SoftBank Group Corp. (TSE: 9984) has overtaken Toyota Motor Corporation (TSE: 7203) to become Japan’s most valuable listed company, marking a major change at the top of the Japanese equity market. The move came on 1 June 2026, when SoftBank shares jumped 14% and Toyota shares fell 4.5%, according to Reuters. SoftBank’s market capitalisation rose to about ¥48.8 trillion, or roughly US$306.0 billion, while Toyota’s fell to about ¥45.9 trillion.
The crossover is symbolic because Toyota has represented the strength of Japan’s manufacturing economy for decades. SoftBank, by contrast, is being priced increasingly as an AI infrastructure and investment platform. For investors, the key question is not simply which company is larger today. It is whether the market is correctly valuing SoftBank’s exposure to Arm, OpenAI and large-scale AI data centres.
What happened on the Tokyo market
SoftBank’s rally was part of a broader surge in AI-linked Japanese equities. Reuters reported that the Nikkei 225 touched a record 67,231.28 before closing at 66,934.33, up 0.9% for the session. SoftBank alone added more points to the index than the index gained overall, which shows how concentrated the move was. The broader Topix index fell 0.4% on the same day, suggesting the rally was not evenly spread across Japanese stocks.
The immediate catalyst was SoftBank’s commitment to invest about €75 billion in AI infrastructure in France. Euronews reported that the project would develop and operate 5 GW of AI data-centre capacity, with an initial €45 billion by 2031 for the first phase in northern France.
That matters because AI infrastructure has become one of the market’s biggest themes. Training and running large AI models requires data centres, power, chips and networking capacity. SoftBank is trying to position itself across several parts of that chain.
Why investors are re-rating SoftBank
SoftBank is no longer being valued only as a telecom and investment holding company. The market is increasingly treating it as a liquid way to gain exposure to the AI infrastructure cycle.
The first major asset is Arm Holdings plc (NASDAQ: ARM). Arm’s chip architecture is used across smartphones, cloud infrastructure and emerging AI workloads. Arm’s latest annual filing said SoftBank Group beneficially owned about 87.1% of Arm’s issued share capital as of 20 May 2025, making the stake a central part of SoftBank’s asset value.
The second major asset is OpenAI. SoftBank said in February 2026 that it had invested an aggregate US$34.6 billion in OpenAI through SoftBank Vision Fund 2 since September 2024. OpenAI later announced US$110 billion in new investment at a US$730 billion pre-money valuation, including US$30 billion from SoftBank.
Put simply, SoftBank’s market value now depends heavily on how investors price the next stage of AI growth. If demand for AI compute keeps rising, SoftBank’s exposure to chips, models and data-centre infrastructure could remain powerful. If the AI cycle cools, the same exposure could work in reverse.
The bull case and the bear case
The bull case is that SoftBank has assembled a rare set of AI-linked assets at the right time. Arm gives it exposure to semiconductor architecture. OpenAI gives it exposure to frontier AI models. The France data-centre plan gives it a physical infrastructure angle in Europe. Together, those assets help explain why investors are willing to pay a premium for SoftBank over more traditional Japanese industrial names.
The bear case is that the valuation now relies on several big assumptions. SoftBank’s value is highly exposed to Arm’s share price, OpenAI’s private-market valuation and the economics of massive data-centre projects. These are not low-risk assets. They can be volatile, capital intensive and sensitive to changes in investor appetite.
There is also concentration risk. Reuters noted that the broader Japanese market did not rise in line with SoftBank’s move, with the Topix falling even as SoftBank drove the Nikkei higher. That kind of narrow rally can be strong while momentum lasts, but it can also reverse quickly if the lead stocks stumble.
What to watch next
The next thing to watch is execution on the France AI infrastructure project. A €75 billion commitment is large enough to move sentiment, but investors will still need details on funding, customers, construction timelines, power availability and returns on capital.
Arm is another key marker. If Arm continues to benefit from AI-related chip demand, SoftBank’s holding remains a major support for the investment case. If Arm’s valuation pulls back, SoftBank’s own market value could feel the pressure quickly.
OpenAI is the third major variable. SoftBank’s exposure gives it a major place in the AI story, but private-market valuations can change. Any shift in OpenAI’s growth rate, funding needs or path toward a possible public listing would be closely watched.
Toyota has not suddenly become less important. It remains one of the world’s most profitable and influential automakers. What has changed is the market’s preference at this moment. On 1 June 2026, investors placed a higher value on SoftBank’s AI infrastructure story than on Toyota’s industrial strength. Whether that shift lasts will depend on whether SoftBank can turn its bold AI positioning into durable earnings and cash flow.
