Atlas Venture Life Science Advisors, LLC reported 7 positions worth $881.29M for the quarter ended Jun 30, 2026, up 11.6% on the prior quarter. It opened 1 new position, added to 1, trimmed 3 and exited 0. Its largest holding is Kymera Therapeutics, Inc. at 37.1% 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.
| Holding | Shares | Trade Value | Weight |
|---|---|---|---|
| KLRA Kailera Therapeutics, Inc. | +5.17M | $113.92M | 12.93% |
No positions were closed this quarter.
| # | Activity | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| 1 | KYMR Kymera Therapeutics, Inc. | Healthcare | 2.85M | $326.53M | 37.05% | -1.73M | -37.8% | Reduced | 2.9% |
| 2 | DYN Dyne Therapeutics, Inc. | Healthcare | 6.80M | $151.03M | 17.14% | -2.33M | -25.5% | Reduced | 4.1% |
| 3 | SION Sionna Therapeutics, Inc. | Healthcare | 3.00M | $131.78M | 14.95% | 0 | 0.0% | Unchanged | 6.63% |
| 4 | KLRA Kailera Therapeutics, Inc. | Healthcare | 5.17M | $113.92M | 12.93% | +5.17M | – | New | 3.99% |
| 5 | IRON Disc Medicine, Inc. | Healthcare | 1.51M | $110.72M | 12.56% | 0 | 0.0% | Unchanged | 3.91% |
| 6 | QTTB Q32 Bio Inc. | Healthcare | 2.72M | $34.62M | 3.93% | +625.0K | +29.9% | Added | 11.45% |
| 7 | KRRO Korro Bio, Inc. | Healthcare | 962.9K | $12.69M | 1.44% | -174.3K | -15.3% | Reduced | 5.47% |
Tip. Select a row to see that position’s full history at Atlas Venture Life Science Advisors.
As of its Q2 2026 13F filing, Atlas Venture Life Science Advisors, LLC’s five largest positions were Kymera Therapeutics, Inc. (KYMR) at 37.1%, Dyne Therapeutics, Inc. (DYN) at 17.1%, Sionna Therapeutics, Inc. (SION) at 15.0%, Kailera Therapeutics, Inc. (KLRA) at 12.9%, Disc Medicine, Inc. (IRON) at 12.6% of the reported portfolio.
Atlas Venture Life Science Advisors, LLC reported a 13F portfolio worth $881.29M across 7 positions for Q2 2026. That is up 11.6% from the previous quarter.
Its largest purchases by value were Kailera Therapeutics, Inc. ($113.92M), Q32 Bio Inc. ($7.96M). It opened 1 new positions.
Its largest sales by value were Kymera Therapeutics, Inc. ($198.43M), Dyne Therapeutics, Inc. ($51.76M), Korro Bio, Inc. ($2.30M). It exited 0 positions entirely.
From the Form 13F-HR reports Atlas Venture Life Science Advisors, LLC 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.