Geoff Mcdonough - 02 Feb 2026 Form 4 Insider Report for Generation Bio Co. (GBIO)

Reporting relationship: Director
Issuer ticker: GBIO
Reported as of: 02 Feb 2026
Net transaction value: -$3,102
SEC form: 4
Accepted by SEC: 04 Feb 2026, 16:05:27 UTC
Prior SEC filing: 16 Jan 2026
Next SEC filing: 09 Feb 2026
Source filing: View source filing
Reporting owner signature: /s/ Shawna-Gay White, Attorney-in-Fact

Key filing fact

Geoff Mcdonough filed Form 4 for Generation Bio Co. (GBIO) on 04 Feb 2026.

Key facts

This page summarizes Geoff Mcdonough's Form 4 filing for Generation Bio Co. (GBIO).
3 reported transactions and 1 derivative row are listed below.
Accepted by SEC: 04 Feb 2026, 16:05.

Change

Previous filing in this sequence was filed on 16 Jan 2026.
Current net transaction value: -$3,102.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001732701 Primary reporting owner

MCDONOUGH GEOFF

Relationship: Director
Address: C/O GENERATION BIO CO., 301 BINNEY ST, CAMBRIDGE
Signature: /s/ Shawna-Gay White, Attorney-in-Fact
Signature date: 04 Feb 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

GBIO transaction

Common Stock

Options Exercise

Transaction value
Shares: +1,582
Change %: +1.2%
Price
Shares after: 139,042
Date: 02 Feb 2026
Ownership: Direct
Footnotes: F1

GBIO transaction

Common Stock

Tax liability

Transaction value: $3,102
Shares: -550
Change %: -0.4%
Price: $5.64
Shares after: 138,492
Date: 02 Feb 2026
Ownership: Direct

GBIO holding

Common Stock

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after: 22,646
Date: 02 Feb 2026
Ownership: By 2018 Trust
Footnotes: F2

GBIO holding

Common Stock

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after: 27,500
Date: 02 Feb 2026
Ownership: By 2020 Trust
Footnotes: F3

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

GBIO transaction Derivative

Restricted Stock Units

Options Exercise

Transaction value: $0
Shares: -1,582
Change %: -100%
Price: $0.000000
Shares after: 0
Date: 02 Feb 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 1,582
Exercise price
Footnotes: F1, F4

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 4 footnotes

Footnote F1

Each restricted stock unit represents the right to receive one share of the company's common stock.

Footnote F2

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.

Footnote F3

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.

Footnote F4

On January 20, 2023, the reporting person was granted 8,437 restricted stock units. Pursuant to the terms of that certain Agreement and Plan of Merger, by and among the Issuer, XOMA Royalty Corporation ("Parent") and Parent's wholly-owned subsidiary, XRA 7 Corp., dated as of December 15, 2025 (the "Merger Agreement"), prior to the effective time of the merger as contemplated by the Merger Agreement, each restricted stock unit of the Issuer that was outstanding and unvested became vested in full on February 2, 2026.