What happened
SoftBank shares closed at ¥5,839 on Sept 14, down 10.72%, after OpenAI CEO Sam Altman ruled out a 2026 IPO and both Altman and Anthropic CEO Dario Amodei called for slower AI development on safety grounds.
SoftBank Group shares closed at ¥5,839 on September 14, 2026, down 10.72% (¥701) in Tokyo — their steepest one-day drop since late June — after OpenAI CEO Sam Altman ruled out a 2026 IPO and both Altman and Anthropic CEO Dario Amodei called for a slower AI pace on safety grounds.
Investors are watching whether AI regulatory pressure and a potential moderation in AI development timelines could delay returns on SoftBank's debt-financed bets. Daiwa's Yugo Tsuboi flagged worry that OpenAI's value may not be as high as previously expected, while Morningstar's Dan Baker cited regulatory slowdown risks and loss-of-control fears.
The market reaction underscores a broader repricing of AI-adjacent equities: Wire services reported intraday drops ranging from 11% to 14%, with Bloomberg noting a $32 billion market-cap wipeout. SoftBank CFO signaling another ~$10 billion in borrowing for October's final OpenAI payment adds leverage risk to the story.
Timeline
June 2026 — SoftBank shares hit ¥9,074 peak. Sept 14 — Altman/Amodei safety calls + OpenAI no-IPO news trigger selloff. Shares close ¥5,839.
Key Numbers
~$65B OpenAI commitment | $11.87B loan | -30% from June peak | 10.72% close | 52-week ¥3,365–¥9,074
What to Watch
October 1 OpenAI tranche payment, CFO's ~$10B borrowing signal, and whether AI safety regulation actually slows deployment timelines.
Why it matters for me
Investors face a structural repricing of SoftBank's debt-financed AI bets, with leverage rising as the $11.87B loan and ~$10B more borrowing for October's OpenAI tranche add risk.
Money
Individual Investors · Institutional Investors
SoftBank investors lost ~$32 billion in market cap in a single session as shares dropped 10.72% to close at ¥5,839.
Work
Technology Ai Watchers
AI safety calls from Altman and Amodei may slow deployment timelines, affecting AI-adjacent equity valuations and tech sector employment projections.
Daily Life
General Market Readers
SoftBank's debt-financed Vision Fund model faces a structural test as leverage rises and AI returns stay uncertain.
What to remember
SoftBank's ~$65B OpenAI commitment is now under a regulatory microscope — AI safety calls plus IPO delay are testing whether the Vision Fund model survives.
SoftBank shares drop 10.72% as OpenAI rules out 2026 IPO. Investors rethink ~$65B bet.
Verified sources (4)
SoftBank share price tumbles 14%| What investors need to know
↗SoftBank Shares Slide 13% After AI Chiefs Sound Alarm on Safety
↗SoftBank gets upsized $11.9 billion loan in OpenAI funding push; SoftBank plunges
↗SoftBank Group plunges 11% after OpenAI says no IPO this year
↗Claims and linked sources
8 claimsSoftBank Group Corp shares closed at ¥5,839 on September 14, 2026, down ¥701 (10.72%) from the previous close of ¥6,540, their steepest one-day drop since late June 2026.
The selloff was triggered by weekend statements from OpenAI CEO Sam Altman and Anthropic CEO Dario Amodei calling for a more measured pace of AI development citing safety, and Altman's confirmation that OpenAI would not pursue an IPO in 2026.
SoftBank's total investment in OpenAI is expected to reach close to $65 billion by October 2026, giving it an expected stake of about 13% at a $730 billion pre-money valuation; the third $10 billion tranche is scheduled for October 2026.
SoftBank secured a $11.87 billion two-year loan from roughly 20 banks to support its OpenAI investment on 14 September 2026, on top of a planned ¥1 trillion (~$6.5 billion) retail bond sale.
SoftBank shares had already fallen roughly 30% from their June 2026 peak; the 52-week low is ¥3,365 and the 52-week high is ¥9,074.
Daiwa Securities chief strategist Yugo Tsuboi said there is 'worry that OpenAI's value may not be as high as previously expected,' with investors watching whether the pace of AI development could moderate.
Wire services vary on the drop magnitude: Bloomberg cites >13%, Nikkei Asia reports ~11% close, WION reports ~11.6% at ¥5,781, AP reports 11.2%; the Livemint headline figure of 14% is a peak/intraday characterization, with the confirmed closing drop at 10.72%.
SoftBank repaid the full $25.9 billion OpenAI-related bridge facility on 15 September 2026 and CFO commentary points to another ~$10 billion of borrowing to fund October's final OpenAI payment.
Community signals
Signal-only · not reporting“There's worry that OpenAI's value may not be as high as previously expected.”
“SoftBank's share price slide probably reflects the possibility that AI development may be slowed by regulators to try to avoid the worst case outcomes.”
“An IPO this year would be ill-advised given the current concerns around AI safety.”