Mexico's anti-trust commission has hit billionaire Carlos Slim's cellphone subsidiary with a 12 billion peso ($1 billion) fine, parent company America Movil announced.
The Federal Competition Commission said the cellphone subsidiary, Telcel, engaged in monopolistic practices associated with call terminations, America Movil said in a filing with the Mexican stock exchange late Friday.
The company said it is studying the fine and all options for appeal.
America Movil is the largest provider of wireless service in Latin America with 225 million subscribers. Its 2009 revenue totaled $30 billion.
Named the richest man in the world by Fortune Magazine, Slim is estimated to be worth $74 billion. His companies have come under various allegations of monopolistic practices in the past.