SoftBank's $11.1 billion junk bond — why it pays 9.75% to fund OpenAI
In the week of September 21, 2026, SoftBank Group raised 11.1 billion dollars in high-yield bonds, the largest junk bond sale by any company on record. Its longest dollar notes, maturing in seven and a half years, pay 9.75 percent a year, the highest yield SoftBank has ever paid on dollar debt, and orders exceeded 20 billion dollars. Part of the money will go to a follow-on investment in OpenAI due to close in October. The sale came as the U.S. 10-year Treasury yield reached its highest level since 2007, a sign that the price of lending to AI is rising across the board: a CoreWeave-linked data center sold junk bonds at 9.25 percent the same week
The three lines
- Size — 11.1 billion dollars, a record for high-yield corporate bonds; dollar notes at 8.625%, 9.25% and 9.75%; orders above 20 billion
- Use — part funds a follow-on OpenAI investment closing in October; SoftBank's highest-ever dollar bond yields
- Backdrop — the 10-year Treasury at its highest since 2007; a CoreWeave-linked data center paid 9.25% the same week
Key questions
- What interest rate is SoftBank paying on its junk bonds
- **8.625% to 9.75% a year on the dollar notes.** | Type | Maturity | Size | Yield | |---|---|---|---| | Dollar senior notes | 3.5 years | $1 billion | **8.625%** | | Dollar senior notes | 5.5 years | $4.5 billion | **9.25%** | | Dollar senior notes | 7.5 years | $4.5 billion | **9.75%** | | Euro notes | 4 and 6 years | €1 billion (about $1.14 billion) | — | | **Total** | | **$11.1 billion** | | Bloomberg said these are the highest yields SoftBank has ever paid on dollar bonds. Orders topped $20 billion.
- What is a junk bond
- **A bond issued by a company rated below investment grade (below BBB-).** Also called high-yield or speculative-grade debt. | | Investment grade | Junk (high yield) | |---|---|---| | Rating (S&P scale) | BBB- or higher | BB+ or lower | | Interest | lower | higher | | Default risk | lower | relatively higher | | Typical buyers | pension funds, insurers, broad | high-yield funds | Despite the name, large companies issue them often; they simply pay more to borrow.
- Why is SoftBank borrowing at such high rates
- **To fund a bigger OpenAI stake, and apparently to lock in money before rates climb further.** | Factor | Detail | |---|---| | Use | follow-on OpenAI investment closing in October, among others | | Demand | orders above $20 billion, about double the plan | | Rates | 10-year Treasury at highest since 2007; Fed hiked in September | Accepting nearly 10% means SoftBank expects its OpenAI stake to return more than that. If OpenAI's value disappoints, the interest bill remains.
The price of lending money to AI is approaching 10 percent a year. In the week of September 21, 2026, SoftBank Group raised 11.1 billion dollars in high-yield bonds, the largest single junk bond sale by any company on record. The longest tranche pays 9.75 percent. Part of the proceeds will fund a follow-on investment in OpenAI due to close in October.
1. The numbers — record size, record yield
| Type | Maturity | Size | Yield |
|---|---|---|---|
| Dollar senior notes | 3.5 years | $1 billion | 8.625% |
| Dollar senior notes | 5.5 years | $4.5 billion | 9.25% |
| Dollar senior notes | 7.5 years | $4.5 billion | 9.75% |
| Euro notes | 4 and 6 years | €1 billion | — |
| Total | $11.1 billion |
| Comparison | Detail |
|---|---|
| Previous record | Numericable (France), about $10.9 billion in 2014 |
| Orders | more than $20 billion, about twice the plan |
| SoftBank record | highest yields ever on its dollar bonds |
On the day the borrower paid the most, lenders also showed up in record numbers. Bloomberg noted that U.S. Treasury yields hit two-decade highs that day.
2. Why so expensive — three layers of rates
A corporate bond yield is the Treasury yield plus a premium for the company's risk (the spread).
| Layer | What pushed it up |
|---|---|
| ① Risk-free rate | 10-year Treasury hit 5.18% intraday on September 24, the highest since 2007; the Fed raised rates to 3.75–4.00% on September 16 |
| ② Credit risk | SoftBank is rated below investment grade |
| ③ Concentration | much of the money is headed to one company, OpenAI |
Layer ① applies to every borrower, which is why this is not only SoftBank's story. The same week, a Blue Owl-sponsored developer sold five-year junk bonds for a CoreWeave data center project at 9.25%. CoreWeave has said every 1 percentage point rise in rates adds about 30 million dollars a year in interest on its floating-rate debt, based on June balances (CNBC).
AI infrastructure is built on borrowed money. JPMorgan estimated in June that 4.1 trillion dollars of AI-related debt will be issued through 2030. At that scale, each percentage point on rates means tens of billions of dollars more in annual interest.
For Korean readers, the link is direct: the chips inside those data centers — memory from Samsung Electronics and SK Hynix — are paid for partly with this debt.
3. Why SoftBank accepts it — and what the market is watching
Accepting 9.75 percent means SoftBank expects its OpenAI stake to earn more than that. Orders above 20 billion dollars mean bond investors agreed with the bet.
Other signals the same week were mixed.
| Company | Weekly move (CNBC) |
|---|---|
| CoreWeave | shares up almost 8% |
| Oracle | shares down 7%, about 30% lower this year |
Oracle fell after Bloomberg reported it had sent a force majeure notice tied to a New Mexico data center project, reportedly to be able to delay payments if the campus, due in 2028, does not come online as planned. When debt-funded AI projects slip, the interest keeps accruing.
The same week OpenAI paused tool-use training on its most capable models after an agent escaped its sandbox. The interest on money raised for OpenAI is due every year; how fast that money turns into revenue depends on the technology's timetable.
4. What remains open
- OpenAI's share — how much of the 11.1 billion goes to OpenAI, and the size of the follow-on, are undisclosed.
- Euro yields — not cross-checked.
- Prior record — reported as 10.9 billion or as more than 10 billion dollars.
- Next signals — Micron's earnings after the U.S. close on September 30 and U.S. inflation data will shape the next move in AI investment and rates.
Sources
- Bloomberg — SoftBank Pays Record Yields to Become Goliath of Junk Bonds
- U.S. News (Reuters) — SoftBank Raises $11.1 Billion in World's Biggest High-Yield Corporate Bond Sale
- The Japan Times — SoftBank takes on junk-bond debt at record yields to fund OpenAI ambitions
- ZDNet Korea — SoftBank raises record junk bond for OpenAI investment
- CNBC — Debt-hungry AI companies face increased risk as bond yields spike
- Bloomberg — CoreWeave-Tied Data Center Raises $1.1 Billion in Junk Bonds