certain information from the registrant's definitive Proxy Statement for its 2021 annual meeting of shareholders , which the registrant intends to file pursuant to Regulation 14A with the Securities and Exchange Commission not later than 120 days after the registrant's fiscal year end of December 31 , 2020. Except with respect to information specifically incorporated by reference in this Form 10 - K , the Proxy Statement is not deemed to be filed as part of this Form 10 - K .