{"filing":{"accession_number":"0001819438-26-000049","cik":"0001819438","ticker":"GWH-WT","company_name":"ESS Tech, Inc.","form":"8-K","filing_date":"2026-06-18","report_date":null,"primary_document":"wk-20260612.htm","primary_document_url":"https://www.sec.gov/Archives/edgar/data/1819438/000181943826000049/wk-20260612.htm"},"events":[{"id":12008,"run_id":10569,"accession_number":"0001819438-26-000049","anchor_item_number":"5.02","event_type":"exec_departure","event_domain":"governance","is_material":true,"confidence":0.95,"summary":"Rich Hossfeld resigned from the Board and Audit Committee effective June 12, 2026. The principal disclosed action is a director's departure. While the filing also mentions Raffi Garabedian replacing him on the Audit Committee, the core event is Hossfeld's resignation. The company explicitly states the resignation was not due to disagreement, and board composition changes are material to investors assessing governance and oversight.","company_name":"ESS Tech, Inc.","ticker":"GWH-WT","filing_date":"2026-06-18","form":"8-K","submitted_at":null,"items":[{"id":8740,"accession_number":"0001819438-26-000049","item_number":"5.02","item_title":"Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.","event_type":"exec_departure","event_domain":"governance","is_material":true,"confidence":0.95,"reasoning":"Rich Hossfeld resigned from the Board and Audit Committee effective June 12, 2026. The principal disclosed action is a director's departure. While the filing also mentions Raffi Garabedian replacing him on the Audit Committee, the core event is Hossfeld's resignation. The company explicitly states the resignation was not due to disagreement, and board composition changes are material to investors assessing governance and oversight.","classifier_version":"claude-haiku-4-5-20251001+prompt-9e0ffca5","taxonomy_version":"v1","classified_at":"2026-06-18T21:29:08.002920+00:00","company_name":"","ticker":null,"filing_date":""}]}],"classifications":[{"id":8740,"accession_number":"0001819438-26-000049","item_number":"5.02","item_title":"Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.","event_type":"exec_departure","event_domain":"governance","is_material":true,"confidence":0.95,"reasoning":"Rich Hossfeld resigned from the Board and Audit Committee effective June 12, 2026. The principal disclosed action is a director's departure. While the filing also mentions Raffi Garabedian replacing him on the Audit Committee, the core event is Hossfeld's resignation. The company explicitly states the resignation was not due to disagreement, and board composition changes are material to investors assessing governance and oversight.","classifier_version":"claude-haiku-4-5-20251001+prompt-9e0ffca5","taxonomy_version":"v1","classified_at":"2026-06-18T21:29:08.002920+00:00","company_name":"ESS Tech, Inc.","ticker":"GWH-WT","filing_date":"2026-06-18"}]}