[3] The company's roots stretch back to May 1911 with the foundation of Sociedad General de Obras y Construcciones Obrascón, S.A. in Bilbao, whose first project was the construction of two wharfs in the Port of Lisbon.

[7] In May 2014, Miguel Fraile testified to Quebec's Charbonneau Commission that a Quebec-based competitor firm, SNC-Lavalin (SNC), wanted the business of the McGill University Health Centre (MUHC) to itself.

“He said that if we won the contract, he would make our lives impossible.”[8] The senior management of SNC, including Ben Aissa, has since been charged or dismissed under suspicion, and the premises have been raided by the Royal Canadian Mounted Police.

[8] In 2019, it is being investigated for the alleged payment of irregular commissions by managers of the construction company to municipalities and autonomous communities in exchange for public works awards.

[10] In July 2022, the company was fined €21.5 million, along with five other contractors, by the Comisión Nacional de los Mercados y la Competencia (CNMC) for bidding collusion in public tenders for building and civil infrastructure works.