Generation Bio (GBIO) director cashes out as XOMA buyout closes at $4.29 plus CVR

Rhea-AI Filing Summary

Generation Bio Co. director Catherine Stehman-Breen reported the disposition of her equity in connection with the company’s sale to XOMA Royalty Corporation. She tendered 4,752 shares of common stock, which were exchanged for $4.2913 in cash per share plus one non-tradeable contingent value right (CVR) per share, with an estimated maximum contingent cash payment of $25.01 per CVR. Following completion of the tender offer, XRA 7 Corp. merged into Generation Bio on February 9, 2026, making it a wholly owned subsidiary of XOMA Royalty. Her in-the-money stock options vested, were cancelled, and converted into cash based on the spread to the cash amount, while out-of-the-money options were cancelled for no consideration, leaving her with 0 shares and 0 options reported as beneficially owned.

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Equity analyst

Form 4 shows director fully cashed out as XOMA’s acquisition of Generation Bio closes.

This filing documents how Catherine Stehman-Breen, a director of Generation Bio Co., exited her position through the completed sale to XOMA Royalty Corporation. Her 4,752 common shares were exchanged for $4.2913 in cash per share plus one CVR per share, with an estimated maximum of $25.01 per CVR.

The merger closed on February 9, 2026, after a tender offer in which shares were first exchanged, followed by a back-end merger making Generation Bio a wholly owned XOMA subsidiary. This Form 4 clarifies that Stehman-Breen no longer reports any beneficial ownership in common stock or options after the transaction mechanics were completed.

Her in-the-money options became fully vested, were cancelled, and converted into a cash payment equal to the excess of the $4.2913 cash amount over each option’s exercise price, multiplied by the underlying shares. Options with exercise prices at or above the cash amount were cancelled for no consideration, consistent with the agreed merger terms.

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

OMB APPROVAL

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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^*

Stehman-Breen Catherine

(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)		4,752	D	(1)(2)	0	D

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)	$3.874	02/09/2026		D			3,000	(3)	(3)	Common Stock	3,000	(3)	0	D
Stock Option (right to buy)	$190	02/09/2026		D			5,200	(4)	(4)	Common Stock	5,200	(4)	0	D
Stock Option (right to buy)	$265.9	02/09/2026		D			1,500	(4)	(4)	Common Stock	1,500	(4)	0	D
Stock Option (right to buy)	$61.9	02/09/2026		D			1,920	(4)	(4)	Common Stock	1,920	(4)	0	D
Stock Option (right to buy)	$48.3	02/09/2026		D			2,500	(4)	(4)	Common Stock	2,500	(4)	0	D
Stock Option (right to buy)	$33.2	02/09/2026		D			6,000	(4)	(4)	Common Stock	6,000	(4)	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. 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 ("Issuer Option") that was outstanding and unexercised as of immediately prior to the Effective Time and had an exercise price per Share that was less than the Cash Amount (each, an "In-The-Money Option"), became fully vested and was automatically cancelled and converted into the right to receive an amount in cash, without interest, equal to the product obtained by multiplying (x) the excess of the Cash Amount over the exercise price per share of Common Stock underlying such In-the-Money Option at the Effective Time by (y) the number of shares of Common Stock underlying such In-the-Money Option at the Effective Time.

4. Pursuant to the terms of the Merger Agreement, effective as of immediately prior to the Effective Time, each Issuer Option 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
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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FAQ

What did Generation Bio (GBIO) director Catherine Stehman-Breen report in this Form 4?

Catherine Stehman-Breen reported the disposition of all her Generation Bio equity. She tendered 4,752 common shares into XOMA Royalty’s offer and had all reported stock options cancelled or cashed out under the merger terms, leaving her with zero shares and zero options beneficially owned.

What consideration did Generation Bio (GBIO) shareholders receive in the XOMA Royalty merger?

Shareholders received a mix of cash and contingent value rights. Each Generation Bio common share tendered was exchanged for $4.2913 in cash plus one non-tradeable CVR, which carries an estimated maximum contingent cash consideration of $25.01 per CVR, as described in the merger agreement footnotes.

How were Generation Bio (GBIO) stock options treated when the XOMA merger closed?

In-the-money options vested and were paid in cash; out-of-the-money options were cancelled. Each in-the-money option was fully vested, cancelled, and converted into cash equal to the cash amount minus exercise price, times underlying shares. Options with exercise prices at or above the cash amount were cancelled for no consideration.

Does Catherine Stehman-Breen still own Generation Bio (GBIO) stock after the merger?

No, the Form 4 shows she reports zero beneficially owned shares after the deal. Following the tender of 4,752 shares into the cash-and-CVR offer and the cancellation or cash-out of all reported options, her post-transaction beneficial ownership is listed as 0 common shares and 0 derivative securities.

When did Generation Bio (GBIO) become a wholly owned subsidiary of XOMA Royalty Corporation?

The merger became effective on February 9, 2026. After completion of the tender offer, XRA 7 Corp., XOMA Royalty’s wholly owned subsidiary, merged with and into Generation Bio on that date, leaving Generation Bio as the surviving corporation wholly owned by XOMA Royalty.

What is the maximum potential payout of the Generation Bio contingent value rights (CVRs)?

Each CVR has an estimated maximum contingent cash consideration of $25.01. For every Generation Bio share tendered, shareholders received one non-tradeable CVR. These CVRs entitle holders to certain contingent cash payments, up to an estimated maximum of $25.01 per CVR, subject to agreement conditions.