In its bid to convince U.S. regulators that a combined AT&T, T-Mobile would be good for the wireless industry and not stifle competition, AT&T is aware that it will have to divest some assets. That's why the company has hired Bank of America Merrill Lynch.
According to The Wall Street Journal:
The U.S. telecommunications giant hired Bank of America Merrill Lynch to line up buyers of customers and wireless spectrum. The assets sales could be worth $8 billion or more, people [familiar with the matter] said, based on internal analyses of the customer markets that might have to be shed to gain regulatory approval.
Officially, AT&T said there would be "some divestitures," but called speculation as to an amount "premature." Observers say the divestitures are more likely to come from T-Mobile's holdings than AT&T's. The process won't start until regulators are closer to approving the merger, which could happen by the end of the first quarter of 2012.