ESS TECH INC

Item 3.01 Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard; Transfer of Listing. On October 2, 2026, the New York Stock Exchange (the “NYSE”) notified ESS Tech, Inc. (the “Company”) that the staff of NYSE Regulation (“NYSE Regulation”) had determined to commence proceedings to delist the Company’s common stock (the “Common Stock”) from the NYSE and that trading in the Common Stock was suspended immediately. NYSE Regulation reached its decision to commence delisting proceedings pursuant to Section 802.01B of the NYSE Listed Company Manual because the Company had fallen below the NYSE’s continued listing standard requiring listed companies to maintain an average global market capitalization over a consecutive 30 trading day period of at least $15,000,000. This determination is separate from, and in addition to, the previously disclosed determination by NYSE Regulation on September 24, 2026 to commence proceedings to delist the Common Stock pursuant to Section 802.02 of the NYSE Listed Company Manual, which the Company disclosed in its Current Report on Form 8-K filed with the Securities and Exchange Commission (the “SEC”) on September 30, 2026. The Company remains subject to that determination. NYSE Regulation indicated that it will apply to the SEC to delist the Common Stock upon completion of all applicable procedures. Under the NYSE’s delisting procedures, the Company has a right to a review of NYSE Regulation’s determination by a Committee of the Board of Directors of the NYSE, provided that the Company files a written request for such review with the Corporate Secretary of the NYSE within ten business days after its receipt of the notice. The Company anticipates that the Common Stock will be quoted and traded in the over-the-counter market under its current trading symbol “GWHT” following the suspension of trading on the NYSE. The over-the-counter market is a significantly more limited market than the NYSE, and quotation on the over-the-counter market likely will result in a less liquid market for existing and potential holders of the Common Stock and could further depress the trading price of the Common Stock. The Company can provide no assurance whether broker-dealers will continue to provide public quotes of the Common Stock on this market or whether the trading volume of the Common Stock will be sufficient to provide for an efficient trading market.

Item 7.01 Regulation FD Disclosure. On October 5, 2026, the Company issued a press release related to the foregoing. A copy of the press release is attached as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated by reference to this Item 7.01. The information in this Item 7.01, including Exhibit 99.1, is being furnished and shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and is not to be incorporated by reference into any filing by Company under the Securities Act of 1933, as amended, or the Exchange Act, regardless of any general incorporation language contained in such filing, unless otherwise expressly stated in such filing.