SoftBank borrows $11.1 billion at up to 9.75 percent to make its last $10 billion payment to OpenAI

SoftBank priced $11.1 billion of bonds on 24 September to fund the final $10 billion tranche of its $30 billion OpenAI investment. By our arithmetic the interest comes to about $1 billion a year, and S&P and Fitch rate the bonds one step below investment grade.

24 September 2026 · 3 min read · Band Money · The Pulse, 24 September 2026

In this story: OpenAI

What happened

On 24 September SoftBank Group set the terms for about $11.1 billion of new bonds: $10 billion in dollars and 1 billion euros, in five parts that mature between 2030 and 2034. SoftBank says the money is "for funding the USD 10 billion payment for the third and final tranche of the USD 30 billion follow-on investments in OpenAI Group PBC entered into in February 2026", a payment it expects to close on 1 October, and for general corporate purposes. The bonds are due to be issued on 29 September. At the same time, SoftBank expects to cancel the $10 billion it never drew from a $40 billion bridge loan it signed in March. About two weeks earlier, on 9 September, it said it would repay the $25.9 billion still owed on that bridge loan on 15 September.

Why it matters

This is borrowed money paying for an AI company's growth. The interest rates run from 7.125 percent on the shorter euro bonds to 9.75 percent on the longest dollar bonds. On that longest part alone, $4.5 billion at 9.75 percent, SoftBank will pay about $439 million a year in interest. Across all five parts, at the exchange rate in SoftBank's release, the interest comes to roughly $1 billion a year, by our arithmetic. S&P and Fitch both rate the bonds BB+, one step below investment grade. Reuters, reporting the launch on 21 September, said that at its planned size the sale would be the largest non-financial corporate bond deal on record from Asia-Pacific and Japan, ahead of 7-Eleven's $10.93 billion sale in January 2021, according to LSEG data.

Japan Credit Rating Agency, which rates SoftBank A with a negative outlook, wrote in April that SoftBank's total investment in OpenAI is expected to reach $64.6 billion, including the investment announced in February. It also wrote that SoftBank's loan-to-value ratio, a measure of its debt against the value of what it owns, may come close to 25 percent because of the $30 billion OpenAI investment planned for 2026.

What would change it

The next date is 1 October, when SoftBank expects the OpenAI payment to close, two days after the bonds are issued. After that, watch the ratings: a change by S&P, Fitch or Japan Credit Rating Agency would show how they judge this level of borrowing. So would the interest rate SoftBank has to pay the next time it sells bonds.

What we do not know

Reuters' report on the launch is the one independent account of this sale behind this story. The rating agencies' own reports on these bonds were not read; their BB+ ratings appear here as SoftBank's release lists them. Japan Credit Rating Agency's figures date from April, before this sale, so they describe SoftBank's position going in. We also do not know what the third tranche changes in SoftBank's stake in OpenAI, or whether more money will be committed.

What this changes for you

Nothing changes in what you pay for ChatGPT or any OpenAI product today. What it shows is how the money behind those products arrives: a large part of it is borrowed, at interest rates of up to 9.75 percent, by an investor one step away from the product itself.

Sources

Everything above is written from these. Each line says what that document proves.

1. group.softbank: SoftBank's own release, 24 September 2026: about $11.1 billion of notes in five parts from 2030 to 2034 at 7.125 to 9.75 percent, issue date 29 September, BB+ ratings from S&P and Fitch, the use of proceeds for the third and final $10 billion OpenAI tranche expected to close on 1 October, and the cancellation of $10 billion of undrawn bridge capacity.
2. whtc.com: Reuters' report on the launch, 21 September 2026, read in a syndicated copy: the maturity ladder, the record-size comparison with 7-Eleven's $10.93 billion sale in January 2021 from LSEG data, and Fitch's BB+ rating on the proposed notes.
3. group.softbank: SoftBank's release of 9 September 2026: repaying on 15 September the $25.9 billion outstanding on its $40 billion bridge facility, of which $30 billion had been drawn.
4. jcr.co.jp: Japan Credit Rating Agency's rating note of 30 April 2026: SoftBank rated A with a negative outlook, its OpenAI investment expected to reach $64.6 billion, and a loan-to-value ratio that may come close to 25 percent.

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