Atlas Venture Life Science Advisors, LLC
Position in SION — Sionna Therapeutics, Inc.
CIK 1917529
CAMBRIDGE, MA
Position in SION
as of Jun 30, 2026
· filed Aug 13, 2026
Position Value
$131,776,531
+$11,682,847 QoQ
Shares Held
2,995,602
0.0% QoQ
Ownership
6.63%
of shares outstanding
% of Portfolio
14.95%
of 13F equity value
Holder Rank
#4
of 146 holders
Holding Since
Mar 2025
6 quarters on record
Voting authority
Sole 100%
Shared 0%
None 0%
Common Shares in SION Over Time
Shares Held
Position Value (USD)
Position in Biotechnology
Healthcare · as of Jun 30, 2026Atlas Venture Life Science Advisors, LLC holds $881,289,155 across 7 Biotechnology names. SION ranks #3 (15.0% of the industry book) .
| # | Ticker | Company | Shares | Value (USD) | Open |
|---|---|---|---|---|---|
| 1 | KYMR |
Kymera Therapeutics, Inc.
|
2,847,541 | $326,527,526 | |
| 2 | DYN |
Dyne Therapeutics, Inc.
|
6,800,099 | $151,030,198 | |
| 3 | SION |
Sionna Therapeutics, Inc.
This page
|
2,995,602 | $131,776,531 | |
| 4 | KLRA |
Kailera Therapeutics, Inc.
|
5,171,282 | $113,923,342 | |
| 5 | IRON |
Disc Medicine, Inc.
|
1,513,875 | $110,724,817 | |
| 6 | QTTB |
Q32 Bio Inc.
|
2,717,106 | $34,615,930 | |
| 7 | KRRO |
Korro Bio, Inc.
|
962,884 | $12,690,811 |
All Filings in SION
Export CSV
6 filing rows on record
| Report Date | Value (USD) | Shares | Type | Discretion | Filed | |
|---|---|---|---|---|---|---|
| 2026-06-30 | $131,776,531 | 2,995,602 | Shares | Sole | 2026-08-13 | |
| 2026-03-31 | $120,093,684 | 2,995,602 | Shares | Sole | 2026-05-14 | |
| 2025-12-31 | $123,239,066 | 2,995,602 | Shares | Sole | 2026-02-13 | |
| 2025-09-30 | $106,332,649 | 3,615,527 | Shares | Sole | 2025-11-13 | |
| 2025-06-30 | $64,091,247 | 3,694,020 | Shares | Sole | 2025-08-12 | |
| 2025-03-31 | $38,639,449 | 3,694,020 | Shares | Sole | 2025-05-14 | |
| No filing history on record for this holder in this stock. | ||||||