Masayoshi Son, the Chief Executive Officer (CEO) of Japanese multinational investment giant SoftBank Group, experienced a significant hit to his net worth, which decreased by nearly $5 billion following a more than 10% drop in the company's shares during Tuesday's stock market session. This sharp decline was primarily driven by increasing concerns surrounding SoftBank's substantial investments in artificial intelligence (AI), particularly its big bet on OpenAI, the creator of ChatGPT.

The market's apprehension intensified after a rally in Google stocks, fueled by its new Gemini 3.0 artificial intelligence model, prompted questions about the competitive landscape of AI and the valuation of SoftBank's existing AI stakes. This event underscores the volatile nature of the AI sector and the scrutiny faced by major investors in the space.

SoftBank Group's strategic moves in the AI domain have been notable. Earlier in November 2025, the investment giant reportedly sold its entire stake in the US-based AI chipmaking giant Nvidia in a substantial $5.83 billion deal. This divestment was part of SoftBank's broader strategy to increase its focus and investments specifically with OpenAI. Furthermore, in February of the same year, Masayoshi Son actively participated in plans to invest an astonishing $500 billion in a colossal artificial intelligence project known as Stargate, joining prominent figures such as US President Donald Trump, OpenAI's Sam Altman, and Oracle's Larry Ellison.

The impact on Masayoshi Son's personal wealth was immediate and substantial. According to data from the Forbes Rich List, the SoftBank Group CEO's net worth plummeted by $4.9 billion in a single day, marking a 9.11% drop in his overall real-time net worth. As of November 25, 2025, his net worth stood at $49.3 billion. Despite this recent setback, Masayoshi Son, who founded and continues to run SoftBank Group, remains a global titan of industry, ranking as the 32nd richest person in the world on the Forbes billionaires rich list.

SoftBank Group's share price performance on the Tokyo Stock Exchange reflected the market's unease. The stock closed 9.95% lower at 15,390 Japanese Yen (JPY) on Tuesday, November 25, 2025, a significant decrease from its previous market close of JPY 17,090. During intraday trading on Tuesday, the shares dropped even further, hitting a day's low of JPY 15,180, representing an 11% decline compared to the preceding day's closing price. This single-day fall contributed to a broader negative trend for the company's shares in the short term.

Despite the recent downturn, SoftBank Group has demonstrated robust long-term growth for its investors. Over the last five years, the company's shares have delivered more than 112% returns, and in the last one-year period, investors have seen over 73% returns. On a year-to-date (YTD) basis in 2025, the shares had risen by 66.67%. However, the recent market movements have significantly eroded these gains, with SoftBank Group stock losing more than 39.58% in the last one month and trading down 22.47% over the last five market sessions. The shares' 52-week high was JPY 27,695, while the 52-week low stood at JPY 5,730. As of the stock market close on Tuesday, November 25, 2025, the company's market capitalisation (M-Cap) was JPY 24.35 trillion.