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Atlas Venture Life Science Advisors, LLC

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13F filer, CIK 1917529, CAMBRIDGE, MA

Atlas Venture Life Science Advisors, LLC reported $662,354,749 across 11 holdings for the quarter ended 2025-06-30, in a 13F-HR filed 2025-08-12. Its ten largest share positions make up 99.6% of the portfolio.

Filed (acceptance time not in the bulk data set), ingested 13F-HR 0001104659-25-076898

Period
2025-06-30
Reported value
$662M
Holdings
11
Top 10 weight
99.6%
New
0
Sold out
2

Largest buys vs the previous quarter

None.

Largest sells vs the previous quarter

SecurityShares changeApprox. value
AEROVATE THERAPEUTICS INCexited-1,799,232-$4.52M
SPROexited-305,255-$220K

Ranked by the share change valued at this quarter's implied price (value over shares in the 13F). A position sold out is valued at the previous quarter's price, its last report.

Holdings, Q2 2025

Share positions as resolved from 13F-HR 0001104659-25-076898, largest first. % of portfolio is the value over $662,354,749, the sum of the share positions whose value is usable for ratios (method).

SecurityHistorySharesValue% of portfolioChangeLatest eventTimeline
KYMRKYMERA THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 4,896,462 shares; 2024Q4: 4,896,462 shares; 2025Q1: 4,896,462 shares; 2025Q2: 4,896,462 shares 4,896,462$214M32.26%0Timeline
IRONDISC MEDICINE INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 2,509,456 shares; 2024Q4: 2,509,456 shares; 2025Q1: 2,384,456 shares; 2025Q2: 2,384,456 shares 2,384,456$126M19.07%0Timeline
DYNDYNE THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 8,020,136 shares; 2024Q4: 8,019,354 shares; 2025Q1: 9,130,465 shares; 2025Q2: 9,130,465 shares 9,130,465$86.9M13.12%0Timeline
SIONSIONNA THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: 3,694,020 shares; 2025Q2: 3,694,020 shares 3,694,020$64.1M9.68%0Timeline
THRDTHIRD HARMONIC BIO INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 10,907,859 shares; 2024Q4: 10,402,286 shares; 2025Q1: 10,402,286 shares; 2025Q2: 10,402,286 shares 10,402,286$56.5M8.53%0Timeline
VIGIL NEUROSCIENCE INCVIGIL NEUROSCIENCE INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 5,836,874 shares; 2024Q4: 5,836,874 shares; 2025Q1: 5,836,874 shares; 2025Q2: 5,836,874 shares 5,836,874$46.4M7.01%0
DAWNDAY ONE BIOPHARMACEUTICALS IQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 6,430,257 shares; 2024Q4: 6,430,257 shares; 2025Q1: 6,430,257 shares; 2025Q2: 6,430,257 shares 6,430,257$41.8M6.31%0Timeline
KRROKORRO BIO INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 1,137,149 shares; 2024Q4: 1,137,149 shares; 2025Q1: 1,137,149 shares; 2025Q2: 1,137,149 shares 1,137,149$14.2M2.14%0Timeline
IKENA ONCOLOGY INCIKENA ONCOLOGY INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 5,018,178 shares; 2024Q4: 5,018,178 shares; 2025Q1: 5,018,178 shares; 2025Q2: 5,018,178 shares 5,018,178$6.72M1.02%0
QTTBQ32 BIO INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 2,092,106 shares; 2024Q4: 2,092,106 shares; 2025Q1: 2,092,106 shares; 2025Q2: 2,092,106 shares 2,092,106$3.12M0.47%0Timeline
GENERATION BIO COGENERATION BIO COQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 8,279,484 shares; 2024Q4: 8,279,484 shares; 2025Q1: 8,279,484 shares; 2025Q2: 8,279,484 shares 8,279,484$2.65M0.4%0

Sold out in Q2 2025

Positions in the previous quarter's report that this quarter's report no longer lists.

SecurityShares beforeValue beforeType
AEROVATE THERAPEUTICS INCAEROVATE THERAPEUTICS INC1,799,232$4.52Mshares
SPROSPERO THERAPEUTICS INC305,255$220Kshares

How Q2 2025 was built

Available 13F filings of this filer for the quarter and their roles: the base report is the latest original or restatement, NEW HOLDINGS amendments filed after it are added (method).

FilingRoleAmendmentFiledAcceptedIngested
13F-HR 0001104659-25-076898 base2025-08-12acceptance time not in the bulk data set