[Form 4] HilleVax, Inc. Insider Trading Activity

Rhea-AI Filing Summary

HilleVax, Inc. (HLVX) was acquired via a merger effective September 17, 2025. Under the Merger Agreement the purchasers completed a tender offer paying $1.95 cash per share plus one contingent value right (CVR) per share for certain contingent cash payments. As part of the closing, Merger Sub merged into HilleVax, which continues as a wholly owned subsidiary of the purchaser. Reporting person Jaime Sepulveda saw 59,224 shares disposed in a transaction coded "U" and reports 0 shares beneficially owned following the transaction. Outstanding restricted stock units vested and were canceled in exchange for cash equal to $1.95 times the underlying shares plus one CVR per share.

Positive

• Merger consideration specified: Purchasers paid $1.95 cash per share plus one CVR per share, providing clear base cash consideration.
• RSUs treated consistently with agreement: All outstanding restricted stock units vested and were canceled for cash and CVRs per the Merger Agreement.

Negative

• Reporting person reduced ownership to zero: 59,224 shares disposed and 0 shares beneficially owned following the transaction.
• Contingent value right details not included: CVR terms and potential payout amounts are referenced but not disclosed in this Form 4.

Insights

Financial Analyst

TL;DR: The Form 4 documents disposition of all reported shares due to a completed merger that paid $1.95 per share plus CVRs.

This filing shows the reporting person disposed of 59,224 common shares on 09/17/2025 in connection with the Merger Agreement where consideration was $1.95 cash per share plus a CVR. The disposition is coded as "U," indicating it was due to a corporate event rather than an open-market sale. The economic effect and valuation implications depend on the CVR terms which are referenced but not detailed here; therefore the cash consideration is explicit while contingent payments remain unspecified in this Form 4.

Corporate Governance Expert

TL;DR: The Form 4 reflects a governance milestone: a completed acquisition that altered insider ownership to zero for the reporting person.

The filing confirms that immediately before the effective time, RSUs vested and were canceled for cash and CVRs per the Merger Agreement, and the reporting person no longer holds beneficial ownership following the transaction. This is a routine disclosure following a change-in-control transaction; it documents execution of contractual merger terms and vesting provisions rather than a discretionary insider disposition.

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).

1. Name and Address of Reporting Person^*

Sepulveda Jaime

(Last) (First) (Middle)

C/O HILLEVAX, INC.

321 HARRISON AVE, SUITE 500

(Street)

BOSTON MA 02118

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
HilleVax, Inc. [ HLVX ]

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)
09/17/2025

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	09/17/2025		U		59,224	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

Explanation of Responses:

1. In connection with that certain Agreement and Plan of Merger, dated as of August 4, 2025 (the "Merger Agreement"), by and among the Issuer, XOMA Royalty Corporation ("Parent") and XRA 4 Corp., a wholly owned subsidiary of Parent ("Merger Sub" and together with Parent, the "Purchasers"), the Purchasers completed a tender offer to acquire all of the issued and outstanding shares of Common Stock of the Issuer in exchange for (a) $1.95 in cash per share (the "Cash Amount"), plus (b) one contingent value right ("CVR") representing the right to receive certain contingent cash payments equal to the "CVR Proceeds" as further described in that certain CVR Agreement entered into between the Purchasers and a representative to the CVR holders. After completion of the tender offer, Merger Sub merged with and into the Issuer, effective as of September 17, 2025 (the "Effective Time"), with the Issuer continuing as the surviving corporation and as a wholly owned subsidiary of Parent.

2. Pursuant to the terms of the Merger Agreement, immediately prior to the Effective Time, each outstanding restricted stock unit ("RSU") immediately vested in full and was canceled in exchange for the right to receive (a) an amount in cash, without interest, equal to the product obtained by multiplying (x) the Cash Amount by (y) the number of shares underlying such RSU at the Effective Time and (b) one CVR for each share underlying such RSU.

	/s/ Paul Bavier, Attorney-in-Fact for Jaime Sepulveda	09/17/2025
	** 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 the Form 4 for HLVX filed on 09/17/2025 report?

The Form 4 reports a disposition of 59,224 shares by Jaime Sepulveda on 09/17/2025 in connection with a merger, leaving the reporting person with 0 shares beneficially owned.

What consideration did HilleVax shareholders receive in the merger?

Shareholders received $1.95 in cash per share plus one contingent value right (CVR) representing rights to certain contingent cash payments.

Why were the restricted stock units (RSUs) canceled?

Per the Merger Agreement, each outstanding RSU vested immediately prior to the effective time and was canceled in exchange for cash equal to $1.95 times the underlying shares plus one CVR per underlying share.

Does the Form 4 disclose the CVR payout amounts?

No. The Form 4 references the CVR Agreement and the right to receive CVR proceeds but does not disclose the specific contingent payout amounts or triggers.

What does transaction code "U" mean on this Form 4?

The filing shows transaction code "U," indicating the disposition was due to a corporate event (here, the merger). The Form 4 does not indicate an open-market sale.