John Caudwell

John Caudwell founded mobile phone retailer Phones 4u before selling his stake in 2006 and 2011.

Born into a working-class family, he and brother Brian first started selling mobile phones in 1987.

Six years later the brothers founded Singlepoint, a mobile service provider that was acquired by Vodafone in 2003 for $650 million.

Caudwell pumped his share of the money into Phones 4u, which grew into the U.K.'s largest independent mobile phone retailer.

Three years later he sold a majority stake to Providence Equity Partners for $2.8 billion and, in 2011, unloaded the remaining 25% for $272 million.