SoftBank borrowed $11.1 billion to close its $30 billion OpenAI bet
The Japanese tech investor sold bonds in two currencies to fund the final payment on a deal that will make it OpenAI's largest outside backer, with a 13% stake.
Key points
- SoftBank issued $11.1 billion in bonds on Thursday to fund the third and final payment of its $30 billion investment in OpenAI.
- The sale split between $10 billion in US dollar notes and roughly $1.14 billion in euro notes, with proceeds expected to settle by 1 October 2026.
- Once the deal closes, SoftBank's total cumulative investment in OpenAI will reach $64.6 billion, giving it roughly a 13% stake in the ChatGPT maker.
- SoftBank shares jumped more than 7% when Tokyo markets reopened Thursday after a three-day national holiday.
SoftBank, the Japanese technology investment group led by billionaire Masayoshi Son, has sold $11.1 billion in bonds to pay the last instalment of the biggest outside bet ever placed on OpenAI.
The company confirmed Thursday it issued $10 billion in US dollar-denominated senior notes (bonds sold in US dollars that rank ahead of most other debts if the company struggles to repay) and a further 1 billion euros, worth about $1.14 billion, in euro-denominated notes. Proceeds fund a $10 billion payment due on or around 1 October 2026, completing a $30 billion follow-on investment SoftBank first agreed to in February 2026.
How big is SoftBank's total bet on OpenAI?
At $64.6 billion cumulative, it is enormous. When this payment closes, SoftBank will hold approximately 13% of the maker of ChatGPT.
That scale matters because OpenAI is still privately held, meaning SoftBank cannot simply sell shares on a stock market if it wants to exit. Every dollar committed is, for now, locked in.
The number to hold onto is this: one company is spending roughly the GDP of a small country on a single AI lab. Whether that looks like genius or recklessness depends almost entirely on whether OpenAI can eventually generate revenue that justifies it.
Why borrow instead of paying from cash?
Borrowing at this scale to fund a single investment is a deliberate choice, and it is the part of this story worth watching most closely.
Investors have been pressing SoftBank on how it plans to finance its AI ambitions without stretching its balance sheet dangerously thin. Borrowing $11.1 billion through bond markets means SoftBank is betting that future returns from OpenAI, and from its broader AI portfolio, will comfortably outpace the interest it owes bondholders.
We reported on 4 September that SB Energy filed for an IPO carrying a $3.2 billion loss, with its near-term future depending almost entirely on OpenAI, and SoftBank's spending commitments have kept stacking up since. The financing question is no longer abstract.
Markets gave Thursday's move a thumbs-up. SoftBank shares rose more than 7% when Tokyo's stock exchange reopened after a three-day public holiday, suggesting investors, at least for now, back Son's strategy.
But bond markets demand repayment regardless of how OpenAI performs. If the AI boom takes longer to monetise than Son expects, the debt bites. The February deal was audacious. Borrowing $11.1 billion to close it out is the moment that audacity becomes concrete arithmetic.
Common questions
What does this mean for people who use ChatGPT?
Day-to-day, nothing changes for ChatGPT users. SoftBank is an investor, not the company that builds or runs the product. OpenAI's development plans and pricing are set independently.
Could this investment go wrong?
Yes. SoftBank is borrowing money to hold a stake in a private company, which means it cannot sell easily if things go badly. If OpenAI's revenues disappoint or the AI market cools, SoftBank faces repaying bonds while its investment is hard to cash out.
