Former Mexican finance minister Pedro Aspe has an unusual collection on the walls of his offices here: stock and bond certificates from some of the Mexican oil companies that existed before the industry was nationalized in 1938, creating the monopoly Petróleos Mexicanos. The more than 170 such companies that existed at the time had names, such as Co. Lluvia de Oro, or Rain of Gold Co. “Many of these companies were subsidiaries of foreign capital, but there was a Mexican oil industry too. And that’s what we want to recreate,” said Mr. Aspe, a senior managing director of Evercore Partners Inc. and head of the U.S. investment-banking advisory firm’s Mexican unit. Now, as Mexico opens its oil industry to competition for the first time in nearly 80 years, Mr. Aspe is one of several Mexican businessmen who have financed or helped create homegrown oil companies . Mexico plans […]