SCHEDULE 13G/A

LifeStance Health Group Inc

Common Stock, par value $0.01 per share · CUSIP: 53228F101

Event date: 2025-09-30

Reporting persons may disclose overlapping interests. Their amounts are shown individually and are not added into a filing total.

Filing-level shares

Unavailable

Percent of class

Unavailable

• Summit Partners, L.P.

  Shares: 33,524,715 · Class: 8.62%

• Summit Partners Growth Equity Fund IX-A, L.P.

  Shares: 20,529,149 · Class: 5.28%

• Summit Partners Growth Equity Fund IX-B, L.P.

  Shares: 12,818,117 · Class: 3.30%

• Summit Investors GE IX/VC IV (UK), L.P.

  Shares: 14,991 · Class: 0.01%

• Summit Partners Entrepreneur Advisors Fund II, L.P.

  Shares: 19,157 · Class: 0.01%

• Summit Investors GE IX/VC IV, LLC

  Shares: 143,301 · Class: 0.04%

Amounts are as disclosed in this filing. Schedule type alone does not establish investment intent.