The gap is reportedly down to big investors cooling on AI as a tech sell-off unfolds, prompted by disappointing quarterly numbers from Google, Amazon and Intel. OpenAI's answer is to turn elsewhere: it reportedly aims to collect as much as $20 billion from family offices and wealthy individuals.

An IPO is also reportedly on the cards for early next year. Anthropic, meanwhile, has lately been expanding its revenue at a quicker clip and might list as soon as November, which could hand it well over $100 billion in capital to ride out any rough patch. OpenAI has recently won back some market share, though the lead keeps changing hands, and it has been leaning on price cuts and more efficient models to defend its position.