SEC 13F Intelligence

Managers / Q2 2025 · view latest →

Atlas Venture Life Science Advisors, LLC

CIK 0001917529 · 300 TECHNOLOGY SQUARE, 8TH FLOOR, CAMBRIDGE, MA, 02139 · (857) 201-2700

Reported Value
$662M
Q2 2025
Positions
11
Filings on Record
18
2019–present window
Filed
Aug 12, 2025
original filing

Summary

Atlas Venture Life Science Advisors, LLC reported $662M in U.S.-listed holdings across 11 positions for Q2 2025.

The portfolio is heavily concentrated: KYMR alone accounts for 32.3% of reported value.

Compared with Q1 2025, the fund opened 0 new positions and exited 2.

Portfolio Metrics

Turnover
+4.9%
vs prior filed quarter
Top-10 Concentration
+99.6%
share of reported value
Largest Position
+32.3%
Kymera Therapeutics

Methodology: turnover is min(value bought, value sold) ÷ average reported value across the two quarters — value-based, so market moves inflate it slightly versus a share-based measure. Concentration and largest position are shares of the filing’s total reported value, options excluded. New/exited counts compare against the prior filed quarter. All figures derive solely from the fund’s 13F filings.

Reported Value by Quarter

13F Reported Value
Q1 ’22: $791MQ1 ’22Q2 ’22: $598MQ3 ’22: $906MQ4 ’22: $830MQ4 ’22Q1 ’23: $739MQ2 ’23: $804MQ3 ’23: $646MQ3 ’23Q4 ’23: $840MQ1 ’24: $1.1BQ2 ’24: $950MQ2 ’24Q3 ’24: $1.1BQ4 ’24: $820MQ1 ’25: $522MQ1 ’25Q2 ’25: $662MQ3 ’25: $753MQ4 ’25: $865MQ4 ’25Q1 ’26: $790Mfilingsflow.com

Portfolio Composition

By security type
Common Stock: 90.5%Other: 9.5%
  • Common Stock · 90.5% · $599M
  • Other · 9.5% · $63M

Quarter-over-Quarter Changes full breakdown →

vs Q1 2025 (amended baseline)

IssuerMoveShare ΔShares nowValue ΔValue now
Aerovate Therapeutics, Inc.SOLD OUT−1.80M0−$5M$0
SPROSpero Therapeutics, Inc.SOLD OUT−305.3K0−$219,784$0
KYMRKymera Therapeutics, Inc.HELD+04.90M+$80M$214M
VIGLVigil Neuroscience, Inc.HELD+05.84M+$36M$46M
SIONSionna Therapeutics, Inc.HELD+03.69M+$25M$64M
Third Harmonic Bio, Inc.HELD+010.40M+$20M$56M
DAWNGBXDay One Biopharmaceuticals, Inc.HELD+06.43M−$9M$42M
DYNDyne Therapeutics, Inc.HELD+09.13M−$9M$87M

Value changes conflate price moves with buying and selling — share changes are the real signal. Share counts are not split-adjusted.

Holdings — Q2 2025

11 positions
Export to Excel
#IssuerClass% PortfolioValue ↓Shares
1KYMRKymera Therapeutics, Inc.history →Common Stock32.26%$214M4.90M
2IRONDisc Medicine, Inc.history →Common Stock19.07%$126M2.38M
3DYNDyne Therapeutics, Inc.history →Common Stock13.12%$87M9.13M
4SIONSionna Therapeutics, Inc.history →Common Stock9.68%$64M3.69M
5Third Harmonic Bio, Inc.Common Stock8.53%$56M10.40M
6VIGLVigil Neuroscience, Inc.history →Common Stock7.01%$46M5.84M
7DAWNGBXDay One Biopharmaceuticals, Inc.history →Common Stock6.31%$42M6.43M
8KRROKorro Bio, Inc.history →Common Stock2.14%$14M1.14M
9Ikena Oncology, Inc.Common Stock1.02%$7M5.02M
10QTTBQ32 Bio, Inc.Common Stock0.47%$3M2.09M
11Generation Bio, Co.Common Stock0.40%$3M8.28M

Filing History

QuarterReported ValuePositionsFiledTypeLinks
Q1 2026$790M6May 14, 202613F-HRchanges · EDGAR ↗
Q4 2025$865M8Feb 13, 202613F-HRchanges · EDGAR ↗
Q3 2025$753M9Nov 13, 202513F-HRchanges · EDGAR ↗
Q2 2025$662M11Aug 12, 202513F-HRchanges · EDGAR ↗
Q1 2025$522M13May 14, 202513F-HRchanges · EDGAR ↗
Q4 2024$820M13Feb 6, 202513F-HRchanges · EDGAR ↗
Q3 2024$1.1B14Nov 13, 202413F-HRchanges · EDGAR ↗
Q2 2024$950M15Aug 9, 202413F-HRchanges · EDGAR ↗
Q1 2024$1.1B16May 6, 202413F-HRchanges · EDGAR ↗
Q4 2023$840M16Feb 9, 202413F-HRchanges · EDGAR ↗
Q3 2023$646M15Nov 13, 202313F-HRchanges · EDGAR ↗
Q2 2023$804M15Aug 11, 202313F-HRchanges · EDGAR ↗
Q1 2023$739M16May 15, 202313F-HRchanges · EDGAR ↗
Q4 2022$830M17Feb 14, 202313F-HRchanges · EDGAR ↗
Q3 2022$906M17Nov 9, 202213F-HRchanges · EDGAR ↗
Q2 2022$598M16Aug 3, 202213F-HRchanges · EDGAR ↗
Q1 2022$791M17May 16, 202213F-HRchanges · EDGAR ↗

13F filings are due up to 45 days after quarter end, so holdings shown here lag the fund’s current book. Source: original SEC filing on EDGAR ↗.