Q2 2026 13F · SEC CIK 1917529
Atlas Venture Life Science Advisors, LLC
Venture capitalFiled 2026-08-13 for Q2 2026. Open the filing ↗ · All SEC filings ↗
- Reported 13F value
- $881.3M
- Reported positions
- 7
- Top holdings a year, 3 yrs
- +34.7%
- Average holding period
- 3.5 yrs
Atlas Venture Life Science Advisors, LLC is a venture capital that reported 7 positions worth $881.3M in its Q2 2026 13F, filed 2026-08-13. Its largest holdings were Kymera Therapeutics Inc (KYMR, 37.1%), Dyne Therapeutics Inc (DYN, 17.1%), Sionna Therapeutics Inc (15.0%). A portfolio copying its top holdings returned 34.7% a year over the last 3 years, against 20.4% for the S&P 500.
Atlas Venture Life Science Advisors, LLC holdings all 7 positions.
Weights are shares of the filer's total reported 13F value, compared with Q1 2026. Share changes may reflect splits; weight changes also reflect price moves. A 13F shows long US-listed positions only, up to 135 days after the fact.
| Stock | % of 13F value | Share change | Reported value |
|---|---|---|---|
| KYMRKymera Therapeutics Inc | 37.1% | -37.8% | $326.5M |
| DYNDyne Therapeutics Inc | 17.1% | -25.5% | $151.0M |
| 829401108Sionna Therapeutics Inc | 15.0% | +0.0% | $131.8M |
| KLRAKailera Therapeutics Inc | 12.9% | — | $113.9M |
| IRONDisc Medicine Inc | 12.6% | +0.0% | $110.7M |
| QTTBQ32 Bio Inc | 3.9% | +29.9% | $34.6M |
| KRROKorro Bio Inc | 1.4% | -15.3% | $12.7M |
What Atlas Venture Life Science Advisors, LLC bought and sold in Q2 2026, against Q1 2026.
New positions
- KLRA Kailera Therapeutics Inc12.9% of 13F
Added to
- QTTB Q32 Bio Inc+29.9% shares
Reduced
- KYMR Kymera Therapeutics Inc-37.8% shares
- DYN Dyne Therapeutics Inc-25.5% shares
- KRRO Korro Bio Inc-15.3% shares
Sold out
Nothing sold out.
Share counts compared with the Q1 2026 13F; a split also changes share counts.
How the holdings did against the S&P 500.
- 1 year
- +159.3% /yr
- S&P 500 +20.1%
- 3 years
- +34.7% /yr
- S&P 500 +20.4%
- 5 years
- +16.4% /yr
- S&P 500 +15.9%
A portfolio of the filer's 20 largest 13F positions, weighted by value and rebuilt each quarter on the day the filing became public. 13Fs show long US-listed positions only, so this is an estimate of the stock picks, not the fund's reported returns.
Reported 13F value by quarter.
| Quarter | 13F value | Positions |
|---|---|---|
| Q2 2026 | $881.3M | 7 |
| Q1 2026 | $790.0M | 6 |
| Q4 2025 | $865.2M | 8 |
| Q3 2025 | $752.6M | 9 |
| Q2 2025 | $662.4M | 11 |
| Q1 2025 | $521.8M | 13 |
| Q4 2024 | $819.7M | 13 |
| Q3 2024 | $1.1B | 14 |
| Q2 2024 | $949.6M | 15 |
| Q1 2024 | $1.1B | 16 |
| Q4 2023 | $839.8M | 16 |
| Q3 2023 | $645.6M | 15 |
Questions about Atlas Venture Life Science Advisors, LLC's portfolio
What stocks does Atlas Venture Life Science Advisors, LLC own?
Atlas Venture Life Science Advisors, LLC's latest 13F, for Q2 2026 and filed Aug 13, 2026, lists 7 positions worth $881.3M. The largest are Kymera Therapeutics Inc (KYMR) at 37.1%, Dyne Therapeutics Inc (DYN) at 17.1%, Sionna Therapeutics Inc at 15.0%, Kailera Therapeutics Inc (KLRA) at 12.9% and Disc Medicine Inc (IRON) at 12.6%.
What did Atlas Venture Life Science Advisors, LLC buy last quarter?
In Q2 2026, Atlas Venture Life Science Advisors, LLC added a new position in Kailera Therapeutics Inc (KLRA) and Q32 Bio Inc (QTTB) (+29.9% shares), compared with its Q1 2026 filing.
What did Atlas Venture Life Science Advisors, LLC sell last quarter?
In Q2 2026, Atlas Venture Life Science Advisors, LLC Kymera Therapeutics Inc (KYMR) (-37.8% shares), Dyne Therapeutics Inc (DYN) (-25.5% shares) and Korro Bio Inc (KRRO) (-15.3% shares), compared with its Q1 2026 filing.
How has Atlas Venture Life Science Advisors, LLC's portfolio performed?
A portfolio copying Atlas Venture Life Science Advisors, LLC's 20 largest 13F holdings each quarter, from the day each filing was public, returned +34.7% a year over the last 3 years, against +20.4% for the S&P 500. Over 1 year: +159.3% against +20.1%. Over 5 years: +16.4% a year against +15.9%.
When is Atlas Venture Life Science Advisors, LLC's next 13F filing due?
13F filings are due 45 days after each quarter ends. Atlas Venture Life Science Advisors, LLC's filing for the quarter ending Sep 30, 2026 is due by Nov 14, 2026; this page updates the day after it is published.