[Form 4] ESS Tech, Inc. Insider Trading Activity

Rhea-AI Filing Summary

ESS Tech, Inc. (GWH) reported a Form 4 showing a director received 13,513 restricted stock units (RSUs) on 10/13/2025 at a stated price of $0. Following this grant, the director beneficially owns 90,825 shares on a direct basis.

The RSUs vest on the earlier of May 17, 2025 or the day prior to the next annual meeting of stockholders. Settlement has been deferred to a date within 30 days of the earlier of the director’s separation of service (under Section 409A) or a qualifying change of control as defined in the company’s plan.

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

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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).

1. Name and Address of Reporting Person^*

NIGGLI MICHAEL R

(Last) (First) (Middle)

C/O ESS TECH, INC.

26440 SW PARKWAY AVE., BLDG. 83

(Street)

WILSONVILLE OR 97070

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
ESS Tech, Inc. [ GWH ]

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)
10/13/2025

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	10/13/2025		A		13,513(1)	A	$0	90,825	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 reported shares are represented by restricted stock units ("RSUs") which vest on the earlier of (i) May 17, 2025 or (ii) the day prior to the next annual meeting of stockholders. The Reporting Person has elected to defer the settlement of these RSUs to a date within 30 days of the earlier of (i) his or her separation of service from the Issuer within the meaning of Section 409A of the Internal Revenue Code (Section 409A) or (ii) the date on which a change of control (as defined in the Issuer's plan) occurs, provided that such transaction qualifies as a change of control within the meaning of Section 409A.

Remarks:

	/s/ Kate Suhadolnik, by power of attorney	10/15/2025
	** 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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