Atlas Venture Fund X, L.P. - 09 Feb 2026 Form 4 Insider Report for Generation Bio Co. (GBIO)

Role
10%+ Owner
Signature
Atlas Venture Fund X, L.P., By: Atlas Venture Associates X, L.P., Its: General Partner, By: Atlas Venture Associates X, LLC, Its: General Partner, By: /s/ Ommer Chohan, Chief Financial Officer
Issuer symbol
GBIO
Transactions as of
09 Feb 2026
Net transactions value
$0
Form type
4
Filing time
09 Feb 2026, 18:19:16 UTC
Previous filing
27 Mar 2024

Reporting Owners (6)

Name Relationship Address Signature Signature date CIK
Atlas Venture Fund X, L.P. 10%+ Owner 300 TECHNOLOGY SQUARE, 8TH FLOOR, CAMBRIDGE Atlas Venture Fund X, L.P., By: Atlas Venture Associates X, L.P., Its: General Partner, By: Atlas Venture Associates X, LLC, Its: General Partner, By: /s/ Ommer Chohan, Chief Financial Officer 09 Feb 2026 0001628098
ATLAS VENTURE ASSOCIATES X, L.P. 10%+ Owner 300 TECHNOLOGY SQUARE, 8TH FLOOR, CAMBRIDGE Atlas Venture Associates X, L.P., By: Atlas Venture Associates X, LLC, Its: General Partner, By: /s/ Ommer Chohan, Chief Financial Officer 09 Feb 2026 0001742766
Atlas Venture Associates X, LLC 10%+ Owner 300 TECHNOLOGY SQUARE, 8TH FLOOR, CAMBRIDGE Atlas Venture Associates X, LLC, By: /s/ Ommer Chohan, Chief Financial Officer 09 Feb 2026 0001742765
Atlas Venture Opportunity Fund I, L.P. 10%+ Owner 300 TECHNOLOGY SQUARE, 8TH FLOOR, CAMBRIDGE Atlas Venture Opportunity Fund I, L.P., By: Atlas Venture Associates Opportunity I, L.P., Its general partner, By: Atlas Venture Associates Opportunity I, LLC, Its general partner, By: /s/ Ommer Chohan, Chief Financial Officer 09 Feb 2026 0001759241
Atlas Venture Associates Opportunity I, L.P. 10%+ Owner 300 TECHNOLOGY SQUARE, 8TH FLOOR, CAMBRIDGE Atlas Venture Associates Opportunity I, L.P., By: Atlas Venture Associates Opportunity I, LLC, Its general partner, By: /s/ Ommer Chohan, Chief Financial Officer 09 Feb 2026 0001780065
Atlas Venture Associates Opportunity I, LLC 10%+ Owner 300 TECHNOLOGY SQUARE, 8TH FLOOR, CAMBRIDGE Atlas Venture Associates Opportunity I, LLC, By: /s/ Ommer Chohan, Chief Financial Officer 09 Feb 2026 0001780066

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction GBIO Common Stock Disposition pursuant to a tender of shares in a change of control transaction -711,193 -100% 0 09 Feb 2026 Direct F1, F2, F3
transaction GBIO Common Stock Disposition pursuant to a tender of shares in a change of control transaction -116,693 -100% 0 09 Feb 2026 See footnote F1, F2, F4
transaction GBIO Common Stock Disposition pursuant to a tender of shares in a change of control transaction -60 -100% 0 09 Feb 2026 See footnote F1, F2, F5
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Atlas Venture Fund X, L.P. is no longer subject to Section 16 filing requirements. Form 4 or Form 5 obligations may continue.

Explanation of Responses:

Id Content
F1 Pursuant to the terms of that certain Agreement and Plan of Merger (the "Merger Agreement"), by and among Generation Bio. Co. (the "Issuer"), XOMA Royalty Corporation ("Parent") and Parent's wholly-owned subsidiary, XRA 7 Corp. ("Merger Sub"), dated as of December 15, 2025, the shares (the "Shares") of common stock, par value $0.0001 per share, of the Issuer (the "Common Stock") that were tendered to Merger Sub prior to the expiration time of the offer were exchanged for (i) a purchase price of $4.2913 per Share to the stockholders in cash, without interest and less any applicable tax withholding (the "Cash Amount"), plus (ii) one non-tradeable contingent value right per Share (the "CVR"),
F2 (continued from footnote 1) which represents the right to receive certain contingent payments in cash in accordance with the terms and subject to the conditions of a contingent value rights agreement entered into by Parent and the rights agent, with an estimated maximum contingent consideration amount of $25.01 per CVR (the Cash Amount plus one CVR, collectively, the "Offer Price"). After completion of the tender offer, pursuant to the terms of the Merger Agreement, Merger Sub merged with and into the Issuer, effective as of February 9, 2026 (the "Effective Time"), with the Issuer continuing as the surviving corporation and a wholly owned subsidiary of Parent.
F3 The shares are held directly by Atlas Venture Fund X, L.P. ("Atlas Venture Fund X"). The general partner of Atlas Venture Fund X is Atlas Venture Associates X, L.P. ("AVA X LP"). Atlas Venture Associates X, LLC ("AVA X LLC") is the general partner of AVA X LP. Each of AVA X LP and AVA X LLC disclaims Section 16 beneficial ownership of the securities held by Atlas Venture Fund X, except to the extent of its pecuniary interest therein, if any.
F4 The shares are held directly by Atlas Venture Opportunity Fund I, L.P. ("Atlas Venture Opportunity Fund I"). The general partner of Atlas Venture Opportunity Fund I is Atlas Venture Associates Opportunity I, LP ("AVAO I LP"). Atlas Venture Associates Opportunity I, LLC ("AVAO I LLC") is the general partner of AVAO I LP. Each of AVAO I LP and AVAO I LLC disclaims Section 16 beneficial ownership of the securities held by Atlas Venture Opportunity Fund I, except to the extent of its pecuniary interest therein, if any.
F5 The shares are held directly by AVAO I LP. AVAO I LLC is the general partner of AVAO I LP. AVAO I LLC disclaims Section 16 beneficial ownership of the securities held by AVAO I LP except to the extent of its pecuniary interest therein, if any.