Virgin Mobile USA has decided to buy Helio, the company which was started in May 2006 as a joint venture between EarthLink and SK Telecom of South Korea.

The company has been struggling in introducing the advanced features of South Korean phones to the U.S. market. The number of subscribers has come down to 170,000 from nearly 200,000 earlier this year.

The Virgin Mobile payout will be $39 million in stock for Helio, which is considered as a poor payout for Helio Founders.

On the other hand, Virgin Group and SK Telecom will invest $25 million each in Virgin Mobile. SK Telecom owns majority of Helio and this venture would give them a 17 percent stake in Virgin Mobile.

Meanwhile, Virgin will keep on operating Helio's advanced data services and contract based service plans, but the Helio brand will be phased out soon.