Security key
37148K100
GENERATION BIO CO. - COMMON STOCK, $0.0001 PAR VALUE (GBIO)
CUSIP: 37148K100
Q1 2025 13F Holders as of 31 Mar 2025
- Security type / class
- Equity / COMMON STOCK, $0.0001 PAR VALUE
- Total 13F shares
- 47,705,137
- Total 13F value
- $19,320,399
- Share change
- -6,144,966
- Put/Call ratio
- 1%
- SEC-reported price per share
- $0.40
- Number of holders
- 80
- Value change
- -$4,690,760
- Number of buys
- 24
- Number of sells
- 45
- Shares outstanding
- 67,017,829
Holder snapshot
7 signals
Open additional details 1 more signal available
Security identity
Names, identifiers, and filing context for this profile.
1 source field
Report period
Q1 2025
Institutions
80
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 ASSOCIATES ...
Disclosed value leader
PRICE T ROWE ASSOCIATES I...
Comparable rows
0/15
Latest evidence
10 Jan 2025
3/4/5
13F
Highest disclosed value: $9,836,000
15 rows are not safely comparable across share classes.
Showing 1-6 of 15 holder rows.
Quick read
PRICE T ROWE ASSOCIATES INC /MD/ has the largest disclosed position value at $9.84M.
0 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 PRICE T ROWE ASSOCIATES INC /MD/'s linked filing trail.
Disclosed position value
Top 5
ATLAS VENTURE ASSOCIATES X, L.P.
$1.2K
PRICE T ROWE ASSOCIATES INC /MD/
$9.84M
Atlas Venture Life Science Adviso...
$8.78M
BlackRock, Inc.
$3.67M
BANK OF AMERICA CORP /DE/
$3.18M
Value bars compare disclosed positions; verify each figure against the linked filing evidence.
Detailed SEC evidence table Showing 1-6 of 15 holder rows
| Holder | Evidence | Ownership % | Position | 12M Net Δ | As of |
|---|---|---|---|---|---|
| ATLAS VENTURE ASSOCIATES X, L.P. |
3/4/5
10%+ Owner
|
—
denominator unverified
|
$1,161
608 shares
|
— | 27 Sep 2021 |
| PRICE T ROWE ASSOCIATES INC /MD/ |
13F
Company
|
—
denominator unverified
|
$9,836,000
9,279,059 shares
|
— | 31 Dec 2024 |
| Atlas Venture Life Science Advisors, LLC |
13F
Company
|
—
denominator unverified
|
$8,776,253
8,279,484 shares
|
— | 31 Dec 2024 |
| BlackRock, Inc. |
13F
Company
|
—
denominator unverified
|
$3,666,611
3,459,065 shares
|
— | 31 Dec 2024 |
| BANK OF AMERICA CORP /DE/ |
13F
Company
|
—
denominator unverified
|
$3,177,603
2,997,739 shares
|
— | 31 Dec 2024 |
| Siren, L.L.C. |
13F
Individual
|
—
denominator unverified
|
$3,161,697
2,982,733 shares
|
— | 31 Dec 2024 |
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 2025
Investor-level positions for this CUSIP, loaded as an interactive table.
Institutions
80
Shares
47,705,137
Rows available
80
| 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 2025 vs Q1 2026 Across Filers
Q1 2026 holders
1
Q1 2025 holders
80
Holder diff
79
| Investor | Q1 2026 Shares | Q1 2025 Shares | Share Diff | Share Chg % | Q1 2026 value | Q1 2025 value | Value change | Value Chg % |
|---|
Trend: ostatnie 8 kwartałów (+ wybrane okresy porównania).
Quarterly Holders Trend
Quarterly Value Trend
Quarterly Shares Trend