Why Does Even Rival Anthropic Rent Colossus Compute?

In May 2026, Anthropic, the maker of Claude, rented the entire compute capacity of SpaceX’s Colossus 1 data center. At first glance that looks odd: Claude is a direct rival of Grok, which SpaceX owns. It is like Coca-Cola buying production lines from Pepsi.

But the deal shows one thing: AI compute is now a business you can buy and sell. To get to know SpaceX and its AI holdings first, see What Is SpaceX?.

First, what the deal looks like

On May 6, 2026, xAI (now SpaceX’s AI division, SpaceXAI) and Anthropic announced together that Anthropic would use all of Colossus 1’s compute: over 220,000 GPUs and over 300 megawatts of power, to expand Claude’s service capacity. On May 28, Anthropic added that it also has GPU capacity on Colossus 2.

On price, SpaceX’s IPO filing (the S-1) states about US$1.25 billion per month. Anthropic’s own announcement gave no price.

There are two accounts of how long it runs:

The S-1: monthly fees run through May 2029; for the early limits on ending the deal, see the quarterly report below.
Musk (on X, late May 2026): it is a “180-day short lease,” after which either side can end it with 90 days’ notice, and the short term was SpaceX’s own request.

SpaceX’s August 2026 quarterly report (10-Q) only gives the general rule: after the first few months of setup, either side of these compute contracts can end them with 90 days’ notice. It does not mention 180 days. As of October 2026, neither side has publicly explained the gap.

What Colossus is, and why it can be rented out

Colossus is a large AI compute cluster that xAI built itself in Memphis, Tennessee. The key word is “itself”: most AI companies rent compute from cloud providers, but xAI built its own data center and owns the hardware.

That lets SpaceX offer spare compute to outside customers as another source of income. For the whole supply chain, read The AI Hardware Supply Chain, End to End.

Why Anthropic would rent from a rival

The answer is practical: there is not enough compute. AI models keep getting bigger, and demand for GPUs and data centers far exceeds supply. For a fast-growing AI company, getting compute is more urgent than whether the supplier is a rival.

And Anthropic does not rent only from SpaceX. It spreads orders across several providers, and this is just one deal.

Why SpaceX would rent to a rival

First, turning spare compute into cash, so idle capacity becomes a service sold to others.

Second, adding a revenue line. SpaceX listed on Nasdaq on June 12, 2026 (ticker SPCX), and compute rental now shows up in its results: in Q2 2026, AI division revenue was about US$2.56 billion, and the main driver of year-over-year growth was renting compute to outside customers, which added about US$1.6 billion in revenue. For how to read these numbers, see How to Read SpaceX’s IPO Financials.

Anthropic is no longer the only tenant. According to reports, Google pays about US$920 million per month from October 2026 through June 2029, and open-source AI startup Reflection pays about US$150 million per month to use Colossus 2. Compute contracts SpaceX signed in Q2 totaled US$14.1 billion in contract sales over their non-cancellable periods.

The industry truth this deal reveals

AI’s “compute layer” is becoming a business separate from the “model layer.” At the model layer, Grok and Claude are rivals competing for users. At the compute layer, data centers, power, and chips are scarce; whoever builds them first can sell them, and even rivals become customers.

It is like phone brands competing while a parts maker supplies all of them. The cost is dependence: when you rent compute from a rival, after the initial setup period either side can end the deal with 90 days’ notice. The tenant has to carry that risk.

Penchan’s summary

Anthropic renting Colossus from a rival is a rational choice in a compute shortage. Models can be enemies while compute is a business; whoever can build the data centers has even rivals coming to the door.

FAQ

Aren't Anthropic and SpaceX competitors? Why rent compute from it?

At the model layer, Claude and SpaceX’s Grok are rivals; at the compute layer, Anthropic is the customer and SpaceX the supplier. AI compute is in short supply, so getting enough data center capacity matters more than whether the other side is a rival. Anthropic also rents compute from several providers at once; this is just one deal.

What is Colossus?

Colossus is a large AI compute cluster that xAI (now SpaceX’s AI division, SpaceXAI) built itself in Memphis, Tennessee. The first generation, Colossus 1, has over 220,000 graphics chips (GPUs) and over 300 megawatts of power. This compute can be offered to outside customers.

How long is the deal, and how much is it?

The S-1 states a monthly fee of about US$1.25 billion, paid through May 2029; Musk called it a 180-day short lease. The August quarterly report says that after an initial setup period, either side of these contracts can end them with 90 days’ notice. As of October 2026, the accounts of the term still don’t line up.

Why would SpaceX rent compute to a rival?

First, to turn spare compute into cash. Second, to add a revenue line: in Q2 2026, renting compute to outside customers brought SpaceX’s AI division about US$1.6 billion in added revenue, and Google and Reflection also became customers.