He went on to study civil engineering at the National Autonomous University of Mexico, where he also concurrently taught algebra and linear programming. After graduating from college, Slim began his career as a trader in Mexico to hone his business skills. He would then go on to form his own brokerage firm that later expanded to invest in individual businesses, ranging from construction and manufacturing to retail and restaurants. In 1965, he incorporated Inversora Bursátil and bought Jarritos del Sur. In 1966, already worth US$40 million, he founded Inmobiliaria Carso. Three months later, he married Soumaya Domit Gemayel (the Carso name derives from the first three letters of Carlos and the first two of Soumaya), and they remained married until her death in 1999.