ESS Tech
- 🦄Became a unicorn2021
- 📈Peak valuation$1.07 Billion ’21
- 💔Became a Unitard2022
- 💸Last valuation estimate~$64.2M
The rise & fall
6 moments · 2011–2025The key moments, with employee sentiment along the way.
💬 entries paraphrase anonymous, unverified reviews posted publicly on Glassdoor ↗; dated facts carry their source.
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.
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')
Who ran it
- Eric DresselhuysCEO Apr 2021-Feb 2025 who led ESS through its 2021 SPAC listing (peak) and collapse
Current roles as self-reported on LinkedIn, retrieved 2026-08-21. See our methodology.
Disclosed investors (16)
Historical funding participation; lists may be incomplete and do not establish current ownership or investor losses.
* Lead in a funding round · Crunchbase ↗ · 2026-10-23 · Methodology · Leaderboard
