New Delhi: Mukesh Ambani retained the top spot among Indians on Forbes' annual list of the world's billionaires with a net worth of USD 22.3 billion.

The head of Reliance Industries, India's most valuable company, was placed 19th on a list headed by Mexican tycoon Carlos Slim.

"Mukesh Ambani is the world's richest Indian, despite losing USD 4.7bn in the past year," Forbes said.

Lakshmi Mittal was listed as the biggest loser, with Forbes saying Mittal lost USD 10.4 billion, falling to a net worth of USD 20.7 billion and out of the world's top 10 for the first time since 2004. Mittal was placed 21st on the list. The drop came after shares in his company ArcelorMittal, the world's largest steelmaker, fell due to surging costs and soft demand in Europe.

Billionaire brothers Shashi and Ravi Ruia, who control Essar Group, suffered the second largest loss this year, losing USD 8.8 billion on the year and placed 133 on the list with a net worth of USD 7 billion.

Azim Premji, chairman of Wipro, was ranked 41 with a net worth of USD15.9 billion. Savitri Jindal, head of Jindal Steel and Power Ltd, was India's richest woman, 80th on the list with a net worth of USD 10.9 billion.

Sunil Mittal (113), Kumar Birla (116), Anil Ambani (118) and Dilip Shanghvi (124) were among the 48 Indians on the Forbes list.

Carlos Slim retained his position atop the list with an estimated worth of USD 69 billion, while his Mexican rival Ricardo Salinas Pliego enjoyed the largest increase in wealth.

Fifty-eight countries were represented on the list of a record 1,226 billionaires whose average fortune was USD 3.7 billion.