SoftBank shares tumble 13% as AI leaders call for safety slowdown

SoftBank Group’s stock dropped more than 13% on September 14, 2026, its steepest single-day fall since late June. The trigger was not an earnings miss or a regulatory crackdown. It was a pair of essays and statements from the very people running the AI companies SoftBank bet its future on. What Amodei and Altman actually said Anthropic CEO Dario Amodei published an essay on September 12 calling for a deliberate deceleration in the development of the most powerful AI models. His argument was rooted in safety, not competitive strategy: the technology is advancing faster than humanity’s ability to understand or govern it. OpenAI CEO Sam Altman aligned himself with that position and went a step further. He described the current moment as an “ill-advised” time for OpenAI to pursue an initial public offering, a comment that sent a secondary shockwave through SoftBank’s already rattled investor base. That second point matters enormously for SoftBank. The Japanese conglomerate has committed roughly $65 billion to OpenAI, building toward an ownership stake of around 13%. At that scale of exposure, OpenAI’s IPO timeline is not just a corporate milestone. It is SoftBank’s liquidity event, the...