Atlas Venture Life Science Advisors, LLC
In its 13F for Q2 2026 (holdings as of June 30, 2026, filed August 13, 2026), Atlas Venture Life Science Advisors, LLC reported 7 stock positions worth $881.3 million. Its top holding was Kymera Therapeutics (KYMR) at 37.1% of the portfolio, followed by Dyne Therapeutics (DYN, 17.1%) and Sionna Therapeutics (SION, 15.0%). Compared with Q1 2026, it opened 1 new position, added to 1 and reduced 3. The biggest buy was a new position in Kailera Therapeutics (KLRA) and the biggest sale Kymera Therapeutics (KYMR, shares −38%).
- Most Recent 13F
- Q2 2026
- Location
- CAMBRIDGE, MA
- CIK
- 0001917529
- Portfolio Value
- $881.3M (Q2 2026)
- SEC Filing
- 0001104659-26-095933 ↗ filed Aug 13, 2026
Holdings Value
Holdings 7 stocks · $881.3M
| KYMR Kymera Therapeutics Inc. | 37.05% | 2,847,541 | $326.5M | Reduce -37.8% |
| DYN Dyne Therapeutics Inc. | 17.14% | 6,800,099 | $151.0M | Reduce -25.5% |
| SION Sionna Therapeutics Inc. | 14.95% | 2,995,602 | $131.8M | No change |
| KLRA Kailera Therapeutics Inc. | 12.93% | 5,171,282 | $113.9M | New |
| IRON Disc Medicine Inc. | 12.56% | 1,513,875 | $110.7M | No change |
| QTTB Q32 Bio Inc. | 3.93% | 2,717,106 | $34.6M | Add +29.9% |
| KRRO Korro Bio Inc. | 1.44% | 962,884 | $12.7M | Reduce -15.3% |
Portfolio Sells Q1 2026 → Q2 2026
Portfolio Buys Q1 2026 → Q2 2026
All Filings
| Quarter | Positions | 13F Reported Value | Top Holdings |
|---|---|---|---|
| Q2 2026 | 7 | $881.3M | KYMR, DYN, SION, KLRA, IRON |
| Q1 2026 | 6 | $790.0M | KYMR, DYN, SION, IRON, QTTB |
| Q4 2025 | 8 | $865.2M | KYMR, DYN, SION, IRON, DAWN |
| Q3 2025 | 9 | $752.6M | KYMR, IRON, DYN, SION, KRRO |
| Q2 2025 | 11 | $662.4M | KYMR, IRON, DYN, SION, THRD |
| Q1 2025 | 13 | $521.8M | KYMR, IRON, DYN, DAWN, SION |
| Q4 2024 | 13 | $819.7M | KYMR, DYN, IRON, THRD, DAWN |
| Q3 2024 | 14 | $1.1B | DYN, KYMR, THRD, IRON, QTTB |
| Q2 2024 | 15 | $949.6M | DYN, KYMR, THRD, IRON, DAWN |
| Q1 2024 | 16 | $1.1B | DYN, KYMR, IRON, DAWN, THRD |