Stargate was to be the world’s biggest AI investment: a $500bn infrastructure project to “secure American leadership in AI”. Never shy of hyperbole, its key backer, the ChatGPT-maker OpenAI, promised “massive economic benefit for the entire world” with facilities to help people “use AI to elevate humanity”.

Now, OpenAI appears to be dropping out of a part of the deal – the expansion of a flagship datacentre stretching across a swathe of land in Abilene, Texas, which has become one of the most visible manifestations of a frenzy of investment in the chips and power plants required to build and run AI. There has been a breakdown in negotiations over project financing, as well as the timeline of when the expanded capacity might come online.

This may be fine for OpenAI; it can presumably find other datacentres. It is less fine for OpenAI’s partner on the project, Oracle, which has already spent billions on hardware for the site. It is one of a number of cracks appearing in the capital side of the AI economy that are making investors rather nervous.

Both companies have said the development will not derail their AI plans. They also said that a month ago, when a different $100bn deal melted down between OpenAI and Nvidia, the world’s biggest maker of the chips that train AI models and respond to the billions of questions people ask them daily.

The fate of such deals for the global economy is only increasing in importance. Future datacentre leases agreed by the largest cloud computing companies (including Amazon, Oracle and Microsoft) are up nearly 340% in two years and now top $700bn, according to Bloomberg. It is a lot of money if the technology does not start delivering on its promise to supercharge economic productivity. On Friday, more than three years since the launch of ChatGPT unleashed the AI hype, the UK reported zero GDP growth for January.