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☑ ☐ UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , DC 20549 FORM 10 - K ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31 , 2020 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 001-37722 AEGLEA BIOTHERAPEUTICS , INC . Delaware ( Exact name of Registrant as specified in its charter ) ( State or Other Jurisdiction of Incorporation or Organization ) 805 Las Cimas Parkway Suite 100 Austin , TX ( Address of Principal Executive Offices ) 46-4312787 ( I.R.S. Employer Identification No. ) 78746 ( Zip Code ) Registrant's Telephone Number , including area code : ( 512 ) 942-2935 Securities registered pursuant to Section 12 ( b ) of the Exchange Act : Title of each class Common Stock , $ 0.0001 Par Value Per Share Trading Symbol ( s ) AGLE Name of each exchange on which registered The Nasdaq Stock Market LLC ( Nasdaq Global Market ) Securities registered pursuant to Section 12 ( g ) of the Exchange 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 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 ( §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 . Large accelerated filer ☐ Non - accelerated filer ☑ ப 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 the voting stock held by non - affiliates of the Registrant on June 30 , 2020 ( the last business day of the Registrant's second fiscal quarter ) , based upon the closing price of $ 9.25 of the Registrant's common stock as reported on The Nasdaq Global Market , was approximately $ 386.0 million . Indicate the number of shares outstanding of each of the issuer's classes of common stock , as of the latest practicable date . Outstanding at March 12 , 2021 48,015,892 shares Class Common stock , $ 0.0001 par value per share DOCUMENTS INCORPORATED BY REFERENCE Portions of the Registrant's Definitive Proxy Statement ( " Proxy Statement " ) relating to the 2021 Annual Meeting of Stockholders will be filed with the Commission within 120 days after the end of the Registrant's 2020 fiscal year and is incorporated by reference into Part III of this Report . TABLE OF CONTENTS