Security key
37148K100
GENERATION BIO CO. - COMMON STOCK, $0.0001 PAR VALUE (GBIO)
CUSIP: 37148K100
Q1 2024 13F Holders as of 31 Mar 2024
- Security type / class
- Equity / COMMON STOCK, $0.0001 PAR VALUE
- Total 13F shares
- 54,950,269
- Total 13F value
- $223,660,626
- Share change
- +2,391,549
- SEC-reported price per share
- $4.07
- Number of holders
- 75
- Value change
- +$10,865,322
- Number of buys
- 36
- Number of sells
- 38
- Shares outstanding
- 67,017,829
Holder snapshot
6 signals
Security identity
Names, identifiers, and filing context for this profile.
1 source field
Report period
Q1 2024
Institutions
75
Top holders
10
GBIO full security history
Ownership snapshot
Full 13F holder table
Newer quarter: Q4 2025
Generation Bio Co. SEC filings
Generation Bio Co. company facts
Broader feeds
Reporting periods
Holder history for CUSIP 37148K100
Recent filing periods:
Ownership snapshot
Top reported holders of GBIO - GENERATION BIO CO. - COMMON STOCK, $0.0001 PAR VALUE (13F + 13D/G + 3/4/5)
Grouped by holder across the latest SEC ownership disclosures. Start with comparable ownership when available, then verify the linked 13F, 13D/G, or 3/4/5 evidence.
Comparable stake leader
Atlas Venture Life Scienc...
Disclosed value leader
Atlas Venture Life Scienc...
Comparable rows
15/15
Latest evidence
31 Dec 2023
13F
Lead comparable stake: 12%
Showing 1-6 of 15 holder rows.
Quick read
Atlas Venture Life Science Advisors, LLC leads the comparable SEC ownership view at 12%.
15 of 15 rows have a safely comparable ownership percentage. Use this as a filing-backed starting point, then open the detailed table for source links, reporting role, position value, share count, and filing date.
Open SEC evidence
Opens Atlas Venture Life Science Advisors, LLC's linked filing trail.
Comparable ownership
Top 5
Atlas Venture Life Science Adviso...
12%
PRICE T ROWE ASSOCIATES INC /MD/
10%
FMR LLC
8%
Bellevue Group AG
5.4%
BlackRock Finance, Inc.
4.7%
Ownership % is shown only when SEC disclosures are safely comparable across share classes.
Detailed SEC evidence table Showing 1-6 of 15 holder rows
| Holder | Evidence | Ownership % | Position | 12M Net Δ | As of |
|---|---|---|---|---|---|
| Atlas Venture Life Science Advisors, LLC |
13F
Company
|
12%
|
$13,661,149
8,279,484 shares
|
— | 31 Dec 2023 |
| PRICE T ROWE ASSOCIATES INC /MD/ |
13F
Company
|
10%
|
$11,429,000
6,926,174 shares
|
— | 31 Dec 2023 |
| FMR LLC |
13F
Company
|
8%
|
$8,831,459
5,352,399 shares
|
— | 31 Dec 2023 |
| Bellevue Group AG |
13F
Company
|
5.4%
|
$5,968,182
3,617,080 shares
|
— | 31 Dec 2023 |
| BlackRock Finance, Inc. |
13F
Company
|
4.7%
|
$5,227,885
3,168,415 shares
|
— | 31 Dec 2023 |
| Artal Group S.A. |
13F
Company
|
4.2%
|
$4,643,000
2,814,191 shares
|
— | 31 Dec 2023 |
How to read this table
Rows are grouped by holder and ranked first by SEC-reported ownership % when it is safely comparable, then by disclosed holdings value. — indicates unavailable or non-comparable values; "mixed-class rows" means the latest filing spans non-comparable classes.
13F holder rows
Institutional holders as of Q1 2024
Investor-level positions for this CUSIP, loaded as an interactive table.
Institutions
75
Shares
54,950,269
Rows available
75
| Investor | Option | Weight % | Change % | SEC-reported value | * Price | Shares | Share Change | Activity | Report Period |
|---|
* SEC-reported price is the security price as of the portfolio date and can indicate the last known price at which the security was still held. The marker flags a reported price that did not pass the local price check.
Compare Q1 2024 vs Q4 2025 Across Filers
Q4 2025 holders
1
Q1 2024 holders
75
Holder diff
74
| Investor | Q4 2025 Shares | Q1 2024 Shares | Share Diff | Share Chg % | Q4 2025 value | Q1 2024 value | Value change | Value Chg % |
|---|
Trend: ostatnie 8 kwartałów (+ wybrane okresy porównania).
Quarterly Holders Trend
Quarterly Value Trend
Quarterly Shares Trend