Antoinette Paone - Jul 15, 2023 Form 4 Insider Report for Generation Bio Co. (GBIO)

Role: CHIEF OPERATING OFFICER
Signature: /s/ Benjamin Waters, Attorney-in-Fact
Stock symbol: GBIO
Transactions as of: Jul 15, 2023
Transactions value $: -$6,152
Form type: 4
Date filed: 7/18/2023, 04:35 PM
Previous filing: Apr 26, 2023
Next filing: Aug 25, 2023

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	GBIO	Common Stock	Options Exercise		+4.13K	+132.38%		7.24K	Jul 15, 2023	Direct	F1, F2
transaction	GBIO	Common Stock	Tax liability	-$6.15K	-1.21K	-16.72%	$5.08	6.03K	Jul 15, 2023	Direct

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	-4.13K	-33.33%	$0.00	8.25K	Jul 15, 2023	Common Stock	4.13K		Direct	F1, F3

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

Explanation of Responses:

Id	Content
F1	Each restricted stock unit represents the right to receive one share of the company's common stock.
F2	Includes 3,116 shares acquired under the company's employee stock purchase plan since April 26, 2023.
F3	On January 21, 2022, the reporting person was granted 33,000 restricted stock units. The shares underlying the restricted stock units vest over two years, with 25% of the shares vested on July 15, 2022 and the remaining shares vesting in equal quarterly installments thereafter.