Steel tycoon Lakshmi Mittal along with the Ambani brothers--Mukesh and Anil--are among the 10 wealthiest CEOs in the world, according to American magazine Forbes.Out of the world's 10 wealthiest CEOs, four positions have been grabbed by Indians--Lakshmi Mittal is ranked at the second place followed by Mukesh Ambani (6th place), Anil Ambani (7th) and Wipro chief Azim Premji (9th).The list has been topped by Warren Buffet, chief executive, Berkshire Hathaway, with a fortune of $52 billion.Lakshmi Mittal, chief of ArcelorMittal, has a net worth of $32 billion, while Mukesh Ambani and Anil Ambani have fortunes worth $20.1 billion and $18.2 billion respectively.Azim Premji, chief of IT bellweather Wipro has a net worth of $17.1 billion.However, these net worth figures are not current and have been taken from a list prepared almost a year back for Indian businessmen and from a September list for those from the US.Forbes said that the list of wealthiest CEOs was prepared after perusing the ranks of the Forbes 400 list of the richest Americans from September and its annual billionaires' list from last March."We found the 10 richest CEOs around, some of whom founded their own companies, others who benefited from large inheritances and still others who built their fortunes through other means," the magazine said.About Mukesh Ambani, chairman and managing director, Reliance Industries, the magazine said: "Ambani fulfils the duties of CEO at his company, even though he does not carry the title. He is the son of the late Dhirubhai Ambani, the legendary Indian tycoon and founder of Reliance Industries. A few years after the elder Ambani's death in 2002, his sons split the family fortune, with Mukesh retaining Reliance Industries and Reliance Petroleum."Younger brother Anil Ambani took over the family's telecom, finance and power interests.About Anil Ambani, chairman, Reliance Anil Dhirubhai Ambani Group (ADAG), Forbes said: "Like his brother Mukesh, Anil does not call himself Chief Executive, even though he shares the duties of a CEO with two other executives at Reliance ADAG."Pointing out that Azim Premji, like Ambani brothers, does not hold the title of CEO, the magazine said his company, Wipro, was one of India's largest information technology firms."Earlier this month, he denied market rumours that Wipro was interested in acquiring CapGemini of France," it said.Other names in the list are Sheldon Adelson, chairman and chief executive, Las Vegas Sand, with a fortune of $28 billion ranked at third position, Bernard Arnault, chairman and chief executive, LVMH Group, at fourth place with a net worth of $26 billion, and Lawrence Ellison, chief executive, Oracle, in fifth place with a fortune of $26 billion.Michael Dell, chairman and chief executive, Dell Corporation, with a fortune of $17.2 billion ranks below the Ambani brothers at the eighth place though ahead of Premji.Charles Koch, chairman and chief executive, Koch Industries, with a net worth of $17 billion is at the 10th position.