Japan’s richest man Masayoshi Son added US$7.4 billion to his fortune in a single day, the second-largest increase worldwide after Elon Musk.
The CEO of investment giant SoftBank Group saw his wealth increased by 10% from the previous day to $80.2 billion, maintaining his position as one of the richest in Asia and ranking 25th globally.
The world’s biggest wealth gainers and losers, Oct. 1, 2026. Graphics by Forbes
Musk, the CEO of U.S.-based electric carmaker Tesla, added $9.1 billion to his wealth, which went up almost 1% to $933.3 billion.
Son has benefited from the rise of SoftBank shares. In the past five days the stock has gone up 8%, and since the beginning of the year, it has increased by 45%.
Large investment into AI companies explains the stock surge. SoftBank said Thursday it invested another $10 billion in OpenAI, the operator of ChatGPT, bringing its total investment to $64.6 billion and its ownership stake to approximately 13%.
Masayoshi Son, Chairman & CEO of SoftBank Group Corp. attends a press conference in Tokyo on June 16, 2026. Photo by The Yomiuri Shimbun via AFP
Son is committing billions of dollars to AI, including the $500 billion Stargate Project, a partnership with OpenAI, Oracle and MGX to build AI infrastructure in the U.S.
In November 2025, SoftBank sold its entire stake in chipmaker Nvidia for nearly $6 billion to finance its investment in OpenAI. It plans to invest $30 billion in three installments between April and October 2026.