Rank change: Down
The baby-faced CFO of the world's largest steelmaker -- founded by dad Lakshmi -- helped cut the company's debt 30% after orchestrating the company's mega-takeover of Arcelor. Now Mittal is focused on driving growth in hot markets like Brazil, India, and China. This year he helped retool his company's strategy in India, where the steel market is expected to triple by 2020.
Side deals: Mittal is on the board of PPR; earlier this year his wife bought bankrupt luxury-fashion brand Escada. Says Mittal: "I told her to pursue it like no tomorrow."
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Last updated October 14 2010: 1:25 PM ET