---
schema_version: "secwatch.filing_event.v1"
accession: "0001819438-26-000022"
form_type: "8-K"
ticker: "GWH"
cik: "0001819438"
company_name: "ESS Tech, Inc."
filed_at: "2026-04-15T23:59:59+00:00"
generated_at: "2026-05-15T06:09:11.978540+00:00"
event_type: "leadership"
sentiment: "neutral"
materiality_score: 0.25
calibrated_materiality_score: 0.25
confidence: "high"
source: SEC EDGAR
---

# Director Michael Niggli resigns from ESS Tech board, effective May 29, 2026

## Summary
- Michael Niggli notified resignation from Board, Audit Committee, and Nominating and Corporate Governance Committee.
- Resignation effective as of the date of the 2026 annual meeting of stockholders on May 29, 2026.
- Resignation not due to any disagreement with the Company regarding operations, policies, or practices.
- Niggli served as Founding Chairman of the Company.

## SEC filing metadata
- accession: 0001819438-26-000022
- form_type: 8-K
- ticker: GWH
- cik: 0001819438
- company_name: ESS Tech, Inc.
- filed_at: 2026-04-15T23:59:59+00:00
- event_type: leadership
- sentiment: neutral
- materiality_score: 0.25
- calibrated_materiality_score: 0.25
- confidence: high
- sec_items: 5.02
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1819438/000181943826000022/0001819438-26-000022-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1819438/000181943826000022/wk-20260410.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001819438-26-000022
- JSON: https://secwatch.observer/filing/0001819438-26-000022.json
- Plain text: https://secwatch.observer/filing/0001819438-26-000022.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.