Depends on the rules and laws. The system tends to be very good at punishing rich people that swindle money from other rich people.
Steve Jobs, Bill Gates, Sergey Brin, Mark Zuckerburg are better examples of oligarchs because they managed to create their own wealth and with that obtained political clout.
Haha, there's that fiction. See how deeply it pervades all thinking about power and success in the US?
… Eventually? I'm surely not the only one who thinks of Madoff first, and he got away with it for almost a decade after suspicions were first reported.