OBRASCÓN HUARTE LAIN, S.A. (the “Company”), pursuant to article 226 of the consolidated text of the Spanish Securities Market Act approved by Royal Legislative Decree 4/2015, of 23 October, hereby notifies the Spanish National Securities Market Commission (Comisión Nacional del Mercado de Valores) the following

INSIDE INFORMATION

Following the communication of inside information (comunicación de información privilegiada) published by the Company on 23 December 2024 (with official registry number 2,536), the Company hereby announces that on 21 March 2025, the Paris Court of Appeal issued a judgment dismissing the request to block the performance guarantees and advance payment guarantees provided by the Joint Venture formed by the Company and Rizzani de Eccher in favour of Kuwait under the Jamal Abdul Nasser Street contract and lifting the interim measures.

The performance guarantees (for which the Company is liable for approximately EUR 35.3 million) and the advance payment guarantees (for which the Company is liable for approximately EUR 3.9 million) were executed by Kuwait on 31 July 2024 and have been blocked by the French courts to date.

In Madrid, 21 March 2025.