4. Gianluigi & Rafaela Aponte: $6.5 Billion
The ambitious nature of billionaires radiates in this power couple who own MSC, the second largest container shipping company with over 400 vessels. Gianluigi took an interest in the world of shipping when he worked as a ferry ship captain in the 1960s. In 1970, together with his wife Rafaela, Gianluigi decided to launch his own cargo shipping company, which was then called Mediterranean Shipping. Four decades later, they have stamped their names as the wealthiest shipping couple.