In the overall rich list of world's billionaires, as per an annual ranking published today by business magazine Forbes, Mukesh Ambani is ranked 22nd, while the second-richest Indian Lakshmi Mittal is at 41st position with a networth of USD 16.5 billion.
Slim has topped the rankings with a networth of USD 73 billion, followed by Bill Gates (USD 67 billion), Spain's Amancio Ortega (USD 57 billion), Warren Buffett (USD 53.5 billion) and Larry Ellison (USD 43 billion) in top five.
There are a total 55 billionaires from India on the list of 1,426 persons from across the world having a minimum networth of USD 1 billion.
Among the Indians, Mukesh Ambani and Lakshmi Mittal are followed by Azim Premji, Dilip Shanghvi, Shashi & Ravi Ruia, Kumar Mangalam Birla, Savitri Jindal, Sunil Mittal, Shiv Nadar, K P Singh and Anil Ambani.
Globally, Anil Ambani is ranked 233rd (USD 5.2 billion), while the global top-100 list has only three Indians Mukesh Ambani, Lakshmi Mittal and Azim Premji (91st position).
About Mukesh Ambani, Forbes said that his fortune has dropped by USD one billion over the past one year, but he "remains India's richest person and his Reliance Industries remains country's most valuable company".
On the other hand, his younger brother Anil Ambani saw his networth drop by USD 2.6 billion in the past one year, "continuing a three-year decline in his fortune."
Globally, Forbes said, the world's billionaire club has reached a record high level, with 1,426 persons and an aggregate net worth of USD 5.4 trillion (up from USD 4.6 trillion a year ago).
The US leads the list 442 billionaires, followed by Asia-Pacific (386), Europe (366), the Americas (129) and the Middle East & Africa (103).
Carlos Slim and Bill Gates have retained their top two positions, while Amancio Ortega of Spanish retailer Zara has moved up to the third position for the first time with the biggest gain of USD 19.5 billion to his fortune in year.
As a result, Buffett has slipped to the fourth rank, despite an increase of USD 9.5 billion in his networth. Forbes said this is the first year since 2000 that Buffett has not been among the top three.
Forbes said that it has included the fortunes of family members wherever one one person is the founder and in control of the business.
The figures are based on stock prices and exchange rates as on February 14, 2013, it added.
Those from India also include Uday Kotak, Micky Jagtiani, Cyrus Poonawalla, Adi Godrej, Jamshyd Godrej, Anil Agarwal, Kalanithi Maran, Gautam Adani, Malvinder and Shivinder Singh, Subhash Chandra and Desh Bandhu Gupta.
Other Indians include B L Munjal, Rahul Bajaj, Rajan Raheja, Habil Khorakiwala, N R Narayana Murthy, K Anji Reddy, MA Yusuff Ali, Vikas Oberoi, S Gopalakrishnan, Murali Divi, Nandan Nilekani, Ranjan Pai, Venugopal Dhoot, Rakesh Jhunjhunwala, Yusuf Hamied, Baba Kalyani, G M Rao and Joy Alukkas.