Masayoshi Son Adds $4 Billion to His Wealth on Arm’s 192% Rally

Masayoshi Son has added about $3.8 billion to his net worth this year as the surging stock price of Arm Holdings Plc bolsters the value of his holdings in SoftBank Group Corp.

The pace of increase in his wealth puts the Japanese billionaire in the top 30 gainers among the world’s 500 richest people tracked by the Bloomberg Billionaires Index. The 66-year-old founder of SoftBank Group was worth $15.1 billion as of Tuesday, compared with $11.3 billion at the end of last year.

Son is personally benefiting from Arm’s rally because he owns roughly a third of SoftBank Group, which ...