Mexican billionaire Carlos Slum will invest 500 million euros ($624 million) in Spanish construction firm FCC and receive a controlling stake in the company.
Fomento de Construcciones y Contratas SA says in a statement Slim's stake will be 25.6 percent.
The company's largest stakeholder, Spaniard Esther Koplowitz, will have her stake reduced from more than 50 percent to 22.4 percent.
Slim is making the investment through his Control Empresarial de Capitales SA in a deal that will see FCC's capital increased by 1 billion euros to reduce debt.
He is also expected to invest 150 million euros to pay Koplowitz for rights to subscribe to the offer and buy new shares.
FCC stock rose nearly 4 percent to 15.89 euros per share in Madrid after the deal was announced Thursday.