Sec Form 3 Filing - Third Rock Ventures VI, L.P. @ Tango Therapeutics, Inc. - 2023-08-11

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 Third Rock Ventures VI, L.P. 2. Issuer Name and Ticker or Trading Symbol Tango Therapeutics, Inc. [ TNGX] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 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) 08/11/2023 (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 194,174 ( 1 ) D ( 2 )

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 T hird Rock Ventures VI, L.P. C/O THIRD ROCK VENTURES, LLC 201 BROOKLINE AVE, SUITE 1401 BOSTON, MA02215 X Third Rock Ventures GP VI, L.P. C/O THIRD ROCK VENTURES, LLC 201 BROOKLINE AVE, SUITE 1401 BOSTON, MA02215 X TRV GP VI, 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 VI, LLC, general partner of Third Rock Ventures GP VI, L.P., general partner of Third Rock Ventures VI, L.P. 08/22/2023 Signature of Reporting Person Date /s/ Kevin Gillis, Chief Operating Officer of TRV GP VI, LLC, general partner of Third Rock Ventures GP VI, L.P. 08/22/2023 Signature of Reporting Person Date /s/ Kevin Gillis, Chief Operating Officer of TRV GP VI, LLC 08/22/2023 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The shares of common stock were acquired by the Reporting Person pursuant to a securities purchase agreement in a private placement offering of shares of the Issuer's common stock, which offering closed on August 11, 2023. ( 2 )These shares are directly held by Third Rock Ventures VI, L.P. ("TRV VI"). The general partner of TRV VI is Third Rock Ventures GP VI, L.P. ("TRV GP VI"). The general partner of TRV GP VI is TRV GP VI, LLC ("TRV GP VI LLC"). Each of TRV GP VI and TRV GP VI LLC disclaims beneficial ownership of the 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.

Remarks: Reid Huber, a partner at Third Rock Ventures, LLC, has been deputized to represent the Reporting Persons (and other funds affiliated with Third Rock Ventures, LLC that hold shares of the Issuer's stock) on the board of directors of the Issuer. By virtue of Mr. Huber's representation, for purposes of Section 16 of the Securities Exchange Act of 1934, each of the Reporting Person may be deemed directors by deputization of the Issuer.

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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