ESS Tech, Inc.
Business
ESS Tech, Inc. is a long-duration energy storage company that designs and manufactures iron flow battery technology for grid and commercial energy applications. Its main products and services include modular iron flow battery systems, core power trains, electrolyte management solutions, and project warranty and insurance offerings. Key product lines comprise the behind-the-meter Energy Warehouse, the modular containerized Energy Center, the gigawatt-scale configurable Energy Base, and deployable power-train components for on-site assembly. ESS serves utilities, independent power producers and commercial and industrial customers in both front-of-the-meter and behind-the-meter markets globally through modular deliveries, on-site integration and strategic partnerships.
Summary from filing dated 2025-03-31
Financials
Consolidated Statement of Income
| Concept | Trend | FY 2025 2025-12-31 | FY 2024 2024-12-31 | FY 2023 2023-12-31 | FY 2022 2022-12-31 | FY 2021 2021-12-31 |
|---|---|---|---|---|---|---|
| Total revenue | 2 | 6 | 8 | 894,000 | 0 | |
| Cost of revenue | 29 | 52 | 20 | 0 | — | |
| Gross loss | −28 | −45 | −13 | 894,000 | — | |
| Research and development | 8 | 12 | 43 | 72 | 30 | |
| Sales and marketing | 4 | 9 | 8 | 7 | 3 | |
| General and administrative | 18 | 24 | 23 | 27 | 27 | |
| Total operating expenses | 30 | 44 | 73 | 106 | 61 | |
| Loss from operations | −57 | −90 | −86 | −105 | −61 | |
| Interest (expense) income, net | −5 | 4 | — | — | — | |
| Gain on revaluation of common stock warrant liabilities | 229,000 | 115,000 | 2 | 26 | −38 | |
| Other expense, net | −807,000 | −113,000 | 773,000 | −452,000 | 926,000 | |
| Total other (expense) income, net | −6 | 4 | 8 | 28 | −417 | |
| Net loss to common stockholders | −63 | −86 | −78 | −78 | −477 | |
| Comprehensive loss to common stockholders | −63 | −86 | −78 | −78 | −477 | |
| Net loss per share - basic (in USD per share) | −4.34 | −7.32 | −7.27 | −0.51 | −5.73 | |
| Net loss per share - diluted (in USD per share) | −4.34 | −7.32 | −7.27 | −0.51 | −5.73 | |
| Weighted average shares used in per share calculation - basic (in shares) | 15 | 12 | 11 | 153 | 83 | |
| Weighted average shares used in per share calculation - diluted (in shares) | 15 | 12 | 11 | 153 | 83 |
Consolidated Balance Sheet
| Concept | Trend | FY 2025 2025-12-31 | FY 2024 2024-12-31 | FY 2023 2023-12-31 | FY 2022 2022-12-31 | FY 2021 2021-12-31 |
|---|---|---|---|---|---|---|
| Cash and cash equivalents | 15 | 13 | 20 | 35 | 239 | |
| Restricted cash, current | 806,000 | 906,000 | 1 | 1 | 1 | |
| Accounts receivable, net | 13,000 | 215,000 | 2 | 5 | 451,000 | |
| Short-term investments | 8 | 18 | 88 | 105 | 0 | |
| Inventory | 140,000 | 6 | 3 | 0 | — | |
| Prepaid expenses and other current assets | 3 | 5 | 3 | 6 | 5 | |
| Total current assets | 26 | 43 | 118 | 152 | 246 | |
| Property and equipment, net | 17 | 21 | 16 | 18 | 5 | |
| Intangible assets, net | 3 | 5 | 5 | 0 | — | |
| Operating lease right-of-use assets | 4 | 2 | 2 | 3 | 0 | |
| Restricted cash, non-current | 618,000 | 948,000 | 945,000 | 675,000 | 75,000 | |
| Other non-current assets | 634,000 | 760,000 | 833,000 | 271,000 | 105,000 | |
| Total assets | 51 | 72 | 143 | 174 | 250 | |
| Accounts payable | 3 | 8 | 3 | 3 | 2 | |
| Accrued and other current liabilities | 11 | 9 | 11 | 14 | 6 | |
| Accrued product warranties | 985,000 | 3 | 2 | 2 | 0 | |
| Operating lease liabilities, current | 2 | 2 | 2 | 1 | 0 | |
| Deferred revenue, current | 400,000 | 5 | 3 | 6 | 4 | |
| Financing obligations, current | 8 | 0 | — | — | — | |
| Total current liabilities | 25 | 28 | 20 | 28 | 14 | |
| Operating lease liabilities, non-current | 2 | 0 | 957,000 | 3 | 0 | |
| Deferred revenue, non-current - related parties | 5 | 14 | 18 | 2 | 0 | |
| Common stock warrant liabilities | 573,000 | 802,000 | 917,000 | 3 | — | |
| Financing obligations, non-current | 9 | 0 | — | — | — | |
| Other non-current liabilities | 41,000 | 125,000 | 0 | 85,000 | 552,000 | |
| Total liabilities | 43 | 43 | 40 | 37 | 45 | |
| Commitments and contingencies (Note 11) | — | — | — | — | — | |
| Preferred stock ($0.0001 par value; 200,000,000 shares authorized, none issued and outstanding as of December 31, 2025 and 2024) | 0 | 0 | 0 | 0 | 0 | |
| Common stock ($0.0001 par value; 1,000,000,000 shares authorized, 22,377,003 and 11,986,516 shares issued and outstanding as of December 31, 2025 and 2024, respectively) | 2,000 | 1,000 | 1,000 | 16,000 | 16,000 | |
| Additional paid-in capital | 854 | 811 | 800 | 756 | 746 | |
| Accumulated deficit | −846 | −782 | −696 | −619 | −541 | |
| Total stockholders equity | 9 | 29 | 103 | 137 | 205 | |
| Total liabilities and stockholders equity | 51 | 72 | 143 | 174 | 250 |
Consolidated Statement of Cash Flows
| Concept | Trend | FY 2025 2025-12-31 | FY 2024 2024-12-31 | FY 2023 2023-12-31 | FY 2022 2022-12-31 | FY 2021 2021-12-31 |
|---|---|---|---|---|---|---|
| Depreciation and amortization | 6 | 5 | 7 | 2 | 572,000 | |
| Asset abandonment | 2 | 0 | — | — | — | |
| Non-cash interest (income) expense | 5 | −2 | −4 | −1 | — | |
| Non-cash lease expense | 2 | 1 | 1 | 1 | 0 | |
| Stock-based compensation expense | 5 | 12 | 11 | 12 | 8 | |
| Other non-cash (income) expenses, net | 388,000 | 459,000 | −60,000 | 483,000 | −868,000 | |
| Accounts receivable, net | 202,000 | 2 | 4 | −2 | 0 | |
| Inventory | 5 | −3 | −15 | 0 | — | |
| Prepaid expenses and other assets | 2 | −2 | 2 | −311,000 | −5 | |
| Accounts payable | −4 | 4 | −229,000 | 1 | 886,000 | |
| Accrued and other liabilities | −3 | −1 | −3 | 7 | 2 | |
| Accrued product warranties | −2 | 1 | 486,000 | 2 | 0 | |
| Deferred revenue | −3 | −918,000 | 12 | 2 | 4 | |
| Operating lease liabilities | −2 | −2 | −1 | −1 | 0 | |
| Net cash used in operating activities | −50 | −72 | −55 | −82 | −52 | |
| Purchases of property and equipment | −3 | −7 | −6 | −14 | −3 | |
| Maturities and purchases of short-term investments, net | 11 | 72 | 21 | −104 | 0 | |
| Net cash provided by investing activities | 8 | 65 | 15 | −118 | −3 | |
| Proceeds from issuance of common stock and common stock warrants, net of issuance costs | 38 | 0 | 27 | 0 | — | |
| Proceeds from financing arrangements | 27 | 0 | — | — | — | |
| Debt issuance costs | −308,000 | 0 | — | — | — | |
| Payments on financing obligations | −21 | 0 | — | — | — | |
| Proceeds from stock options exercised | 83,000 | 86,000 | 237,000 | 0 | 671,000 | |
| Repurchase of shares from employees for income tax withholding purposes | −50,000 | −297,000 | −310,000 | −3 | 0 | |
| Proceeds from contributions to Employee Stock Purchase Plan | 107,000 | 385,000 | 541,000 | 492,000 | 0 | |
| Net cash provided by financing activities | 43 | 174,000 | 26 | −4 | 288 | |
| Net change in cash, cash equivalents and restricted cash | 706,000 | −7 | −14 | −204 | 234 | |
| Operating leases included in cash used in operating activities | 2 | 2 | 2 | 2 | 0 | |
| Interest | 520,000 | 0 | 0 | 154,000 | 2 | |
| Purchase of property and equipment included in accounts payable and accrued and other current liabilities | 28,000 | 2 | 704,000 | 1 | 526,000 | |
| Adjustment to right-of-use assets from lease modification | 4 | 686,000 | — | — | — | |
| Transfers between inventory and property and equipment, net | 668,000 | 1 | 0 | — | — | |
| Application of deferred revenue to financing obligations | 7 | 0 | — | — | — |