Summit Partners L.P. has filed its Form 13F-HR, disclosing equity securities held as of September 30, 2026. The filing lists a total of five positions held by the firm.
The largest position reported is in Klaviyo, Inc., where Summit holds 13,852,778 shares of Class A common stock. The filing notes that the total shares reported for Klaviyo reflect Class B shares held by Summit and its affiliates, which are voluntarily disclosed despite not being on the official Section 13F List of Securities as of the report date.
Summit also holds a position in Lifestance Health Group Inc., reporting ownership of 16,623,824 shares. Another notable holding is AKA Brands Holding Corp., for which the filing reports 6,053,693 shares. The filing clarifies that the share count for AKA Brands reflects the total shares held through a holding company controlled by Summit Partners, L.P., and that the total proceeds related to these shares may be lower than the reported value.
The remaining positions include 6005 shares of MACOM Technology Solutions Holdings I, Inc., and 200,065 shares of A10 Networks, Inc.
