Helio

Company name: Helio
Where it's based: N/A
When it was founded: 2005
What year it was a Fierce 15: 2006
Website: N/A

Why it was a Fierce 15: Backed with millions of dollars of investment by Korea's SK Telecom and EarthLink, Helio sought to break into the nascent but at the time burgeoning MVNO space by targeting younger subscribers with flashy handsets and services. Click here for more.

What has happened since it was awarded the Fierce 15: Virgin Mobile USA purchased flagging Helio for just $38 million in 2008 to add a branded postpaid service to its portfolio. Sprint Nextel recently announced plans to acquire Virgin.