New York, March 2008 -  Mukesh Ambani, who runs the Reliance Industries group, also saw the highest fluctuation of about $35 billion in his net worth over the past year even as he trailed his estranged brother Anil as the world's second biggest wealth creator.

Mukesh, however, managed to maintain a slender lead of $1 billion over Anil in terms of net worth, as per a Forbes billionaire list released on Thursday. The magazine has ranked Mukesh as world's fifth richest with a net worth of $43 billion, followed by Anil with $42 billion.

According to the magazine, Anil emerged as the biggest gainer in the world with his wealth soaring by $23.8 billion, followed by $22.9 billion gained by Mukesh.

In Forbes' 2007 list, Mukesh's net worth stood at $20.1 billion, as against Anil Ambani's $18.2 billion. Mukesh and Anil were ranked at 14th and 18th positions respectively on the previous year's list.