With 5.7 million U-verse TV customers and 20.3 million DirecTV customers in the U.S., the combined AT&T-DirecTV would serve 26 million. That would make it the second-largest pay TV operator behind a combined Comcast-Time Warner Cable, which would serve 30 million under a $45 billion merger proposed in February.
AT&T and DirecTV expect the deal to close within 12 months. Under the terms agreed to Sunday, DirecTV shareholders will receive $28.50 per share in cash and $66.50 per share in AT&T stock. The total transaction value is $67.1 billion, including DirecTV's net debt.
The deal could face tough scrutiny from the Federal Communications Commission and antitrust regulators at the Department of Justice.
Unlike Comcast Corp. and Time Warner Cable which don't compete in the same territory AT&T's U-verse, offered in 22 states, competes directly for TV customers with DirecTV, which is available nationwide.
The combination would reduce consumers' options for pay TV providers from four to three for about 25 percent of U.S. households, according to Morgan Stanley analyst Ben Swinburne. Fewer competitors could result in higher prices, a situation that usually gives regulators cause for concern.
The deal is also subject to regulatory approval in Latin America, where DirecTV has more than 18 million customers. To facilitate approval there, AT&T said it will divest its interest in wireless provider America Movil.
Analysts question the strategic benefits of a deal that would give AT&T a larger presence in the mature market for pay TV.
Last year, pay TV subscribers in the U.S. fell for the first time, dipping 0.1 percent to 94.6 million, according to Leichtman Research Group.
While AT&T and DirecTV are doing better than cable companies at attracting TV subscribers, DirecTV's growth in the U.S. has stalled while AT&T is growing the fastest of any TV provider.
Long term, the deal may offer little help to AT&T as viewers continue to watch more video online.
DirecTV offers neither fixed-line nor mobile Internet service, and its rights to airwave frequencies for satellite TV are not the kind that AT&T can use to improve its mobile phone network.
Still, Stephenson has talked exuberantly about how the growth of online video helps boost demand for its Internet and mobile services. Last month, AT&T entered a joint venture with the Chernin Group to invest in online video services.
DirecTV would continue to be based in El Segundo, California, following the merger, the companies said.