Summit Partners L P reported 5 positions worth $490.89M for the quarter ended Sep 30, 2026, down 19.4% on the prior quarter. It opened 0 new positions, added to 0, trimmed 2 and exited 0. Its largest holding is Klaviyo, Inc. at 44.4% of the portfolio.
Reported 13F market value at each quarter end. A change mixes trading with price moves in the positions held.
Dollar value of shares bought and sold each quarter, at that quarter’s price. It counts trading only, not price changes.
How many positions were opened, added to, trimmed or closed each quarter.
Share of reported value in each sector at every quarter end.
No positions were added to this quarter.
No new positions this quarter.
No positions were closed this quarter.
| # | Activity | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| 1 | KVYO Klaviyo, Inc. | Technology | 13.85M | $217.90M | 44.39% | -5.00M | -26.5% | Reduced | 4.67% |
| 2 | LFST LifeStance Health Group, Inc. | Healthcare | 16.62M | $199.98M | 40.74% | -6.69M | -28.7% | Reduced | 4.33% |
| 3 | AKA A.K.A. Brands Holding Corp. | Consumer Discretionary | 6.05M | $65.86M | 13.42% | 0 | 0.0% | Unchanged | 55.22% |
| 4 | ATEN A10 Networks, Inc. | Technology | 200.1K | $5.42M | 1.1% | 0 | 0.0% | Unchanged | 0.28% |
| 5 | MTSI MACOM Technology Solutions Holdings, Inc. | Technology | 6,005 | $1.71M | 0.348% | 0 | 0.0% | Unchanged | 0.01% |
Tip. Select a row to see that position’s full history at Summit Partners L P.
As of its Q3 2026 13F filing, Summit Partners L P’s five largest positions were Klaviyo, Inc. (KVYO) at 44.4%, LifeStance Health Group, Inc. (LFST) at 40.7%, A.K.A. Brands Holding Corp. (AKA) at 13.4%, A10 Networks, Inc. (ATEN) at 1.1%, MACOM Technology Solutions Holdings, Inc. (MTSI) at 0.3% of the reported portfolio.
Summit Partners L P reported a 13F portfolio worth $490.89M across 5 positions for Q3 2026. That is down 19.4% from the previous quarter.
Its largest sales by value were LifeStance Health Group, Inc. ($80.44M), Klaviyo, Inc. ($78.65M). It exited 0 positions entirely.
From the Form 13F-HR reports Summit Partners L P files with the SEC each quarter, within 45 days of quarter end. A 13F lists long positions in US-listed equities and options; it excludes short positions, cash, bonds and most non-US holdings.
13F data reflects long positions in US-listed equities and options as reported to the SEC up to 45 days after quarter end. It excludes short positions, cash, bonds and most non-US securities, so it is not a complete picture of a manager’s assets.