Reliance Industries chairman Mukesh Ambani retained the top spot among the 55 Indians on Forbes’ annual list of billionaires on Monday with an estimated worth of $21.5 billion (about Rs. 1.18 lakh crore). Forbes’ 2013 list of the world's richest people includes 1,426 billionaires. Ambani was placed 22nd on a list headed by Mexican tycoon Carlos Slim.

“Mukesh Ambani’s fortune dropped $1 billion ( Rs. 5,490 crore) though he remains India’s richest person and his Reliance Industries remains (the) country’s most valuable company,” Forbes said.

Slim came first for the fourth straight year with a fortune estimated at $73 billion (about Rs. 4 lakh crore). Microsoft chairman Bill Gates was placed second with a fortune of $67 billion (about Rs. 3.6 lakh crore).

Indian-origin steel baron Lakshmi Mittal was 41st and Wipro chairman Azim Premji made it to the 91st position. Chairman of the Anil Dhirubhai Ambani Group Anil Ambani was ranked 11th on the India list and 233rd in world rankings.