Atlas Venture Life Science Advisors, LLC — 13F Holdings & Portfolio
CIK 1917529 · latest 13F-HR filed 2026-08-13
Atlas Venture Life Science Advisors, LLC manages $881.3M in 13F-reported U.S. long-equity assets across 7 reported positions as of its 2026-06-30 13F-HR filing. Its largest disclosed positions are KYMR (37.05%), DYN (17.14%), SION (14.95%). Quarter over quarter (versus its 2026-03-31 filing) the fund opened 1 new position, exited 0, added to 3, and trimmed 2.
AUM is the long-equity portion reported on Form 13F-HR. Excludes short positions, cash, foreign holdings, and non-13F assets. For informational purposes only — not investment advice.
$881.3M
Long-equity book
7
Distinct positions
2026-06-30
Filed 2026-08-13
+1 / −0 / ↑3 / ↓2
vs 2026-03-31
Portfolio charts
Latest quarter's book, what changed, and how the portfolio has evolved across filings.
| Name | Title / Status | Ownership | Type |
|---|
Quarter-over-quarter changes
Share-count changes vs the prior 13F.
Top Adds (vs prior quarter)
- Q32 Bio, Inc.$21.2M +157.7%
- Disc Medicine, Inc.$13.9M +14.4%
- Sionna Therapeutics, Inc.$11.7M +9.7%
Rows tagged Call or Put are options positions, not stock. Per SEC Form 13F-HR, Value shows the notional value of the underlying (shares covered × underlying price), not the option premium. Shares is the number of underlying shares covered (divide by 100 for contract count).
| # | Issuer | Symbol | CUSIP | Value | Weight | Shares | Type |
|---|---|---|---|---|---|---|---|
| 1 | Kymera Therapeutics, Inc. | KYMR | 501575104 | $326.5M | 37.05% | 2,847,541 | SH |
| 2 | Dyne Therapeutics, Inc. | DYN | 26818M108 | $151.0M | 17.14% | 6,800,099 | SH |
| 3 | Sionna Therapeutics, Inc. | SION | 829401108 | $131.8M | 14.95% | 2,995,602 | SH |
| 4 | Kailera Therapeutics, Inc. | KLRA | 482931102 | $113.9M | 12.93% | 5,171,282 | SH |
| 5 | Disc Medicine, Inc. | IRON | 254604101 | $110.7M | 12.56% | 1,513,875 | SH |
| 6 | Q32 Bio, Inc. | QTTB | 746964105 | $34.6M | 3.93% | 2,717,106 | SH |
| 7 | Korro Bio, Inc. | KRRO | 500946108 | $12.7M | 1.44% | 962,884 | SH |
| Period | Filed | AUM | Holdings | Accession |
|---|---|---|---|---|
| 2026-06-30 | 2026-08-13 | $881.3M | 7 | 0001104659-26-095933 |
| 2026-03-31 | 2026-05-14 | $790.0M | 6 | 0001104659-26-061232 |
| 2025-12-31 | 2026-02-13 | $865.2M | 8 | 0001104659-26-014463 |
| 2025-09-30 | 2025-11-13 | $752.6M | 9 | 0001104659-25-111321 |
CAMBRIDGE, MA 02139