ESS Tech updates $75M at-the-market stock program
ESS Tech, Inc. is updating the terms of its at-the-market equity program for up to $75,000,000 of common stock under an Amended Sales Agreement.
Rhea-AI Filing Summary
ESS Tech, Inc. is updating the terms of its at-the-market equity program for up to $75,000,000 of common stock under an Amended Sales Agreement. The company removed BMO Capital Markets, Canaccord Genuity, Needham & Company, and Stifel from the group of sales agents and added Roth Capital Partners as a new Agent.
Roth has also replaced Canaccord as the qualified independent underwriter under FINRA Rule 5121, and ESS Tech has agreed to indemnify Roth against certain liabilities, including under the Securities Act of 1933. From December 11, 2025 through this supplement date, ESS Tech sold 4,324,577 shares of common stock for an aggregate offering price of approximately $6,238,450, leaving common stock with an aggregate offering price of approximately $68,761,550 available to be offered under the Amended Sales Agreement.
The company’s common stock trades on the NYSE under the symbol GWH, and the last quoted sale price on July 15, 2026 was $1.02 per share.
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Filing Explained
The July 16 supplement changes the ATM program’s sales-agent and qualified-independent-underwriter arrangements, but it does not itself report a new share sale. The amended program leaves approximately
Key Figures
ATM program size: $75,000,000
Shares sold to date: 4,324,577 shares
Aggregate offering price sold: $6,238,450
+4 more
7 metrics
ATM program size
$75,000,000
Maximum aggregate gross sales price of common stock under the Sales Agreement
Shares sold to date
4,324,577 shares
Common stock sold from December 11, 2025 through the date of this supplement
Aggregate offering price sold
$6,238,450
Total gross proceeds from shares sold under the Original Sales Agreement
Remaining ATM capacity
$68,761,550
Aggregate offering price of common stock still available under the Amended Sales Agreement
Recent share price
$1.02 per share
Last quoted sale price on NYSE on July 15, 2026
Prospectus date
December 11, 2025
Date of the original ATM Prospectus Supplement and Base Prospectus
Amendment date
July 16, 2026
Date of the amendment creating the Amended Sales Agreement
Key Terms
at-the-market offering, qualified independent underwriter, Rule 5121 of the Financial Industry Regulatory Authority, Sales Agreement, +1 more
5 terms
at-the-market offering financial
"which relate to the offer and sale of shares of our common stock pursuant to the Amended Sales Agreement"
An at-the-market offering is a method companies use to sell new shares of stock directly into the open market over time, rather than all at once. This allows them to raise money gradually, similar to selling small pieces of a product instead of a large batch. For investors, it means the company can access funding more flexibly, but it may also increase the supply of shares and influence the stock’s price.
qualified independent underwriter regulatory
"Roth has assumed the responsibilities of acting as a “qualified independent underwriter” within the meaning of Rule 5121"
A qualified independent underwriter is a financial firm that is both eligible under regulatory rules and free of close ties to the issuing company, so it can buy, price and sell a new batch of securities without conflicts of interest. Investors treat its involvement like a neutral referee: its role helps set a fair market price, adds credibility to the deal and reduces the risk that shares are being pushed on biased or poorly vetted terms.
Rule 5121 of the Financial Industry Regulatory Authority regulatory
"acting as a “qualified independent underwriter” within the meaning of Rule 5121 of the Financial Industry Regulatory Authority"
Sales Agreement financial
"we entered into a Sales Agreement (the “Original Sales Agreement”) with Yorkville Ives & Co., LLC"
A sales agreement is a written contract that sets out the terms for selling goods, services, or assets, specifying price, delivery, payment schedule and responsibilities of each side. For investors it matters because it creates a predictable stream of revenue or cash obligations, clarifies timing and risk, and can change a company’s value or forecasts much like a signed order turns a customer’s verbal intent into a firm commitment.
Prospectus Supplement regulatory
"This supplement amends, supplements or modifies certain information contained in the prospectus supplement"
A prospectus supplement is an additional document provided alongside a company's main offering details, offering updated or extra information about a specific financial product being sold. It helps investors understand the latest terms, risks, and details of the investment, similar to how an update or revision clarifies or expands on original instructions, ensuring they have current and complete information before making a decision.
Offering Details
ATM
Offering
Offering Type
ATM
FAQ
AI-generated questions and answers. How Rhea-AI works. Not financial advice.
What change to the ATM program does ESS Tech (GWH) disclose in this supplement?
ESS Tech updates its at-the-market program for up to $75,000,000 of common stock, removing several prior agents and adding Roth Capital Partners as an Agent under an Amended Sales Agreement.
How much stock has ESS Tech (GWH) already sold under its ATM agreement?
ESS Tech has sold 4,324,577 shares of common stock for an aggregate offering price of approximately $6,238,450 since December 11, 2025 under the Original Sales Agreement governing the ATM program.
What capacity remains under ESS Tech’s (GWH) ATM facility after this supplement?
After selling about $6,238,450 of stock, ESS Tech has common stock with an aggregate offering price of approximately $68,761,550 still available to be offered under the Amended Sales Agreement.
Which firms are agents under ESS Tech’s (GWH) amended ATM Sales Agreement?
Under the Amended Sales Agreement, ESS Tech has Yorkville Ives & Co., LLC and Roth Capital Partners, LLC as Agents, while BMO, Canaccord, Needham, and Stifel have been removed.
Who is ESS Tech’s (GWH) qualified independent underwriter and what is their role?
Roth Capital Partners serves as the qualified independent underwriter under FINRA Rule 5121, and ESS Tech has agreed to indemnify Roth against certain liabilities, including those under the Securities Act of 1933.
What was the recent trading price of ESS Tech (GWH) common stock?
On July 15, 2026, the last quoted sale price of ESS Tech’s common stock on the NYSE was $1.02 per share, providing a reference point for the ongoing at-the-market offering.
AI-generated analysis. How Rhea-AI works. Not financial advice.
Filed pursuant to Rule 424(b)(5)
Registration No. 333-291506
PROSPECTUS SUPPLEMENT NO. 1
(To Prospectus dated December 11, 2025)
Up to $75,000,000
Common Stock
This supplement amends, supplements or modifies certain information contained in the prospectus supplement, dated December 11, 2025 (the “ATM Prospectus Supplement”), and the accompanying prospectus, dated December 11, 2025 (the “Base Prospectus,” and together with the ATM Prospectus Supplement, any supplement thereto, and the documents deemed incorporated by reference in each, the “Prospectus”), which relate to the offer and sale of shares of our common stock, par value $0.0001 per share (the “common stock”), pursuant to the Amended Sales Agreement (as defined below). Capitalized terms used and not defined herein shall have the meanings ascribed to such terms in the ATM Prospectus Supplement.
You should carefully read the entire Prospectus and this supplement before investing in our common stock. This supplement should be read in conjunction with the Prospectus, and is qualified by reference thereto, except to the extent that the information herein amends or supersedes the information contained in the Prospectus. This supplement is not complete without, and may only be delivered or utilized in connection with, the Prospectus and any future amendments or supplements thereto.
On November 13, 2025, we entered into a Sales Agreement (the “Original Sales Agreement”) with Yorkville Ives & Co., LLC (formerly Yorkville Securities, LLC) (“Yorkville Ives”), BMO Capital Markets Corp. (“BMO”), Canaccord Genuity LLC (“Canaccord”), Needham & Company, LLC (“Needham”) and Stifel, Nicolaus & Company, Incorporated (“Stifel”) (each of Yorkville Ives, BMO, Canaccord, Needham and Stifel individually an “Agent” and collectively, the “Agents”), pursuant to which we may offer and sell shares of our common stock under the Prospectus having an aggregate gross sales price of up to $75,000,000, from time to time through or to the Agents, as sales agents or principals.
This supplement is being filed to reflect that, on July 16, 2026, (i) we terminated the Original Sales Agreement with respect to BMO, Canaccord, Needham and Stifel; (ii) we added Roth Capital Partners, LLC (“Roth”) as an additional Agent under the Amended Sales Agreement (as defined below) and (iii) Roth has assumed the responsibilities of acting as a “qualified independent underwriter” within the meaning of Rule 5121 of the Financial Industry Regulatory Authority in connection with this offering, replacing Canaccord as “qualified independent underwriter” (collectively, the “Amendments”). We have agreed to indemnify Roth for acting as a qualified independent underwriter against certain liabilities, including liabilities under the Securities Act of 1933, as amended, and to contribute to payments that may be required to be made for these liabilities. In connection with the Amendments, we entered into an amendment, dated July 16, 2026, to the Original Sales Agreement (as amended, the “Amended Sales Agreement”). Accordingly, (i) each reference to the term “Agent” in the ATM Prospectus Supplement is hereby amended to include Roth and remove each of BMO, Canaccord, Needham and Stifel, (ii) each reference to the “qualified independent underwriter,” in the ATM Prospectus Supplement is hereby amended to replace Canaccord with Roth as the “qualified independent underwriter” and (iii) each reference to the term “Sales Agreement” is hereby amended to refer to the Amended Sales Agreement.
From December 11, 2025, the date of the ATM Prospectus Supplement, through the date of this supplement, we sold an aggregate of 4,324,577 shares of common stock pursuant to the Original Sales Agreement, for an aggregate offering price of approximately $6,238,450, leaving common stock having an aggregate offering price of approximately $68,761,550 available to be offered under the Amended Sales Agreement pursuant to this supplement and the Prospectus.
Our common stock is listed on the New York Stock Exchange (the “NYSE”) under the symbol “GWH.” On July 15, 2026, the last quoted sale price for our common stock as reported on the NYSE was $1.02 per share.
Investing in our securities involves a high degree of risk. See “Risk Factors” beginning on page S-3 of the ATM Prospectus Supplement as well as the documents incorporated by reference in this prospectus supplement, for a discussion of the factors you should carefully consider before deciding to purchase our securities. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement or the accompanying prospectus is truthful or complete. Any representation to the contrary is a criminal offense.
| Yorkville Ives | Roth Capital Partners | ||||
The date of this prospectus supplement is July 16, 2026.