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LifeStance Health Group, Inc. (LFST) is the issuer whose common stock is covered by a Schedule 13G/A in which Summit Partners, L.P. reports beneficial ownership of 16,623,824 shares, or 4.37%. The percentage is calculated using 380,190,724 shares outstanding as of October 28, 2026.
Summit Partners Growth Equity Fund IX-A, L.P. separately reports 10,179,742 shares (2.68%), and Summit Partners Growth Equity Fund IX-B, L.P. reports 6,356,090 shares (1.67%). The reporting persons disclose shared voting and dispositive power. Peter Y. Chung, Darren M. Black and Craig D. Frances may be deemed to have authority as investment-committee members, but each disclaims beneficial ownership.
Summit Partners, L.P. beneficial ownership16,623,824 shares4.37% of the class
Shares outstanding380,190,724 sharesAs of October 28, 2026; used to calculate reported ownership percentages
Fund IX-A beneficial ownership10,179,742 sharesSummit Partners Growth Equity Fund IX-A, L.P.; 2.68% of the class
Fund IX-B beneficial ownership6,356,090 sharesSummit Partners Growth Equity Fund IX-B, L.P.; 1.67% of the class
Key Terms
beneficial ownership, shared voting power, shared dispositive power
3 terms
beneficial ownershipregulatory
"Aggregate Amount Beneficially Owned by Each Reporting Person"
Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.
shared voting powerregulatory
"Shared Voting Power 16,623,824.00"
Shared voting power occurs when two or more parties jointly have the right to vote or decide how a block of company shares is cast, like co-owners who must agree before moving a piece of furniture. Investors care because who controls voting rights affects board elections, major corporate decisions and takeover outcomes, and shared control can alter regulatory disclosures and the practical influence any holder has over a company’s direction and value.
shared dispositive powerregulatory
"Shared Dispositive Power 16,623,824.00"
FAQ
AI-generated questions and answers. How Rhea-AI works. Not financial advice.
How many LFST shares does Summit Partners report owning?
Summit Partners, L.P. reports beneficial ownership of 16,623,824 LFST common shares, or 4.37% of the class. The percentage is calculated using 380,190,724 shares outstanding as of October 28, 2026.
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
(Amendment No. 5)
LifeStance Health Group, Inc.
(Name of Issuer)
Common Stock, par value $0.01 per share
(Title of Class of Securities)
53228F101
(CUSIP Number)
09/30/2026
(Date of Event Which Requires Filing of this Statement)
Check the appropriate box to designate the rule pursuant to which this Schedule is filed:
Rule 13d-1(b)
Rule 13d-1(c)
Rule 13d-1(d)
schemaVersion:
SCHEDULE 13G
CUSIP Number(s):
53228F101
1
Names of Reporting Persons
Summit Partners, L.P.
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
DELAWARE
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
16,623,824.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
16,623,824.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
16,623,824.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
4.37 %
12
Type of Reporting Person (See Instructions)
PN
Comment for Type of Reporting Person: *Calculated based on 380,190,724 shares of common stock, par value $0.01 per share ("Common Stock") outstanding as of October 28, 2026, as reported on the Issuer's Form 10-Q, filed with the Securities and Exchange Commission ("SEC") on November 5, 2026.
SCHEDULE 13G
CUSIP Number(s):
53228F101
1
Names of Reporting Persons
Summit Partners Growth Equity Fund IX-A, L.P.
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
DELAWARE
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
10,179,742.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
10,179,742.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
10,179,742.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
2.68 %
12
Type of Reporting Person (See Instructions)
PN
Comment for Type of Reporting Person: *Calculated based on 380,190,724 shares of Common Stock outstanding as of October 28, 2026, as reported on the Issuer's Form 10-Q, filed with the SEC on November 5, 2026.
SCHEDULE 13G
CUSIP Number(s):
53228F101
1
Names of Reporting Persons
Summit Partners Growth Equity Fund IX-B, L.P.
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
DELAWARE
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
6,356,090.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
6,356,090.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
6,356,090.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
1.67 %
12
Type of Reporting Person (See Instructions)
PN
Comment for Type of Reporting Person: *Calculated based on 380,190,724 shares of Common Stock outstanding as of October 28, 2026, as reported on the Issuer's Form 10-Q, filed with the SEC on November 5, 2026.
SCHEDULE 13G
CUSIP Number(s):
53228F101
1
Names of Reporting Persons
Summit Investors GE IX/VC IV (UK), L.P.
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
CAYMAN ISLANDS
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
7,434.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
7,434.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
7,434.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
0.00 %
12
Type of Reporting Person (See Instructions)
PN
Comment for Type of Reporting Person: *Calculated based on 380,190,724 shares of Common Stock outstanding as of October 28, 2026, as reported on the Issuer's Form 10-Q, filed with the SEC on November 5, 2026.
SCHEDULE 13G
CUSIP Number(s):
53228F101
1
Names of Reporting Persons
Summit Partners Entrepreneur Advisors Fund II, L.P.
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
DELAWARE
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
9,499.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
9,499.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
9,499.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
0.00 %
12
Type of Reporting Person (See Instructions)
PN
Comment for Type of Reporting Person: *Calculated based on 380,190,724 shares of Common Stock outstanding as of October 28, 2026, as reported on the Issuer's Form 10-Q, filed with the SEC on November 5, 2026.
SCHEDULE 13G
CUSIP Number(s):
53228F101
1
Names of Reporting Persons
Summit Investors GE IX/VC IV, LLC
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
DELAWARE
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
71,059.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
71,059.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
71,059.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
0.02 %
12
Type of Reporting Person (See Instructions)
OO
Comment for Type of Reporting Person: *Calculated based on 380,190,724 shares of Common Stock outstanding as of October 28, 2026, as reported on the Issuer's Form 10-Q, filed with the SEC on November 5, 2026.
SCHEDULE 13G
Item 1.
(a)
Name of issuer:
LifeStance Health Group, Inc.
(b)
Address of issuer's principal executive offices:
4800 N. Scottsdale Road, Suite 2500 Scottsdale, Arizona 85251
Item 2.
(a)
Name of person filing:
This statement is filed by the entities and persons listed below, all of whom together are referred to herein as the "Reporting Persons":
(i) Summit Partners, L.P.;
(ii) Summit Partners Growth Equity Fund IX-A, L.P.;
(iii) Summit Partners Growth Equity Fund IX-B, L.P.;
(iv) Summit Investors GE IX/VC IV (UK), L.P.;
(v) Summit Partners Entrepreneur Advisors Fund II, L.P.; and
(vi) Summit Investors GE IX/VC IV, LLC
(b)
Address or principal business office or, if none, residence:
222 Berkeley Street, 18th Floor Boston, MA 02116
(c)
Citizenship:
See response to Item 4 on each cover page
(d)
Title of class of securities:
Common Stock, par value $0.01 per share
(e)
CUSIP No.:
53228F101
Item 3.
If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)
Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)
Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)
Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)
Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)
An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)
An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)
A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)
A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)
A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)
A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J),
please specify the type of institution:
(k)
Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.
Ownership
(a)
Amount beneficially owned:
See responses to Item 9 on each cover page.
(b)
Percent of class:
See responses to Item 11 on each cover page.
(c)
Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
See responses to Item 5 on each cover page.
(ii) Shared power to vote or to direct the vote:
See responses to Item 6 on each cover page.
(iii) Sole power to dispose or to direct the disposition of:
See responses to Item 7 on each cover page.
(iv) Shared power to dispose or to direct the disposition of:
See response to Item 8 on each cover page.
Summit Partners, L.P. is the managing member of Summit Partners GE IX, LLC, which is general partner of Summit Partners GE IX, L.P., 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. Summit Master Company, LLC, as the sole member of Summit Partners Entrepreneur Advisors GP II, LLC, the managing member of Summit Investors Management, LLC and general partner of Summit Partners, L.P., 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 the reported securities held by Summit Partners, L.P., through a three-person investment committee. Peter Y. Chung, Darren M. Black and Craig D. Frances are the current members of the investment committee, and as such may be deemed to have voting and dispositive authority over the reported securities, but each of the foregoing disclaim such beneficial ownership. This Statement shall not be construed as an admission that the Reporting Persons or any of the members of the investment committee are, for the purpose of Section 13(d) or 13(g) of the Securities Exchange Act of 1934, the beneficial owner of any securities covered by this Statement.
Item 5.
Ownership of 5 Percent or Less of a Class.
Ownership of 5 percent or less of a class
Item 6.
Ownership of more than 5 Percent on Behalf of Another Person.
Not Applicable
Item 7.
Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
Not Applicable
Item 8.
Identification and Classification of Members of the Group.
Not Applicable
Item 9.
Notice of Dissolution of Group.
Not Applicable
Item 10.
Certifications:
Not Applicable
SIGNATURE
After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.
Summit Partners, L.P.
Signature:
By: Summit Master Company, LLC / /s/ Adam H. Hennessey, as Member
Name/Title:
Its: General Partner / Adam H. Hennessey, as Power of Attorney
Date:
11/13/2026
Summit Partners Growth Equity Fund IX-A, L.P.
Signature:
By: Summit Partners GE IX, L.P. / /s/ Adam H. Hennessey, as POA
Name/Title:
Its: General Partner / Adam H. Hennessey, as Power of Attorney
Date:
11/13/2026
Summit Partners Growth Equity Fund IX-B, L.P.
Signature:
By: Summit Partners GE IX, L.P. / /s/ Adam H. Hennessey, as POA
Name/Title:
Its: General Partner / Adam H. Hennessey, as Power of Attorney
Date:
11/13/2026
Summit Investors GE IX/VC IV (UK), L.P.
Signature:
By: Summit Investors Management, LLC / /s/ Adam H. Hennessey, as POA
Name/Title:
Its: Manager / Adam H. Hennessey, as Power of Attorney
Date:
11/13/2026
Summit Partners Entrepreneur Advisors Fund II, L.P.
Signature:
By: Summit Partners Entrepreneur Advisors GP II, LLC / /s/ Adam H. Hennessey, as POA
Name/Title:
Its: General Partner / Adam H. Hennessey, as Power of Attorney
Date:
11/13/2026
Summit Investors GE IX/VC IV, LLC
Signature:
By: Summit Investors Management, LLC / /s/ Adam H. Hennessey, as POA
Name/Title:
Its: Manager / Adam H. Hennessey, as Power of Attorney
Date:
11/13/2026
Exhibit Information
Exhibit A: Joint Filing Agreement, dated as of February 4, 2022, incorporated herein by reference to the statement on Schedule 13G filed by the Reporting Persons on February 4, 2022.
Exhibit B: Powers of Attorney, dated as of October 25, 2021, incorporated herein by reference to the statement on Schedule 13G filed by the Reporting Persons on February 4, 2022.
