[SCHEDULE 13D/A] HilleVax, Inc. SEC Filing

Rhea-AI Filing Summary

HilleVax, Inc. (HLVX) agreed to be acquired and taken private by XOMA Royalty Corporation through a cash tender offer and subsequent merger. Shareholders received $1.95 per share plus one non-transferable contractual contingent value right (CVR) for each share. The tender offer expired and was completed on September 15, 2025, and the merger became effective September 17, 2025, with Merger Sub merging into HilleVax and HilleVax continuing as the surviving corporation and a wholly owned subsidiary of Parent. As a result, HilleVax common stock ceased to be publicly traded, Nasdaq delisting and deregistration steps were requested, and the company plans to suspend Exchange Act reporting by filing Form 15.

Positive

• Transaction completed—tender offer accepted and merger became effective, providing a clear exit for public shareholders at $1.95 per share
• Certainty of payment—Reporting states Parent irrevocably accepted and paid for validly tendered shares
• Regulatory steps initiated—Nasdaq delisting and Form 25/Form 15 filings underway to formally transition to private status

Negative

• Loss of public market liquidity—Common Stock is no longer listed and the company will cease periodic public reporting
• Remaining value contingent—portion of consideration is a non-transferable CVR, creating uncertainty about future payouts
• Reporting persons reduced holdings to zero—Takeda entities no longer hold beneficial ownership above 5%, signaling complete transfer of economic interest

Insights

M&A Specialist

TL;DR: Completed tender offer and merger took HilleVax private for $1.95 per share plus CVR; delisting and reporting suspension initiated.

The transaction is material: a completed cash tender offer followed by a merger converted all outstanding shares into cash consideration and CVRs, removing HilleVax from public markets. This eliminates public liquidity for shareholders and transfers control to XOMA Royalty. Regulatory steps—Form 25 to withdraw registration and Form 15 to suspend reporting—are standard post-close actions. The presence of CVRs suggests contingent post-close value drivers that may affect residual consideration but are not described in detail here.

Corporate Governance Expert

TL;DR: Governance and disclosure obligations will cease publicly as the company becomes a private subsidiary after the merger.

The merger produces significant governance changes: board composition and corporate documents were modified as part of the Merger, and the company will no longer be subject to periodic public reporting. Investors lose access to routine filings and public oversight. Reporting Persons (Takeda entities) report zero beneficial ownership post-transaction. The filing documents the company’s intent to delist and suspend Exchange Act reporting, which has immediate implications for transparency and minority shareholder rights.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 1)

HILLEVAX, INC.

(Name of Issuer)

Common Stock, par value $0.0001 per share

(Title of Class of Securities)

43157M102

(CUSIP Number)

Paul Sundberg
1-1, Nihonbashi-Honcho 2-Chome Chuo-Ku,
Tokyo, M0, 103-8668
81-3-3278-2111

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

09/17/2025

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

SCHEDULE 13D

CUSIP No. 43157M102

1

Name of reporting person

Takeda Pharmaceutical Company Limited

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

OO

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

JAPAN

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

0.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.0 %

14

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13D

CUSIP No. 43157M102

1

Name of reporting person

Takeda Vaccines Inc.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

OO

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

0.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.0 %

14

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13D

Item 1.	Security and Issuer
(a)	Title of Class of Securities: Common Stock, par value $0.0001 per share
(b)	Name of Issuer: HILLEVAX, INC.
(c)	Address of Issuer's Principal Executive Offices: 321 HARRISON AVE, SUITE 500, BOSTON, MASSACHUSETTS , 02118.
Item 1 Comment: This Amendment No. 1 ("Amendment") to Schedule 13D (the "Statement") amends the Statement originally filed with the U.S. Securities and Exchange Commission (the "SEC") on May 9, 2022, with respect to the common stock, par value $0.0001 per share (the "Common Stock") per share of Hillevax, Inc., a Delaware corporation (the "Company"), whose principal executive offices are located at 321 Harrison Avenue, Boston, Massachusetts 02118. Capitalized terms used herein and not defined herein have the meanings ascribed thereto in the Statement. Except as set forth below, all previous Items and disclosures set forth in the Statement remain unchanged.
Item 4.	Purpose of Transaction
	The cash tender offer (the "Tender Offer") by XOMA Royalty Corporation, a Nevada corporation ("Parent") and XRA 4 Corp., a Delaware corporation ("Merger Sub") and a wholly owned subsidiary of Parent, to purchase all of the outstanding shares of the Common Stock (collectively, the "Shares" and each, a "Share") at an offer price of (i) $1.95 per Share and (ii) one non- transferable contractual contingent value right ( "CVR"), 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 September 17, 2025. As all conditions to the Tender Offer were satisfied or waived, on September 15, 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. On September 17, 2025, following the consummation of the Tender Offer, upon the terms and conditions set forth in the Agreement and Plan of Merger, dated as of August 4, 2025, the Company filed a Certificate of Merger with the Secretary of State of the State of Delaware, pursuant to which the merger (the "Merger") became effective. In the Merger, Merger Sub merged with and into the Company, with the Company continuing as the surviving corporation (the "Surviving Corporation"). As a result of the Merger, the Company ceased to be a publicly traded company and became a privately held company and a subsidiary of Parent. At the effective time of the Merger (the "Effective Time"), all 6,724,000 Shares held by the Reporting Persons and each other Share issued and outstanding immediately prior to the Effective Time was converted into the right to receive (i) an amount in cash equal to $1.95 per Share, without interest, and subject to deduction for any required tax withholding and (ii) one CVR. As a result of the Merger, the Common Stock will no longer be listed on any securities exchange or quotation system, including the Nasdaq Global Select Market ("Nasdaq") and the Company will cease to be a publicly traded company. On September 17, 2025 Hillevax requested that Nasdaq file an application on Form 25 with the SEC to withdraw registration of the Common Stock under the Securities Exchange Act of 1934 (the "Exchange Act"). The deregistration will become effective 90 days after the filing of Form 25, or such shorter period as may be determined by the SEC. The Company intends to suspend its reporting obligations under the Exchange Act by filing a Form 15 with the SEC in approximately 10 days following the filing of the Form 25. The Company's reporting obligations under the Exchange Act will be suspended immediately as of the filing date of the Form 15. The consummation of the Merger and the other transactions described in this Item 4 have resulted or will result in a number of the actions specified in clauses (a)-(j) of Item 4 of Schedule 13D with respect to the Company, including the acquisition or disposition of securities of the Company, a merger or other extraordinary transaction involving the Company, a change to the board of directors of the Company (as the surviving corporation), causing a class of securities of the Company to be delisted from a national securities exchange, a class of equity securities of the Company becoming eligible for termination of registration and a change in the Company's articles of incorporation and bylaws.
Item 5.	Interest in Securities of the Issuer
(a)	As of the date of this Amendment, the Reporting Persons do not beneficially own any Common Stock.
(b)	As of the date of this Amendment, the Reporting Persons do not beneficially own any Common Stock.
(c)	Except as set forth herein, the Reporting Persons have not effected any transaction in shares of Common Stock in the past 60 days.
(d)	Not applicable.
(e)	At the Expiration Time, each of the Reporting Persons ceased to be the beneficial owner of more than 5% of the Common Stock.
Item 6.	Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer
	The information disclosed under Item 4 of this Amendment is hereby incorporated by reference into this Item 6.
Item 7.	Material to be Filed as Exhibits.
	Exhibit 1: Joint Filing Agreement, Exhibit 1.A: Schedule A

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Takeda Pharmaceutical Company Limited

Signature:	/s/ Paul Sundberg
Name/Title:	Paul Sundberg / Authorized Signatory
Date:	09/19/2025

Takeda Vaccines Inc.

Signature:	/s/ Max Heuer
Name/Title:	Max Heuer / Authorized Signatory
Date:	09/19/2025

FAQ

What consideration did HLVX shareholders receive in the transaction?

Each HLVX share was converted into $1.95 cash plus one non-transferable CVR per share.

When did the tender offer and merger close for HilleVax (HLVX)?

The tender offer expired and was completed on September 15, 2025, and the Merger became effective on September 17, 2025.

Will HilleVax remain listed on Nasdaq after the merger?

No. HilleVax requested Nasdaq to file Form 25 to withdraw registration and the Common Stock will no longer be listed.

When will HilleVax suspend public reporting under the Exchange Act?

The company intends to file Form 15 approximately 10 days after filing Form 25; reporting obligations will be suspended immediately upon filing Form 15.

Do Takeda entities still own HilleVax shares after the merger?

No. The Reporting Persons state they do not beneficially own any Common Stock as of this Amendment.