AT&T vs Ernst & Young

AT&T Inc. is an American multinational telecommunications corporation, headquartered at Whitacre Tower in downtown Dallas, Texas. AT&T Inc. began its existence as Southwestern Bell Corporation, one of seven Regional Bell Operating Companies created in 1983 in the divestiture of the American Telephone and Telegraph Company following the 1982 United States v. AT&T antitrust lawsuit. Southwestern Bell changed its name to SBC Communications Inc. in 1995. In 2005, SBC purchased former parent AT&T Corp. and took on its branding, with the merged entity naming itself AT&T Inc. and using the iconic AT&T Corp. logo and stock-trading symbol.

Ernst & Young Global Limited is a multinational professional services firm headquartered in London, United Kingdom. It is one of the "Big Four" audit firms and is the third largest professional services firm in the world by aggregated revenue in 2014, after Deloitte and PwC. The organization operates as a network of member firms which are separate legal entities in individual countries. It has 190,000 employees in over 700 offices around 150 countries in the world. It provides assurance, tax, consulting and advisory services to companies.