Masayoshi Son Reshapes SoftBank Around Mega AI Bets as Governance Questions Intensify

How SoftBank Surpassed Toyota and Placed a $65bn Bet on OpenAI

On 1 June, Masayoshi Son’s SoftBank overtook Toyota to become the most valuable company in Japan for the first time since the dotcom boom. The milestone marks a dramatic comeback for the billionaire founder, whose career has swung between spectacular wins—like Alibaba and chip designer Arm—and high-profile disasters such as WeWork.

Son is now betting the group’s future on what he calls the “four pillars of superintelligence”: data centres, AI models, chips and robots. Through Arm, a massive $64.6 billion stake in OpenAI for a 13% holding, and a web of other tech investments, SoftBank has placed itself at the centre of the artificial intelligence boom. Arm’s shares have soared roughly 175% this year, and the SoftBank stake in the British chip firm alone now exceeds the Japanese parent’s entire market capitalisation.

Near-term plans include a series of high-profile IPOs—of OpenAI, robotics company Roze and energy developer SB Energy—that could cement the group’s AI franchise. Yet the stock has fallen about 25% since early June amid rumours that the OpenAI float may be delayed by competition from SpaceX and Anthropic, underscoring the heavy expectations resting on Son’s vision.

Where Son’s Control, Arm’s Valuation and the OpenAI IPO Gamble Leave SoftBank

SoftBank’s Discount Puzzle and the Arm Asymmetry

SoftBank trades at a roughly 50% discount to net asset value, largely because the market prices in governance risks and the opacity of its complex financing. The most glaring anomaly is Arm: SoftBank owns about 90%, yet the value of that stake exceeds the group’s own market cap. The discount reflects investor unease about the group’s use of asset-backed loans and bridge financing—the latest being $40 billion raised for the OpenAI investment—which pushes borrowing capacity close to its limit.

The OpenAI Gamble and IPO Overhang

The record $64.6 billion OpenAI bet is Son’s single biggest wager, and SoftBank’s stock recovery depends heavily on a successful IPO. Jefferies analyst Atul Goyal has warned that OpenAI’s reliance on SoftBank funding is a two-way street: the Japanese group benefits from rising valuations of ChatGPT’s owner, but “risks for investors are increasing.” Delays in the offering, or a flop, would not only damage Son’s reputation but also raise fresh questions about his tendency to invest late in cycles when valuations are already stretched.

Concentration of Power and Governance Frictions

Son has doubled his personal office staff to 60 while senior executives have departed, leaving a thin layer of checks on the founder. CFO Yoshimitsu Goto’s ability to push back is described as limited. Investors further flag the opacity of Son’s personal co-investments through SB Northstar and Vision Fund 2, which could generate conflicts of interest. The board defends the structure, but a growing number of shareholders argue that the group’s strategy is too tightly bound to one individual.

Systemic Stakes and Geopolitical Reach

Son’s influence extends well beyond SoftBank. He is a central figure in Japan’s AI strategy, has pledged up to €75 billion for data centres in France after talks with President Macron, maintains regular contact with Donald Trump and holds major Chinese investments such as ByteDance. Several bankers and officials now view SoftBank as near “too big to fail,” while some directors privately believe the group would not survive Son’s departure—a risk magnified by his latest decision to delay retirement by another 10–15 years.

Concrete Steps for Investors and Advisers Evaluating SoftBank’s AI-Fueled Rise

• Track the liquidity clock: SoftBank’s debt-to-value ratio sat at 17% at end-March, but the $40 billion bridge facility for OpenAI means borrowing headroom is thin. Watch for any refinancing announcements or asset sales that could signal strain.
• Map the IPO pipeline: The near-term listing plans for OpenAI, Roze (target valuation up to $100 billion) and SB Energy are the clearest catalysts for a re-rating. A filing delay or down-round in any of these would directly hit the discount to NAV.
• Stress-test Arm’s valuation contribution: With Arm’s stock contributing more than 100% of SoftBank’s market cap, any correction in the chip designer’s share price—driven by AI spending slowdowns or competitive pressure—would widen the conglomerate discount disproportionately.
• Monitor governance milestones: Son’s personal co-investment vehicles and the absence of a clear succession plan remain material risks. The next board meeting and annual meeting will be key venues for any push by investors to ring-fence conflicts of interest and formalise a CEO transition timeline.
• Assess geopolitical exposure: SoftBank’s large China footprint, alongside deepening ties with the US and French governments, creates a multifaceted regulatory risk. Shifts in AI export controls or sanctions could force a reassessment of the group’s cross-border asset valuations.