According to the China-based Hurun India Rich List, Ambani retained the top position for the second year even after a wealth decrease of 2 per cent.
Ambani is followed by London-based steel baron L N Mittal with assets of $15.9 billion. Mittal's wealth declined by 6 per cent from last year.
Sun Pharmaceuticals' founder Dilip Shanghvi broke into the top three for the first time with a 66 per cent surge in his wealth.
"This rise in stock price was supported by the expected sales of the cancer drug Doxil, following Janssen Pharma Inc's admission of shortage of the drug supply," the report said.
Ambani retained the top position for the 2ndyear even after a wealth decrease
Among others in the top 10 are: Wipro's Azim Premji (4th) with assets of $12 billion, HCL Technology's Shiv Nadar (5th, $8.6 billion), Grasim Industries' Kumar Mangalam Birla (6th, $8.4 billion), Godrej Group's Adi Godrej (7th, $8.1 billion).
The other three who make the list of top 10 billionaires are Pallonji Mistry of Shapoorji Pallonji & Co ($8 billion) ranked 8th, Shashi & Ravi Ruia (Essar Energy, $7.6 billion) ranked 9th and Sunil Mittal (Bharti Airtel, $7.3 billion).
Anil Ambani of Anil Dhirubhai Ambani Group occupies the 11th position with a personal fortune of $7.1 billion.
Bollywood superstar Shah Rukh Khan, who set up Red Chillies Entertainment, was ranked 114th and has personal assets of $400 million.
Men dominate the rich list with only 4 per cent occupied by women.
Steel baroness Savitri Jindal, the non-executive chairperson of O P Jindal Group, is the richest Indian woman with a personal fortune pegged at $5.1 billion, followed by Anu Aga, Kiran Mazumdar-Shaw and Shobhana Bhartia ranked third, fourth and fifth richest Indian women, respectively.
"Despite a sluggish economic growth of around 5 per cent, average net worth of millionaires in Hurun India Rich list 2012 increased by USD 100 million in 2013, demonstrating the resilience of Indian corporates during these tough times," said Anas Rahman Junaid, Publisher at Large, Hurun Report India.
The minimum cut-off mark for finding a place in this year's coveted list was $300 million and wealth calculations were as of October 18, 2013, when the rate of exchange to the US dollar was Rs. 61.5.