# EDGAR Filing Document

**Accession Number:** 0001819438
**File Stem:** 0001819438-26-000015
**Filing Date:** 2026-3
**Character Count:** 21535
**Document Hash:** 1f0e6611ae1f34817ebbd8c4be141118
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001819438-26-000015.hdr.sgml**: 20260305

**ACCESSION NUMBER**: 0001819438-26-000015

**CONFORMED SUBMISSION TYPE**: S-8

**PUBLIC DOCUMENT COUNT**: 15

**FILED AS OF DATE**: 20260305

**DATE AS OF CHANGE**: 20260305

**EFFECTIVENESS DATE**: 20260305

**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:** S-8
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 333-294052
- **FILM NUMBER:** 26726399

**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

**As filed with the Securities and Exchange Commission on March 5, 2026**

**Registration No. 333-** 

**UNITED STATES** 

**SECURITIES AND EXCHANGE COMMISSION** 

**Washington, D.C. 20549** 

**FORM S-8** 

**REGISTRATION STATEMENT** 

***UNDER***

***THE SECURITIES ACT OF 1933***

**ESS TECH, INC.** 

**(Exact name of registrant as specified in its charter)** 

---

| | |
|:---|:---|
| **Delaware** | **98-1550150** |
| **(State or other jurisdiction of**<br>**incorporation or organization)** | **(I.R.S. Employer**<br>**Identification No.)** |

---

**26440 SW Parkway Ave., Bldg. 83** 

**Wilsonville, OR 97070** 

**(Address of Principal Executive Offices, including zip code)** 

**ESS Tech, Inc. 2021 Equity Incentive Plan**

**ESS Tech, Inc. 2021 Employee Stock Purchase Plan**

**(Full title of the plan)** 

**Drew Buckley**

**Chief Executive Officer** 

**26440 SW Parkway Ave., Bldg. 83** 

**Wilsonville, OR 97070** 

**(855) 423-9920** 

**(Name, address and telephone number, including area code, of agent for service)** 

*Copies to:* 

---

| | |
|:---|:---|
| **Mark B. Baudler**<br>**Lianna Whittleton**<br>**Rachel Nagashima**<br>**Wilson Sonsini Goodrich & Rosati, P.C.**<br>**650 Page Mill Road**<br>**Palo Alto, California 94304**<br>**(650) 493-9300** | **Kate Suhadolnik** <br>**Chief Financial Officer**<br>**26440 SW Parkway Ave., Bldg. 83**<br>**Wilsonville, Oregon 97070**<br>**(855) 423-9920** |

---

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of "large accelerated filer," "accelerated filer," "smaller reporting company," and "emerging growth company" in Rule 12b-2 of the Exchange Act.

---

| | | | |
|:---|:---|:---|:---|
| Large accelerated filer | ☐ | Accelerated filer | ☐ |
| Non-accelerated filer | ☒ | Smaller reporting company | ☒ |
| | | 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 7(a)(2)(B) of the Securities Act. ☐

------

**EXPLANATORY STATEMENT**

ESS Tech, Inc. (the "Registrant") is filing this Registration Statement with the Securities and Exchange Commission (the "SEC") to register additional securities of the same class as other securities for which a registration statement on Form S-8 relating to the same employee benefit plan is effective. The number of the Registrant's common stock, par value $0.0001 per share ("Common Stock"), available for grant and issuance under the 2021 Equity Incentive Plan (the "2021 Plan") is subject to an annual increase on the first day of each fiscal year beginning with fiscal year 2022, in an amount equal to the least of (i) 1,017,333 shares, (ii) five percent (5%) of the outstanding shares of Common Stock on the last day of the immediately preceding fiscal year or (iii) such number of shares of Common Stock determined by the 2021 Plan administrator. On January 1, 2026, the number of shares of the Registrant's common stock available for grant and issuance under the 2021 Plan increased by 1,017,333 shares. The number of shares of Common Stock, available for grant and issuance under the 2021 Employee Stock Purchase Plan (the "2021 ESPP") is subject to an annual increase on the first day of each fiscal year beginning with fiscal year 2022, in an amount equal to the least of (i) 204,000 shares, (ii) one percent (1%) of the outstanding shares of Common Stock on the last day of the immediately preceding fiscal year or (iii) such number of shares of Common Stock determined by the 2021 ESPP administrator. On January 1, 2026, the number of shares of Common Stock available for grant and issuance under the 2021 ESPP increased by 204,000 shares. This Registration Statement registers such additional shares of Common Stock under the 2021 Plan and the 2021 ESPP.

In accordance with General Instruction E of Form S-8, this Registration Statement hereby incorporates by reference the contents of (i) the registration statement on Form S-8 filed with the SEC on <u>[December 15, 2021](https://www.sec.gov/Archives/edgar/data/1819438/000119312521357104/d420614ds8.htm)</u> (File No. 333-261649), (ii) the registration statement on Form S-8 filed with the SEC on <u>[March 4, 2022](https://www.sec.gov/Archives/edgar/data/1819438/000162828022005036/ess-2022evergreenformsx8.htm)</u> (File No. 333-263281), (iii) the registration statement on Form S-8 filed with the SEC on <u>[March 2, 2023](https://www.sec.gov/Archives/edgar/data/1819438/000162828023005951/ess-2023evergreenformsx8.htm)</u> (File No. 333-270211), (iv) the registration statement on Form S-8 filed with the SEC on <u>[February 9, 2024](https://www.sec.gov/Archives/edgar/data/0001819438/000162828024004113/esstechinc-sx82024evergreen.htm)</u> (File No. 333-276988) and (v) the registration statement on Form S-8 filed with the SEC on <u>[March 31, 2025](https://www.sec.gov/Archives/edgar/data/0001819438/000162828025015654/esstechinc-sx82025evergreen.htm)</u> (File No. 333-286259), to the extent supplemented, amended or superseded by the information set forth herein. In accordance with the instructional note to Part I of Form S-8 promulgated by the SEC, the information specified by Part I of Form S-8 has been omitted from this Registration Statement.

**PART II** 

**INFORMATION REQUIRED IN THE REGISTRATION STATEMENT** 

**Item 3. Incorporation of Documents by Reference.** 

The Registrant hereby incorporates by reference into this Registration Statement the following documents previously filed with the SEC:

(1) Our Annual Report on Form 10-K (File No. 001-39525) for the fiscal year ended December 31, 2025 filed with the SEC on <u>[March](https://www.sec.gov/ix?doc=/Archives/edgar/data/1819438/000181943826000012/ghw-20251231.htm)[5](https://www.sec.gov/ix?doc=/Archives/edgar/data/1819438/000181943826000012/ghw-20251231.htm)[, 2026](https://www.sec.gov/ix?doc=/Archives/edgar/data/1819438/000181943826000012/ghw-20251231.htm)</u> (the "Annual Report");

(2) Our Current Reports on Form 8-K (File No. 001-39525) filed with the SEC on <u>[January 6, 2026](https://www.sec.gov/ix?doc=/Archives/edgar/data/0001819438/000181943826000003/wk-20260101.htm)</u>, <u>[January 29, 2026](https://www.sec.gov/ix?doc=/Archives/edgar/data/0001819438/000162828026003973/gwh-20260123.htm)</u> and <u>[January 30, 2026](https://www.sec.gov/ix?doc=/Archives/edgar/data/0001819438/000162828026004263/gwh-20260129.htm)</u> (other than information furnished rather than filed);

(3) The description of our Common Stock contained in our Registration Statement on Form 8-A filed with the SEC on <u>[October 8, 2021](https://www.sec.gov/Archives/edgar/data/1819438/000119312521295421/d157489d8a12b.htm)</u> pursuant to Section 12(b) of the Exchange Act, as updated by <u>[Exhibit 4.2](https://www.sec.gov/Archives/edgar/data/1819438/000181943826000012/exhibit42-descriptionofsec.htm)</u> to the Annual Report, including any amendments or reports filed for the purpose of updating such description.

All documents filed by the Registrant with the SEC pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act on or after the date of this Registration Statement and prior to the filing of a post-effective amendment to this Registration Statement that indicates that all securities offered have been sold or that deregisters all securities then remaining unsold shall be deemed to be incorporated by reference in this Registration Statement and to be part hereof from the date of filing of such documents; *provided*, *however*, that documents or information deemed to have been furnished and not filed in accordance with the rules of the SEC (including, without limitation, information furnished under Item 2.02 or Item 7.01 of Current Reports on Form 8-K and the exhibits related to such items furnished under Item 9.01) shall not be deemed incorporated by reference into this Registration Statement.

Any statement contained in this Registration Statement, or in a document incorporated or deemed to be incorporated by reference herein, shall be deemed to be modified or superseded for purposes of this Registration

------

Statement to the extent that a statement contained herein or in any subsequently filed document which also is incorporated or deemed to be incorporated by reference herein modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this Registration Statement.

**Item 8. Exhibits.** 

The Registrant has filed the exhibits listed on the accompanying Exhibit Index of this Registration Statement.

**EXHIBIT INDEX** 

---

| | | | | | |
|:---|:---|:---|:---|:---|:---|
| | | **Incorporated By Reference** | **Incorporated By Reference** | **Incorporated By Reference** | **Incorporated By Reference** |
| **Exhibit** | **Description** | **Form** | **File No.** | **Exhibit No.** | **Filing Date** |
| 4.1 | <u>[Certificate of Incorporation of ESS Tech, Inc.](https://www.sec.gov/Archives/edgar/data/1819438/000119312521300138/d231955dex31.htm)</u> | 8-K | 001-39525 | 3.1 | October 15, 2021 |
| 4.2 | <u>[Certificate of Amendment to the Certificate of Incorporation](https://www.sec.gov/Archives/edgar/data/1819438/000162828023019289/certificateofamendmentoffi.htm) of ESS Tech, Inc.</u> | 8-K | 001-39525 | 3.1 | May 22, 2023 |
| 4.3 | <u>[Certificate of Amendment to the Certificate of Incorporation of ESS Tech, Inc.](https://www.sec.gov/Archives/edgar/data/1819438/000162828024038349/a2024reversestocksplit-cha.htm)</u> | 10-Q | 001-39525 | 3.1 | August 23, 2024 |
| 4.4 | <u>[Amended and Restated Bylaws of ESS Tech, Inc.](https://www.sec.gov/Archives/edgar/data/0001819438/000162828022028231/amendedandrestatedbylawsof.htm)</u> | 10-Q | 001-39525 | 3.2 | November 3, 2022 |
| 5.1\* | <u>[Opinion of Wilson Sonsini Goodrich & Rosati, P.C. with respect to the legality of the securities being registered](exhibit51s-8legalopinion.htm)</u> |  |  |  |  |
| 23.1\* | <u>[Consent of KPMG LLP, Independent Registered Public Accounting Firm](exhibit231kpmgconsent-2026.htm)</u> |  |  |  |  |
| 23.2\* | Consent of Wilson Sonsini Goodrich & Rosati, P.C. (included in Exhibit 5.1 hereto) |  |  |  |  |
| 24.1\* | Power of Attorney (contained on signature page hereto) |  |  |  |  |
| 99.1† | <u>[2021 Equity Incentive Plan and form of award agreements thereunder](https://www.sec.gov/Archives/edgar/data/1819438/000162828023005933/a109ess-2021equityincentiv.htm)</u> | 10-K | 001-39525 | 10.9 | March 2, 2023 |
| 99.2† | <u>[2021 Employee Stock Purchase Plan](https://www.sec.gov/Archives/edgar/data/0001819438/000162828023005933/a1010ess-2021employeestock.htm)</u> | 10-K | 001-39525 | 10.10 | March 2, 2023 |
| 107\* | <u>[Calculation of Filing Fee Table](exfilingfees.htm)</u> |  |  |  |  |

---

\* Filed herewith. <br> † Indicates management contract or compensatory plan or arrangement.

------

**SIGNATURES** 

Pursuant to the requirements of the Securities Act of 1933, as amended, the registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Wilsonville, State of Oregon, on March 5, 2026.

---

| | |
|:---|:---|
| **ESS TECH, INC.** | **ESS TECH, INC.** |
| By: | */s/ Drew Buckley* |
|  | Drew Buckley |
|  | Chief Executive Officer |

---

**POWER OF ATTORNEY** 

KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below constitutes and appoints Drew Buckley and Kate Suhadolnik, and each one of them, as his or her true and lawful attorneys-in-fact and agents, with full power of substitution and resubstitution, for them and in their name, place and stead, in any and all capacities, to sign any and all amendments (including post-effective amendments) to this registration statement on Form S-8, and to file the same, with all exhibits thereto and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in connection therewith, as fully to all intents and purposes as they might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents or any of them, or their substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act of 1933, this registration statement has been signed by the following persons in the capacities and on the dates indicated.

---

| | | |
|:---|:---|:---|
| **Signature** | **Title** | **Date** |
| */s/ Drew Buckley* | *Chief Executive Officer and Director* | March 5, 2026 |
| **Drew Buckley** | (Principal Executive Officer) |  |
| */s/ Kate Suhadolnik* | *Chief Financial Officer* | March 5, 2026 |
| **Kate Suhadolnik** | (Principal Financial and Accounting Officer) |  |
| */s/ Harry Quarls* | *Chairman of the Board and Director* | March 5, 2026 |
| **Harry Quarls** |  |  |
| */s/ Michael Niggli* | *Founding Chairman and Director* | March 5, 2026 |
| **Michael Niggli** |  |  |
| */s/ Raffi Garabedian* | *Director* | March 5, 2026 |
| **Raffi Garabedian** |  |  |
|  | *Director* |  |
| **Rich Hossfeld** |  |  |
| */s/ Sandeep Nijhawan* | *Director* | March 5, 2026 |
| **Sandeep Nijhawan** |  |  |
| */s/ Kyle Teamey* | *Director* | March 5, 2026 |
| **Kyle Teamey** |  |  |
| */s/ Alexi Wellman* | *Director* | March 5, 2026 |
| **Alexi Wellman** |  |  |

---

## Ex-Filing

?xml version='1.0' encoding='ASCII'? exfilingfees

**Exhibit 107**

**Calculation of Filing Fee Tables**

**Form S-8**

(Form Type)

**ESS Tech, Inc.** 

(Exact name of registrant as specified in its charter)

---

| | | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|:---|
| **Table 1 - Newly Registered Securities** | **Table 1 - Newly Registered Securities** | **Table 1 - Newly Registered Securities** | **Table 1 - Newly Registered Securities** | **Table 1 - Newly Registered Securities** | **Table 1 - Newly Registered Securities** | **Table 1 - Newly Registered Securities** | **Table 1 - Newly Registered Securities** |
| **Security Type** | **Security Class Title** | **Fee Calculation Rule** | **Amount Registered (1)** | **Proposed Maximum Offering Price Per Unit** | **Maximum Aggregate Offering Price** | **Fee Rate** | **Amount of Registration Fee** |
| Equity | Common Stock, $0.0001 par value per share, reserved for issuance pursuant to the ESS Tech, Inc. 2021 Equity Incentive Plan (the "2021 Plan") | Other | 1017333  | $1.59 (2) | $1617559.47 | $0.00013810 | $223.38 |
| Equity | Common Stock, $0.0001 par value per share, reserved for issuance pursuant to the ESS Tech, Inc. 2021 Employee Stock Purchase Plan (the "2021 ESPP") | Other | 204000 | $1.36 (3) | $277440.00 | $0.00013810 | $38.32 |
| **Total Offering Amounts** | **Total Offering Amounts** | **Total Offering Amounts** | **Total Offering Amounts** |  | $1894999.47 |  | $261.70 |
| **Total Fee Offsets** | **Total Fee Offsets** | **Total Fee Offsets** | **Total Fee Offsets** |  |  |  | - |
| **Net Fee Due** | **Net Fee Due** | **Net Fee Due** | **Net Fee Due** |  |  |  | $261.70 |

---

(1)&nbsp;&nbsp;&nbsp;&nbsp;Represents shares of common stock, par value $0.0001 per share (the "**Common Stock**") ESS Tech, Inc. (the "**Registrant**") available for issuance pursuant to awards granted pursuant to each of the Registrant's 2021 Plan and 2021 ESPP. Pursuant to Rule 416(a) of the Securities Act of 1933, as amended (the "**Securities Act**"), this registration statement on Form S-8 (the "**Registration Statement**") shall also cover any additional shares of the Registrant's Common Stock that become issuable with respect to the securities identified in the above table under each of the 2021 Plan and 2021 ESPP by reason of any stock dividend, stock split, recapitalization or other similar transaction effected without the Registrant's receipt of consideration which results in an increase in the number of outstanding shares of Common Stock.

------

(2)&nbsp;&nbsp;&nbsp;&nbsp;Estimated in accordance with Rule 457(c) and Rule 457(h) of the Securities Act solely for the purpose of calculating the registration fee on the basis of $1.59 per share, which is the average of the high and low prices of Common Stock, as reported on the New York Stock Exchange, on February 27, 2026, which date is within five business days prior to the filing of this Registration Statement

(3)&nbsp;&nbsp;&nbsp;&nbsp;Estimated in accordance with Rule 457(c) and Rule 457(h) of the Securities Act solely for the purpose of calculating the registration fee on the basis of 85% of $1.59 per share, which is the average of the high and low prices of Common Stock, as reported on the New York Stock Exchange, on February 27, 2026, which date is within five business days prior to the filing of this Registration Statement.

## Exhibit 5.1

**Exhibit 5.1**

---

| | |
|:---|:---|
| ![image_1.jpg](image_1.jpg) | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Wilson Sonsini Goodrich & Rosati<br>Professional Corporation<br>650 Page Mill Road<br>Palo Alto, California 94304-1050<br>o: 650.493.9300<br>f: 650.493.6811 |

---

March 5, 2026

ESS Tech, Inc.

26440 SW Parkway Ave., Bldg. 83

Wilsonville, OR 97070

**Re:&nbsp;&nbsp;&nbsp;&nbsp;Registration Statement on Form S-8**

Ladies and Gentlemen:

At your request, we have examined the Registration Statement on Form S-8 (the "**Registration Statement**") to be filed by ESS Tech, Inc., a Delaware corporation (the "**Company**"), with the Securities and Exchange Commission (the "**Commission**"), on or about the date hereof, relating to the registration under the Securities Act of 1933, as amended (the "**Act**"), of an aggregate of 1,221,333 shares of your common stock, par value $0.0001 per share (the "**Shares**"), consisting of: (i) 1,017,333 shares of common stock to be issued under the ESS Tech, Inc. 2021 Equity Incentive Plan (the "**2021 Plan**") and (ii) 204,000 shares of common stock to be issued under the ESS Tech, Inc. 2021 Employee Stock Purchase Plan (the "**2021 ESPP**," and together with the 2021 Plan, the "**Plans**"). As your legal counsel, we have reviewed the actions proposed to be taken by you in connection with the issuance and sale of the Shares to be issued under the Plans.

On the basis of the foregoing, and in reliance thereon, we are of the opinion that the Shares, when issued and sold in the manner described in the Plans and pursuant to the agreements that accompany the Plans, will be legally and validly issued, fully paid and nonassessable.

We hereby consent to the filing of this opinion as an exhibit to the above-referenced Registration Statement and to the use of our name wherever it appears in the Registration Statement and in any amendments thereto. In giving such consent, we do not thereby admit that we are in the category of persons whose consent is required under Section 7 of the Act or the rules and regulations of the Commission thereunder.

Very truly yours, <br>

/s/ Wilson Sonsini Goodrich & Rosati, P.C.

WILSON SONSINI GOODRICH & ROSATI

Professional Corporation

AUSTIN BOSTON BOULDER BRUSSELS HONG KONG LONDON LOS ANGELES NEW YORK PALO ALTO<br>SALT LAKE CITY SAN DIEGO SAN FRANCISCO SEATTLE SHANGHAI WASHINGTON, DC WILMINGTON, DE

## Exhibit 23.1

**Exhibit 23.1**

**Consent of Independent Registered Public Accounting Firm**

We consent to the use of our report dated March 5, 2026, with respect to the financial statements of ESS Tech, Inc., incorporated herein by reference.

/s/ KPMG LLP

Portland, Oregon

March 5, 2026

<br>