Shares slid 6.5% to $19.78 as SoftBank Group priced the largest high-yield corporate bond sale in history — an $11.1 billion offering to complete its massive bet on OpenAI. The cost of insuring SoftBank's debt against default has shot up, with the five-year credit default swap spread exceeding 400 basis points this week — a level that signals real stress. For shareholders, the question is whether Masayoshi Son's conviction trade will pay off before the debt bill comes due.
The Borrowing Is Enormous, and the Interest Rates Prove It. SoftBank is offering $1 billion in 3.5-year notes at 8.625%, $4.5 billion each in 5.5- and 7.5-year notes at 9.25% and 9.75% , plus two €500 million euro tranches at 7.125% and 8% . Those are punishing rates — roughly double what investment-grade companies pay — meaning interest expenses alone will run well over $900 million a year. SoftBank has already sold nearly $15 billion in multi-currency notes this year, making it 2026's largest junk-rated borrower in the bond markets.
Nearly All of SoftBank's Value Now Rides on Two Assets. SoftBank's holdings in Arm and OpenAI make up three-quarters of the group's asset value at current levels , according to CreditSights. SoftBank's cumulative investment in OpenAI will reach $64.6 billion, giving it approximately 13% of the company upon completion. That concentration means any setback in AI spending — or a downturn in Arm's chip business — would hit SoftBank's balance sheet with outsized force.
The IPO Exit SoftBank Needs Has Been Pushed Back. Shares fell as much as 13% on September 14 after Sam Altman confirmed OpenAI's IPO won't happen until 2027, with CFO Sarah Friar warning the company isn't ready for public markets. SoftBank was counting on a listing to create liquidity and reduce its reliance on debt. Hopes for cash through public listings of OpenAI and data-center subsidiary SB Energy were dented as both delayed IPO plans set to launch as early as this month.
Credit Analysts Are Sounding Alarms. CreditSights' Mark Chapman wrote: "Risks for SoftBank credit are material and have increased as concentration has increased and cash flow has come under material strain."
The yield on SoftBank's dollar bond maturing in 2031 rose to 8.2% from as low as 6.7% in January , a widening that directly raises the cost of every future dollar SoftBank borrows. If the AI thesis works, Son looks prescient. If it stumbles, this debt wall turns a liquidity problem into an existential one.