Sec Form 3 Filing - Fairmount Funds Management LLC @ Aeglea BioTherapeutics, Inc. - 2023-06-22

FORM 3 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Fairmount Funds Management LLC 2. Issuer Name and Ticker or Trading Symbol Aeglea BioTherapeutics, Inc. [ AGLE] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 200 BARR HARBOR DRIVE, SUITE 400 3. Date of Earliest Transaction (MM/DD/YY) 06/22/2023 (Street) WEST CONSHOHOCKEN, PA19428 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 276,082 I By Fairmount Healthcare Fund LP( ( 1 ) Common Stock 9,184,458 I By Fairmount Healthcare Fund II LP ( 1 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Stock Option (Right to Buy) $ 0.3 ( 2 )( 3 ) 06/22/2033 Common Stock 1,950,000 I By Peter Harwin ( 4 ) Stock Option (Right to Buy) $ 0.3 ( 2 )( 3 ) 06/22/2033 Common Stock 1,950,000 I By Tomas Kiselak ( 4 ) Series A Preferred Stock ( 5 ) ( 5 ) ( 5 ) Common Stock 12,675,000 I By Fairmount Healthcare Fund LP ( 1 ) Series A Preferred Stock ( 5 ) ( 5 ) ( 5 ) Common Stock 424,362,000 I By Fairmount Healthcare Fund II LP ( 1 ) Series A Preferred Stock ( 5 ) ( 5 ) ( 5 ) Common Stock 85,887,000 I By Fairmount Healthcare Co-Invest LP ( 1 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Fairmount Funds Management LLC 200 BARR HARBOR DRIVE, SUITE 400 WEST CONSHOHOCKEN, PA19428 X X Fairmount Healthcare Fund L.P. 200 BARR HARBOR DRIVE, SUITE 400 WEST CONSHOHOCKEN, PA19428 X X Fairmount Healthcare Fund II L.P. 200 BARR HARBOR DRIVE, SUITE 400 WEST CONSHOHOCKEN, PA19428 X X Fairmount Healthcare Co-Invest L.P. 200 BARR HARBOR DRIVE, SUITE 400 WEST CONSHOHOCKEN, PA19428 X X Kiselak Tomas 200 BARR HARBOR DRIVE, SUITE 400 WEST CONSHOHOCKEN, PA19428 X X Harwin Peter Evan 200 BARR HARBOR DRIVE, SUITE 400 WEST CONSHOHOCKEN, PA19428 X X Signatures /s/ Tomas Kiselak, Managing Member of Fairmount Funds Management LLC 06/30/2023 Signature of Reporting Person Date /s/ Tomas Kiselak, Managing Member of Fairmount Healthcare Fund LP 06/30/2023 Signature of Reporting Person Date /s/ Tomas Kiselak, Managing Member of Fairmount Healthcare Fund II LP 06/30/2023 Signature of Reporting Person Date /s/ Tomas Kiselak, Managing Member of Fairmount Healthcare Co-Invest LP 06/30/2023 Signature of Reporting Person Date /s/ Tomas Kiselak 06/30/2023 Signature of Reporting Person Date /s/ Peter Harwin 06/30/2023 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Fairmount Funds Management LLC ("Fairmount") is the investment manager for Fairmount Healthcare Fund LP, Fairmount Healthcare Fund II LP and Fairmount Healthcare Co-Invest LP. The general partner of Fairmount is Fairmount Funds Management GP LLC ("Fairmount GP"), of which Peter Harwin and Tomas Kiselak are the managing members. Fairmount, Fairmount GP, Mr. Harwin, and Mr. Kiselak disclaim beneficial ownership of any of the reported securities, except to the extent of their pecuniary interest therein. ( 2 )This option award is contingent upon receiving stockholder approval of the amendment and/or restatement of the 2016 Equity Incentive Plan to increase the number of shares available for issuance thereunder. ( 3 )The stock option vests and becomes exercisable in 12 equal monthly installments beginning on July 22, 2023, or on the date of the next annual meeting of stockholders, if earlier, subject to the continuing service of the Reporting Person on each vesting date. ( 4 )Under the Reporting Person's arrangement with Fairmount Funds Management LLC (the "Adviser"), the Reporting Person holds the option for one or more investment vehicles managed by the Adviser (each, a "Fairmount Fund"). The Reporting Person is obligated to turn over to the Adviser any net cash or stock received from the option for the benefit of such Fairmount Fund. The Reporting Person therefore disclaims beneficial ownership of the option and underlying common stock. ( 5 )Following stockholder approval of the conversion of Series A Preferred Stock into shares of Common Stock, each share of Series A Preferred Stock will automatically convert into 1,000 shares of Common Stock, subject to certain limitations.

Remarks: The Reporting Persons may each be deemed a director by deputization of Issuer by virtue of the fact that each of Peter Harwin and Tomas Kiselak serve on the board of directors of Issuer and are also each a Managing Member of Fairmount Funds Management LLC.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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