A logo of Spain's telecommunications giant Telefonica is seen on a building in Madrid December 3, 2012. Spain's Telefonica SA is working on plans to list 10-15 percent of its Latin American unit, its chief executive said in an interview with the Financial Times published on... Spanish telecommunications company Telefonica SA has expressed interest in buying AT&T Inc's pay TV assets in Latin America, which could be valued at around $10 billion, according to people familiar with the matter.