He leapt above Warren Buffett and France's Bernard Arnault with an estimated net worth of $57 billion (£37.7bn).
Mexico's Carlos Slim, who has taken a hit from the slump in the share price of his Movil telecoms group since the list was compiled, remains on top with a fortune of $73bn.
Microsoft co-founder Bill Gates held on to the number two spot with a net worth of $67bn.
Ortega's fortune rose by $19.5 billion, the biggest gain for any of the billionaires.
He jumped two places and knocked Buffett out of the top four for the first time since 2000.