# EDGAR Filing Document

**Accession Number:** 0001819438
**File Stem:** 0001819438-25-000077
**Filing Date:** 2025-11
**Character Count:** 26847
**Document Hash:** c4cc1ca6d8e90230ed10c55488c8ae8a
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001819438-25-000077.hdr.sgml**: 20251113

**ACCESSION NUMBER**: 0001819438-25-000077

**CONFORMED SUBMISSION TYPE**: 8-K

**PUBLIC DOCUMENT COUNT**: 15

**CONFORMED PERIOD OF REPORT**: 20251113

**ITEM INFORMATION**: Results of Operations and Financial Condition

**ITEM INFORMATION**: Financial Statements and Exhibits

**FILED AS OF DATE**: 20251113

**DATE AS OF CHANGE**: 20251113

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** ESS Tech, Inc.
- **CENTRAL INDEX KEY:** 0001819438
- **STANDARD INDUSTRIAL CLASSIFICATION:** MISCELLANEOUS ELECTRICAL MACHINERY, EQUIPMENT & SUPPLIES [3690]
- **ORGANIZATION NAME:** 04 Manufacturing
- **EIN:** 981550150
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 8-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-39525
- **FILM NUMBER:** 251479120

**BUSINESS ADDRESS:**
- **STREET 1:** 26440 SW PARKWAY AVE.
- **STREET 2:** BLDG. 83
- **CITY:** WILSONVILLE
- **STATE:** OR
- **ZIP:** 97070
- **BUSINESS PHONE:** (855) 423-9920

**MAIL ADDRESS:**
- **STREET 1:** 26440 SW PARKWAY AVE.
- **STREET 2:** BLDG. 83
- **CITY:** WILSONVILLE
- **STATE:** OR
- **ZIP:** 97070

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** ACON S2 Acquisition Corp.
- **DATE OF NAME CHANGE:** 20200728

?xml version='1.0' encoding='ASCII'? wk-20251113

**UNITED STATES**

**SECURITIES AND EXCHANGE COMMISSION**

**Washington, D.C. 20549**

**FORM 8-K**

**CURRENT REPORT**

**Pursuant to Section 13 or 15(d)**

**of the Securities Exchange Act of 1934**

**Date of report (Date of earliest event reported): November 13, 2025**

**ESS TECH, INC.**

**(Exact Name of Registrant as Specified in Charter)**

---

| | | |
|:---|:---|:---|
| **Delaware** | **001-39525** | **98-1550150** |
| **(State or other jurisdiction**<br>**of incorporation)** | **(Commission**<br>**File Number)** | **(I.R.S. Employer**<br>**Identification Number)** |

---

---

| | |
|:---|:---|
| **26440 SW Parkway Ave., Bldg. 83**<br>**Wilsonville, Oregon** | **97070** |
| **(Address of principal executive offices)** | **(Zip code)** |

---

**(855) 423-9920**

**(Registrant's telephone number, including area code)**

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the Registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

---

| | | |
|:---|:---|:---|
| **Title of each class** | **Trading**<br>**Symbol(s)** | **Name of each exchange**<br>**on which registered** |
| Common Stock, $0.0001 par value per share | GWH | The New York Stock Exchange |
| Warrants, each fifteen warrants exercisable for one share of common stock at an exercise price of $172.50 | GWH.W | The New York Stock Exchange |

---

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2).

Emerging growth company ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

------

**Item 2.02&nbsp;&nbsp;&nbsp;&nbsp;Results of Operations and Financial Condition.** 

On November 13, 2025, ESS Tech, Inc. (the "Company") issued a press release announcing financial results for the quarter ended September 30, 2025. A copy of the press release is furnished as <u>Exhibit 99.1</u> to this Current Report on Form 8-K and is incorporated herein by reference.

The information furnished in this Item 2.02 and <u>Exhibit 99.1</u> of this Current Report on Form 8-K shall not be deemed to be "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the "**Exchange Act**"), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such a filing.

**Item 9.01&nbsp;&nbsp;&nbsp;&nbsp;Financial Statements and Exhibits** 

*(d) Exhibits* 

---

| | |
|:---|:---|
| **Exhibit**<br>**No.** | |
| 99.1 | <u>[Press release, dated November 13, 2025](a2025q3earningsrelease.htm)</u> |
| 104 | Cover page interactive data file |

---

------

**SIGNATURE** 

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, hereunto duly authorized.

Dated: November 13, 2025

---

| | |
|:---|:---|
| **ESS TECH, INC.** | **ESS TECH, INC.** |
| By: | */s/ Kate Suhadolnik* |
| Name: | Kate Suhadolnik |
| Title: | Interim Chief Financial Officer |

---

## Exhibit 99.1

**Exhibit 99.1**![esslogoa.jpg](esslogoa.jpg)

**ESS Tech, Inc. Announces Third Quarter 2025 Financial Results** 

**Announced 50 MWh long-duration storage pilot project with Salt River Project (SRP)**

**Closed $40 million financing with Yorkville Advisors Global and subsequently repaid $15 million of the promissory note; completed the $25 million Standby Equity Purchase Agreement (SEPA)** 

**Announced plans to launch a $75 million at-the-market (ATM) program with Yorkville, BMO, Canaccord, Needham, and Stifel**

**Investor Day planned for January 2026 to provide an in-depth update on execution and strategic priorities**

**WILSONVILLE, Ore**. – November 13, 2025 – ESS Tech, Inc. ("ESS," "ESS, Inc." or the "Company") (NYSE: GWH), a leading manufacturer of long-duration energy storage systems (LDES) for commercial and utility-scale applications, today announced financial results for its third quarter ended September 30, 2025.

The third quarter continued ESS's steady execution of its strategic plan. Following leadership additions and organizational alignment earlier in the year, the Company advanced key customer programs and strengthened its capital position, laying the groundwork for manufacturing of its first Energy Base projects and broader commercialization commencing in 2026. During the quarter, ESS announced a 50 MWh Energy Base pilot project with Salt River Project ("SRP"), a major validation from one of the nation's leading utilities, which marks the first large-scale deployment of the Company's next-generation platform. Soon after, ESS completed a $40 million financing with YA II PN, Ltd., an investment fund managed by Yorkville Advisors Global, L.P. ("Yorkville"), further enhancing liquidity to support manufacturing readiness and upcoming project execution.

"We've built strong momentum over the course of 2025," said Kelly Goodman, Interim Chief Executive Officer of ESS. "With key customer programs underway and new capital secured, our focus is now squarely on execution—delivering the Energy Base platform and demonstrating the performance and reliability that customers are demanding. Our technology is well-positioned to support the fast-growing digital infrastructure sector, where long-duration storage is essential to enabling a resilient, decarbonized grid."

Since the financing, ESS has repaid $15 million of the first tranche of $30 million of the Yorkville promissory note and completed the $25 million Standby Equity Purchase Agreement ("SEPA"), reflecting continued capital discipline and proactive balance sheet management. These steps provide near-term flexibility and demonstrate the Company's ability to efficiently access and deploy capital as needed.

ESS announced plans to launch a $75 million at-the-market ("ATM") program with a syndicate including Yorkville, BMO, Canaccord, Needham, and Stifel to further strengthen that flexibility. The program is designed to provide efficient, discretionary access to capital when market conditions are favorable, ensuring ESS can raise funds opportunistically—not out of necessity—as it executes its next phase of growth.

As ESS advances into 2026, its focus will remain on execution, fulfilling the SRP pilot program, scaling manufacturing processes, and proving out the long-term economics of the Energy Base platform. This work will lay the foundation for broader commercialization and future contracts. Over the next 18 months, ESS expects its success to be measured less by traditional product revenue and more by operational progress, which includes validating performance, building customer confidence, and preparing for volume growth.

ESS also plans to host an Investor Day in January 2026, where management will outline progress across key initiatives and share its roadmap for 2026 and beyond.

------

**Conference Call Details** 

ESS will hold a conference call on Thursday, November 13, 2025 at 5:00 p.m. EDT to discuss financial results for its third quarter 2025 ended September 30, 2025. Interested parties may join the conference call beginning at 5:00 p.m. EDT on Thursday, November 13, 2025 via telephone by calling +1 (646) 844-6383 and entering conference ID 359373. A telephone replay will be available until November 20, 2025, by dialing (866) 813-9403 in the U.S., or for international callers, +1 (929) 458-6194 with conference ID 302525. A live webcast of the conference call will be available on ESS' Investor Relations website at http://investors.essinc.com/.

A replay of the call will be available via the web at http://investors.essinc.com/.

**About ESS, Inc.** 

ESS (NYSE: GWH) is the leading manufacturer of long-duration iron flow energy storage solutions. ESS was established in 2011 with a mission to accelerate decarbonization safely and sustainably through longer lasting energy storage. Using easy-to-source iron, salt, and water, ESS iron flow technology enables energy security, reliability and resilience. We build flexible storage solutions that allow our customers to meet increasing energy demand without power disruptions and maximize the value potential of excess energy. For more information visit www.essinc.com.

**Use of Non-GAAP Financial Measures**

In this press release and the accompanying earnings call, the Company includes Non-GAAP Operating Expenses and Adjusted EBITDA, which are non-GAAP performance measures that the Company uses to supplement its results presented in accordance with U.S. GAAP. As required by the rules of the Securities and Exchange Commission ("SEC"), the Company has provided herein a reconciliation of the non-GAAP financial measures contained in this press release and the accompanying earnings call to the most directly comparable measures under GAAP. The Company's management believes Non-GAAP Operating Expenses and Adjusted EBITDA are useful in evaluating its operating performance and are similar measures reported by publicly-listed U.S. companies, and regularly used by securities analysts, institutional investors, and other interested parties in analyzing operating performance and prospects. By providing these non-GAAP measures, the Company's management intends to provide investors with a meaningful, consistent comparison of the Company's profitability for the periods presented. Adjusted EBITDA is not intended to be a substitute for net income/loss or any U.S. GAAP financial measure and, as calculated, may not be comparable to other similarly titled measures of performance of other companies in other industries or within the same industry. Further, Non-GAAP Operating Expenses are not intended to be a substitute for GAAP Operating Expenses or any U.S. GAAP financial measure and, as calculated, may not be comparable to other similarly titled measures of performance of other companies in other industries or within the same industry.

The Company defines and calculates Non-GAAP Operating Expenses as GAAP Operating Expenses adjusted for stock-based compensation. The Company defines and calculates Adjusted EBITDA as net loss before interest, other non-operating expense or income, and depreciation and amortization, and further adjusted for stock-based compensation and other special items determined by management, including, but not limited to, fair value adjustments for certain financial liabilities associated with debt and equity transactions as they are not indicative of business operations.

**Forward-Looking Statements** 

This communication contains certain forward-looking statements, including statements regarding ESS and its management team's expectations, hopes, beliefs, intentions or strategies regarding the future. The words "anticipate", "believe", "continue", "could", "estimate", "expect", "intends", "may", "might", "plan", "possible", "potential", "predict", "project", "should", "will" "would" and similar expressions may identify forward-looking statements, but the absence of these words does not mean that a statement is not forward-looking. Examples of forward-looking statements include, among others, statements regarding the Company's manufacturing plans, the development and launch of the Energy Base product, the Company's order and sales pipeline, the Company's ability to successfully bid on projects and execute on orders, the Company's ability to effectively manage costs, the Company's partnerships with third parties, relationships with current and potential customers, and potential capital raising measures, including under the ATM program. These forward-looking statements are based on ESS' current expectations and beliefs concerning future developments and their potential effects on ESS. Many factors could

------

cause actual future events to differ materially from the forward-looking statements in this communication. There can be no assurance that the future developments affecting ESS will be those that we have anticipated. These forward-looking statements involve a number of risks, uncertainties (some of which are beyond ESS control) or other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements, which include, but are not limited to, delays, disruptions, or quality control problems in the Company's manufacturing operations; issues related to the development and launch of the Energy Base product; failure to successfully bid on projects and acquire customers; issues related to the Company's partnerships with third parties; risk of loss of government funding for customer projects; failure to raise additional capital, including under the ATM program, on acceptable terms or at all; and the Company's need to achieve significant business growth to achieve sustained, long-term profitability. Except as required by law, ESS is not undertaking any obligation to update or revise any forward-looking statements whether as a result of new information, future events or otherwise.

**Contacts** 

**Investors:** 

investors@essinc.com

**Source:** ESS Tech, Inc.

------

**ESS Tech, Inc.**

**Condensed Statements of Operations and Comprehensive Loss** 

**(unaudited)**

**(in thousands, except share and per share data)** 

---

| | | | | |
|:---|:---|:---|:---|:---|
| | **Three Months Ended September 30,** | **Three Months Ended September 30,** | **Nine Months Ended September 30,** | **Nine Months Ended September 30,** |
| | **2025** | **2024** | **2025** | **2024** |
| **Revenue:** |  |  |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Revenue | $189 | $355 | $816 | $2911 |
| &nbsp;&nbsp;&nbsp;&nbsp;Revenue - related parties | 25 | 4 | 2355 | 534 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Total revenue | 214 | 359 | 3171 | 3445 |
| **Cost of revenue** | 4939 | 12741 | 21144 | 35615 |
| **Gross profit (loss)** | (4725) | (12382) | (17973) | (32170) |
| **Operating expenses** |  |  |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Research and development | 1027 | 2684 | 4929 | 9066 |
| &nbsp;&nbsp;&nbsp;&nbsp;Sales and marketing | 360 | 2529 | 3614 | 7274 |
| &nbsp;&nbsp;&nbsp;&nbsp;General and administrative | 3699 | 6087 | 12998 | 17791 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Total operating expenses | 5086 | 11300 | 21541 | 34131 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Loss from operations | (9811) | (23682) | (39514) | (66301) |
| **Other (expense) income, net** |  |  |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Interest (expense) income, net | (456) | 807 | (210) | 3097 |
| &nbsp;&nbsp;&nbsp;&nbsp;Gain on revaluation of common stock warrant liabilities |  | 343 | 344 | 459 |
| &nbsp;&nbsp;&nbsp;&nbsp;Other (expense) income, net | (108) | 39 | (77) | 2 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Total other (expense) income, net | (564) | 1189 | 57 | 3558 |
| **Net loss and comprehensive loss to common stockholders** | $(10375) | $(22493) | $(39457) | $(62743) |
| **Net loss per share - basic and diluted** | $(0.73) | $(1.90) | $(3.08) | $(5.35) |
| **Weighted-average shares used in per share calculation - basic and diluted** | 14154333 | 11814580 | 12822333 | 11722378 |

---

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**ESS Tech, Inc.**

**Condensed Balance Sheets**

**(unaudited)** 

**(in thousands, except share data)** 

---

| | | |
|:---|:---|:---|
| | **September 30, 2025** | **December 31, 2024** |
| **Assets** | | |
| **Current assets:** | | |
| &nbsp;&nbsp;Cash and cash equivalents | $3539 | $13341 |
| &nbsp;&nbsp;Restricted cash, current | 806 | 906 |
| &nbsp;&nbsp;Accounts receivable, net | 108 | 215 |
| &nbsp;&nbsp;Short-term investments |  | 18263 |
| &nbsp;&nbsp;Inventory | 4653 | 5641 |
| &nbsp;&nbsp;Prepaid expenses and other current assets | 2451 | 4998 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**Total current assets** | 11557 | 43364 |
| &nbsp;&nbsp;Property and equipment, net | 18484 | 20582 |
| &nbsp;&nbsp;Intangible assets, net | 4456 | 4656 |
| &nbsp;&nbsp;Operating lease right-of-use assets | 391 | 1503 |
| &nbsp;&nbsp;Restricted cash, non-current | 618 | 948 |
| &nbsp;&nbsp;Other non-current assets | 639 | 760 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**Total assets** | $36145 | $71813 |
| **Liabilities and stockholders' (deficit) equity** |  |  |
| **Current liabilities:** |  |  |
| &nbsp;&nbsp;Accounts payable | $9467 | $8070 |
| &nbsp;&nbsp;Accrued and other current liabilities | 8143 | 9315 |
| &nbsp;&nbsp;Accrued product warranties | 2198 | 3288 |
| &nbsp;&nbsp;Operating lease liabilities, current | 439 | 1692 |
| &nbsp;&nbsp;Deferred revenue, current | 1330 | 5237 |
| &nbsp;&nbsp;Financing obligation, current | 2226 |  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**Total current liabilities** | 23803 | 27602 |
| &nbsp;&nbsp;Financing obligation, non-current | 8292 |  |
| &nbsp;&nbsp;Deferred revenue, non-current - related parties | 5297 | 14400 |
| &nbsp;&nbsp;Common stock warrant liabilities | 458 | 802 |
| &nbsp;&nbsp;Other non-current liabilities | 62 | 125 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**Total liabilities** | 37912 | 42929 |
| **Stockholders' equity:** |  |  |
| &nbsp;&nbsp;Preferred stock ($0.0001 par value; 200,000,000 shares authorized, none issued and outstanding as of September 30, 2025 and December 31, 2024) |  |  |
| &nbsp;&nbsp;Common stock ($0.0001 par value; 1,000,000,000 shares authorized, 15,390,884 and 11,986,516 shares issued and outstanding as of September 30, 2025 and December 31, 2024, respectively) | 2 | 1 |
| &nbsp;&nbsp;Additional paid-in capital | 820067 | 811262 |
| &nbsp;&nbsp;Accumulated deficit | (821836) | (782379) |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**Total stockholders' (deficit) equity** | (1767) | 28884 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**Total liabilities and stockholders' (deficit) equity** | $36145 | $71813 |

---

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**ESS Tech, Inc.**

**Condensed Statements of Cash Flows**

**(unaudited)**

**(in thousands)**

---

| | | |
|:---|:---|:---|
| | **Nine Months Ended September 30,** | **Nine Months Ended September 30,** |
| | **2025** | **2024** |
| **Cash flows from operating activities:** |  |  |
| &nbsp;&nbsp;**Net loss** | $(39457) | $(62743) |
| &nbsp;&nbsp;Adjustments to reconcile net loss to net cash used in operating activities: |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;Depreciation and amortization | 4571 | 3302 |
| &nbsp;&nbsp;&nbsp;&nbsp;Non-cash interest income | &nbsp;&nbsp;&nbsp;&nbsp;(402) | (2094) |
| &nbsp;&nbsp;&nbsp;&nbsp;Non-cash lease expense | &nbsp;&nbsp;&nbsp;&nbsp;1112 | 1000 |
| &nbsp;&nbsp;&nbsp;&nbsp;Stock-based compensation expense | 3945 | 8538 |
| &nbsp;&nbsp;&nbsp;&nbsp;Change in fair value of common stock warrant liabilities | (344) | (459) |
| &nbsp;&nbsp;&nbsp;&nbsp;Other non-cash expenses, net | 192 | 311 |
| &nbsp;&nbsp;&nbsp;&nbsp;Changes in operating assets and liabilities: |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Accounts receivable, net | 108 | 1352 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Inventory | 320 | (4722) |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Prepaid expenses and other assets | 2668 | (1709) |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Accounts payable | 353 | 5671 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Accrued and other liabilities | (4494) | (95) |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Accrued product warranties | (1090) | 1169 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Deferred revenue | (2659) | (122) |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Operating lease liabilities | (1253) | (1142) |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**Net cash used in operating activities** | (36430) | (51743) |
| **Cash flows from investing activities:** |  |  |
| &nbsp;&nbsp;Purchases of property and equipment | (1074) | (3823) |
| &nbsp;&nbsp;Maturities and purchases of short-term investments, net | 18411 | 47709 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**Net cash provided by investing activities** | 17337 | 43886 |
| **Cash flows from financing activities:** |  |  |
| &nbsp;&nbsp;Proceeds from issuance of common stock and common stock warrants, net of commission fees | 4789 |  |
| &nbsp;&nbsp;Proceeds from financing arrangements | 4000 |  |
| &nbsp;&nbsp;Proceeds from stock options exercised | 5 | 80 |
| &nbsp;&nbsp;Proceeds from contributions to Employee Stock Purchase Plan | 103 | 214 |
| &nbsp;&nbsp;Repurchase of shares from employees for income tax withholding purposes | (36) | (245) |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**Net cash provided by financing activities** | 8861 | 49 |
| **Net change in cash, cash equivalents and restricted cash** | (10232) | (7808) |
| **Cash, cash equivalents and restricted cash, beginning of period** | 15195 | 22483 |
| **Cash, cash equivalents and restricted cash, end of period** | $4963 | $14675 |

---

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**ESS Tech, Inc.**

**Condensed Statements of Cash Flows (continued)**

**(unaudited)** 

**(in thousands)**

---

| | | |
|:---|:---|:---|
| | **Nine Months Ended September 30,** | **Nine Months Ended September 30,** |
| | **2025** | **2024** |
| **Supplemental disclosures of cash flow information:** |  |  |
| &nbsp;&nbsp;Cash paid for operating leases included in cash used in operating activities | $1330 | $1306 |
| &nbsp;&nbsp;Non-cash investing and financing transactions: |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Purchase of property and equipment included in accounts payable and accrued and other current liabilities | 2303 | 2844 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Adjustment to right-of-use assets from lease modification |  | 686 |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Application of deferred revenue to financing arrangements | 6518 |  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Transfers between inventory and property and equipment, net | 668 | 1051 |
| Cash and cash equivalents | $3539 | $12822 |
| Restricted cash, current | 806 | 906 |
| Restricted cash, non-current | 618 | 947 |
| &nbsp;&nbsp;&nbsp;&nbsp;Total cash, cash equivalents and restricted cash shown in the condensed statements of cash flows | $4963 | $14675 |

---

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**ESS Tech, Inc.**

**Reconciliation of GAAP to Non-GAAP Operating Expenses**

**(unaudited)** 

**(in thousands)**

---

| | | | | |
|:---|:---|:---|:---|:---|
| | **Three Months Ended September 30,** | **Three Months Ended September 30,** | **Nine Months Ended September 30,** | **Nine Months Ended September 30,** |
| | **2025** | **2024** | **2025** | **2024** |
| Research and development | $1027 | $2684 | $4929 | $9066 |
| &nbsp;&nbsp;Less: stock-based compensation | (223) | (614) | (552) | (1923) |
| Non-GAAP research and development | $804 | $2070 | $4377 | $7143 |
| Sales and marketing | $360 | 2529 | $3614 | $7274 |
| &nbsp;&nbsp;Less: stock-based compensation | 113 | (209) | (389) | (467) |
| Non-GAAP sales and marketing | $473 | $2320 | $3225 | $6807 |
| General and administrative | $3699 | $6087 | $12998 | $17791 |
| &nbsp;&nbsp;Less: stock-based compensation | (482) | (1306) | (1405) | (4280) |
| Non-GAAP general and administrative | $3217 | $4781 | $11593 | $13511 |
| Total operating expenses | $5086 | $11300 | $21541 | $34131 |
| &nbsp;&nbsp;Less: stock-based compensation | (592) | (2129) | (2346) | (6670) |
| Non-GAAP total operating expenses | $4494 | $9171 | $19195 | $27461 |

---

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**ESS Tech, Inc.**

**Reconciliation of GAAP Net Loss to Adjusted EBITDA**

**(unaudited)** 

**(in thousands)**

---

| | | | | |
|:---|:---|:---|:---|:---|
| | **Three Months Ended September 30,** | **Three Months Ended September 30,** | **Nine Months Ended September 30,** | **Nine Months Ended September 30,** |
| | **2025** | **2024** | **2025** | **2024** |
| Net loss | $(10375) | $(22493) | $(39457) | $(62743) |
| &nbsp;&nbsp;&nbsp;Interest (expense) income, net | 456 | (807) | 210 | (3097) |
| &nbsp;&nbsp;&nbsp;Stock-based compensation | 1041 | 2658 | 3945 | 8538 |
| &nbsp;&nbsp;&nbsp;Depreciation and amortization | 1486 | 781 | 4571 | 3302 |
| &nbsp;&nbsp;&nbsp;Gain on revaluation of common stock warrant liabilities |  | (343) | (344) | (459) |
| &nbsp;&nbsp;&nbsp;Environmental, Health & Safety compliance estimate |  | 390 |  | 390 |
| &nbsp;&nbsp;&nbsp;Financing costs | 114 | 983 | 1100 | 983 |
| &nbsp;&nbsp;&nbsp;Other (expense) income, net | 108 | (39) | 77 | (2) |
| &nbsp;&nbsp;&nbsp;&nbsp;Adjusted EBITDA | $(7170) | $(18870) | $(29898) | $(53088) |

---

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