[Form 4] HilleVax, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Takeda Pharmaceutical Company Limited and its subsidiary Takeda Vaccines, Inc. reported disposal of all their HilleVax, Inc. (HLVX) common stock held through Takeda Vaccines. On 09/17/2025, 6,724,000 shares were sold pursuant to a cash tender offer by XOMA Royalty Corporation and XRA 4 Corp. at a price of $1.95 per share, with closing announced on 09/17/2025.

The filing states that following the transaction the reporting persons hold 0 shares beneficially. The shares were held directly by Takeda Vaccines, Inc., an indirect wholly owned subsidiary of Takeda Pharmaceutical Company Limited, and the filing explains the ownership chain among Takeda entities.

Positive

• Completed sale via formal tender offer with disclosed price of $1.95 per share, providing clear transaction terms
• Filing discloses ownership chain showing securities held directly by Takeda Vaccines, Inc. and the parent company structure

Negative

• Reporting persons reduced beneficial ownership to 0, disposing 6,724,000 shares which removes a prior director/10% owner's stake
• Large block disposition may materially change HLVX's shareholder composition and insider ownership alignment

Insights

Corporate Governance Expert

TL;DR: Major shareholder sold entire stake via tender offer, eliminating beneficial ownership—significant corporate governance event.

The Form 4 records a disposal of 6,724,000 HLVX shares at $1.95 per share on 09/17/2025, resulting in reported beneficial ownership of zero. From a governance perspective, a director/10% owner exiting fully through a third-party tender offer is material: it removes a sizable strategic shareholder and could affect board alignment and monitoring. The filing also clearly documents the ownership chain, attributing holdings to Takeda Vaccines, Inc. and ultimately Takeda Pharmaceutical Company Limited.

Securities Analyst

TL;DR: Large block sale executed at disclosed tender price; transaction is material to HLVX float and ownership profile.

The transaction disposed of 6,724,000 common shares at $1.95 per share via a completed tender offer announced 09/17/2025. The reporting persons are a director and identified as 10% owners prior to the sale; post-transaction beneficial ownership is reported as zero. This change materially alters the company’s shareholder base and reduces insider ownership concentration as disclosed in the Form 4.

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^*

TAKEDA PHARMACEUTICAL CO LTD

(Last) (First) (Middle)

1-1, NIHONBASHI-HONCHO 2-CHOME

(Street)

CHUO-KU, TOKYO M0 103-8668

(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)

	Director	X	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)

	Form filed by One Reporting Person
X	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		6,724,000	D	$1.95(1)	0	I	See Explanation of Responses(2)

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

1. Name and Address of Reporting Person^*

TAKEDA PHARMACEUTICAL CO LTD

(Last) (First) (Middle)

1-1, NIHONBASHI-HONCHO 2-CHOME

(Street)

CHUO-KU, TOKYO M0 103-8668

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

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

1. Name and Address of Reporting Person^*

Takeda Vaccines, Inc.

(Last) (First) (Middle)

75 SIDNEY STREET

(Street)

CAMBRIDGE MA 02139

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

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

Explanation of Responses:

1. These shares were sold pursuant to the cash tender offer (the "Tender Offer") by XOMA Royalty Corporation, a Nevada corporation ("Parent") and XRA 4 Corp., a Delaware corporation and a wholly owned subsidiary of Parent, to purchase all of the outstanding shares of common stock of the Issuer at an offer price of (i) $1.95 per share of common stock and (ii) one non-transferable contractual contingent value right. The Tender Offer expired as scheduled at one minute after 11:59 p.m., Eastern Time, on September 15, 2025 (the "Expiration Time") and closing of the Tender Offer was announced on September 17, 2025. As all conditions to the Tender Offer were satisfied or waived, on September 17, 2025, Parent irrevocably accepted for payment all shares validly tendered into and not validly withdrawn from the Tender Offer and paid for all such shares in accordance with the Tender Offer.

2. Takeda Pharmaceutical Company Limited has beneficial ownership of the reported securities, all of which are held directly by Takeda Vaccines, Inc., an indirect wholly-owned subsidiary of Takeda Pharmaceutical Company Limited. Takeda Vaccines, Inc. is owned directly by Takeda Pharmaceuticals U.S.A., Inc., which is owned directly by both Takeda Pharmaceutical Company Limited (72.70%) and Takeda Pharmaceuticals International AG (27.30%). Takeda Pharmaceuticals International AG is a wholly-owned direct subsidiary of Takeda Pharmaceutical Company Limited.

Remarks:

Intentional misstatements or omissions of facts constitute Federal Criminal Violations.

	/s/ Paul Sundberg, Authorized Signatory, Takeda Pharmaceutical Company Limited	09/19/2025
	/s/ Max Heuer, Authorized signatory, Takeda Vaccines, Inc.	09/19/2025
	** 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 Takeda entities report in the Form 4 for HLVX?

They reported the disposal of 6,724,000 HilleVax (HLVX) common shares on 09/17/2025 via a tender offer, at $1.95 per share, resulting in 0 shares beneficially owned.

Was the sale executed through a tender offer and who conducted it?

Yes. The sale was pursuant to a cash tender offer conducted by XOMA Royalty Corporation (Parent) and XRA 4 Corp.

Do the filings explain how Takeda entities held the shares?

Yes. The Form 4 states the shares were held directly by Takeda Vaccines, Inc., an indirect wholly-owned subsidiary of Takeda Pharmaceutical Company Limited, and details the intermediate ownership percentages.

When was the tender offer closing announced?

Closing of the tender offer was announced on 09/17/2025, and the tender offer expired at one minute after 11:59 p.m. Eastern Time on 09/15/2025.

How much cash consideration was paid per share?

The tender offer paid $1.95 in cash per HLVX common share.