BILL GATES, founder of the Microsoft Corporation, is the worldÕs richest private individual, with $12.9 billion (£8.3 billion). He has knocked a Japanese real estate magnate off the top of the annual list compiled by Forbes magazine. GatesÕs wealth rose from $8.1 billion in the past year as MicrosoftÕs stock price soared, said the Forbes issue published yesterday. A year ago Gates was the richest American, but ranked second worldwide.