AT&T Inc., formerly known as the American Telephone and Telegraph Company and commonly abbreviated as "AT&T," operates as an American multinational telecommunications holding company. The corporation is headquartered at Whitacre Tower in Downtown Dallas, Texas. AT&T holds the position of the world's fourth-largest telecommunications company in terms of revenue and is recognized as the largest wireless carrier in the United States. In 2023, AT&T secured the 13th position in the Fortune 500 rankings, which assesses the largest corporations in the United States, reporting revenues amounting to $120.7 billion.