#6 Lakshmi Mittal, chairman and CEO, ArcelorMittal (Real-time net worth: $11.5 billion): Lakshmi Mittal serves as chairman and CEO of ArcelorMittal, the world's biggest steelmaker. Hailing from a steel clan, he separated from his siblings to start Mittal Steel, then went on to merge the company with France's Arcelor in 2006. Benefiting from the steel recovery, the company reported a surge in net profit to $4.6 billion in 2017 on revenue of $68.7 billion. ArcelorMittal, along with Italian steel firm Marcegaglia, acquired Italy's loss-making steel group Ilva for $2.1 billion in June 2017. (REUTERS/Benoit Tessier)