Portfolio Co Investors 2026 for Atlas Venture: investors, rounds, and co-investor patterns from StartupFundraising.com research, updated for 2026.
Atlas Venture accounts for 64 tracked companies with verified cap-table data, 64 of which disclose round sizes totalling $13B. The median disclosed raise is $132M, and the largest is Kailera Therapeutics at $1.6B, ahead of DataRobot ($1.1B) and ACELYRIN ($758M).
The names that recur most often on these co-invested cap tables are Atlas Venture (64 companies), OrbiMed (9 companies), RA Capital Management (9 companies), 5AM Ventures (8 companies), Alexandria Venture Investments (7 companies), Access Biotechnology (6 companies). By latest disclosed round, the market skews Series A (22), Series B (18), Series C (10), IPO (3).
Companies tracked: 64
Disclosed funding total: $13B across 64 companies
Median disclosed raise: $132M
Largest raise: Kailera Therapeutics — $1.6B
Stage mix: Series A 22 · Series B 18 · Series C 10 · IPO 3
