[Form 4] HilleVax, Inc. Insider Trading Activity

Rhea-AI Filing Summary

HilleVax, Inc. (HLVX) – Form 4 filing dated 06/25/2025

Non-employee director Patrick J. Heron reported the receipt of 17,199 Restricted Stock Units (RSUs) on 06/23/2025 at a cost basis of $0.00. The award was made under the company’s Non-Employee Director Compensation Program.

• Vesting: 100% on the earlier of (i) 06/23/2026 or (ii) a Change in Control, subject to continued board service.
• Post-transaction direct holdings: 17,199 shares.
• Indirect holdings: 8,535,337 shares held through Frazier Life Sciences X, L.P., for which Mr. Heron shares voting and investment control.

No derivative securities were reported. The filing represents routine director equity compensation rather than open-market activity and does not involve the sale or disposal of shares.

Positive

• Director equity grant strengthens alignment between board member and shareholders through time-based RSUs.

Negative

• None.

Insights

Corporate Governance Analyst

TL;DR: Routine RSU grant aligns director incentives; minimal immediate market impact.

The award of 17,199 RSUs to Director Patrick Heron is standard board compensation and helps align his interests with shareholders. The single-year cliff vesting plus change-in-control trigger is conventional for biotech boards. Importantly, no shares were sold, and the director’s sizable indirect stake (8.5 million shares) remains unchanged, signaling continued long-term exposure. I view the disclosure as governance-neutral with a slight positive bias due to incentive alignment.

Securities Analyst

TL;DR: Transaction is immaterial to float; neutral for valuation.

The 17,199 RSUs represent a de minimis 0.04% of HLVX’s 43 million share count (latest 10-Q), thus having no dilution concern. Because the units vest over a year or upon a change in control, there is no immediate liquidity event. The large indirect holding through Frazier Life Sciences X underscores existing insider ownership but is unchanged. Overall, the filing does not alter my earnings or valuation model.

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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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^*

Heron Patrick J

(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)
06/23/2025

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	06/23/2025		A		17,199(1)	A	$0.00	17,199	D
Common Stock								8,535,337	I	By Frazier Life Sciences X, L.P.(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

Explanation of Responses:

1. The Restricted Stock Units ("RSUs") were granted on June 23, 2025 pursuant to the Registrant's Non-Employee Director Compensation Program. 100% of the total number of RSUs granted shall vest on the first to occur of (i) the first anniversary of the date of grant or (ii) a Change in Control (as defined in the Registrant's 2022 Incentive Award Plan), in each case, subject to the non-employee director continuing in service on the Registrant's board of directors through such vesting date.

2. The shares reported herein are held of record by Frazier Life Sciences X, L.P. ("FLS X"). The general partner of FLS X is FHMLS X, L.P., and the general partner of FHMLS X, L.P. is FHMLS X, L.L.C. James Topper, M.D., Ph.D., and Patrick Heron are the sole managing members of FHMLS X, L.L.C. and share voting and investment power of the securities held by FLS X. Dr. Topper and Mr. Heron disclaim beneficial ownership of such securities except to the extent of their pecuniary interest therein.

	/s/ Paul Bavier, Attorney-in-Fact for Patrick Heron	06/25/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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FAQ

How many HLVX shares did Director Patrick Heron acquire?

He received 17,199 Restricted Stock Units, each convertible into one common share upon vesting.

When do the newly granted RSUs to Patrick Heron vest?

100% vest on the earlier of 06/23/2026 or a company Change in Control, subject to continued board service.

What is Patrick Heron’s total indirect ownership in HLVX?

He has 8,535,337 shares held indirectly through Frazier Life Sciences X, L.P.

Did the Form 4 report any share sales by the director?

No. The filing only shows an acquisition of RSUs; there were no disposals of common stock.

Was this transaction made under a Rule 10b5-1 trading plan?

The checkbox for Rule 10b5-1 was not marked, indicating the grant was not under such a plan.