[Form 4] HilleVax, Inc. Insider Trading Activity

Rhea-AI Filing Summary

HilleVax, Inc. (HLVX) completed a change in beneficial ownership tied to a merger transaction. Under a Merger Agreement dated August 4, 2025, XOMA Royalty Corporation and its subsidiary acquired all outstanding HilleVax shares by a tender offer and subsequent merger effective September 17, 2025. Each share was exchanged for $1.95 in cash plus one contingent value right (CVR) that may pay additional cash under a separate CVR Agreement. Reporting person Shelley Chu, a director, shows a Form 4 sale/disposition of 17,199 shares on 09/17/2025, leaving 0 shares beneficially owned following the transaction. The filing also discloses that outstanding restricted stock units automatically vested and were canceled in exchange for cash equal to $1.95 per underlying share and one CVR per share.

Positive

• Merger completed with Purchasers paying $1.95 per share in cash plus one CVR per share
• RSUs vested and were canceled
• Form 4 discloses transaction details including dates, amounts (17,199 shares disposed), and resulting beneficial ownership (0 shares)

Negative

• Reporting person disposed of 17,199 shares, reducing their beneficial ownership to 0 shares
• Consideration includes a CVR (contingent value right), which means part of the deal value is contingent and not immediate cash

Insights

M&A Specialist

TL;DR: Transaction reflects a completed acquisition with standard cash-and-CVR consideration; insider shareholdings were extinguished as part of the deal.

The Form 4 documents a change in beneficial ownership resulting directly from a corporate acquisition. The Purchasers completed a tender offer and merged Merger Sub into the issuer, making the issuer a wholly owned subsidiary of Parent. Consideration paid was $1.95 per share in cash plus one CVR per share, consistent with typical deal structures that allocate part of consideration to contingent earnouts or milestone-based payments. The reporting person disposed of 17,199 shares and now holds zero shares; RSUs vested and were canceled for cash and CVRs per the Merger Agreement. From an M&A standpoint, this filing is procedural and confirms deal mechanics, not new operational information.

Corporate Governance Expert

TL;DR: Director disposition aligns with merger terms; RSU treatment and issuance of CVRs are disclosed clearly.

The filing shows corporate governance actions tied to the merger: immediate vesting and cancellation of RSUs in exchange for cash equal to the cash consideration and issuance of CVRs, and a director-held position reduced to zero shares due to the transaction. The Form 4 is properly signed by an attorney-in-fact and identifies the reporting person as a director. These disclosures fulfill Section 16 reporting obligations and explain the mechanics of equity extinguishment under the Merger Agreement.

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).

1. Name and Address of Reporting Person^*

Chu Shelley

(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		17,199	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 Shelley Chu	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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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FAQ

What did Shelley Chu report on Form 4 for HLVX?

Shelley Chu reported a disposition of 17,199 shares on 09/17/2025, resulting in 0 shares beneficially owned following the transaction.

What consideration did HilleVax shareholders receive in the transaction?

Shareholders received $1.95 in cash per share plus one contingent value right (CVR) representing potential additional cash payments under the CVR Agreement.

How were restricted stock units (RSUs) treated in the merger?

Immediately prior to the merger effective time, each outstanding RSU vested in full and was canceled in exchange for cash equal to $1.95 per underlying share and one CVR per underlying share.

When did the merger become effective?

The merger was effective as of September 17, 2025, the same date listed for the reported transaction.

Who acquired HilleVax in the transaction?

The Purchasers were XOMA Royalty Corporation (Parent) and its wholly owned subsidiary XRA 4 Corp. (Merger Sub).

Who signed the Form 4 on behalf of the reporting person?

The Form 4 was signed by Paul Bavier, Attorney-in-Fact for Shelley Chu on 09/17/2025.