OpenAI's Altman Warns of 'Unsustainable Silliness' in AI Compute Buildout, Flags Neocloud Bubble

OpenAI CEO Sam Altman warned on Alex Heath's Sources podcast that he is seeing 'the first signs of what feels to me like unsustainable silliness' — new 'neocloud' companies pledging gigantic amounts of compute for next year with no matching revenue or buyers. Altman drew a sharp line between OpenAI ('I'm not worried about our compute buildout plans') and the rest of the market ('I am worried about the world's compute buildout plans'), and traders have used the comments this week to reassess CoreWeave, Nebius and IREN.