SoftBank stock surged up to 7% on Thursday before nearly giving back the entire advance, underscoring how divided investors remain over the economics of Masayoshi Son’s OpenAI bet.
The stock touched ¥6,793 after Tokyo reopened from a holiday, then fell to ¥6,351 by 10:57 am before recovering to about ¥6,507 by 11:29 am.
The move came as SoftBank completed an $11.1 billion bond sale to fund another $10 billion investment in OpenAI.
SoftBank solved the funding problem
SoftBank sold $10 billion of dollar-denominated senior notes alongside €1 billion of euro debt.
The dollar tranches included $1 billion due in 3.5 years at 8.625%, $4.5 billion due in 5.5 years at 9.25% and another $4.5 billion due in 7.5 years at 9.75%.
The euro offering was split into two €500 million tranches paying 7.125% and 8%.
The proceeds will largely fund the final $10 billion instalment of SoftBank’s latest $30 billion follow-on investment in OpenAI, scheduled to close around October 1. Once completed, SoftBank says its cumulative investment in OpenAI will reach $64.6 billion.
Investor demand for the deal exceeded $20 billion in preliminary orders, according to a Bloomberg report.
The initial share-price reaction therefore had logic. SoftBank converted a near-term financing requirement into longer-dated debt.
Bloomberg Intelligence analyst Kirk Boodry said issuing bonds “pushes the maturity out by several years”, reducing the immediate refinancing pressure.
The price of that extra time is high
Longer maturities improve SoftBank’s funding timetable, but they do not make the OpenAI wager cheap.
Almost half of the dollar issuance carries a 9.75% coupon, while another $4.5 billion costs 9.25% annually. Those rates show bond investors demanded substantial compensation despite the strong order book.
Analysts warned that SoftBank’s funding costs were rising as offshore bond spreads widened amid concerns about debt supply and its expanding OpenAI exposure.
They also noted that delays to an eventual OpenAI listing could postpone SoftBank’s ability to monetise its stake.
That is the central equity-market problem. SoftBank is borrowing at close to 10% on part of the financing today in the expectation that OpenAI will create substantially more value tomorrow.
OpenAI timing now matters more
SoftBank’s exposure will become increasingly sensitive to events it does not fully control.
Morningstar analyst Dan Baker said after SoftBank’s sharp September 14 selloff that the weakness “probably reflects the possibility that AI development may be slowed by regulators” in response to safety concerns raised by leading AI companies.
That risk matters more when capital is expensive, as OpenAI does not need to fail for SoftBank’s returns to disappoint.
A delayed listing, slower development, additional restrictions or a weaker valuation could simply push the eventual payoff further into the future.
Thursday’s opening surge also reflected catch-up trading after Japanese markets reopened, with local AI and semiconductor shares reacting to gains in overseas technology stocks during the holiday break. That makes it difficult to attribute the full early jump to the bond sale alone.
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