This story is part of Forbes’ coverage of Japan’s Richest 2025. See the full list here.

SoftBank Group founder Masayoshi Son is doubling down on AI, aiming to transform the investment conglomerate (revenue: $48.3 billion) into an AI juggernaut.

In April, SoftBank unveiled a plan to invest $40 billion in OpenAI, of which $10 billion will be syndicated out to co-investors, valuing the ChatGPT creator at $300 billion. Billed as the world’s largest startup financing deal, it followed SoftBank investments totaling $2.2 billion in OpenAI since September.

Son, whose net worth increased by 4% to $28.2 billion in the past year, has made another bold bet with the $500 billion Stargate Project, unveiled in January by U.S. President Donald Trump. This joint venture between SoftBank, OpenAI, Oracle and Abu Dhabi-based MGX will build massive AI data centers across the U.S., supercharging OpenAI’s infrastructure.

As part of its AI plans, SoftBank announced in December it would buy California-based Ampere Computing, which develops high-performance chips for data centers. The deal, valued at $6.5 billion, is expected to close later this year.

Meanwhile, SoftBank reported its first annual profit in four years, posting $7.8 billion in net profit for the year ended March 2025, driven by the upswing in American wireless network operator T-Mobile in which it has a stake and surging valuations of portfolio companies such as PayPay and ByteDance, which are also betting on AI.