Meta Quietly Became One of Microsoft's Biggest AI Buyers

Meta spends its days telling the world it will build artificial intelligence at a scale nobody else can match. It turns out the company is also one of Microsoft's largest AI customers. Bloomberg reported on 20 August that Meta pays Microsoft hundreds of millions of dollars a year to use outside AI models through Azure's Foundry marketplace, and runs trillions of tokens through them every week.

What is Meta doing with all that outside compute? Much of it, according to the report, goes to software development and testing. In one striking detail, Meta engineers use OpenAI's models to grade the output of Meta's own systems. The maker of Llama is renting a rival's judgement to mark its own homework.

A loop that pays Microsoft at every turn

The arrangement is a tidy illustration of how tangled the AI economy has become. Meta builds models. Microsoft distributes models on Azure, including those from OpenAI and Anthropic. Meta buys that access to sharpen its own products. Microsoft then hosts Meta's improved models for other customers. Microsoft collects a fee on every leg of that circle.

That circularity is exactly what has made some investors uneasy. A growing share of AI revenue comes from AI companies selling to one another, which can make demand look sturdier than it really is. We looked at that worry recently when we asked whether the AI bubble is about to burst, and again when Nvidia turned to Wall Street to fund a half-trillion-dollar buildout.

Read it with some caution

One note of restraint. Both companies declined to comment, so the dollar figures, the token volumes and Meta's exact rank among Microsoft's customers all rest on Bloomberg's sourcing rather than anything either firm has confirmed. What is not in doubt is the wider pattern. Meta has guided investors toward $130bn to $145bn in capital spending this year, even as it reportedly plans a cloud business to compete with the very company it is now buying from. The lines between customer, supplier and competitor in AI have all but dissolved.