15) Thai Lee (Net worth: $1.1 billion)

Age: 56 years; Source: IT; State: New Jersey

Thai Lee is the co-founder and CEO of SHI International. The company has $6 billion sales. With her former husband she bought an IT company for less than $1 million in 1989; today the company has $6 billion in sales from customers such as AT&T, Johnson & Johnson and Boeing.