Ad hoc announcement pursuant to Art. 53 LR

YVERDON-LES-BAINS, Switzerland, 13^th of August, 2026 – Leclanché SA (SIX: LECN) (“Leclanché” or the “Company“) one of the world’s leading energy storage companies, announces that in its decision of 12^th August 2026, the Issuers Committee approved a temporary exemption from the publication of the 2025 annual report and to file such report with SIX Exchange Regulation AG until 31 August 2026 at the latest.

The temporary exemption from the publication duty of the 2025 annual report follows a previous extension granted on 29^th April 2026 to publish the 2025 annual report until 31^st May 2026 and an extension granted on 9^th June 2026 to publish the 2025 annual report until 31 July 2026.

The Company had to file for a further extension of the deadline to publish the 2025 annual report as the Company is currently not able to demonstrate that it is a going concern, at least until June 2027. The Company is currently actively pursuing its efforts and is confident of meeting the requirements for being treated and viewed as a going concern business.

In its decision dated 12^th August 2026, the Issuers Committee requested Leclanché to publish the following extract:

• The temporary exemption from the publication of the 2025 annual report and to file such report with SIX Exchange Regulation AG until 31 August 2026 at the latest is granted with the following reservation (lit. a) and under the following conditions (lit. b):

• SIX Exchange Regulation AG has temporarily suspended trading of the registered shares of Leclanché SA on 01 June 2026 according to Art. 57 LR, until Leclanché SA publishes its 2025 annual report in accordance with the provisions on ad hoc publicity (Art. 53 LR in connection with the DAH) and files it with SIX Exchange Regulation AG.

• Leclanché SA is required to publish a notice in accordance with the provisions on ad hoc publicity concerning this decision until Thursday, 13 August 2026, 7.30 am CET, at the latest. The notice must contain:

• the unaltered reproduction of the wording of para. I. of this decision, placed in a prominent position;

• the reasons for the application of the Issuer requesting an extension of the deadline to publish its 2025 annual report and to file such report with SIX Exchange Regulation AG.

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About Leclanché

Leclanché is a world leading provider of low-carbon footprint energy storage solutions based on lithium-ion cell technology. Established in 1909 in Yverdon-les-Bains, Switzerland, Leclanché’s history and heritage is rooted in battery and energy storage innovation. The company’s Swiss culture for precision and quality, together with its production facilities in Germany, make Leclanché the partner of choice for companies seeking the very best in battery performance and who are pioneering positive changes in how energy is produced, distributed and consumed around the world. Leclanché is organised into three business units: energy storage solutions, e-Mobility solutions and specialty battery systems. The company currently employs over 350 people with representative offices in eight countries around the world. Leclanché is listed on the Swiss Stock Exchange (SIX: LECN).

SIX Swiss Exchange : ticker symbol LECN | ISIN CH 011 030 311 9

Disclaimer

This press release contains certain forward-looking statements relating to Leclanché’s business, which can be identified by terminology such as “strategic”, “proposes”, “to introduce”, “will”, “planned”, “expected”, “commitment”, “expects”, “set”, “preparing”, “plans”, “estimates”, “aims”, “would”, “potential”, “awaiting”, “estimated”, “proposal”, or similar expressions, or by expressed or implied discussions regarding the ramp up of Leclanché’s production capacity, potential applications for existing products, or regarding potential future revenues from any such products, or potential future sales or earnings of Leclanché or any of its business units. You should not place undue reliance on these statements. Such forward-looking statements reflect the current views of Leclanché regarding future events, and involve known and unknown risks, uncertainties and other factors that may cause actual results to be materially different from any future results, performance or achievements expressed or implied by such statements. There can be no guarantee that Leclanché’s products will achieve any particular revenue levels. Nor can there be any guarantee that Leclanché, or any of the business units, will achieve any particular financial results.

Media contacts:

Switzerland / Europe: 

Thierry Meyer

T: +41 (0) 79 785 35 81

E-Mail: tme@dynamicsgroup.ch

Germany:

Christoph Miller

T: +49 (0) 711 947 670

E-Mail: leclanche@sympra.de

Investor contacts:

Pierre Blanc

T: +41 (0) 24 424 65 00

E-Mail: invest.leclanche@leclanche.com