Atlas Venture Life Science Advisors, LLC

Concentrated strategyQuality / disciplined sizingLong-term holder

Total reported value

$790.0M

Reporting period: 2026-03-31 · Number of holdings: 6

Atlas Venture Life Science Advisors, LLC disclosed 6 holdings in its latest 13F filing for the period ending 2026-03-31, with total reported value of $790.0M and a quarterly turnover rate of 16.1%.

Personality snowflake

Concentration: 100
Portfolio Stability: 16.08
Momentum/Contrarian: 50
Sector conviction: 0
Diversification: 12
Sizing Uniformity: 89.65

Recent moves

Add KYMR
-1.8%　$18.7M
Trim IRON
0.0%　-$23.4M
Add SION
0.0%　-$3.1M
Add QTTB
0.0%　$6.5M
Add KRRO
0.0%　$3.8M
Add DYN
0.0%　-$13.1M

Holdings Map

New buyAddUnchangedTrim

Top 10 holdings by weight

Full holdings list this quarter

#	Ticker	Issuer	Asset Subclass	Weight	Weight Change	Shares Change
1	KYMR	Kymera Therapeutics INC	Stock-Other	48.26%	+6.35%	-1.76%
2	DYN	Dyne Therapeutics INC	Stock-Other	20.95%	+0.31%	—
3	SION	Sionna Therapeutics INC	Stock-Other	15.20%	+0.96%	—
4	IRON	Disc Medicine INC	Stock-Other	12.25%	-1.65%	—
5	QTTB	Q32 Bio INC	Stock-Other	1.70%	+0.90%	—
6	KRRO	Korro Bio INC	Stock-Other	1.63%	+0.58%	—

Reported value over time

Sector allocation

Not enough sector-mapped data yet

Sector allocation over time

Quarterly history

Period	Holdings	Total value	Stability	Top holdings
2026-03-31	6	$790.0M	16	1KYMR 2DYN 3SION Top holdings2026-03-31 1.KYMR 2.DYN 3.SION 4.IRON 5.QTTB 6.KRRO
2025-12-31	8	$865.2M	32	1KYMR 2DYN 3SION Top holdings2025-12-31 1.KYMR 2.DYN 3.SION 4.IRON 5.DAWNGBX 6.KRRO 7.QTTB 8.37148K
2025-09-30	9	$752.6M	51	1KYMR 2IRON 3DYN Top holdings2025-09-30 1.KYMR 2.IRON 3.DYN 4.SION 5.KRRO 6.DAWNGBX 7.GBIOGBX 8.QTTB 9.IMA
2025-06-30	11	$662.4M	0	1KYMR 2IRON 3DYN Top holdings2025-06-30 1.KYMR 2.IRON 3.DYN 4.SION 5.88427A 6.VIGL 7.DAWNGBX 8.KRRO 9.45175G 10.QTTB
2025-03-31	13	$521.8M	0	1KYMR 2IRON 3DYN Top holdings2025-03-31 1.KYMR 2.IRON 3.DYN 4.DAWNGBX 5.SION 6.88427A 7.KRRO 8.VIGL 9.45175G 10.008064
2024-12-31	13	$819.7M	0	1KYMR 2DYN 3IRON Top holdings2024-12-31 1.KYMR 2.DYN 3.IRON 4.88427A 5.DAWNGBX 6.KRRO 7.VIGL 8.GBIOGBX 9.45175G 10.QTTB
2024-09-30	14	$1.1B	0	1DYN 2KYMR388427A Top holdings2024-09-30 1.DYN 2.KYMR 3.88427A 4.IRON 5.QTTB 6.DAWNGBX 7.KRRO 8.GBIOGBX 9.VIGL 10.TECX
2024-06-30	15	$949.6M	0	1DYN 2KYMR388427A Top holdings2024-06-30 1.DYN 2.KYMR 3.88427A 4.IRON 5.DAWNGBX 6.KRRO 7.QTTB 8.GBIOGBX 9.VIGL 10.REPL
2024-03-31	16	$1.1B	0	1DYN 2KYMR 3IRON Top holdings2024-03-31 1.DYN 2.KYMR 3.IRON 4.DAWNGBX 5.88427A 6.KRRO 7.008064 8.QTTB 9.GBIOGBX 10.VIGL
2023-12-31	16	$839.8M	0	1KYMR 2IRON 3DYN Top holdings2023-12-31 1.KYMR 2.IRON 3.DYN 4.88427A 5.DAWNGBX 6.KRRO 7.008064 8.VIGL 9.REPL 10.GBIOGBX
2023-09-30	15	$645.6M	0	1IRON 2DAWNGBX 3DYN Top holdings2023-09-30 1.IRON 2.DAWNGBX 3.DYN 4.KYMR 5.88427A 6.REPL 7.VIGL 8.GBIOGBX 9.008064 10.45175G
2023-06-30	15	$803.6M	0	1IRON 2KYMR 3DYN Top holdings2023-06-30 1.IRON 2.KYMR 3.DYN 4.DAWNGBX 5.VIGL 6.88427A 7.REPL 8.GBIOGBX 9.008064 10.45175G
2023-03-31	16	$738.6M	0	1KYMR 2DYN 3DAWNGBX Top holdings2023-03-31 1.KYMR 2.DYN 3.DAWNGBX 4.IRON 5.VIGL 6.88427A 7.008064 8.REPL 9.GBIOGBX 10.AKRO
2022-12-31	17	$830.2M	0	1DAWNGBX 2KYMR 3DYN Top holdings2022-12-31 1.DAWNGBX 2.KYMR 3.DYN 4.VIGL 5.IRON 6.008064 7.REPL 8.88427A 9.AKRO 10.GBIOGBX
2022-09-30	17	$906.2M	0	188427A2DAWNGBX 3KYMR Top holdings2022-09-30 1.88427A 2.DAWNGBX 3.KYMR 4.DYN 5.REPL 6.VIGL 7.GBIOGBX 8.008064 9.AKRO 10.45175G
2022-06-30	16	$598.2M	0	1DAWNGBX 2KYMR 3DYN Top holdings2022-06-30 1.DAWNGBX 2.KYMR 3.DYN 4.REPL 5.GBIOGBX 6.008064 7.45175G 8.AKRO 9.VIGL 10.36870G
2022-03-31	17	$791.0M	0	1KYMR 2DYN 3DAWNGBX Top holdings2022-03-31 1.KYMR 2.DYN 3.DAWNGBX 4.GBIOGBX 5.008064 6.REPL 7.VIGL 8.AKRO 9.45175G 10.98422T
2021-12-31	16	$1.1B	0	1KYMR 2DAWNGBX 3DYN Top holdings2021-12-31 1.KYMR 2.DAWNGBX 3.DYN 4.REPL 5.45175G 6.GBIOGBX 7.AKRO 8.98422T 9.008064 10.05455M

Holding changes this quarter

Atlas Venture Life Science Advisors, LLC's most significant position changes for 2026-03-31: Sold out: Day One Biopharmaceuticals I (DAWNGBX); Sold out: ; Trim: Kymera Therapeutics INC (KYMR) — shares -1.76%.

Position changes disclosed by Atlas Venture Life Science Advisors, LLC for the quarter ending 2026-03-31, including ticker, issuer, weight change, shares change, and action
#	Ticker	Issuer	Weight Change	Shares Change	Action
1	KYMR	Kymera Therapeutics INC	+6.4%	-1.76%	Trim
2	SION	Sionna Therapeutics INC	+1%	—	Unchanged
3	QTTB	Q32 Bio INC	+0.9%	—	Unchanged
4	KRRO	Korro Bio INC	+0.6%	—	Unchanged
5	DYN	Dyne Therapeutics INC	+0.3%	—	Unchanged
6	IRON	Disc Medicine INC	-1.7%	—	Unchanged
7	DAWNGBX	Day One Biopharmaceuticals I	—	EXIT	Sold out
8	✓		—	EXIT	Sold out

FAQ

What is Atlas Venture Life Science Advisors, LLC and what type of investor is it?

Atlas Venture Life Science Advisors, LLC is a investment manager that files SEC Form 13F quarterly, disclosing its U.S. public equity holdings to regulators. As of the most recent reporting period (2026-03-31), the firm manages a tracked equity portfolio valued at approximately $790.0M, spread across 6 disclosed positions.

What are Atlas Venture Life Science Advisors, LLC's largest equity positions?

Based on the latest 13F filing, Atlas Venture Life Science Advisors, LLC's top holdings by market value are: 1. Kymera Therapeutics INC (KYMR) — $381.3M (48.3%) 2. Dyne Therapeutics INC (DYN) — $165.5M (20.9%) 3. Sionna Therapeutics INC (SION) — $120.1M (15.2%) 4. Disc Medicine INC (IRON) — $96.8M (12.3%) 5. Q32 Bio INC (QTTB) — $13.4M (1.7%)

What changes did Atlas Venture Life Science Advisors, LLC make in its most recent portfolio filing?

In the latest quarter, Atlas Venture Life Science Advisors, LLC took a more defensive posture — trimming 1 positions and completely exiting 2 holdings. The largest of these moves: Sold out: Day One Biopharmaceuticals I (DAWNGBX); Sold out: ; Trim: Kymera Therapeutics INC (KYMR) — shares -1.76%

What sectors does Atlas Venture Life Science Advisors, LLC focus on?

Sector breakdown data is not yet available for Atlas Venture Life Science Advisors, LLC. Check back after the next 13F processing cycle.