LFST

SEC source: 0001193125-26-102645 · ownership.xml · nonDerivative · entry 2

Pardo Ryan · CIK 0001865531 · Director · See Remarks

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,051,351

F2 · shares: Represents performance-based restricted stock units ("PSUs") previously granted to the Reporting Person on March 6, 2025, which vested on March 9, 2026.

SEC source: 0001193125-26-102645 · ownership.xml · nonDerivative · entry 1

Pardo Ryan · CIK 0001865531 · Director · See Remarks

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,011,097

F1 · kind: Represents the number of shares withheld by the Issuer to satisfy tax withholding obligations in connection with the net settlement of restricted stock units ("RSUs") that vested on March 9, 2026. The shares withheld represent a reduction of shares issued to the Reporting Person upon settlement of vested RSUs and do not constitute any open-market sale.

SEC source: 0001193125-26-102657 · ownership.xml · nonDerivative · entry 5

Burdick Kenneth A · CIK 0001498992 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 3,425,315

F5 · kind: Represents the number of shares withheld by the Issuer to satisfy tax withholding obligations in connection with the net settlement of PSUs that vested on March 9, 2026. The shares withheld represent a reduction of shares issued to the Reporting Person upon settlement of vested PSUs and do not constitute any open-market sale.

SEC source: 0001193125-26-102657 · ownership.xml · nonDerivative · entry 4

Burdick Kenneth A · CIK 0001498992 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 3,703,507

F4 · shares: Represents PSUs previously granted to the Reporting Person on February 27, 2025, which vested on March 9, 2026.

SEC source: 0001193125-26-102657 · ownership.xml · nonDerivative · entry 3

Burdick Kenneth A · CIK 0001498992 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 2,996,547

F3 · kind: Represents the number of shares withheld by the Issuer to satisfy tax withholding obligations in connection with the net settlement of PSUs that vested on March 9, 2026. The shares withheld represent a reduction of shares issued to the Reporting Person upon settlement of vested PSUs and do not constitute any open-market sale.

SEC source: 0001193125-26-102657 · ownership.xml · nonDerivative · entry 2

Burdick Kenneth A · CIK 0001498992 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 3,009,748

F2 · shares: Represents performance-based restricted stock units ("PSUs") previously granted to the Reporting Person on March 6, 2025, which vested on March 9, 2026.

SEC source: 0001193125-26-102657 · ownership.xml · nonDerivative · entry 1

Burdick Kenneth A · CIK 0001498992 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 2,976,204

F1 · kind: Represents the number of shares withheld by the Issuer to satisfy tax withholding obligations in connection with the net settlement of restricted stock units ("RSUs") that vested on March 9, 2026. The shares withheld represent a reduction of shares issued to the Reporting Person upon settlement of vested RSUs and do not constitute any open-market sale.

SEC source: 0001193125-26-102652 · ownership.xml · nonDerivative · entry 5

Bourdon David · CIK 0001823690 · Director · Chief Executive Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,398,247

F5 · kind: Represents the number of shares withheld by the Issuer to satisfy tax withholding obligations in connection with the net settlement of PSUs that vested on March 9, 2026. The shares withheld represent a reduction of shares issued to the Reporting Person upon settlement of vested PSUs and do not constitute any open-market sale.

SEC source: 0001193125-26-102652 · ownership.xml · nonDerivative · entry 4

Bourdon David · CIK 0001823690 · Director · Chief Executive Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,484,271

F4 · shares: Represents PSUs previously granted to the Reporting Person on February 27, 2025, which vested on March 9, 2026.

SEC source: 0001193125-26-102652 · ownership.xml · nonDerivative · entry 3

Bourdon David · CIK 0001823690 · Director · Chief Executive Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,278,721

F3 · kind: Represents the number of shares withheld by the Issuer to satisfy tax withholding obligations in connection with the net settlement of PSUs that vested on March 9, 2026. The shares withheld represent a reduction of shares issued to the Reporting Person upon settlement of vested PSUs and do not constitute any open-market sale.

SEC source: 0001193125-26-102652 · ownership.xml · nonDerivative · entry 2

Bourdon David · CIK 0001823690 · Director · Chief Executive Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,330,195

F2 · shares: Represents performance-based restricted stock units ("PSUs") previously granted to the Reporting Person on March 6, 2025, which vested on March 9, 2026.

SEC source: 0001193125-26-102652 · ownership.xml · nonDerivative · entry 1

Bourdon David · CIK 0001823690 · Director · Chief Executive Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,207,201

F1 · kind: Represents the number of shares withheld by the Issuer to satisfy tax withholding obligations in connection with the net settlement of restricted stock units ("RSUs") that vested on March 9, 2026. The shares withheld represent a reduction of shares issued to the Reporting Person upon settlement of vested RSUs and do not constitute any open-market sale.

SEC source: 0001193125-26-102646 · ownership.xml · nonDerivative · entry 5

Varanakis Ann · CIK 0001965703 · Chief People Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 422,037

F5 · kind: Represents the number of shares withheld by the Issuer to satisfy tax withholding obligations in connection with the net settlement of PSUs that vested on March 9, 2026. The shares withheld represent a reduction of shares issued to the Reporting Person upon settlement of vested PSUs and do not constitute any open-market sale.

SEC source: 0001193125-26-102646 · ownership.xml · nonDerivative · entry 4

Varanakis Ann · CIK 0001965703 · Chief People Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 447,061

F4 · shares: Represents PSUs previously granted to the Reporting Person on February 27, 2025, which vested on March 9, 2026.

SEC source: 0001193125-26-102646 · ownership.xml · nonDerivative · entry 3

Varanakis Ann · CIK 0001965703 · Chief People Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 387,272

F3 · kind: Represents the number of shares withheld by the Issuer to satisfy tax withholding obligations in connection with the net settlement of PSUs that vested on March 9, 2026. The shares withheld represent a reduction of shares issued to the Reporting Person upon settlement of vested PSUs and do not constitute any open-market sale.

SEC source: 0001193125-26-102646 · ownership.xml · nonDerivative · entry 2

Varanakis Ann · CIK 0001965703 · Chief People Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 398,504

F2 · shares: Represents performance-based restricted stock units ("PSUs") previously granted to the Reporting Person on March 6, 2025, which vested on March 9, 2026.

SEC source: 0001193125-26-102646 · ownership.xml · nonDerivative · entry 1

Varanakis Ann · CIK 0001965703 · Chief People Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 371,668

F1 · kind: Represents the number of shares withheld by the Issuer to satisfy tax withholding obligations in connection with the net settlement of restricted stock units ("RSUs") that vested on March 9, 2026. The shares withheld represent a reduction of shares issued to the Reporting Person upon settlement of vested RSUs and do not constitute any open-market sale.

SEC source: 0001193125-26-102640 · ownership.xml · nonDerivative · entry 2

Paunovich Vukasin · CIK 0001938690 · Chief Technology Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 309,296

F2 · kind: Represents the number of shares withheld by the Issuer to satisfy tax withholding obligations in connection with the net settlement of PSUs that vested on March 9, 2026. The shares withheld represent a reduction of shares issued to the Reporting Person upon settlement of vested PSUs and do not constitute any open-market sale.

SEC source: 0001193125-26-102640 · ownership.xml · nonDerivative · entry 1

Paunovich Vukasin · CIK 0001938690 · Chief Technology Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 327,837

F1 · shares: Represents performance-based restricted stock units ("PSUs") previously granted to the Reporting Person on June 11, 2025, which vested on March 9, 2026.

SEC source: 0001193125-26-099056 · ownership.xml · nonDerivative · entry 2

Miller Lisa K · CIK 0002036749 · See Remarks

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 330,577

F2 · kind: Represents the number of shares withheld by the Issuer to satisfy tax withholding obligations in connection with the net settlement of RSUs that vested on March 6, 2026. The shares withheld represent a reduction of shares issued to the Reporting Person upon settlement of vested RSUs and do not constitute any open-market sale.

SEC source: 0001193125-26-099067 · ownership.xml · nonDerivative · entry 2

Pardo Ryan · CIK 0001865531 · See Remarks

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,023,377

F2 · kind: Represents the number of shares withheld by the Issuer to satisfy tax withholding obligations in connection with the net settlement of RSUs that vested on March 6, 2026. The shares withheld represent a reduction of shares issued to the Reporting Person upon settlement of vested RSUs and do not constitute any open-market sale.

SEC source: 0001193125-26-099063 · ownership.xml · nonDerivative · entry 1

Burdick Kenneth A · CIK 0001498992 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 3,012,020

F1 · kind: Represents the number of shares withheld by the Issuer to satisfy tax withholding obligations in connection with the net settlement of restricted stock units ("RSUs") that vested on March 6, 2026. The shares withheld represent a reduction of shares issued to the Reporting Person upon settlement of vested RSUs and do not constitute any open-market sale.

SEC source: 0001193125-26-099064 · ownership.xml · nonDerivative · entry 2

Bourdon David · CIK 0001823690 · Director · Chief Executive Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,218,085

F2 · kind: Represents the number of shares withheld by the Issuer to satisfy tax withholding obligations in connection with the net settlement of RSUs that vested on March 6, 2026. The shares withheld represent a reduction of shares issued to the Reporting Person upon settlement of vested RSUs and do not constitute any open-market sale.

SEC source: 0001193125-26-099053 · ownership.xml · nonDerivative · entry 2

Varanakis Ann · CIK 0001965703 · Chief People Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 380,375

F2 · kind: Represents the number of shares withheld by the Issuer to satisfy tax withholding obligations in connection with the net settlement of RSUs that vested on March 6, 2026. The shares withheld represent a reduction of shares issued to the Reporting Person upon settlement of vested RSUs and do not constitute any open-market sale.

SEC source: 0001193125-26-099052 · ownership.xml · nonDerivative · entry 1

McGroarty Ryan · CIK 0002059196 · See Remarks

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 727,611

F1 · shares: Includes 179,856 restricted stock units ("RSUs") granted on March 5, 2026. Each RSU represents a contingent right to receive one share of the Issuer's common stock.

SEC source: 0001193125-26-099056 · ownership.xml · nonDerivative · entry 1

Miller Lisa K · CIK 0002036749 · See Remarks

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 352,167

F1 · shares: Includes 107,914 restricted stock units ("RSUs") granted on March 5, 2026. Each RSU represents a contingent right to receive one share of the Issuer's common stock.

SEC source: 0001193125-26-099067 · ownership.xml · nonDerivative · entry 1

Pardo Ryan · CIK 0001865531 · See Remarks

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,045,231

F1 · shares: Includes 129,496 restricted stock units ("RSUs") granted on March 5, 2026. Each RSU represents a contingent right to receive one share of the Issuer's common stock.

SEC source: 0001193125-26-099064 · ownership.xml · nonDerivative · entry 1

Bourdon David · CIK 0001823690 · Director · Chief Executive Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,283,922

F1 · shares: Includes 395,683 restricted stock units ("RSUs") granted on March 5, 2026. Each RSU represents a contingent right to receive one share of the Issuer's common stock.

SEC source: 0001193125-26-099068 · ownership.xml · nonDerivative · entry 1

Eken Stephanie Carin · CIK 0002112639 · Chief Medical Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 115,107

F1 · shares: Includes 115,107 restricted stock units ("RSUs") granted on March 5, 2026. Each RSU represents a contingent right to receive one share of the Issuer's common stock.

SEC source: 0001193125-26-099062 · ownership.xml · nonDerivative · entry 1

Paunovich Vukasin · CIK 0001938690 · Chief Technology Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 264,902

F1 · shares: Includes 86,331 restricted stock units ("RSUs") granted on March 5, 2026. Each RSU represents a contingent right to receive one share of the Issuer's common stock.

SEC source: 0001193125-26-099053 · ownership.xml · nonDerivative · entry 1

Varanakis Ann · CIK 0001965703 · Chief People Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 401,941

F1 · shares: Includes 86,331 restricted stock units ("RSUs") granted on March 5, 2026. Each RSU represents a contingent right to receive one share of the Issuer's common stock.

SEC source: 0001999371-26-005046 · lifestance-form4_030426.xml · nonDerivative · entry 1

TPG GP A, LLC · CIK 0001903793 · 10% owner

COULTER JAMES G · CIK 0001099776 · 10% owner

WINKELRIED JON · CIK 0001366946 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See Explanation of Responses

Disclosed balance after: 140,026,557

F1 · ownership.nature: Each of James G. Coulter and Jon Winkelried own entities that control TPG GP A, LLC (together with Messrs. Coulter and Winkelried, the "Reporting Persons"), which exercises direct or indirect control over entities that collectively hold 100% of the shares of Class B common stock (which represents a majority of the combined voting power of the common stock) of TPG Inc., which is the sole member of TPG GPCo, LLC, which is the sole member of TPG Holdings II-A, LLC, which is the general partner of TPG Operating Group II, L.P., which is the sole member of TPG Holdings I-A, LLC, which is the general partner of TPG Operating Group I, L.P., which is the sole member of TPG GenPar VIII Advisors, LLC, which is the general partner of TPG GenPar VIII, L.P., which is the general partner of TPG VIII Lynnwood Holdings Aggregation, L.P. ("TPG VIII Lynnwood"), which directly holds 140,026,557 shares of Common Stock of LifeStance Health Group, Inc.

F2 · ownership.nature: Because of the relationship between the Reporting Persons and TPG VIII Lynnwood, the Reporting Persons may be deemed to beneficially own the securities reported herein to the extent of the greater of their respective direct or indirect pecuniary interests in the profits or capital accounts of TPG VIII Lynnwood. Each of TPG VIII Lynnwood and each Reporting Person disclaims beneficial ownership of the securities reported herein, except to the extent of TPG VIII Lynnwood's or such Reporting Person's pecuniary interest therein, if any.

F3 · ownership.nature: Pursuant to Rule 16a-1(a)(4) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), this filing shall not be deemed an admission that the Reporting Persons are, for purposes of Section 16 of the Exchange Act or otherwise, the beneficial owners of any equity securities in excess of their respective pecuniary interests.

SEC source: 0001193125-26-091471 · ownership.xml · nonDerivative · entry 1

BLACK DARREN M. · CIK 0001843861 · Director

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnotes.

Disclosed balance after: 29,209,776

F1 · shares: Represents 2,642,291 shares sold by Summit Partners Growth Equity Fund IX-A, L.P., 1,649,809 shares sold by Summit Partners Growth Equity Fund IX-B, L.P., 18,444 shares sold by Summit Investors GE IX/VC IV, LLC, 2,466 shares sold by Summit Partners Entrepreneur Advisors Fund II, L.P. and 1,929 shares sold by Summit Investors GE IX/VC IV (UK), L.P.

F2 · balance_after: The reported securities are held as follows: 17,886,858 shares in the name of Summit Partners Growth Equity Fund IX-A, L.P.; 11,168,308 shares in the name of Summit Partners Growth Equity Fund IX-B, L.P.; 124,857 shares in the name of Summit Investors GE IX/VC IV, LLC; 16,691 shares in the name of Summit Partners Entrepreneur Advisors Fund II, L.P.; and 13,062 shares in the name of Summit Investors GE IX/ VC IV (UK), L.P.

F3 · ownership.nature: 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 managing member 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.

F4 · ownership.nature: 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, Darren M. Black 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. Black and Dr. Frances disclaim beneficial ownership of the shares, except, in each case, to the extent of such person's or entity's pecuniary interest therein.

SEC source: 0001193125-25-331253 · ownership.xml · nonDerivative · entry 4

Bessler Robert · CIK 0001864881 · Director

10b5-1 filing: Plan reported

Ownership: Indirect · Shama LLC

Disclosed balance after: 1,434,932

F4 · price: The price reported is a weighted average price. These shares were sold in multiple transactions ranging from $7.03 to $7.04 inclusive. The Reporting Person undertakes to provide to the Company, any security holder of the Company or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

F3 · ownership.nature: The Reporting Person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein, and the inclusion of these securities on this report shall not be deemed an admission that the Reporting Person is the beneficial owner of the reported securities for purposes of Section 16 of the Exchange Act or for any other purpose.

SEC source: 0001193125-25-331253 · ownership.xml · nonDerivative · entry 3

Bessler Robert · CIK 0001864881 · Director

10b5-1 filing: Plan reported

Ownership: Indirect · Vitthal LLC

Disclosed balance after: 1,318,133

F4 · price: The price reported is a weighted average price. These shares were sold in multiple transactions ranging from $7.03 to $7.04 inclusive. The Reporting Person undertakes to provide to the Company, any security holder of the Company or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

F2 · ownership.nature: The Reporting Person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein, and the inclusion of these securities on this report shall not be deemed an admission that the Reporting Person is the beneficial owner of the reported securities for purposes of Section 16 of the Exchange Act of 1934 (the "Exchange Act") or for any other purpose.

SEC source: 0001193125-25-331253 · ownership.xml · nonDerivative · entry 2

Bessler Robert · CIK 0001864881 · Director

10b5-1 filing: Plan reported

Ownership: Indirect · Shama LLC

Disclosed balance after: 1,435,783

F1 · price: The price reported is a weighted average price. These shares were sold in multiple transactions ranging from $7.00 to $7.065 inclusive. The Reporting Person undertakes to provide to the Company, any security holder of the Company or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

F3 · ownership.nature: The Reporting Person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein, and the inclusion of these securities on this report shall not be deemed an admission that the Reporting Person is the beneficial owner of the reported securities for purposes of Section 16 of the Exchange Act or for any other purpose.

SEC source: 0001193125-25-331253 · ownership.xml · nonDerivative · entry 1

Bessler Robert · CIK 0001864881 · Director

10b5-1 filing: Plan reported

Ownership: Indirect · Vitthal LLC

Disclosed balance after: 1,318,983

F1 · price: The price reported is a weighted average price. These shares were sold in multiple transactions ranging from $7.00 to $7.065 inclusive. The Reporting Person undertakes to provide to the Company, any security holder of the Company or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

F2 · ownership.nature: The Reporting Person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein, and the inclusion of these securities on this report shall not be deemed an admission that the Reporting Person is the beneficial owner of the reported securities for purposes of Section 16 of the Exchange Act of 1934 (the "Exchange Act") or for any other purpose.

SEC source: 0001193125-25-327010 · ownership.xml · nonDerivative · entry 2

Bessler Robert · CIK 0001864881 · Director

10b5-1 filing: Plan reported

Ownership: Indirect · Shama LLC

Disclosed balance after: 1,495,754

F1 · price: The price reported is a weighted average price. These shares were sold in multiple transactions ranging from $7.00 to $7.025 inclusive. The Reporting Person undertakes to provide to the Company, any security holder of the Company or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

F3 · ownership.nature: The Reporting Person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein, and the inclusion of these securities on this report shall not be deemed an admission that the Reporting Person is the beneficial owner of the reported securities for purposes of Section 16 of the Exchange Act or for any other purpose.

SEC source: 0001193125-25-327010 · ownership.xml · nonDerivative · entry 1

Bessler Robert · CIK 0001864881 · Director

10b5-1 filing: Plan reported

Ownership: Indirect · Vitthal LLC

Disclosed balance after: 1,378,954

F1 · price: The price reported is a weighted average price. These shares were sold in multiple transactions ranging from $7.00 to $7.025 inclusive. The Reporting Person undertakes to provide to the Company, any security holder of the Company or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

F2 · ownership.nature: The Reporting Person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein, and the inclusion of these securities on this report shall not be deemed an admission that the Reporting Person is the beneficial owner of the reported securities for purposes of Section 16 of the Exchange Act of 1934 (the "Exchange Act") or for any other purpose.

SEC source: 0001193125-25-327000 · ownership.xml · nonDerivative · entry 1

Varanakis Ann · CIK 0001965703 · Chief People Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 315,610

F1 · price: The price reported is a weighted average price. These shares were sold in multiple transactions ranging from $6.89 to $6.92 inclusive. The Reporting Person undertakes to provide to the Company, any security holder of the Company or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

SEC source: 0001193125-25-321342 · ownership.xml · nonDerivative · entry 4

Bessler Robert · CIK 0001864881 · Director

10b5-1 filing: Plan reported

Ownership: Indirect · Shama LLC

Disclosed balance after: 1,492,790

F4 · price: The price reported is a weighted average price. These shares were sold in multiple transactions ranging from $7.00 to $7.01 inclusive. The Reporting Person undertakes to provide to the Company, any security holder of the Company or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

F3 · ownership.nature: The Reporting Person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein, and the inclusion of these securities on this report shall not be deemed an admission that the Reporting Person is the beneficial owner of the reported securities for purposes of Section 16 of the Exchange Act or for any other purpose.

SEC source: 0001193125-25-321342 · ownership.xml · nonDerivative · entry 3

Bessler Robert · CIK 0001864881 · Director

10b5-1 filing: Plan reported

Ownership: Indirect · Vitthal LLC

Disclosed balance after: 1,375,989

F4 · price: The price reported is a weighted average price. These shares were sold in multiple transactions ranging from $7.00 to $7.01 inclusive. The Reporting Person undertakes to provide to the Company, any security holder of the Company or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

F2 · ownership.nature: The Reporting Person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein, and the inclusion of these securities on this report shall not be deemed an admission that the Reporting Person is the beneficial owner of the reported securities for purposes of Section 16 of the Exchange Act of 1934 (the "Exchange Act") or for any other purpose.

SEC source: 0001193125-25-321342 · ownership.xml · nonDerivative · entry 2

Bessler Robert · CIK 0001864881 · Director

10b5-1 filing: Plan reported

Ownership: Indirect · Shama LLC

Disclosed balance after: 1,498,975

F1 · price: The price reported is a weighted average price. These shares were sold in multiple transactions ranging from $7.00 to $7.045 inclusive. The Reporting Person undertakes to provide to the Company, any security holder of the Company or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

F3 · ownership.nature: The Reporting Person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein, and the inclusion of these securities on this report shall not be deemed an admission that the Reporting Person is the beneficial owner of the reported securities for purposes of Section 16 of the Exchange Act or for any other purpose.

SEC source: 0001193125-25-321342 · ownership.xml · nonDerivative · entry 1

Bessler Robert · CIK 0001864881 · Director

10b5-1 filing: Plan reported

Ownership: Indirect · Vitthal LLC

Disclosed balance after: 1,382,175

F1 · price: The price reported is a weighted average price. These shares were sold in multiple transactions ranging from $7.00 to $7.045 inclusive. The Reporting Person undertakes to provide to the Company, any security holder of the Company or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

F2 · ownership.nature: The Reporting Person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein, and the inclusion of these securities on this report shall not be deemed an admission that the Reporting Person is the beneficial owner of the reported securities for purposes of Section 16 of the Exchange Act of 1934 (the "Exchange Act") or for any other purpose.

SEC source: 0001193125-25-297294 · ownership.xml · nonDerivative · entry 1

Miller Lisa K · CIK 0002036749 · See Remarks

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 261,292

F1 · price: The price reported is a weighted average price. These shares were sold in multiple transactions ranging from $6.41 to $6.50 inclusive. The Reporting Person undertakes to provide to the Company, any security holder of the Company or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

SEC source: 0001193125-25-280594 · ownership.xml · nonDerivative · entry 1

Miller Lisa K · CIK 0002036749 · See Remarks

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 318,532

F1 · kind: Represents the number of shares withheld by the Issuer to satisfy tax withholding obligations in connection with the net settlement of RSUs that vested on November 10, 2025. The shares withheld represent a reduction of shares issued to the Reporting Person upon settlement of vested RSUs and do not constitute any open-market sale.

SEC source: 0001193125-25-189985 · ownership.xml · nonDerivative · entry 1

Varanakis Ann · CIK 0001965703 · Chief People Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 369,335

F1 · kind: Represents the number of shares withheld by the Issuer to satisfy tax withholding obligations in connection with the net settlement of RSUs that vested on August 26, 2025. The shares withheld represent a reduction of shares issued to the Reporting Person upon settlement of vested RSUs and do not constitute any open-market sale.

SEC source: 0001193125-25-252453 · ownership.xml · nonDerivative · entry 1

Personette Sarah · CIK 0001667675 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 74,766

F1 · shares: Includes 74,766 restricted stock units ("RSUs"). Each RSU represents a contingent right to receive one share of the Issuer's common stock.

SEC source: 0001415889-25-022457 · form4-08202025_080825.xml · nonDerivative · entry 1

SUMMIT PARTNERS L P · CIK 0000830588 · 10% owner

Summit Partners Growth Equity Fund IX-A, L.P. · CIK 0001634415 · shareholder

Summit Partners Growth Equity Fund IX-B, L.P. · CIK 0001634426 · shareholder

SUMMIT INVESTORS GE IX/VC IV, LLC · CIK 0001654074 · owner

SUMMIT INVESTORS GE IX/VC IV (UK), L.P. · CIK 0001846709 · Owner

Summit Partners Entrepreneur Advisors Fund II, L.P. · CIK 0001660981 · Owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 33,524,715

F1 · shares: Represents 5,148,494 shares sold by Summit Partners Growth Equity Fund IX-A, L.P., 3,214,648 shares sold by Summit Partners Growth Equity Fund IX-B, L.P., 35,938 shares sold by Summit Investors GE IX/VC IV, LLC, 4,804 shares sold by Summit Partners Entrepreneur Advisors Fund II, L.P. and 3,759 shares sold by Summit Investors GE IX/VC IV (UK), L.P.

F2 · balance_after: The reported securities are held as follows: 20,529,149 shares in the name of Summit Partners Growth Equity Fund IX-A, L.P.; 12,818,117 shares in the name of Summit Partners Growth Equity Fund IX-B, L.P.; 143,301 shares in the name of Summit Investors GE IX/VC IV, LLC; 19,157 shares in the name of Summit Partners Entrepreneur Advisors Fund II, L.P.; and 14,991 shares in the name of Summit Investors GE IX/ VC IV (UK), L.P.

F3 · ownership.direct: 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.

F4 · ownership.direct: 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 four-person investment committee, currently composed of Peter Y. Chung, Mark A. deLaar, Darren M. Black 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, Mr. Black and Dr. Frances disclaim beneficial ownership of the shares, except, in each case, to the extent of such person's or entity's pecuniary interest therein.

SEC source: 0000950170-25-110461 · ownership.xml · nonDerivative · entry 1

Silversmith Partners I GP, LLC · CIK 0001866164 · Member of 10% Group

Silversmith Partners I GP, L.P. · CIK 0001866163 · Member of 10% Group

Silversmith Capital Partners I-A, L.P. · CIK 0001649052 · Member of 10% Group

Silversmith Capital Partners I-B, L.P. · CIK 0001649051 · Member of 10% Group

Silversmith Capital Partners I-C, L.P. · CIK 0001649053 · Member of 10% Group

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See Explanation of Responses

Disclosed balance after: 14,324,197

F1 · ownership.nature: Silversmith Partners I GP, LLC is the general partner of Silversmith Partners I GP, L.P., which is the general partner of Silversmith Capital Partners I-A, L.P., Silversmith Capital Partners I-B, L.P. and Silversmith Capital Partners I-C, L.P. (collectively, the "Silversmith Entities"). Silversmith Capital Partners I-A, L.P. holds 9,855,844 shares of common stock of the Issuer, Silversmith Capital Partners I-B, L.P. holds 3,565,133 shares of common stock of the Issuer, and Silversmith Capital Partners I-C, L.P. holds 903,220 shares of common stock of the Issuer.

F2 · ownership.nature: Each Reporting Person disclaims beneficial ownership of all of the securities that are or may be beneficially owned by the Silversmith Entities or any of their affiliates, except to the extent of its pecuniary interest therein, and this report shall not be deemed an admission that such Reporting Person is the beneficial owner of the Shares for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose.

F3 · ownership.nature: Silversmith Capital Partners I-A, L.P., Silversmith Capital Partners I-B, L.P. and Silversmith Capital Partners I-C, L.P. have entered into a Stockholders Agreement with certain persons who are owners of more than 10% of the Issuer's outstanding common stock and, as a result, the Silversmith Entities may be deemed a member of a "group" (as such term is used under Section 13(d) of the Securities Exchange Act of 1934, as amended) with such persons.