ACON S2 Acquisition Corp. will transfer common shares and warrants to the NYSE

September 28, 2021 – ACON S2 Acquisition Corp. (NASDAQ: STWO) (“STWO” or the “Company”) announced today that, in completing its Pending Business Combination with ESS Tech, Inc. (“ESS” or “ESS Inc.” ) (the “Business Combination”), it intends to list its common shares and warrants on the New York Stock Exchange (the “NYSE”) under the ticker symbols “GWH” and “GWH. W ”, respectively. The decision to be listed on the NYSE has been taken into consideration for the Business Combination and allows the post-businessCombined company, ESS Tech, Inc., will be listed alongside comparable companies that are also listed on the New York Stock Exchange. Trading is currently expected to begin on the NYSE on or around October 11, 2021 after the completion of the business combination, which is currently scheduled to take place on October 8, 2021, subject to final shareholder approval at the extraordinary general meeting. of STWO on October 5, 2021, and the satisfaction of other customary closing conditions. Until the business combination is completed, the common shares, warrants and Class A units of STWO will continue to trade under the ticker symbols “STWO”, “STWOW” and “STWOU”, respectively, on the Nasdaq Capital Market (“Nasdaq”). Listing on the NYSE and delisting from the Nasdaq is subject to the closing of the business combination and compliance with all NYSE listing requirements. STWO expects the last day of trading on the Nasdaq to be on or around October 8, 2021.

As previously announced, the Company will hold the Extraordinary General Meeting at 10:30 a.m. Central time on October 5, 2021, at the offices of Kirkland & Ellis LLP located at 609

Main Street, Houston, TX 77002, and via live webcast to https://www.cstproxy.com/acon/sm2021. The proxy statement / prospectus regarding the business combination, as well as a proxy card for voting, have been mailed to the shareholders of the company. Shareholders are encouraged to attend the extraordinary general meeting and vote as soon as possible by signing, dating and returning the proxy card attached to the proxy statement / prospectus. If you have any questions, please contact Okapi Partners, our proxy lawyer, by calling (877) 285-5990, or banks and brokers can call collect at (212) 297-0720, or by sending an email [email protected].

About ACON S2 Acquisition Corp.

STWO is a blank check company whose business object is to effect a merger, capital stock exchange, asset acquisition, share purchase, reorganization or similar business combination with one or more companies. STWO focuses on companies that use a strategic approach to sustainability; that is, a company whose pursuit of sustainability – environmental, social and / or economic – is at the heart of its performance and success. The sponsor of STWO is a subsidiary of ACON Investments, LLC

About ACON Investments, LLC

ACON Investments, LLC, headquartered in Washington, DC, is a global private equity firm investing in North America, Latin America and Europe. Founded in 1996, ACON Investments, LLC has managed approximately $ 6 billion in capital to date and has professionals in Washington, DC, Los Angeles, Mexico City, São Paulo, Bogotá and Madrid. For more information visit www.aconinvestments.com.

About ESS inc.

ESS Inc. designs, manufactures and deploys environmentally sustainable and low cost iron flux batteries for long life commercial and utility energy storage applications requiring 4 to 12 hours of flexible energy capacity. The Energy Warehouse â„¢ and Energy Center â„¢ use iron, salt and water abundant in the earth for the electrolyte, resulting in a sustainable and environmentally safe energy storage solution for the environment. global renewable energy infrastructure. Founded in 2011, ESS Inc. enables project developers, utilities, and commercial and industrial facility owners to transition to more flexible lithium-ion-free storage that is better suited to the grid and the environment. For more information, visit www.essinc.com.

Forward-looking statements

This press release may include “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. All statements other than statements of historical fact included in this press release are forward-looking statements. When used in this press release, words such as “anticipate”, “believe”, “estimate”, “expect”, “intend” and similar expressions, in relation to us or our management team, identify forward-looking statements. These forward-looking statements are based on the beliefs of management, as well as on the assumptions made by the management of the Company and on the information currently available to the latter. Actual results could differ materially from those contemplated by forward-looking statements due to certain factors detailed in documents filed by the Company with the SEC. All subsequent written or oral forward-looking statements attributable to us or to persons acting on our behalf are qualified in their entirety by this paragraph. Forward-looking statements are subject to numerous conditions, many of which are beyond the control of the Company, including those set out in the Risk Factors section of the Company’s registration statement and prospectus relating to the initial public offering of the Company. Company filed with the SEC. The Company assumes no obligation to update these statements for revisions or changes after the date of this posting, except as required by law.

Important information about the proposed business combination and where to find it

STWO has filed, and the SEC has declared effective, a registration statement on Form S-4 containing a management proxy circular / final prospectus from STWO relating to the proposed business combination. STWO has sent the Management Proxy Circular / Final Prospectus and other relevant documents to its shareholders. Investors, STWO shareholders and other interested persons are invited to read the proxy statement / final prospectus in connection with the solicitation of proxies by STWO for the general meeting to be held to approve the business combination, as these documents will contain important information on ESS and STWO and on the Business Combination Project. The proxy circular / final prospectus was sent to STWO shareholders on the registration date of August 16, 2021; shareholders who hold their shares in registered form have the right to vote for their shares held on the date of the meeting. Shareholders may also obtain free copies of the Proxy Circular / Final Prospectus and other documents filed with the SEC on the SEC website at http://www.sec.gov, or by directing a request to: 1133 Connecticut Avenue NW, Ste. 700 Washington, DC 20036.

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Participants in the call for tenders

STWO and its directors and officers may be considered participants in the solicitation of proxies from STWO shareholders with respect to the business combination. A list of the names of such directors and officers and a description of their interests in STWO are included in the Management Proxy Circular / Final Prospectus for the proposed business combination and are available at www.sec.gov.

ESS and its directors and executive officers may also be considered participants in the solicitation of proxies from STWO shareholders in connection with the proposed business combination. A list of the names of such directors and officers and information regarding their interests in the proposed business combination is included in the management proxy circular / final prospectus for the proposed business combination.

Contacts

For ESS Inc .:

Investors:

Erik Bylin [email protected]

Media: Gene Hunt

Trevi Communications, Inc. 978.750.0333 x.101 [email protected]

For ACON S2 Acquisition Corp. :

Emily Claffey / Julie Rudnick / Kevin Siegel

Sard Verbinnen & Co

[email protected]

Okapi Partners:

Bruce Goldfarb / Chuck Garske / Christian Jacques

1. 297-0720[email protected]

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Disclaimer

Acquisition company ACON S2 published this content on September 28, 2021 and is solely responsible for the information it contains. Distributed by Public, unedited and unmodified, on September 28, 2021 06:51:08 PM UTC.