Form 4: ESS Tech director acquires 13,513 RSUs at $0; 27,859 owned

Rhea-AI Filing Summary

ESS Tech (GWH) reported a Form 4 showing a director acquired 13,513 restricted stock units on 10/13/2025 at $0. Following the transaction, the reporting person beneficially owns 27,859 shares directly.

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 within 30 days of the earlier of separation from service or a qualifying change of control under Section 409A.

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^*

Hossfeld Rich

(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	27,859(2)	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.

2. A portion of these securities are RSUs. Each RSU represents a contingent right to receive one share of the Issuer's Common Stock.

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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What did ESS Tech (GWH) disclose in this Form 4?

A director acquired 13,513 RSUs on 10/13/2025 at $0 and now beneficially owns 27,859 shares directly.

How many RSUs were involved and at what price?

The filing shows 13,513 RSUs at a price of $0.

What are the vesting terms for the RSUs?

They vest on the earlier of May 17, 2025 or the day prior to the next annual meeting of stockholders.

What is the reporting person’s ownership after the transaction?

Beneficial ownership is 27,859 shares, held directly.

Were the RSUs settled immediately upon vesting?

No. Settlement is deferred to within 30 days of separation from service or a qualifying change of control under Section 409A.

What is the relationship of the reporting person to ESS Tech (GWH)?

The reporting person is a Director.