Mexican businessman Carlos Slim Helú is believed to be the richest man in the world. As chairman of Teléfonos de Mexico, better known as Telmex (NYSE: TMX) and América Móvil (NYSE: AMX), Slim has substantial influence over the telecommunications industry in Mexico, and much of Latin America as well.

The past year has been good to Slim. In the spring, with an estimated net worth of $53.1 billion, he overtook investing guru Warren Buffett as the world's second richest person. By the end of the summer, Fortune reported that Slim's net worth had grown to $59 billion, allowing him to overtake Microsoft founder Bill Gates as the world's wealthiest person.

Carlos Slim's personal wealth grew by $12 billion during the year, and he also controls a $150 billion business empire. His family's holdings represented more than 5% of Mexico's 2006 gross domestic product, and Slim-controlled companies made up one-third of the $422 billion Mexican stock exchange.

With his political connections and business savvy, Slim has managed to fend off accusations of monopolistic business practices for years, but the hammer may finally be about to fall. A probe of Carlos Slim's empire by Mexican antitrust regulators is scheduled to ramp up in the new year. Will 2008 see his empire crumble?