Security key
37148K100
GENERATION BIO CO. - COMMON STOCK, $0.0001 PAR VALUE (GBIO)
CUSIP: 37148K100
Q4 2025 13F Holders as of 31 Dec 2025
- Security type / class
- Equity / COMMON STOCK, $0.0001 PAR VALUE
- Total 13F shares
- 26
- Total 13F value
- $16,993
- Share change
- -858,464
- SEC-reported price per share
- $653.58
- Number of holders
- 1
- Value change
- -$5,171,907
- Number of sells
- 4
- Shares outstanding
- 67,017,829
Holder snapshot
5 signals
Security identity
Names, identifiers, and filing context for this profile.
1 source field
Report period
Q4 2025
Institutions
1
Top holders
1
GBIO full security history
Ownership snapshot
Full 13F holder table
Newer quarter: Q1 2026
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
SymBiosis Capital Partner...
Disclosed value leader
PRICE T ROWE ASSOCIATES I...
Comparable rows
15/15
Latest evidence
30 Sep 2025
13D/G
13F
Lead comparable stake: 6.3%
13D/G row: SymBiosis Capital Partners, LLC
Showing 1-6 of 15 holder rows.
Quick read
SymBiosis Capital Partners, LLC leads the comparable SEC ownership view at 6.3%.
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 SymBiosis Capital Partners, LLC's linked filing trail.
Comparable ownership
Top 5
SymBiosis Capital Partners, LLC
6.3%
RENAISSANCE TECHNOLOGIES LLC
4.3%
FMR LLC
3.5%
PRICE T ROWE ASSOCIATES INC /MD/
3.1%
BlackRock, Inc.
1.7%
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 |
|---|---|---|---|---|---|
| SymBiosis Capital Partners, LLC |
13D/G
|
6.3%
|
$2,582,018
421,926 shares
|
$0 | 30 Sep 2025 |
| RENAISSANCE TECHNOLOGIES LLC |
13F
13D/G
Company
|
4.3%
from 13D/G
|
$2,106,890
344,263 shares
|
— | 30 Sep 2025 |
| FMR LLC |
13D/G
13F
Company
|
3.5%
|
$750,600
2,345,624 shares
|
-$729,735 | 30 Jun 2025 |
| PRICE T ROWE ASSOCIATES INC /MD/ |
13F
13D/G
Company · T. Rowe Price Associates, Inc.
|
3.1%
from 13D/G
|
$3,531,000
576,789 shares
|
— | 30 Sep 2025 |
| BlackRock, Inc. |
13D/G
13F
Company
|
1.7%
|
$414,737
1,152,047 shares
|
$0 | 30 Jun 2025 |
| Siren, L.L.C. |
13F
Individual
|
4.4%
|
$1,816,979
296,892 shares
|
— | 30 Sep 2025 |
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 Q4 2025
Investor-level positions for this CUSIP, loaded as an interactive table.
Institutions
1
Shares
26
Rows available
1
| 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 Q4 2025 vs Q4 2025 Across Filers
Q4 2025 holders
1
Q4 2025 holders
1
Holder diff
0
| Investor | Q4 2025 Shares | Q4 2025 Shares | Share Diff | Share Chg % | Q4 2025 value | Q4 2025 value | Value change | Value Chg % |
|---|
Trend: ostatnie 8 kwartałów (+ wybrane okresy porównania).
Quarterly Holders Trend
Quarterly Value Trend
Quarterly Shares Trend