People became the fastest billionaires in the shortest amount of time

Gary Winnick – 2.5 years

In 1997, financier Gary Winnick founded Global Crossing, the company that laid the first privately-funded transatlantic fiber optic cable network, with a $15 million (£11.7m) investment. Money well spent, the investment paid off in a big way when Global Crossing went public in 1998, rewarding Winnick with a windfall of $4.5 billion (£3.5bn).