Number two US carrier Verizon Wireless plans to buy fifth-ranked Alltel in a deal valued at $28.1 billion dollars. The possibility of an Alltel buyout was first reported Tuesday by Reuters, citing individuals familiar with the negotiations. Neither company would comment ahead of the official announcement on Wednesday. Alltel was previously acquired in 2007 by a partnership of private equity firms TPG Capital and GS Capital Partners for $27.5 billion. If it receives regulatory approval, the deal would phase out the last of the major sub-national carriers, as well as returning Verizon Wireless to the number one spot as ranked by subscribers, combining that company's 67 million users with Alltel's 13 million.