Kate Suhadolnik - 01 Aug 2025 Form 3 Insider Report for ESS Tech, Inc. (GWH)

Role: Interim CFO
Signature: /s/ Bianca Boschmans, by power of attorney
Issuer symbol: GWH
Transactions as of: 01 Aug 2025
Net transactions value: $0
Form type: 3
Filing time: 28 Aug 2025, 18:24:03 UTC
Next filing: 29 Aug 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Suhadolnik Kate Eileen	Interim CFO	C/O ESS TECH, INC., 26440 SW PARKWAY AVE., BLDG. 83, WILSONVILLE	/s/ Bianca Boschmans, by power of attorney	28 Aug 2025	0002083724

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
holding	GWH	Common Stock						30,186	01 Aug 2025	Direct	F1, F2

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

Explanation of Responses:

Id	Content
F1	Of the reported shares, 23,805 are represented by restricted stock units, or RSUs, awarded prior to the date on which the reporting person became subject to Section 16. An award representing 394 RSUs was awarded on December 23, 2021. The remaining 48 RSUs vest in two equal quarterly installments beginning on August 20, 2025. An award representing 184 RSUs was awarded on February 8, 2022. The remaining 33 RSUs vest in three equal quarterly installments beginning on August 20, 2025. An award representing 821 RSUs was awarded on November 2, 2022. The remaining 128 RSUs vest in two equal quarterly installments beginning on August 20, 2025.
F2	An award representing 5,351 RSUs was awarded on March 13, 2023. The remaining 2,338 RSUs vest in seven equal quarterly installments beginning on August 20, 2025. An award representing 5,867 RSUs was awarded on February 15, 2024. The remaining 4,032 RSUs vest in eleven equal quarterly installments beginning on August 20, 2025. An award representing 18,375 RSUs was awarded on April 13, 2025. The remaining 17,226 RSUs vest in fifteen equal quarterly installments beginning on August 20, 2025.

Content

Of the reported shares, 23,805 are represented by restricted stock units, or RSUs, awarded prior to the date on which the reporting person became subject to Section 16. An award representing 394 RSUs was awarded on December 23, 2021. The remaining 48 RSUs vest in two equal quarterly installments beginning on August 20, 2025. An award representing 184 RSUs was awarded on February 8, 2022. The remaining 33 RSUs vest in three equal quarterly installments beginning on August 20, 2025. An award representing 821 RSUs was awarded on November 2, 2022. The remaining 128 RSUs vest in two equal quarterly installments beginning on August 20, 2025.

An award representing 5,351 RSUs was awarded on March 13, 2023. The remaining 2,338 RSUs vest in seven equal quarterly installments beginning on August 20, 2025. An award representing 5,867 RSUs was awarded on February 15, 2024. The remaining 4,032 RSUs vest in eleven equal quarterly installments beginning on August 20, 2025. An award representing 18,375 RSUs was awarded on April 13, 2025. The remaining 17,226 RSUs vest in fifteen equal quarterly installments beginning on August 20, 2025.

Remarks:

Exhibit 24.1 Power of Attorney