Ad hoc announcement pursuant to Art. 53 LR

Leclanché SA announces Temporary Exemption from the Disclosure Obligation in connection with the Publication and the Filing of the 2025 Annual Report

• The Issuers Committee has granted the Company’s request to temporary exempt the Company from the publication of the 2025 annual report and to file such report with SIX Exchange Regulation AG (SER) until 31^st July 2026.

• The trading of the registered shares of Leclanché SA remain suspended according to Art. 57 LR, until Leclanché SA publishes its 2025 annual report as stated in the decision of the Issuers Committee concerning the temporary exemption from the disclosure obligation in connection with the publication and the filing of the annual report 2025 dated 9^th June 2026.

YVERDON-LES-BAINS, Switzerland, 10^th of June, 2026 – Leclanché SA (SIX: LECN), one of the world's leading energy storage companies, announces that in its decision of 9^th June 2026, the Issuers Committee approved a temporary exemption from the publication of Leclanché SA's 2025 annual report and to file such report with SER until 31^st July 2026.

The temporary exemption from the publication duty of the 2025 annual report follows a previous extension granted on 29^th April 2026, which extended the original 30^th April 2026 deadline to publish the 2025 annual report to 31^st May 2026.

The Issuers Committee requested Leclanché SA to insert the below excerpt of its 9^th June 2026 decision in this ad hoc disclosure:

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

a. SIX Exchange Regulation AG did temporarily suspend trading of the registered shares of Leclanché S.A. on 01 June 2026 according to Art. 57 LR, until Leclanché S.A. 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.

b. Leclanché S.A. is required to publish a notice in accordance with the provisions on ad hoc publicity concerning this decision until Wednesday, 10 June 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.

For more information, write to info@leclanche.com or visit www.leclanche.com.

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.

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