There’s a lot of mystery around the finances of major AI labs, and as Anthropic inches towards it IPO, we’re starting to get some answers. In particular, the company is finally disclosing more about the economics of compute, and how much of Anthropic’s skyrocketing revenue is being lost to compute costs.

In a new filing on Monday, Anthropic released data that showed those margins on compute actually getting worse. The filing was an update to the S-1 released last week — but where that filing’s financial disclosures only covered through June 30 of this year, the new data extended to disclose results through an extra quarter, to September 30. Broadly, Anthropic had a good quarter: revenue reached $17 billion, up from $11.5 billion in the previous quarter, suggesting durable growth. But the operating loss grew at the same time, thanks in large part to growing compute costs.

Looking at the compute margins makes the picture even worse. In the new quarter, compute took up 58% of the company’s revenue, up from 48% the quarter before. At a moment when the company could win over IPO investors by showing margins improving, they’re getting worse.

A chart in the filing shows this even more clearly, tracking the company’s revenue for every dollar spent on compute. Since the start of 2025, it’s been steadily growing, peaking at just over 2x this past quarter, then falling back down to 1.72x.

Image Credits:Anthropic S-1 filing

Many indications imply that this shift in compute margins is more of a blip than a long-term problem, but it still tells us important things about the business of running a major lab. Trying to keep up with demand, Anthropic’s compute bill shot up to $10 billion for the quarter, including, as the filing notes, “$5.0 billion of compute under short-term commitments, which currently costs significantly more than comparable compute procured under our multi-year commitments.” Basically, demand was growing so fast that Anthropic had to scramble for compute, which meant paying higher rates.

Some of those deals have already played out in public. Anthropic has been paying SpaceX $1.25 billion a month for compute, alongside multibillion-dollar deals with Nscale, Akamai, and Volta. In the parlance of the industry, these are neoclouds rather than hyperscalers — smaller outfits that offer more flexible compute deals at higher rates.

Anthropic’s margins got worse in Q3 because of deals like these, and there’s no sign they’ll be able to do without them anytime soon. As the new filing puts it, “We expect compute and infrastructure expenses to increase in absolute dollars and remain our largest operating expense for the foreseeable future as additional committed compute becomes available to us under multi-year arrangements with CSPs, and as we continue to invest in additional compute.”

Anthropic is still trying to lower its compute costs. In particular, the company talks quite a bit about its efforts to build its own compute base under a project it calls “Anthropic Direct.” But with demand growing so fast, those efforts aren’t going to be able to keep pace, and the neoclouds will continue to be the best option they have.

In a sense, these are champagne problems. As long as revenue is growing at nearly 50% a quarter, few investors will worry about high compute costs — and the moment demand slows down, investors may be comforted by a compute picture that has gotten a lot sunnier. But it’s a reminder of how much AI labs still depend on the trillion-dollar infrastructure buildout — and how vulnerable they are to hiccups in that process. It’s easy to imagine the data center buildout slowing down over the next year if bond markets get skittish or local opposition gets more intense. There’s not much Anthropic can do to address either of those risks, and either one would make a messy compute picture a whole lot messier.

In the meantime, the future of Anthropic and other labs will be at the mercy of compute prices.