Many of the names on our list have had their fortunes handed down by their families. Not Ayman Asfari. The boss of oil services giant Petrofac, Asfari sits at the helm of one of the fastest growing FTSE 100 businesses. By any measure, Asfari is a success story. He took his first role in construction in Oman in his early 20s in a bid to fund an MBA at Wharton. It turned out to be unnecessary; less than a decade later, he was a millionaire with his own firm.