In one of the largest-ever private equity takeovers, US mobile phone network Alltel, which has the largest geographic reach in the US, has agreed to be bought by TPG Capital and Goldman Sachs for $27.5 billion.

Based in Little Rock, Arkansas, Alltel''s mobile phone network covers a total 35 states in the US.

The value of the deal translates to $71.50 per Alltel share, a premium of 10 per cent over Alltel''s Friday closing price of $65.21. Alltel''s board of directors has unanimously approved the deal, which is due to be completed by the end of this year, or start of 2008.

Scott Ford, Alltel''s chief executive officer, who will retain his title after the company changes hands, said the transaction "delivers substantial and certain value to our shareholders."

The deal was announced within days of Chrysler, contact lens manufacturer Bausch & Lomb and credit card processor Alliance Data agreeing to be bought by private equity firms.