SoftBank Group Corp. founder Masayoshi Son has enjoyed a $12 billion renaissance the past three months, easing the pressure on his intricately engineered personal finances.

With SoftBank Group’s shares surging to their highest price in two decades, Son’s net worth hit $20 billion (¥2.14 trillion) on Thursday, more than doubling from $8.4 billion in March, according to the Bloomberg Billionaires Index. It is the first time the 62-year-old’s fortune has topped $20 billion since January 2013, when the ranking first started tracking his wealth.

The calculation excludes about $13.3 billion of his SoftBank Group shares pledged as collateral, representing some 40 percent of his stake, according to regulatory filings. A further 26 percent of his holding is lent out for a fee to different entities, mostly brokerages, likely to add liquidity to the market. Those shares are included in Son’s net worth calculation because he retains control over them.