Japan’s richest man Masayoshi Son trails only Elon Musk in one-day wealth gain

Japan's wealthiest individual, Masayoshi Son, saw his fortune surge by 10% to $80.2 billion in one day, securing his place as one of Asia's richest and 25th globally. Meanwhile, Elon Musk, the CEO of Tesla, added $9.1 billion to his wealth, reaching almost a 1% increase to $933.3 billion. Son's wealth boost was primarily driven by SoftBank shares.

Over five days, these shares have climbed 8%, and since the start of the year, they have risen 45%. This surge was fueled by significant investments in artificial intelligence (AI) companies. SoftBank recently committed an additional $10 billion to OpenAI, the developer of ChatGPT, raising its total investment to $64.6 billion and its ownership to around 13%.

Son's commitment to AI is substantial, including the $500 billion Stargate Project, a joint venture with OpenAI, Oracle, and MGX to develop AI infrastructure in the United States. In November 2025, SoftBank divested its entire stake in Nvidia, a chipmaker, for nearly $6 billion, funding its investment in OpenAI. The company plans to invest $30 billion in three tranches between April and October 2026.