Saudi Arabia's Prince Alwaleed Bin Talal has accused Forbes magazine of understating his wealth.
In its 2013 list of the world's richest people, Forbes estimated Prince Alwaleed's net worth at $20bn (£13bn), putting him in 26th place.
According to reports, the prince estimates his net worth to be $29.6bn, which would put him in the top 10.
Forbes said it had examined the prince's wealth "deeply" following claims he had exaggerated his fortune.
In an article published on its website, Forbes also said that the prince often went to great lengths to affect his ranking and had complained in previous years about the valuation Forbes had put on his wealth.
"Of the 1,426 billionaires on our list, not one - not even the vainglorious Donald Trump - goes to greater measure to try to affect his or her ranking," the magazine claimed.
Citing former associates of Prince Alwaleed, the magazine said his ranking was very important to the prince.
"This is how he wants the world to judge his success or his stature," an anonymous source was quoted as saying.The list, published on Monday, saw Mexico's Carlos Slim retain the top slot for the fourth straight year with a net worth of $73bn.
The 10th spot on the list went to Bernard Arnault and family of the luxury goods group LVMH, with a net worth of $29bn.