Masayoshi Son’s bold bets on artificial intelligence have propelled him past Uniqlo billionaire Tadashi Yanai to become Japan’s richest person, Bloomberg reports. Son’s net worth surged 248% this year to $55.1 billion, edging about $23 million ahead of Yanai, who has led the country’s wealth rankings for much of the past decade and continuously since April 2022, according to the Bloomberg Billionaires Index.
The spike in Son’s fortune mirrors the performance of SoftBank Group Corp., where the 68-year-old billionaire is the largest shareholder, controlling roughly one-third of the company. Son’s global portfolio spans chipmakers, startups, and other technology ventures, and he has undertaken an aggressive spending spree this year to position SoftBank as a central player in the global AI boom.
SoftBank shares rose Wednesday following news that the company is among those expressing interest in launching projects in the U.S. during President Donald Trump’s visit to Tokyo. Son has emerged as a key foreign business backer for Trump, pledging $100 billion in U.S. investments earlier this year. Among his most ambitious deals are a planned $30 billion investment in OpenAI and a $500 billion initiative to build AI data centers across the United States in collaboration with OpenAI, Oracle Corp., and Abu Dhabi’s MGX fund. He is also pursuing a partnership with Taiwan Semiconductor Manufacturing Co. for a trillion-dollar industrial complex in Arizona focused on AI and robotics.
The gains from OpenAI, Arm Holdings Plc, and other AI-related ventures have buoyed SoftBank’s stock, making it a proxy for the AI infrastructure boom. Son has also made strategic moves including a surprise $2 billion investment in Intel Corp., the $5.4 billion acquisition of ABB Ltd.’s robotics unit, and new exposure to Nvidia Corp. and TSMC. Bloomberg Intelligence analyst Kirk Boodry noted, “Everything AI-related is going up. The OpenAI connection is certainly a driver, as that company’s deals with Broadcom and AMD have boosted the overall rally.”
Son, an ethnic Korean born in Japan in 1957, started his entrepreneurial journey in the United States by developing an electronic dictionary he sold to Sharp Corp. for around $1 million. Returning to Japan, he founded SoftBank in 1981 as a computer software distributor, building it over four decades into a conglomerate spanning telecommunications, digital payments, and technology investments.
While Son’s fortune has surged in recent months, Yanai’s wealth has remained largely unchanged. The last time Son briefly surpassed Yanai was in 2014. Some investors caution that soaring AI valuations may be inflating wealth figures, warning that OpenAI and Nvidia are contributing to a complex network of transactions that artificially prop up the trillion-dollar AI boom.
Son’s financial journey has been marked by dramatic swings. During the dotcom bubble, his net worth once rose by $10 billion in a single week, briefly making him the richest person in the world, only to see SoftBank’s stock collapse shortly after. Reflecting on those days, Son told Bloomberg in a 2017 interview, “Somehow, I survived. At that time, I said, ‘Now is the time to go next stage, which is the internet will become mobile internet.’” His early investments in Alibaba Group and exclusive rights to Apple iPhone sales in Japan set the stage for his meteoric comeback, even as regulatory crackdowns in China later impacted his fortune.