ESS Tech Transitions to OTC Trading Platform (Form 8-K)

ESS Tech Transitions to OTC Trading Platform

Company Intends to Request Review of NYSE Regulation Determination Within Required Ten-Business-Day Period

ESS Remains an SEC Reporting Company and Continues to Focus on all Strategic Transaction Opportunities

WILSONVILLE, Ore. - October 5, 2026 - ESS Tech, Inc. ("ESS" or the "Company") (GWHT), a leading provider of non-lithium energy storage solutions, today provided an update on the listing status of its common stock.

As of October 5, 2026, ESS common stock may be quoted and traded in the market for unlisted securities (i.e., the "over-the counter" market) under the ticker GWHT.

The platform transition follows the October 2, 2026, notification from the New York Stock Exchange ("NYSE") that the staff of NYSE Regulation had suspended trading in the common stock immediately and determined to commence delisting proceedings. The determination was made pursuant to Section 802.01B of the NYSE Listed Company Manual, which requires listed companies to maintain an average global market capitalization of at least $15 million over a consecutive 30-trading-day period.

The Company currently intends to request review of NYSE Regulation's determination by a Committee of the Board of Directors of the NYSE by submitting a written request within ten business days of receiving the notice as permitted pursuant to NYSE procedures.

Shareholders are not required to take any steps related to the suspension. Shares of common stock remain outstanding and continue to be held in the same accounts. The Company also remains subject to the reporting requirements of the Securities Exchange Act of 1934, as amended, and intends to continue filing annual, quarterly and current reports with the SEC.

Our focus remains on the pursuit of all strategic transaction opportunities on an expedited basis that would address the market capitalization issues and enable continuation of the listed company," said Drew Buckley, Chief Executive Officer of ESS.

About ESS Tech, Inc.

ESS (NYSE: GWH) is a leading provider of non-lithium energy storage solutions designed to deliver safer, more reliable and resilient energy infrastructure. Founded in 2011, ESS develops and deploys energy storage technologies spanning short-, medium- and long-duration applications, including sodium-ion and iron flow battery systems and advanced energy management software. Using abundant, responsibly sourced materials, ESS solutions help utilities, businesses and critical infrastructure operators meet growing energy demand, integrate renewable energy, improve resilience and maximize the value of energy assets. For more information, visit www.essinc.com.