Skip to content
Disclosery

Atlas Venture Life Science Advisors, LLC

Follow

13F filer, CIK 1917529, CAMBRIDGE, MA

Atlas Venture Life Science Advisors, LLC reported $881,289,158 across 7 holdings for the quarter ended 2026-06-30, in a 13F-HR filed 2026-08-13.

Filed (acceptance time not in the bulk data set), ingested 13F-HR 0001104659-26-095933

Period
2026-06-30
Reported value
$881M
Holdings
7
Top 10 weight
100%
New
1
Sold out
0

Largest buys vs the previous quarter

SecurityShares changeApprox. value
KLRAnew+5,171,282$114M
QTTBadded+625,000$7.96M

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
KYMRreduced-1,730,467-$198M
DYNreduced-2,330,366-$51.8M
KRROreduced-174,265-$2.3M

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 2026

Share positions as resolved from 13F-HR 0001104659-26-095933, largest first. % of portfolio is the value over $881,289,158, 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; 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; 2026Q2: 2,847,541 shares 2,847,541$327M37.05%-1,730,467Timeline
DYNDYNE THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 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; 2026Q2: 6,800,099 shares 6,800,099$151M17.14%-2,330,366Timeline
SIONSIONNA THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 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; 2026Q2: 2,995,602 shares 2,995,602$132M14.95%0Timeline
KLRAKAILERA THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: not reported; 2026Q1: not reported; 2026Q2: 5,171,282 shares 5,171,282$114M12.93%newTimeline
IRONDISC MEDICINE INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 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; 2026Q2: 1,513,875 shares 1,513,875$111M12.56%0Timeline
QTTBQ32 BIO INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 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; 2026Q2: 2,717,106 shares 2,717,106$34.6M3.93%+625,000Timeline
KRROKORRO BIO INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 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; 2026Q2: 962,884 shares 962,884$12.7M1.44%-174,265Timeline

How Q2 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 0001104659-26-095933 base2026-08-13acceptance time not in the bulk data set

Filings

Every filing of this filer: 13F reports and notices, the 13D and 13G it filed or is a reporting person of, and Forms 3, 4 and 5 it reported as an owner.

FilingSubjectFiledAcceptedIngested
13F-HR 0001104659-26-095933 Quarter ended 2026-06-302026-08-13acceptance time not in the bulk data set
13F-HR 0001104659-26-061232 Quarter ended 2026-03-312026-05-14acceptance time not in the bulk data set
13F-HR 0001104659-26-014463 Quarter ended 2025-12-312026-02-13acceptance time not in the bulk data set
13F-HR 0001104659-25-111321 Quarter ended 2025-09-302025-11-13acceptance time not in the bulk data set
13F-HR 0001104659-25-076898 Quarter ended 2025-06-302025-08-12acceptance time not in the bulk data set
13F-HR 0001104659-25-048527 Quarter ended 2025-03-312025-05-14acceptance time not in the bulk data set
13F-HR 0001104659-25-010152 Quarter ended 2024-12-312025-02-06acceptance time not in the bulk data set
13F-HR 0001104659-24-116967 Quarter ended 2024-09-302024-11-13acceptance time not in the bulk data set
13F-HR 0001104659-24-087431 Quarter ended 2024-06-302024-08-09acceptance time not in the bulk data set
13F-HR 0001104659-24-057096 Quarter ended 2024-03-312024-05-06acceptance time not in the bulk data set
13F-HR 0001104659-24-012910 Quarter ended 2023-12-312024-02-09acceptance time not in the bulk data set
13F-HR 0001104659-23-117225 Quarter ended 2023-09-302023-11-13acceptance time not in the bulk data set
13F-HR 0001104659-23-090482 Quarter ended 2023-06-302023-08-11acceptance time not in the bulk data set
13F-HR 0001387131-23-006542 Quarter ended 2023-03-312023-05-15acceptance time not in the bulk data set
13F-HR 0001387131-23-002062 Quarter ended 2022-12-312023-02-14acceptance time not in the bulk data set
13F-HR 0001387131-22-011239 Quarter ended 2022-09-302022-11-09acceptance time not in the bulk data set
13F-HR 0001387131-22-008352 Quarter ended 2022-06-302022-08-03acceptance time not in the bulk data set
13F-HR 0001387131-22-006198 Quarter ended 2021-12-312022-05-16acceptance time not in the bulk data set
13F-HR 0001387131-22-006199 Quarter ended 2022-03-312022-05-16acceptance time not in the bulk data set