Sec Form 4 Filing - Third Rock Ventures IV, L.P. @ Maze Therapeutics, Inc. - 2025-11-04

FORM 4 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 Third Rock Ventures IV, L.P. 2. Issuer Name and Ticker or Trading Symbol Maze Therapeutics, Inc. [ MAZE] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O THIRD ROCK VENTURES, LLC, 201 BROOKLINE AVE, SUITE 1401 3. Date of Earliest Transaction (MM/DD/YY) 11/04/2025 (Street) BOSTON, MA02215 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 11/04/2025 J( 1 ) 1,600,000 D 4,473,958 D ( 2 ) ( 4 ) Common Stock 950,800 I See Footnotes ( 3 ) ( 4 )

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

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Third Rock Ventures IV, L.P. C/O THIRD ROCK VENTURES, LLC 201 BROOKLINE AVE, SUITE 1401 BOSTON, MA02215 X Third Rock Ventures GP IV, L.P. C/O THIRD ROCK VENTURES, LLC 201 BROOKLINE AVE, SUITE 1401 BOSTON, MA02215 X TRV GP IV, LLC C/O THIRD ROCK VENTURES, LLC 201 BROOKLINE AVE, SUITE 1401 BOSTON, MA02215 X Third Rock Ventures V, L.P. C/O THIRD ROCK VENTURES, LLC 201 BROOKLINE AVE, SUITE 1401 BOSTON, MA02215 X Third Rock Ventures GP V, LP C/O THIRD ROCK VENTURES, LLC 201 BROOKLINE AVE, SUITE 1401 BOSTON, MA02215 X TRV GP V, LLC C/O THIRD ROCK VENTURES, LLC 201 BROOKLINE AVE, SUITE 1401 BOSTON, MA02215 X Signatures /s/ Kevin Gillis, Chief Operating Officer of TRV GP IV, LLC, general partner of Third Rock Ventures GP IV, L.P., general partner of Third Rock Ventures IV, L.P. 11/05/2025 Signature of Reporting Person Date /s/ Kevin Gillis, Chief Operating Officer of TRV GP IV, LLC, general partner of Third Rock Ventures GP IV, L.P. 11/05/2025 Signature of Reporting Person Date /s/ Kevin Gillis, Chief Operating Officer of TRV GP IV, LLC 11/05/2025 Signature of Reporting Person Date /s/ Kevin Gillis, Chief Operating Officer of TRV GP V, LLC, general partner of Third Rock Ventures GP V, L.P., general partner of Third Rock Ventures V, L.P. 11/05/2025 Signature of Reporting Person Date /s/ Kevin Gillis, Chief Operating Officer of TRV GP V, LLC, general partner of Third Rock Ventures GP V, L.P. 11/05/2025 Signature of Reporting Person Date /s/ Kevin Gillis, Chief Operating Officer of TRV GP V, LLC 11/05/2025 Signature of Reporting Person Date

Explanation of Responses:

( 1 )On November 4, 2025, Third Rock Ventures IV, L.P. ("TRV IV ") distributed, for no consideration, 1,600,000 shares of Common Stock of the Issuer (the "Shares") to its limited partners and to Third Rock Ventures GP IV, L.P. ("TRV GP IV "), the general partner of TRV IV, representing each such partner's pro rata interest in such Shares. On the same date, TRV GP IV distributed, for no consideration, the Shares it received in the distribution by TRV IV to its partners, representing each such partner's pro rata interest in such Shares. All of the aforementioned distributions were made in accordance with the exemptions afforded by Rules 16a-13 and 16a-9 of the Securities Exchange Act of 1934, as amended. ( 2 )The shares are held directly by TRV IV. The general partner of TRV IV is TRV GP IV. The general partner of TRV GP IV is TRV GP IV LLC. Each of TRV GP IV, and TRV GP IV LLC, disclaims beneficial ownership of these shares except to the extent of its pecuniary interest therein, if any, and this report shall not be deemed an admission that it is the beneficial owner of such shares. ( 3 )The shares are held directly by Third Rock Ventures V, L.P. ("TRV V"). The general partner of TRV V is Third Rock Ventures GP V, L.P. ("TRV GP V"). The general partner of TRV GP V is TRV GP V, LLC ("TRV GP V LLC"). Each of TRV GP V, and TRV GP V LLC, disclaims beneficial ownership of these shares except to the extent of its pecuniary interest therein, if any, and this report shall not be deemed an admission that it is the beneficial owner of such shares. ( 4 )Each of Reporting Persons disclaims the existence of a Section 13(d) "group" as between the TRV IV related parties and the TRV V related parties and this report shall not be deemed an admission that any of such parties is or may be part of such a group with any of the other parties.

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