Two North American mobile phone companies are trying to buy a controlling interest in Telecom Italia. Italy's largest telephone company, but there are complications. US company AT & T and's Mexico America Móvil have made a combined offer of 4.5 billion for a third of Olimpia. a holding company that owns 18% of Telecom Italia. Italian tire company Pirelli has been trying to sell their 80% stake in Olimpi. because it has lost half its value since they acquired it in 2001. Italian politicians are opposed to foreign control of the phone company. After AT & T and America Móvil made their bid, Telecom Italia chairman Guido Rossi resigned his position. despite his reputation as a turnaround specialist.