In 1873 de Rothschild Frères in France and N M Rothschild & Sons of London joined with other investors to acquire the Spanish government's money-losing Rio Tinto copper mines. The new owners restructured the company and turned it into a profitable business. By 1905, the Rothschild interest in Rio Tinto amounted to more than 30 percent. In 1887, the French and English Rothschild banking houses lent money to, and invested in, the De Beers diamond mines in South Africa, becoming its largest shareholders.