SoftBank launches a jumbo junk-bond sale to fund its next OpenAI tranche

SoftBank Group has launched a high-yield bond sale to bankroll its next payment into OpenAI. The offering is multi-currency: $10 billion of dollar-denominated senior unsecured notes at 3.5, 5.5 and 7.5 year maturities, plus 1 billion euros at 4 and 6 years, for a combined equivalent of more than $11 billion. Fitch has assigned the proposed notes a BB+ rating. Pricing is slated for September 24 with settlement on September 29, ahead of an OpenAI transaction expected to close October 1.

The proceeds are earmarked, not general. They cover SoftBank's $10 billion contribution to the third tranche of its OpenAI follow-on investment and the repayment of the bridge loan that had already funded that commitment. SoftBank's cumulative investment in OpenAI is expected to reach roughly $64.6 billion, an ownership stake of about 13%. A common description of SoftBank Group as a telecom company is wrong and worth correcting: the issuer here is the investment holding company, while the Japanese carrier is the separately listed SoftBank Corp.

Two records are in play, and they are different claims. On size, the deal would be the largest non-financial corporate bond ever from Asia Pacific and Japan, topping the $10.93 billion 7-Eleven raised in January 2021. On cost, price talk of about 10% on the 7.5-year dollar notes and the mid-8% area on the 6-year euro notes would exceed SoftBank's own prior high-yield mark, the 8.5% coupon it printed on a 10-year dollar tranche in April 2026. That is a record for SoftBank's issuance history, not for the high-yield market, and as of publication it is talk ahead of pricing rather than a printed coupon.

MarketWatch frames the significance the way the market is reading it: the AI build-out is crossing into junk bonds, where investors expect to be paid more for taking bigger risks . Global AI-related debt issuance has already topped $575 billion in 2026, so the question this deal tests is not whether the money exists but what it now costs.

Early demand has been heavy, with more than $20 billion of indicated interest reported ahead of pricing, which suggests appetite is intact even at a double-digit handle. The numbers to watch Thursday are the final coupons against the talk and whether the book holds at size. A deal that prices inside talk would say AI credit still clears easily; one that widens would be the first hard read that the financing window for this build-out is narrowing.