Phillip Samayoa - 10 Jan 2025 Form 4 Insider Report for Generation Bio Co. (GBIO)

Role: CHIEF SCIENTIFIC OFFICER
Signature: /s/ Shawna-Gay White, Attorney-in-Fact
Issuer symbol: GBIO
Transactions as of: 10 Jan 2025
Transactions value $: $0
Form type: 4
Filing time: 14 Jan 2025, 16:05:12 UTC
Previous filing: 17 Oct 2024
Next filing: 17 Jan 2025
SEC: View on sec.gov

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
holding	GBIO	Common Stock						127K	10 Jan 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	Stock Option (right to buy)	Award	$0	+251K		$0.00	251K	10 Jan 2025	Common Stock	251K	$0.93	Direct	F2

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	Includes 4,863 shares acquired under the company's employee stock purchase plan since October 15, 2024.
F2	The option to purchase 251,030 shares was granted on January 10, 2025. The shares underlying the option vest over four years, with 25% of the shares vesting on January 10, 2026 and the remaining shares vesting in equal quarterly installments thereafter.