GEOFF MCDONOUGH - 15 Jul 2025 Form 4 Insider Report for Generation Bio Co. (GBIO)

Role
PRESIDENT AND CEO, Director
Signature
/s/ Shawna-Gay White, Attorney-in-Fact
Issuer symbol
GBIO
Transactions as of
15 Jul 2025
Transactions value $
-$659
Form type
4
Filing time
17 Jul 2025, 16:10:06 UTC
Previous filing
17 Apr 2025
Next filing
17 Oct 2025
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
MCDONOUGH GEOFF PRESIDENT AND CEO, Director C/O GENERATION BIO CO., 301 BINNEY ST, CAMBRIDGE /s/ Shawna-Gay White, Attorney-in-Fact 17 Jul 2025 0001732701

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction GBIO Common Stock Options Exercise +5,273 +0.39% 1,366,196 15 Jul 2025 Direct F1, F2
transaction GBIO Common Stock Tax liability -$659 -1,548 -0.11% $0.426 1,364,648 15 Jul 2025 Direct
holding GBIO Common Stock 226,462 15 Jul 2025 By 2018 Trust F3
holding GBIO Common Stock 275,000 15 Jul 2025 By 2020 Trust F4

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 -5,273 -14.29% $0 31,638 15 Jul 2025 Common Stock 5,273 Direct F1, F5
* 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 11,259 shares acquired under the company's employee stock purchase plan since April 15, 2025.
F3 The securities are directly held by the McDonough Family 2018 Irrevocable Trust, or the 2018 Trust. The reporting person is the settlor of the 2018 Trust, Allison L. McDonough and David S. Grayzel are trustees for the 2018 Trust, and the 2018 Trust is for the benefit of Graeme and Owen McDonough. The reporting person may be deemed to beneficially own the shares of common stock owned by the 2018 Trust.
F4 The securities are directly held by the McDonough Family 2020 Irrevocable Trust, or the 2020 Trust. The reporting person is the settlor of the 2020 Trust, Allison L. McDonough and David S. Grayzel are trustees for the 2020 Trust, and the 2020 Trust is for the benefit of Allison, Graeme and Owen McDonough. The reporting person may be deemed to beneficially own the shares of common stock owned by the 2020 Trust.
F5 On January 20, 2023, the reporting person was granted 84,375 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.