SoftBank's French Data Center Megaproject Puts Son's AI Bravado to the Test

SoftBank shares surge 14% as Son unveils €75B French AI data centers, calling revolution 50x dot-com. Project finance funded; OpenAI margin loan shrinks to $6B. Hybrid bond test in June.

Masayoshi Son has never been one for half measures. The SoftBank Group chairman used a Paris CNBC appearance to declare the artificial intelligence revolution "50 times bigger than the dot-com boom" and dismissed any pullback as "the best investment opportunity." His timing was no accident—just a day earlier, SoftBank unveiled plans to pump €75 billion into French AI data centers, a project so vast it would become Europe's largest.

The announcement sent SoftBank's shares soaring 14% on Monday to 8,259 yen, just shy of the 8,263 yen record and extending the stock's 2026 rally to more than 70%. That surge vaulted SoftBank past Toyota as Japan's most valuable company, with a market capitalization above 48 trillion yen versus Toyota's roughly 46 trillion yen—ending a 22-year reign by the auto giant.

A Blueprint With Industrial Muscle

The French initiative targets 5 gigawatts of AI computing capacity, with a first phase of €45 billion delivering 3.1 GW across three sites: Dunkerque, Bosquel and Bouchain. The target completion date is 2031, and SoftBank already has industrial partners lined up. Schneider Electric will help build a manufacturing cluster in Dunkerque for data center enclosures, while EDF is working on the Bouchain location. SoftBank estimates the full project, including system costs, could total $750 billion.

Son insists the financing won't strain SoftBank's balance sheet. The approach relies on project finance, with hyperscale cloud customers already committed to buying capacity. "Our equity requirement is very, very small," he told CNBC, adding that existing client relationships are simply being transferred to France. The move taps into France's abundant nuclear power and political desire to reduce dependence on US and Asian AI infrastructure.

The OpenAI Anchor and a Shrinking Margin Loan

SoftBank's AI story is indivisible from OpenAI. The group has committed roughly $65 billion to secure about a 13% stake in the ChatGPT developer, with completion expected by October. Son values that holding at around 20% of SoftBank's net asset value, while chip designer Arm—by far the largest single asset—accounts for more than 50%. OpenAI is reportedly weighing an IPO that could value the company at $1 trillion, adding a potential revaluation trigger.

Yet the market's enthusiasm masks a hardening reality on the financing side. SoftBank had floated plans for a margin loan of up to $10 billion backed by its OpenAI stake, but some lenders balked. The target has now been scaled back to as low as $6 billion, a clear signal that credit markets are scrutinizing the sheer scale of Son's commitments.

A Triple Test in June

The coming weeks will be pivotal. On June 5, SoftBank will set the terms of a ¥260 billion ($1.6 billion) hybrid bond with a 35-year maturity and a coupon range of 4.8% to 5.6%. That instrument will be closely watched as a gauge of investor appetite for SoftBank's debt. The annual general meeting follows on June 24, where seven incumbent and two new external board candidates stand for election. A dividend payment is scheduled for June 30.

Meanwhile, two potential IPOs could reshape SoftBank's valuation narrative. OpenAI is said to be preparing a US listing, and SB Energy, a portfolio company, is also exploring an initial public offering. If both materialize, SoftBank gains fresh public-market benchmarks for its holdings.

A Homegrown Cloud for Japan

SoftBank is not betting exclusively on France and the United States. Its domestic subsidiary, SoftBank Corp., will launch an AI Data Center GPU Cloud in October 2026. The service, built on the Infrinia AI Cloud OS stack and powered by Nvidia GB200 NVL72 systems, promises that all computing and data stays within Japanese jurisdiction—a selling point for companies wary of foreign cloud providers like AWS, Azure or Google Cloud.

Rally Leaves Little Room for Error

With the stock up 70% year-to-date, the market is already pricing in success. Tomo Kinoshita, global market strategist at Invesco Asset Management Japan, attributes the rally to SoftBank's concentrated bet on AI businesses and its ability to ride the global technology wave. But the margin-loan reduction demonstrates that caution is creeping in among lenders, and the combined weight of the French project, the Stargate initiative (a $500 billion US data center joint venture with OpenAI, Oracle and Abu Dhabi's MGX), and the OpenAI stake creates an obligations package that even SoftBank's activists will test.

Son himself frames any turbulence as a buying window. "Every correction is the best investment opportunity," he declared, drawing a parallel to the 1929 Wall Street crash that preceded decades of gains for auto and electric stocks. For shareholders, the question is whether the AI infrastructure juggernaut can generate the earnings to justify the valuation—or whether the rally has simply gotten ahead of the financing reality.