Antoinette Paone - Oct 15, 2025 Form 4 Insider Report for Generation Bio Co. (GBIO)

Role
CHIEF OPERATING OFFICER
Signature
/s/ Shawna-Gay White, Attorney-in-Fact
Stock symbol
GBIO
Transactions as of
Oct 15, 2025
Transactions value $
-$315
Form type
4
Date filed
10/17/2025, 04:05 PM
Previous filing
Jul 17, 2025
Next filing
Oct 31, 2025
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Paone Antoinette CHIEF OPERATING OFFICER C/O GENERATION BIO CO., 301 BINNEY ST, CAMBRIDGE /s/ Shawna-Gay White, Attorney-in-Fact 2025-10-17 0001907682

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction GBIO Common Stock Options Exercise +159 +4.48% 3.71K Oct 15, 2025 Direct F1, F2
transaction GBIO Common Stock Tax liability -$315 -47 -1.27% $6.71 3.66K Oct 15, 2025 Direct F1

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
transaction GBIO Restricted Stock Units Options Exercise $0 -159 -16.67% $0.00 795 Oct 15, 2025 Common Stock 159 Direct F1, F2, F3
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 Amounts reported in this Form 4 reflect the one-for-10 reverse stock split effected by the issuer on July 21, 2025.
F2 Each restricted stock unit represents the right to receive one share of the company's common stock.
F3 On January 20, 2023, the reporting person was granted 2,546 restricted stock units. The shares underlying the restricted stock units vest over four years, with 25% of the shares vested on January 15, 2024 and the remaining shares vesting in equal quarterly installments thereafter.