Drew P. Buckley - 28 Jan 2026 Form 4 Insider Report for ESS Tech, Inc. (GWH)

Role: CEO, Director
Signature: /s/ Kate Suhadolnik, by power of attorney
Issuer symbol: GWH
Transactions as of: 28 Jan 2026
Net transactions value: $0
Form type: 4
Filing time: 29 Jan 2026, 17:25:27 UTC
Previous filing: 29 Jan 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Buckley Drew P	CEO, Director	C/O ESS TECH, INC, 26440 SW PARKWAY AVE, WILSONVILLE	/s/ Kate Suhadolnik, by power of attorney	29 Jan 2026	0002106707

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	GWH	Stock Option (right to buy)	Award	$0	+550,000		$0.000000	550,000	28 Jan 2026	Common Stock	550,000	$1.68	Direct	F1

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	25 % of the shares subject to the option will vest on February 20, 2027 and 1/16th of the shares subject to the option shall vest quarterly thereafter, subject to the Reporting Person remains as Service Provider to the issuer through each such vest date.