Key Takeaways

  • Masayoshi Son’s estimated fortune reached $97 billion as SoftBank Group shares climbed more than 80% this year.
  • SoftBank Group surpassed Toyota Motor in market capitalization amid investor enthusiasm for its AI strategy and Arm Holdings exposure.
  • The rally reflects confidence in artificial intelligence infrastructure, though analysts see signs that momentum may be outpacing fundamentals.

Masayoshi Son has moved ahead of Mukesh Ambani to become Asia’s richest person, a milestone powered by a sharp rise in SoftBank Group’s shares and growing market confidence in its artificial intelligence strategy.

The SoftBank Group founder’s fortune is now estimated at $97 billion, compared with $90 billion for Ambani, chairman of Reliance Industries, according to the Forbes Real-Time Billionaires List. Much of Son’s wealth remains tied to his ownership of the Tokyo-listed investment group, making his ranking particularly sensitive to SoftBank’s stock performance.

That performance has been striking. SoftBank shares have gained more than 80% this year, pushing the group’s market capitalization to about $298 billion. The rally also carried SoftBank past Toyota Motor on Monday, making it Japan’s most valuable publicly traded company by market capitalization.

Beyond the billionaire ranking, the valuation shift indicates how aggressively public markets are pricing AI exposure.

A core driver of this growth is Arm Holdings. SoftBank’s British chip design unit provides the architectural basis for a widening range of computing systems, giving the parent group exposure to demand for processors used across data centers, edge devices, and increasingly AI-focused workloads. SoftBank is also directing capital toward robotics, semiconductors, and what Son calls "physical AI," where AI models interact with machines and real-world environments.

The market backdrop helps explain the enthusiasm. IDC estimated that the IT infrastructure market for AI semiconductors would rise from $42.1 billion in 2022 to $117.5 billion in 2024 and reach $193.3 billion by 2027, representing a five-year compound annual growth rate of 35.7%. European AI spending, meanwhile, is projected to reach $144.6 billion by 2028.

Those forecasts support Son’s argument that AI could become substantially larger than the dot-com boom. Speaking to CNBC on Monday, he described the opportunity as potentially "more than 10x, probably 50x bigger than dot-com," adding that the current period resembles the beginning of the internet.

However, enormous addressable markets do not automatically produce predictable investment returns. AI infrastructure requires expensive chips, data centers, power capacity, and networking equipment. The growth of foundational AI models may create substantial value for infrastructure investors like SoftBank, but the size and timing of future returns will depend on commercial adoption, operating costs, competition, and eventual liquidity options.

Governance will matter too, especially as SoftBank expands from software investments into machines operating in physical environments. Semiconductor and system designs draw on technical work developed through organizations such as the IEEE, while emerging ISO/IEC approaches to AI management are shaping how businesses assess risk, accountability, and trustworthy deployment. These considerations could become more prominent as physical AI moves from experimental projects into industrial operations.

Some market watchers are already urging restraint. A financial analyst noted that recent gains reflected savvy investing but also a broader bull market showing signs of speculative excess. The primary concern centers on investors becoming increasingly focused on short-term momentum while paying less attention to detailed, long-term assumptions.

SoftBank is currently being valued as a blend of an investment group, an AI infrastructure proxy, and a future operating platform. That ambiguity can support a premium when sentiment is strong, but it can also amplify volatility if expectations shift.

Son’s rise above Ambani therefore captures more than a reshuffling of personal fortunes. It shows how aggressively markets are rewarding concentrated exposure to Arm Holdings and the infrastructure behind AI. SoftBank has placed one of the largest corporate bets on that transition. Its record valuation suggests investors currently believe the bet is working, even as the harder question of durable returns remains open.