La SIA S.p.A.

Major Shareholding Notification • Jun 4, 2025

PRESS RELEASE

SUBSTANTIAL CHANGE IN THE OWNERSHIP STRUCTURE, PURSUANT TO ART. 17 OF THE EURONEXT GROWTH MILAN ISSUERS' REGULATION

Rome, June 4, 2025 - La SIA S.p.A. ('La SIA' or the 'Company'), a company operating in the engineering & design sector, whose shares are traded on Euronext Growth Milan, hereby announces, pursuant to the Transparency Regulations and art. 17 of the Euronext Growth Milan Issuers Regulation, that on June 4 it received a communication from the shareholders CSE Holding S.r.l., Aspasia S.r.l. and GLSR S.r.l. pursuant to art. 15 of the Articles of Association, regarding the reduction of their shareholding below the relevance thresholds as a result of the sale - which took place on 30 May 2025 - of all of their respective shareholdings held in the share capital of La SIA.

The Company also announces that on June 4 it received a communication from Mare Engineering Group S.p.A., pursuant to art. 15 of the Articles of Association, regarding the exceeding, on 30 May 2025, of the relevant threshold of 66.6% of the share capital representing shares that confer the right to vote, holding n. 4.000.000 ordinary shares of the Company, equal to 70.6% of the relevant share capital.

Following these changes, pursuant to art. 26 of the Euronext Growth Milan Issuers' Regulation and based on the information in its possession, the updated composition of the shareholder structure is reported below.

Shareholder	N. Ordinary Shares	% Share Capital
Mare Engineering Group S.p.A.	4.000.000	70,6%
NextStage AM	567.000	10,00%
Market	1.099.500	19,40%
Total	5.666.500	100,00%

The composition of the shareholder base is also available on the Company's website https://lasia.it/investorrelations/, section "Investor Relations/Info for Shareholders".

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This press release is available on the Company's website https://investors.lasia.it/, section "Investor Relations/Press Releases".

For the transmission of regulated information La SIA S.p.A. uses the dissemination system (SDIR) "" available at managed by Computershare S.p.A. with registered office in Via Lorenzo Mascheroni 19, Milan.

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Contacts

Alessandra Speranza illimity Bank S.p.A.

Investor Relator Euronext Growth Advisor

www.lasia.it

PRESS RELEASE

Viale Luigi Schiavonetti 286, 00173 Rome (RM)	Via Soperga 9, 20124 Milan
+39 0645441972	+39 0282849699
investorrelator@lasia.it	lasia@illimity.com

• 39 0230561270 +39 02438114200

Specialist Investor & Media Relations

MiT Sim S.p.A. Twister Communications Group S.r.l. Corso Venezia 16, 20121 Milan Via Valparaiso, 3 - 20144 Milan investor.relations@mitsim.it Lucia Saluzzi lasia@twistergroup.it

The Company

La SIA S.p.A. is an innovative SME active in the engineering and design sector, specialising in the design of infrastructures in the fields of telecommunications, civil construction, mobility infrastructures and energy plants, using state-of-the-art technologies and specific know-how. La SIA is among the top 100 engineering companies in Italy, and among the first movers in the introduction of the BIM (Building Information Modeling) methodology, also used for safety, predictive maintenance and the protection of the country's artistic and historical heritage. The Company, established in 2004, operates through three business lines: the 'Civil & Design' line, specialising in the architectural, structural and plant design of complex buildings such as hospitals, data centres and stadiums, guaranteeing high quality and sustainability; the 'Utility & Infrastructure' line, focused on the management and design of infrastructures related to energy, road and rail networks, with particular attention to digital technologies and energy efficiency, and the design of medium voltage and photovoltaic systems; and finally the 'Telecommunications' line, entirely dedicated to the design and construction of fibre optic and mobile radio networks.