Company: RadiumOne

Net worth: $300 Million (est.) 

At 25, Chahal collected $340 million from selling his two advertising companies: ClickAgents and BlueLithium. Now he’s moved forward with his third ad company, RadiumOne, focusing on real-time advertising in hopes of continuing his multi-million-dollar buyout streak. The company pulled together $21 million in financing in 2011 and is billed to be worth over $200 million at the moment. Who knows what he'll do in his 30s.