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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 $521,764,233 across 13 holdings for the quarter ended 2025-03-31, in a 13F-HR filed 2025-05-14. Its ten largest share positions make up 98.65% of the portfolio.

Filed (acceptance time not in the bulk data set), ingested 13F-HR 0001104659-25-048527

Period
2025-03-31
Reported value
$522M
Holdings
13
Top 10 weight
98.65%
New
1
Sold out
1

Largest buys vs the previous quarter

SecurityShares changeApprox. value
SIONnew+3,694,020$38.6M
DYNadded+1,111,111$11.6M

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.

Largest sells vs the previous quarter

SecurityShares changeApprox. value
IRONreduced-125,000-$6.21M
TECXexited-78,447-$3.62M

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, Q1 2025

Share positions as resolved from 13F-HR 0001104659-25-048527, largest first. % of portfolio is the value over $521,764,233, 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; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 4,896,462 shares; 2024Q4: 4,896,462 shares; 2025Q1: 4,896,462 shares 4,896,462$134M25.69%0Timeline
IRONDISC MEDICINE INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 2,509,456 shares; 2024Q4: 2,509,456 shares; 2025Q1: 2,384,456 shares 2,384,456$118M22.69%-125,000Timeline
DYNDYNE THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 8,020,136 shares; 2024Q4: 8,019,354 shares; 2025Q1: 9,130,465 shares 9,130,465$95.5M18.3%+1,111,111Timeline
DAWNDAY ONE BIOPHARMACEUTICALS IQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 6,430,257 shares; 2024Q4: 6,430,257 shares; 2025Q1: 6,430,257 shares 6,430,257$51M9.77%0Timeline
SIONSIONNA THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: 3,694,020 shares 3,694,020$38.6M7.41%newTimeline
THRDTHIRD HARMONIC BIO INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 10,907,859 shares; 2024Q4: 10,402,286 shares; 2025Q1: 10,402,286 shares 10,402,286$36.1M6.92%0Timeline
KRROKORRO BIO INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 1,137,149 shares; 2024Q4: 1,137,149 shares; 2025Q1: 1,137,149 shares 1,137,149$19.8M3.79%0Timeline
VIGIL NEUROSCIENCE INCVIGIL NEUROSCIENCE INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 5,836,874 shares; 2024Q4: 5,836,874 shares; 2025Q1: 5,836,874 shares 5,836,874$10.4M1.99%0
IKENA ONCOLOGY INCIKENA ONCOLOGY INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 5,018,178 shares; 2024Q4: 5,018,178 shares; 2025Q1: 5,018,178 shares 5,018,178$6.42M1.23%0
AEROVATE THERAPEUTICS INCAEROVATE THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 1,799,232 shares; 2024Q4: 1,799,232 shares; 2025Q1: 1,799,232 shares 1,799,232$4.52M0.87%0
QTTBQ32 BIO INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 2,092,106 shares; 2024Q4: 2,092,106 shares; 2025Q1: 2,092,106 shares 2,092,106$3.45M0.66%0Timeline
GENERATION BIO COGENERATION BIO COQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 8,279,484 shares; 2024Q4: 8,279,484 shares; 2025Q1: 8,279,484 shares 8,279,484$3.35M0.64%0
SPROSPERO THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 402,885 shares; 2024Q4: 305,255 shares; 2025Q1: 305,255 shares 305,255$220K0.04%0Timeline

Sold out in Q1 2025

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

SecurityShares beforeValue beforeType
TECXTECTONIC THERAPEUTIC INC78,447$3.62Mshares

How Q1 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 0001104659-25-048527 base2025-05-14acceptance time not in the bulk data set