1. Alexandra Andresen & Katharina Andresen
AGE: 23 &25
NET WORTH: $1.1 billion (each)
These Norwegian sisters each inherited 42% of the investment company Ferd. Alexandra was only 19 years old when she inherited the company shares and became a billionaire. Ferd is a family-owned business, still run by their father, Johan H. Andresen. To this day, Johan holds 70% of the voting rights thanks to a dual-class structure.