The company’s shares moved to over-the-counter trading after the New York Stock Exchange delisted them in early October. They closed Friday down 21% at 7 cents.

ESS Tech, whose investors included SoftBank Group, was valued at about $1.1 billion in May 2021, when its combination with ACON S2 Acquisition Corp. was announced. Its products included sodium-ion batteries. The company described them as “a safer, more robust, and sustainable alternative to lithium-ion technology for short- and medium-duration energy storage” and said they reduced reliance on constrained critical minerals.

On Sept. 2, ESS Tech said it had achieved Awardable status through the Chief Digital and Artificial Intelligence Office’s Tradewinds Solutions Marketplace. The company said the designation “expands our visibility within the U.S. Department of War and broader federal community.”