ESS Tech, Inc.

ESS Tech, Inc. (STWO) is an Oregon-based energy storage company that reached public markets through its merger with ACON S2 Acquisition Corp, a blank-check vehicle sponsored by ACON Investments that completed its IPO in 2021 targeting the clean energy and industrial technology sector. ESS Tech develops iron flow batteries engineered for long-duration, grid-scale energy storage applications. The company filed an 8-K with the Securities and Exchange Commission on May 29, 2026, representing a current-report disclosure from the post-merger public entity. For comprehensive filing data, sponsor background, and deal analytics on STWO and the broader SPAC universe, sign up for full access on SpacDesk.