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

Rhea-AI Filing Summary

ESS Tech, Inc. reported that its Chief Financial Officer, Kate Eileen Suhadolnik, received equity awards on February 13, 2026. She was granted 137,500 stock options with an exercise price of $0.00 per share and 137,500 shares of common stock represented by restricted stock units (RSUs).

Both the options and RSUs vest as to 1/16th on May 20, 2026, with an additional 1/16th vesting quarterly thereafter, so long as she remains a service provider to ESS Tech through each vesting date. Following the RSU grant, her directly owned common stock holdings increased to 165,155 shares.

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).

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^*

Suhadolnik Kate Eileen

(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)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Financial Officer

3. Date of Earliest Transaction (Month/Day/Year)
02/13/2026

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	02/13/2026		A		137,500(1)	A	$0	165,155(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
Stock Option (right to buy)	$1.44	02/13/2026		A		137,500		(3)	02/13/2036	Common Stock	137,500	$0	137,500	D

Explanation of Responses:

1. The reported shares are represented by restricted stock units ("RSUs"), which vest as to 1/16th of the RSUs on May 20, 2026 and 1/16th of the RSUs shall vest quarterly thereafter, subject to the Reporting Person remaining a Service Provider to the Issuer through each such vest date.

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

3. 1/16th of the shares subject to the option shall vest on May 20, 2026 and 1/16th of the shares subject to the option shall vest quarterly thereafter, subject to the Reporting Person remaining a Service Provider to the issuer through each such vest date.

	/s/ Kate Suhadolnik	02/26/2026
	** 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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