Yet another US MVNO stumbles and falls, as US virtual network operator Virgin Mobile USA acquires rival Helio, the joint venture between SK Telecom and EarthLink.

Virgin said it is to acquire Helio from parents SK Telecom and EarthLink for a total of $39m, giving it around 170,000 extra subscribers. However, the Korean operator wants to stay involved in the market, and both Virgin and SK Telecom will each invest $25m of equity capital in the company.

But more importantly, the deal will also give Virgin a much needed postpaid billing and customer care platform. Presently, all of Virgin’s customers come from the typically cash strapped youth prepay demographic, so an acquisition of this sort would give Virgin something to build a postpay customer base from.

Although Richard Branson’s outfit is recognised as the most successful MVNO brand in the world, Virgin’s US operation has also been taking a hammering of late due to the economic downturn.

Helio, like many of its peers, has also felt the heat. The virtual mobile operator joint venture between Earthlink and SK Telecom was launched in 2006, targeting the affluent youth and MySpace addicts. But the company has struggled to get the rich kids to part with their cash and Earthlink has scaled back its investment in the firm and piled the pressure on SKT.

Cool phones were supposed to be Helio’s unique selling point, and it may be that the move can give Virgin a little more sophistication, as the company will also receive Helio’s handset inventory of approximately 85,000 units with a book value of approximately $17m.

Dan Schulman, chief executive officer of Virgin Mobile USA, said, “We believe that the acquisition of Helio and the related strategic investments by SK Telecom and Virgin Group are of enormous benefit to our business, both financially and strategically.

“At the same time, we will acquire an asset, which will add to our scale, allowing us to reduce our network costs and assure that Helio’s customers are immediately profitable when brought on to our cost structure. We expect the combined elements of this deal will drive increased Adjusted EBITDA and free cash flow.”

Both MVNOs piggyback on the Sprint network.