T - AT&T Inc.

The wireless business contributes nearly 70% of AT&T's revenue. The company is the third-largest US wireless carrier, connecting 73 million postpaid and 17 million prepaid phone customers. Fixed-line enterprise services, which account for about 14% of revenue, include internet access, private networking, security, voice, and wholesale network capacity. Residential fixed-line services, about 12% of revenue, primarily consist of broadband internet access, serving 14 million customers. AT&T also has a sizable presence in Mexico, with 24 million customers, but this business only accounts for 3% of revenue. The company recently sold its 70% equity stake in satellite television provider DirecTV to its partner, private equity firm TPG.