The US mobile virtual network operator (MVNO) Amp’d Mobile has filed for Chapter 11 bankruptcy protection. Amp’d is attempting to restructure its business after failing to keep up with rapid network and subscriber growth. The company says its reorganisation plan involves additional financing from an unnamed existing investor. Amp’d Mobile owes a total of almost USD100 million, with USD33 million due to Verizon Wireless, USD16 million to Motorola and USD10 million to Vivendi. It has signed up around 200,000 subscribers since its launch in 2005.