Japan's Richest Man Doubles Fortune With Some Help From Federer

Unlike China, where vast fortunes can be made and lost overnight, it usually takes Japanese billionaires much longer to recover losses.

Tadashi Yanai, founder of Uniqlo operator Fast Retailing Co., has bucked the trend after the firm’s shares surged more than 75 percent over the past year. His wealth has almost doubled since April 2016 to $25.4 billion, according to the Bloomberg Billionaires Index.