Generation Bio (GBIO) director reports share exchange and option cancellation in XOMA merger

Rhea-AI Filing Summary

Generation Bio Co. director Geoff McDonough reported changes in his holdings following the completion of a merger with XOMA Royalty Corporation. Common shares of Generation Bio were exchanged for $4.2913 per share in cash plus one non-tradeable contingent value right (CVR) per share, with an estimated maximum contingent cash consideration of up to $25.01 per CVR under a contingent value rights agreement.

The Form 4 shows 138,492 shares of common stock held directly and additional shares held indirectly through the McDonough Family 2018 and 2020 Irrevocable Trusts being impacted by the transaction. It also reports that, under the merger agreement, stock options with exercise prices at or above the cash amount of $4.2913 per share were automatically cancelled for no consideration immediately prior to the merger’s effective time on February 9, 2026.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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X

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

MCDONOUGH GEOFF

(Last) (First) (Middle)

C/O GENERATION BIO CO.

301 BINNEY ST, SUITE 401

(Street)

CAMBRIDGE MA 02142

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Generation Bio Co. [ GBIO ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
02/09/2026

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	02/09/2026		U(1)(2)		138,492	D	(1)(2)	0	D
Common Stock	02/09/2026		U(1)(2)		22,646	D	(1)(2)	0	I	By 2018 Trust(3)
Common Stock	02/09/2026		U(1)(2)		27,500	D	(1)(2)	0	I	By 2020 Trust(4)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (right to buy)	$51.576	02/09/2026		D			19,903	(5)	(5)	Common Stock	19,903	(5)	0	D
Stock Option (right to buy)	$302.5	02/09/2026		D			25,099	(5)	(5)	Common Stock	25,099	(5)	0	D
Stock Option (right to buy)	$64.9	02/09/2026		D			37,499	(5)	(5)	Common Stock	37,499	(5)	0	D
Stock Option (right to buy)	$18.6	02/09/2026		D			50,624	(5)	(5)	Common Stock	50,624	(5)	0	D
Stock Option (right to buy)	$9.255	02/09/2026		D			90,168	(5)	(5)	Common Stock	90,168	(5)	0	D
Stock Option (right to buy)	$47.05	02/09/2026		D			16,874	(5)	(5)	Common Stock	16,874	(5)	0	D
Stock Option (right to buy)	$13.9	02/09/2026		D			24,046	(5)	(5)	Common Stock	24,046	(5)	0	D

Explanation of Responses:

1. 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"),

2. (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.

3. 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.

4. 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.

5. Pursuant to the terms of the Merger Agreement, effective as of immediately prior to the Effective Time, each option to purchase shares of Common Stock that was outstanding and unexercised as of immediately prior to the Effective Time and had an exercise price per Share that was equal to or greater than the Cash Amount was automatically cancelled for no consideration.

	/s/ Shawna-Gay White, Attorney-in-Fact	02/09/2026
	** Signature of Reporting Person	Date
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FAQ

What insider activity did Geoff McDonough report in Generation Bio (GBIO) Form 4?

The filing reports how Geoff McDonough’s Generation Bio holdings changed when the company was acquired. His common shares and trust-held shares were exchanged, and his outstanding stock options with exercise prices at or above the cash merger amount were automatically cancelled for no consideration.

What were Generation Bio (GBIO) shareholders paid in the XOMA merger?

Shareholders received a cash payment of approximately $4.2913 per share plus one non-tradeable contingent value right (CVR) per share. The CVR offers potential contingent cash payments up to an estimated maximum of $25.01 per CVR, according to the merger documentation.

How were Geoff McDonough’s stock options treated in the Generation Bio (GBIO) merger?

Under the merger agreement, each option to purchase Generation Bio common stock with an exercise price per share equal to or greater than the $4.2913 cash amount was automatically cancelled for no consideration. These cancellations were effective immediately prior to the merger’s effective time on February 9, 2026.

What role did family trusts play in Geoff McDonough’s Generation Bio (GBIO) holdings?

Some Generation Bio shares were held indirectly through the McDonough Family 2018 and 2020 Irrevocable Trusts. The filing explains that Geoff McDonough is the settlor of each trust, with specified trustees and beneficiaries, and that these trust-held shares were also subject to the merger exchange terms.

When did the Generation Bio (GBIO) merger with XOMA Royalty Corporation become effective?

After completion of a tender offer, XRA 7 Corp., a subsidiary of XOMA Royalty Corporation, merged with Generation Bio. The merger became effective on February 9, 2026, with Generation Bio continuing as the surviving corporation and becoming a wholly owned subsidiary of XOMA.

What is the contingent value right (CVR) mentioned in the Generation Bio (GBIO) Form 4?

Each Generation Bio share received one non-tradeable contingent value right, or CVR, in addition to cash. The CVR represents the right to receive certain contingent cash payments, with an estimated maximum contingent consideration of up to $25.01 per CVR under a separate rights agreement.