SoftBank is borrowing $10 billion against its OpenAI stake at a rate that tells you everything about how the banks see AI equity risk.
The Japanese conglomerate is seeking a margin loan secured by its OpenAI shares at SOFR plus 425 basis points, roughly 7.88 percent total interest, with a two-year term and an option to extend a third year, according to Reuters and Bloomberg, which reported the talks separately. When SoftBank borrowed $8 billion against its Alibaba stake in 2018, the rate was LIBOR plus 150 basis points, per The Next Web. Alibaba was publicly traded on the New York Stock Exchange. OpenAI is not. Yet SoftBank is paying nearly triple the 2018 spread for the privilege of using that illiquid collateral.
The spread is not a cost. It is a signal. Banks are nervous about concentration risk in private AI equity, nervous about what happens if OpenAI secondary market pricing falls and SoftBank faces a margin call with no liquid exit. They are pricing that nervousness at 425 basis points over a risk-free rate. Son is paying the premium because he believes the AI thesis will outrun it. The spread tells you he is alone in that room.
SoftBank's cumulative OpenAI commitment reaches $64.6 billion once its $30 billion follow-on investment closes, giving it roughly 13 percent of the company, per The Next Web, which tracks the math against the $852 billion valuation from the March 2026 funding round. The 13 percent stake is notionally worth about $110 billion on paper. The $10 billion loan represents just 9 percent loan-to-value against that paper value, conservatively underwritten by historical standards.
But the paper is the problem. The $110 billion figure is a valuation assigned in a funding round, not a market price. Secondary market transactions suggest the stock has traded at a discount to that round price. If the secondary falls far enough, far fast enough, SoftBank could face a margin call before it has any way to sell.
The $10 billion is not the real pressure. CreditSights estimates SoftBank faces a funding shortfall of roughly $32 billion over the next two years, including bond maturities and other committed investments, per the Japan Times. The margin loan is not a bullish bet. It is a pressure response.
S&P Global acknowledged as much in March, cutting SoftBank credit outlook to negative from stable while affirming its BB+ rating, according to The Hindu BusinessLine, which cited the additional $30 billion OpenAI commitment as the trigger. The implicit message: this is a lot of eggs in one basket, and the basket is private.
SoftBank has already sold its entire Nvidia stake, $5.8 billion, and trimmed its T-Mobile position by $4.8 billion to fund the OpenAI bet, per BanklessTimes. Its Q3 FY2025 earnings call shows liquidity on hand of 3.8 trillion yen, down from 4.2 trillion yen the prior quarter, per BigGo Finance. The LTV ratio stands at 20.6 percent, below the company's 25 percent upper limit. But SoftBank's definition of leverage does not account for the illiquidity of its largest asset.
What makes this worth writing is not the loan itself. Every financial outlet will cover the transaction. The story is what the transaction signals about AI equity as a class.
Son is not the only person borrowing against AI shares. The infrastructure of financial institutions quietly accepting private AI equity as collateral, at a premium but accepting it, means AI has crossed a threshold that most technology stocks never reached. It is no longer just an investment. It is a form of capital, deployable as collateral, creating leverage without dilution.
The danger is symmetrical. When a single asset class becomes the basis for widespread borrowing, a sharp correction in that asset creates margin calls across multiple counterparties simultaneously. The banks know this. The 425bps spread is their way of pricing it. The question is whether the rest of the market understands it too, or whether it is about to find out the hard way.