ESS Tech
- 🦄Became a unicorn2021
- 📈Peak valuation$1.07 Billion ’21
- 💔Became a Unitard2022
- 💸Last valuation~$29.5M
How it happened
ESS Tech makes long-duration iron-flow batteries — using iron, salt and water instead of lithium — and went public in 2021 via a SPAC merger with ACON S2 Acquisition Corp at a $1.07B valuation. Commercialization came slowly and expensively while lithium-ion costs kept falling, and the company burned through cash. The stock collapsed more than 95%; by 2025 ESS warned of a 'survival battle,' nearly shut its Oregon factory and flagged possible 'workforce actions,' leaving it a distressed micro-cap far below $1B. Through the decline, Glassdoor reviewers consistently praised the core technology while faulting disorganized leadership and a bumpy shift from R&D to volume manufacturing — describing morale sliding through repeated layoff rounds and the departure of the founders.
Employee accounts paraphrase anonymous, unverified reviews posted publicly on Glassdoor ↗. See our methodology.
Source: Energy-Storage.News / SEC ($1.07B valuation via ACON S2 Acquisition Corp SPAC, 2021, ~$465M proceeds; shares collapsed from post-listing high to ~$1.74 by Aug 2025; nearly closed its Oregon plant, warned of 'workforce actions')
