Tracy Zimmermann - Jul 15, 2022 Form 4 Insider Report for Generation Bio Co. (GBIO)

Role: CHIEF DEVELOPMENT OFFICER
Signature: /s/ Jennifer Elliott, Attorney-in-Fact
Stock symbol: GBIO
Transactions as of: Jul 15, 2022
Transactions value $: -$31,355
Form type: 4
Date filed: 7/19/2022, 04:09 PM
Previous filing: Jan 25, 2022
Next filing: Oct 18, 2022

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	GBIO	Common Stock	Options Exercise		+14.9K			14.9K	Jul 15, 2022	Direct	F1
transaction	GBIO	Common Stock	Tax liability	-$31.4K	-4.37K	-29.36%	$7.18	10.5K	Jul 15, 2022	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	-14.9K	-25%	$0.00	44.6K	Jul 15, 2022	Common Stock	59.5K		Direct	F1, F2

* 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	On January 21, 2022, the reporting person was granted 59,500 restricted stock units. The shares underlying the restricted stock units vest over two years, with 25% of the shares vesting on July 15, 2022 and the remaining shares vesting in equal quarterly installments thereafter.