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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 $790,032,316 across 6 holdings for the quarter ended 2026-03-31, in a 13F-HR filed 2026-05-14.

Filed (acceptance time not in the bulk data set), ingested 13F-HR 0001104659-26-061232

Period
2026-03-31
Reported value
$790M
Holdings
6
Top 10 weight
100%
New
0
Sold out
2

Largest buys vs the previous quarter

None.

Largest sells vs the previous quarter

SecurityShares changeApprox. value
DAWNexited-6,412,560-$59.8M
KYMRreduced-81,866-$6.82M
GENERATION BIO COexited-827,946-$4.7M

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 2026

Share positions as resolved from 13F-HR 0001104659-26-061232, largest first. % of portfolio is the value over $790,032,316, 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; 2024Q2: restricted; 2024Q3: 4,896,462 shares; 2024Q4: 4,896,462 shares; 2025Q1: 4,896,462 shares; 2025Q2: 4,896,462 shares; 2025Q3: 4,896,462 shares; 2025Q4: 4,659,874 shares; 2026Q1: 4,578,008 shares 4,578,008$381M48.26%-81,866Timeline
DYNDYNE THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q2: restricted; 2024Q3: 8,020,136 shares; 2024Q4: 8,019,354 shares; 2025Q1: 9,130,465 shares; 2025Q2: 9,130,465 shares; 2025Q3: 9,130,465 shares; 2025Q4: 9,130,465 shares; 2026Q1: 9,130,465 shares 9,130,465$166M20.95%0Timeline
SIONSIONNA THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: 3,694,020 shares; 2025Q2: 3,694,020 shares; 2025Q3: 3,615,527 shares; 2025Q4: 2,995,602 shares; 2026Q1: 2,995,602 shares 2,995,602$120M15.2%0Timeline
IRONDISC MEDICINE INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q2: restricted; 2024Q3: 2,509,456 shares; 2024Q4: 2,509,456 shares; 2025Q1: 2,384,456 shares; 2025Q2: 2,384,456 shares; 2025Q3: 2,142,617 shares; 2025Q4: 1,513,875 shares; 2026Q1: 1,513,875 shares 1,513,875$96.8M12.25%0Timeline
QTTBQ32 BIO INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q2: restricted; 2024Q3: 2,092,106 shares; 2024Q4: 2,092,106 shares; 2025Q1: 2,092,106 shares; 2025Q2: 2,092,106 shares; 2025Q3: 2,092,106 shares; 2025Q4: 2,092,106 shares; 2026Q1: 2,092,106 shares 2,092,106$13.4M1.7%0Timeline
KRROKORRO BIO INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q2: restricted; 2024Q3: 1,137,149 shares; 2024Q4: 1,137,149 shares; 2025Q1: 1,137,149 shares; 2025Q2: 1,137,149 shares; 2025Q3: 1,137,149 shares; 2025Q4: 1,137,149 shares; 2026Q1: 1,137,149 shares 1,137,149$12.9M1.63%0Timeline

Sold out in Q1 2026

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

SecurityShares beforeValue beforeType
DAWNDAY ONE BIOPHARMACEUTICALS I6,412,560$59.8Mshares
GENERATION BIO COGENERATION BIO CO827,946$4.7Mshares

How Q1 2026 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 0001104659-26-061232 base2026-05-14acceptance time not in the bulk data set