SoftBank's OpenAI Obsession Meets a $25.9 Billion Repayment and a Record Short Squeeze
Published on 09/11/2026 at 10:50 | Editorial boerse-global.de
SoftBank Group wired off the last of a $25.9 billion loan on Monday, September 15 — the credit line it had originally drawn to bankroll its stake in OpenAI. On paper, that should read as a show of balance-sheet muscle. Instead, it landed in the middle of a week when bearish traders were building their largest bet against the Japanese conglomerate in a decade.
The short interest as a share of free float climbed to 2.27% on Wednesday, the heaviest reading since July 2025. In dollar terms that works out to roughly $3.9 billion in shorted stock — the highest nominal level since at least early 2015. For a company that has spent the past year making headlines with acquisitions and multi-billion-dollar borrowings, the timing is an awkward counterpoint.
A Rally Built on a Single Name
SoftBank's shares had been on a tear for weeks, and Tuesday's session delivered the bill. The stock dropped 4.36% in Tokyo to 6,513 yen, pulling back from a climb that had carried it from around 5,200 yen in late August. Even after the slide, the equity still sits roughly 25% higher than where it started that run.
The advance tracks almost perfectly with the unveiling of OpenAI's new GPT-6 Astra model. When OpenAI president Greg Brockman pitched the release as the opening of the "AGI era," SoftBank's ADR jumped 17.7% in a single trading day. That reaction says less about SoftBank's diversified holdings and more about how the market now treats the conglomerate: as a leveraged proxy for OpenAI, not as a broad-based investment vehicle.
When one product announcement from a portfolio company can move the stock by double digits, that is a vulnerability, not a vote of confidence.
Should investors sell immediately? Or is it worth buying SoftBank Group?
Tuesday's selloff made the point sharply. The Nikkei 225 fell as much as 2.96%, dragged down by a global bond rout triggered by surging oil prices — Brent crude approached $110, and the US 10-year yield touched its highest level in three years. Semiconductor names including Advantest and Tokyo Electron ranked among the worst performers in the Prime segment alongside SoftBank. The pain was market-wide, but it hit a company whose annualized volatility of 61% leaves it unusually exposed to macro shocks.
What the Fundamentals Actually Show
Strip away the momentum and the picture gets less flattering. A discounted cash flow analysis puts fair value roughly 23.6% below the most recent trading level. Other valuation models go further, flagging the stock as more than 100% overvalued on a price-to-sales ratio of just over 5 — against a historical median near 1.6.
Even optimistic scoring frameworks hand SoftBank just 3 out of 10 points for financial strength, while momentum and growth metrics sit near the top of the scale. That is the signature of a hype stock, not a value play.
Free cash flow over the trailing twelve months was negative, at a loss of about 2.1 billion yen. At the same time, the company is juggling enormous financing plans: a planned IPO of its energy subsidiary SB Energy targeting $5 billion to $7 billion in proceeds, and the refinancing of a $40 billion credit facility tied to the OpenAI commitment.
SB Energy itself posted a $3.2 billion loss for the first half — on revenue of just $138.7 million. That ratio alone ought to give pause to anyone reading the recent share-price strength as validation of the business model.
Funding Strategy in Full Swing
The loan repayment slots into a wider capital-markets push. Back on September 4, SoftBank placed a 1 trillion yen retail bond — about $6.3 billion — with a 4.75% coupon on the seven-year notes, the top end of an initially targeted 4.3% to 4.9% range. The pricing suggests investors demanded a meaningful risk premium for their money.
A far larger operation is now underway. From September 14 to 17, SoftBank is sounding out investors in New York for a possible dollar-denominated junk bond, with CFO Yoshimitsu Goto and other executives attending meetings at Citigroup's offices. A deal of $10 billion to $20 billion is under discussion, and a euro tranche is also on the table.
The combination of rising short positions and ongoing debt issuance raises a fair question: how durable is investor confidence, really?
SoftBank Group at a turning point? This analysis reveals what investors need to know now.
As of June 23, SoftBank put its net asset value at 74 trillion yen, or 13,000 yen per share — a figure bulls routinely cite as evidence of undervaluation. The group remains in acquisition mode too, including the roughly $4 billion deal to buy DigitalBridge agreed in December.
Short Sellers Caught Offside
What stands out is how badly the rally burned the bears. Short interest hit its highest nominal level since 2015 at around $3.9 billion, and short sellers were sitting on paper losses of roughly $1 billion in September. Skeptical investors, in other words, misjudged the scale of the move. None of that resolves the gap between valuation and earning power.
Market skepticism has shown up in the price as well. The stock closed at EUR 36.61 on Thursday, down 2.6% from the prior day. Over seven and 30 days, though, it still holds gains of about 20% and 19% respectively — a strong run that preceded the recent softness. An RSI of 68.6 points to buying momentum that is already well advanced, while annualized 30-day volatility of 64% underscores the nervousness surrounding the name.
For investors, the takeaway cuts both ways. The fundamental story remains intact, but the growing short base shows that part of the market is positioning for a correction — in the very week SoftBank closes one major financing chapter and opens another.
Anyone buying SoftBank here is, at bottom, betting on the AI hype around OpenAI continuing. That wager can pay off. It is still a wager, not an investment anchored in solid foundations.
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