ESS Tech, Inc. Announces Closing of $3.2 Million Registered Direct Offering and Concurrent Private Placement

ESS Tech, Inc. (NYSE: GWH) (the “Company”), a leading provider of safer, non-lithium energy storage solutions, today announced the closing of the previously announced registered direct offering with institutional investors for the purchase and sale of 6.4 million shares of common stock at a price of $0.50 per share. In addition, in a concurrent private placement, the Company issued to investors warrants to purchase up to 12.8 million shares of common stock. The warrants have an exercise price of $0.50 per share, will become exercisable immediately following the date of stockholder approval and expire on the fifth anniversary of the date of stockholder approval. The registered direct offering of common stock and the concurrent private placement of warrants are collectively referred to as the offering herein.

The offering consisted of the sale of 6.4 million shares of common stock. The public offering price per share and accompanying warrant is $0.50.

Aggregate gross proceeds to the Company were approximately $3.2 million, before deducting placement agent fees and other offering expenses payable by the Company. The transaction closed on August 21, 2026. The Company expects to use the net proceeds from the offering, together with its existing cash, for general corporate purposes, and working capital. In addition, the Company intends to use approximately $1.5 million to repay amounts owing under its promissory note agreement with YA II PN, Ltd. dated October 14, 2025.