Immuneering (IMRX) CSO acquires 14,880 Class A shares via ESPP

Rhea-AI Filing Summary

Brett Matthew Hall, the company's Chief Scientific Officer and a director, reported an acquisition of 14,880 shares of Immuneering Corp Class A common stock under the company's Employee Stock Purchase Plan (ESPP). The shares were purchased on the ESPP purchase date at a price of $1.428 per share, and the reporting line shows total beneficial ownership of 374,198 shares following the transaction. The filing notes the purchase was made pursuant to the ESPP's terms, which provide for shares to be bought at no less than 85% of the fair market value determined at the enrollment date, and states the transaction is exempt under Rule 16b-3(c).

Positive

• Officer purchased shares through the company ESPP, signaling personal investment in the company's equity
• Purchase made at a discount to fair market value (ESPP pricing at 85% of FMV), providing favorable terms to the insider
• Complete disclosure of number of shares acquired, price, and resulting beneficial ownership

Negative

• None.

Insights

Financial Analyst

TL;DR: Insider purchased common shares under the company ESPP at a discount, modestly increasing direct ownership to 374,198 shares.

The reported transaction shows an officer-level insider acquired 14,880 Class A shares through the ESPP at $1.428 per share, consistent with plan mechanics that allow purchases at up to a 15% discount to fair market value. This is a non-derivative acquisition classified with transaction code "A," and the filing reports the resulting beneficial ownership. The size of the purchase and the filing language indicate this is a routine ESPP acquisition rather than a compensatory grant or option exercise.

Corporate Governance Expert

TL;DR: Transaction is a standard ESPP purchase by an executive; disclosure complies with Section 16 reporting conventions.

The Form 4 discloses a voluntary ESPP purchase by the Chief Scientific Officer and director and cites Rule 16b-3(c) exemption for such transactions. The filing includes the purchase amount, price, and resulting beneficial ownership, and is signed by an attorney-in-fact. There are no disclosures of option grants, sales, or indirect holdings in this filing, and the report appears to follow standard insider reporting practices.

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

OMB Number:			3235-0287
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hours per response:			0.5

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^*

Hall Brett Matthew

(Last) (First) (Middle)

245 MAIN STREET

SECOND FLOOR

(Street)

CAMBRIDGE MA 02142

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Immuneering Corp [ IMRX ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

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

3. Date of Earliest Transaction (Month/Day/Year)
09/15/2025

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
Class A Common Stock(1)	09/15/2025(2)		A		14,880	A	$1.428(3)	374,198	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. The reporting person is voluntarily reporting the acquisition of shares of the issuer's Class A Common Stock pursuant to the Immuneering Corporation 2021 Employee Stock Purchase Plan (the "ESPP"), for the ESPP purchase period of March 16, 2025 through September 15, 2025. This transaction is also exempt pursuant to Rule 16b-3(c) promulgated pursuant to the Securities Exchange Act of 1934.

2. The relevant Offering Period (as defined in the ESPP) ended, and the shares were acquired, on the Purchase Date (as defined in the ESPP) of September 15, 2025.

3. In accordance with the ESPP, the shares were purchased at a price not less than eighty-five percent (85%) of the Fair Market Value (as defined in the ESPP) of a share of Class A Common Stock on the Enrollment Date (as defined in the ESPP) of the relevant Offering Period.

Remarks:

	/s/ Michael D. Bookman, Attorney-in-Fact for Brett Matthew Hall	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 shares did IMRX insider Brett Matthew Hall acquire?

He acquired 14,880 shares of Class A common stock under the company ESPP.

At what price were the IMRX ESPP shares purchased?

The shares were purchased at $1.428 per share.

What is Brett Hall's total beneficial ownership after the transaction?

The filing reports beneficial ownership of 374,198 shares following the transaction.

Was this ESPP transaction exempt from short-swing profit rules?

Yes. The filing states the transaction is exempt pursuant to Rule 16b-3(c).

How does the ESPP pricing work for this purchase?

The filing notes shares were purchased at no less than 85% of the fair market value as defined in the ESPP.