Form
SCHEDULE 13D
Active or control-oriented beneficial ownership filing.
Atlas Venture Fund XI, L.P. - 10 Feb 2025 SCHEDULE 13D Report for SIONNA THERAPEUTICS, INC. Common Stock (SION)
- Filing manager
- Atlas Venture Fund XI, L.P.
- Reporting owner
- Atlas Venture Fund XI, L.P.
- Beneficially owned shares
- 2,886,293 shares
- Large-stake signal
-
Ownership
6.5%Beneficial ownership of this reported class.
Shares
2,886,293 sharesShares beneficially owned as disclosed.
Event date
10 Feb 2025Date tied to the ownership event or amendment.
Accepted by SEC
18 Feb 2025EDGAR acceptance date.
How to read this large-stake filing
- Schedule 13D/G filings focus on beneficial ownership stakes, not a full portfolio.
- Compare this filing with the holder history and issuer page before treating the percentage as a current position.
- Use amendments to understand whether the disclosed stake increased, decreased, or changed reporting status.
- Class ownership
- 6.5%
- Symbol
- SION
- Shares outstanding
- 44,404,508 shares
- SEC form
- SCHEDULE 13D
- Accepted by SEC
- 18 Feb 2025, 16:59:13 UTC
- Event date
- 10 Feb 2025
- Next SEC filing
- 20 Oct 2025
- Source filing
- View source filing
Ownership signal
CIK-linked ownership evidence from parsed SEC filings.
2 signals
Subject security
Names, identifiers, and filing context for this profile.
2 source fields
Source evidence
Original filing metadata and source links for verification.
5 source fields
Key filing fact
Atlas Venture Fund XI, L.P. disclosed 6.5% ownership in SIONNA THERAPEUTICS, INC. Common Stock (SION) on 10 Feb 2025.
Key facts
- Atlas Venture Fund XI, L.P. filed SCHEDULE 13D for SIONNA THERAPEUTICS, INC. Common Stock (SION).
- Disclosed ownership: 6.5%.
- Date of event: 10 Feb 2025.
Change
- No earlier schedule filing is available for direct comparison.
- Current filing was accepted on 18 Feb 2025, 16:59.
Research use
- This page turns one Schedule 13D/G filing into a quick large-stake read before the raw reporting-person rows.
- Use the linked SEC filing as the source of truth for ownership percentages, shares, and reporting-party details.
Evidence
Backed by Schedule 13D/13G
View source filing
Beneficial ownership values are sourced from the original SEC Schedule 13D/13G filing.
Reporting persons
Disclosed reporting parties (6)
Names, ownership percentages, voting power, signatures, titles, and CIKs as disclosed in this Schedule 13D/G filing.
| Name | Ownership | Shares owned | Sole voting power | Shared voting power | Signature | Title | CIK |
|---|---|---|---|---|---|---|---|
| Atlas Venture Fund XI, L.P. | 6.5% | 2,886,293 | 0 | 2,886,293 | /s/ Ommer Chohan | Atlas Venture Associates XI, L.P., its GP, By Atlas Venture Associates XI, LLC, its GP, By: Ommer Chohan, CFO | 0001708269 |
| Atlas Venture Associates XI, L.P. | 6.5% | 2,886,293 | 0 | 2,886,293 | /s/ Ommer Chohan | Atlas Venture Associates XI, LLC, its GP, By: Ommer Chohan, CFO | 0001780068 |
| Atlas Venture Associates XI, LLC | 6.5% | 2,886,293 | 0 | 2,886,293 | /s/ Ommer Chohan | Ommer Chohan, CFO | 0001780067 |
| Atlas Venture Opportunity Fund II, L.P. | 1.8% | 807,727 | 0 | 807,727 | /s/ Ommer Chohan | Atlas Venture Associates Opportunity II, L.P., its GP, By: Atlas Venture Associates Opportunity II, LLC, its GP, By: Ommer Chohan, CFO | 0001885327 |
| Atlas Venture Associates Opportunity II, LP | 1.8% | 807,727 | 0 | 807,727 | /s/ Ommer Chohan | Atlas Venture Associates Opportunity II, LLC, its GP, By: Ommer Chohan, CFO | 0001935814 |
| Atlas Venture Associates Opportunity II, LLC | 1.8% | 807,727 | 0 | 807,727 | /s/ Ommer Chohan | By: Ommer Chohan, CFO | 0001935810 |
CIK / CUSIP context first