Form
SCHEDULE 13G/A
Passive or exempt beneficial ownership filing.
Atlas Venture Fund X, L.P. - 31 Mar 2026 SCHEDULE 13G/A Report for GENERATION BIO CO. COMMON STOCK, $0.0001 PAR VALUE (GBIO)
- Filing manager
- Atlas Venture Fund X, L.P.
- Reporting owner
- Atlas Venture Fund X, L.P.
- Beneficially owned shares
- 0 shares
- Large-stake signal
-
Ownership
0%Beneficial ownership of this reported class.
Shares
0 sharesShares beneficially owned as disclosed.
Event date
31 Mar 2026Date tied to the ownership event or amendment.
Accepted by SEC
14 May 2026EDGAR 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
- 0%
- Symbol
- GBIO
- SEC form
- SCHEDULE 13G/A
- Accepted by SEC
- 14 May 2026, 16:24:25 UTC
- Event date
- 31 Mar 2026
- 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.
1 source field
Source evidence
Original filing metadata and source links for verification.
4 source fields
Key filing fact
Atlas Venture Fund X, L.P. disclosed 0% ownership in GENERATION BIO CO. COMMON STOCK, $0.0001 PAR VALUE (GBIO) on 31 Mar 2026.
Key facts
- Atlas Venture Fund X, L.P. filed SCHEDULE 13G/A for GENERATION BIO CO. COMMON STOCK, $0.0001 PAR VALUE (GBIO).
- Disclosed ownership: 0%.
- Date of event: 31 Mar 2026.
Change
- No earlier schedule filing is available for direct comparison.
- Current filing was accepted on 14 May 2026, 16:24.
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 X, L.P. | 0% | 0 | 0 | 0 | /s/ Ommer Chohan | By: Atlas Venture Associates X, L.P., its GP, By: Atlas Venture Associates X, LLC, its GP, By: Ommer Chohan, CFO | |
| ATLAS VENTURE ASSOCIATES X, L.P. | 0% | 0 | 0 | 0 | /s/ Ommer Chohan | By: Atlas Venture Associates X, LLC, its GP, By: Ommer Chohan, CFO | |
| Atlas Venture Associates X, LLC | 0% | 0 | 0 | 0 | /s/ Ommer Chohan | Ommer Chohan, CFO | |
| Atlas Venture Opportunity Fund I, L.P. | 0% | 0 | 0 | 0 | /s/ Ommer Chohan | By: Atlas Venture Associates Opportunity I, L.P., its GP, By: Atlas Venture Associates Opportunity I, LLC, its GP, By: Ommer Chohan, CFO | |
| Atlas Venture Associates Opportunity I, L.P. | 0% | 0 | 0 | 0 | /s/ Ommer Chohan | By: Atlas Venture Associates Opportunity I, LLC, its GP, By: Ommer Chohan, CFO | |
| Atlas Venture Associates Opportunity I, LLC | 0% | 0 | 0 | 0 | /s/ Ommer Chohan | Ommer Chohan, CFO |
CIK / CUSIP context first