Masayoshi Son has surpassed Fast Retailing Co. Chairman Tadashi Yanai as Japan's richest person after SoftBank Corp.'s worth surged 16 percent since the start of last week.
Son, 57, had a net worth of $16.6 billion as of Tuesday, according to the Bloomberg Billionaires Index.
Yanai, the country's second-richest person, controls a $16.2 billion fortune.