Sec Form 4 Filing - BLACK DARREN M. @ LifeStance Health Group, Inc. - 2021-06-14

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 BLACK DARREN M. 2. Issuer Name and Ticker or Trading Symbol LifeStance Health Group, Inc. [ LFST] 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) 222 BERKELEY STREET, 18TH FLOOR 3. Date of Earliest Transaction (MM/DD/YY) 06/14/2021 (Street) BOSTON, MA02116 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ 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 06/09/2021 A( 1 ) 48,244,251 ( 2 ) A 48,244,251 ( 2 ) I See Footnotes. ( 5 ) ( 6 ) Common Stock 06/14/2021 S 1,368,844 ( 3 ) D $ 17.01 46,875,407 ( 4 ) I See Footnotes. ( 5 ) ( 6 )

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 BLACK DARREN M. 222 BERKELEY STREET, 18TH FLOOR BOSTON, MA02116 X X Signatures Robin W. Devereux, POA for Darren M. Black 06/16/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Shares received in the Organizational Transactions described in the prospectus dated June 9, 2021 relating to the Issuer's initial public offering, filed with the Securities and Exchange Commission on June 11, 2021, in exchange for partnership interests of LifeStance TopCo, L.P. ( 2 )Represents 29,542,786 shares held by Summit Partners Growth Equity Fund IX-A, L.P., 18,446,106 shares held by Summit Partners Growth Equity Fund IX-B, L.P., 206,219 shares held by Summit Investors GE IX/VC IV, LLC, 27,568 shares held by Summit Partners Entrepreneur Advisors Fund II, L.P., and 21,572 shares held by Summit Investors GE IX/VC IV (UK), L.P. ( 3 )Represents 838,224 shares sold by Summit Partners Growth Equity Fund IX-A, L.P., 523,375 shares sold by Summit Partners Growth Equity Fund IX-B, L.P., 5,851 shares sold by Summit Investors GE IX/VC IV, LLC, 782 shares sold by Summit Partners Entrepreneur Advisors Fund II, L.P., and 612 shares sold by Summit Investors GE IX/VC IV (UK), L.P. ( 4 )Represents 28,704,562 shares held by Summit Partners Growth Equity Fund IX-A, L.P., 17,922,731 shares held by Summit Partners Growth Equity Fund IX-B, L.P., 200,368 shares held by Summit Investors GE IX/VC IV, LLC, 26,786 shares held by Summit Partners Entrepreneur Advisors Fund II, L.P., and 20,960 shares held by Summit Investors GE IX/VC IV (UK), L.P. ( 5 )Darren Black is a Managing Director and Member of Summit Master Company, LLC, the general partner of Summit Partners, L.P. Summit Partners, L.P. is the managing member of Summit Partners GE IX, LLC, which is general partner of Summit Partners GE IX, LP, which is the general partner of Summit Partners Growth Equity Fund IX-A, L.P. and Summit Partners Growth Equity Fund IX-B, L.P. Summit Master Company, LLC is (i) the sole member of Summit Partners Entrepreneur Advisors GP II, LLC, which is the general partner of Summit Partners Entrepreneur Advisors Fund II, L.P. and (ii) the general partner of Summit Partners L.P., which is the manager of Summit Investors Management, LLC, which is the manager of Summit Investors GE IX/VC IV, LLC, and the general partner of Summit Investors GE IX/VC IV (UK), L.P. ( 6 )Summit Master Company, LLC, as the sole member of Summit Partners Entrepreneur Advisors GP II, LLC and the managing member of Summit Investors Management, LLC, has delegated investment decisions, including voting and dispositive power, to Summit Partners, L.P. and its investment committee responsible for voting and investment decisions with respect to LifeStance Health Group, Inc. Summit Partners, L.P., through a three-person investment committee, currently composed of Peter Y. Chung, Mark A. deLaar and Craig D. Frances, has voting and dispositive authority over the shares held by each of these entities and therefore beneficially owns such shares. Each of the Summit Funds, Mr. Chung, Mr. deLaar and Dr. Frances disclaim disclaims beneficial ownership of the shares, except, in each case, to the extent of such person's or entity's pecuniary interest therein.

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