Jason P. Rhodes - 04 Jun 2025 Form 4 Insider Report for Generation Bio Co. (GBIO)

Role: Director
Signature: /s/ Ommer Chohan, Attorney-in-Fact
Issuer symbol: GBIO
Transactions as of: 04 Jun 2025
Net transactions value: $0
Form type: 4
Filing time: 06 Jun 2025, 16:05:16 UTC
Previous filing: 03 Jun 2025
Next filing: 09 Feb 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Rhodes Jason P	Director	C/O GENERATION BIO CO., 301 BINNEY ST, CAMBRIDGE	/s/ Ommer Chohan, Attorney-in-Fact	06 Jun 2025	0001577014

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	+30,000		$0.000000	30,000	04 Jun 2025	Common Stock	30,000	$0.3874	Direct	F1, F2

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

Explanation of Responses:

Id	Content
F1	This option was granted on June 4, 2025. The shares underlying the option will fully vest on the earlier of: June 4, 2026 and the date of Generation Bio's 2026 annual meeting of stockholders.
F2	The Reporting Person is a member of Atlas Venture Associates X, LLC and is obligated to transfer the economic benefit, if any, received upon the sale of the shares issuable upon exercise of the option to Atlas Venture Life Science Advisors, LLC. As such, the Reporting Person disclaims beneficial ownership of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, except to the extent of his pecuniary interest therein, if any.

Content

This option was granted on June 4, 2025. The shares underlying the option will fully vest on the earlier of: June 4, 2026 and the date of Generation Bio's 2026 annual meeting of stockholders.

The Reporting Person is a member of Atlas Venture Associates X, LLC and is obligated to transfer the economic benefit, if any, received upon the sale of the shares issuable upon exercise of the option to Atlas Venture Life Science Advisors, LLC. As such, the Reporting Person disclaims beneficial ownership of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, except to the extent of his pecuniary interest therein, if any.