AT&T Inc. is an American multinational telecommunication holding company. In addition to telephone, data and video telecommunications, AT&T also provides mobile communications and internet services for companies, private customers and government organizations. It is the world's largest telecommunications company by revenue, one of the largest providers of mobile telephone services, and the largest provider of fixed telephone services in the U.S. through AT&T Communications. The company began its history as the American District Telegraph Company, formed in St Louis in 1878. After a series of mergers and establishing a network of local telephone subsidiaries in the U.S., the company was rebranded as AT&T Corp. in 1994. Today, AT&T is ranked 13th on the Fortune 500 rankings of the largest U.S. corporations, with revenues of $168.8B (2021). There are currently over 5,500 AT&T locations in the U.S. Their current market cap is $131.2B. AT&T, Inc. (NYSE: T) has an investment grade S&P credit rating of BBB, a long term Moody’s rating of Baa2 and the company is headquartered in Dallas, TX.