The Anthropic-xAI Compute Deal Made Musk Everyone's Landlord

Today we follow the money in the AI arms race.

And it leads somewhere very strange.

One bill. One filing.

One very awkward landlord…

The Anthropic-xAI compute deal proves the AI race stopped being a software fight and became a rent war.

SpaceX's IPO filing dropped Wednesday. It shows Anthropic will pay xAI $1.25bn a month through 2029 to rent the Colossus 1 data centre near Memphis. That single bill, roughly $15bn a year, is the clearest public price tag yet on frontier-scale compute. But the strange part isn't the number. It's who built the data centre, and why he was so keen to hand it to a rival he'd mocked weeks earlier.

Two months ago Musk called Anthropic "misanthropic."

Turns out his evil detector takes cheques.

Anthropic gets the full output of Colossus 1: over 220,000 Nvidia GPUs and 300 megawatts of power.

The total contract could hand xAI more than $40bn by 2029. For scale, the yearly $15bn rent is close to SpaceX's entire annual revenue. Anthropic is not buying these chips.

It is renting them, the way you rent a flat you cannot afford to build.

Now the awkward part.

Colossus 1 was built to train Grok, xAI's own chatbot. But Grok stumbled. App downloads reportedly fell from 20m in January to 8.3m by April, a 60% drop in three months. The kit was also a mess to train on, with three generations of Nvidia chips bolted together. So Musk did the maths: rent the idle hardware to a rival rather than let it gather dust.

SpaceX calls it monetising "unused compute capacity." We call it a landlord papering over an empty building.

The whole industry is caught in the same trap.

The big four (Amazon, Google, Meta, Microsoft) are set to spend up to $700bn on AI infrastructure this year alone. Ideas are cheap now; the GPUs to run them aren't. When the firm you mocked in March is your best tenant by May…

The scarcity has rewritten everyone's rules.

The contract runs on a 90-day exit clause: either side can walk.

So Anthropic has tied a chunk of Claude's capacity to a man who called it the enemy in March. A man who still builds chatbots of his own. The rent looks cheap until the day he changes his mind.

In an arms race, the firm holding the GPUs holds the leash.

Pro: Renting idle compute is smart for both. xAI earns on dead assets, Anthropic skips a multi-year build and ships better Claude limits now.

Con: A 90-day exit clause and a rival's hardware is a fragile foundation for a company burning $15bn a year on rent.

Our read: This is a supply grab dressed as a partnership. The AI race now runs on whoever's bank balance holds out, not whoever's model is smartest.

[Report] U.S. Securities and Exchange Commission — SpaceX Form S-1

The filing discloses the $1.25bn monthly payments and frames the deal as a way to monetise unused compute.

Why it matters: It is the first time the real price of frontier compute has been put on the public record, in black and white.

xAI was using just 11% of its GPUs. Rivals squeeze 40%+.

TechCrunch — Anthropic will pay xAI $1.25bn a month for compute — the clean breakdown of the filing's terms and the 90-day exit clause.

Tom's Hardware — Why Colossus 1 couldn't train Grok — the messy mix of three GPU generations made the cluster easier to rent than to run.

Fortune — Big Tech's $700bn AI spend has no clear end — the capex backdrop making a $15bn rent bill look almost reasonable.

Renting your rival's data centre is:

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