Anthropic rents all of Colossus 1: why Grok's maker is leasing its first supercomputer to a rival

In an unusual deal between AI rivals, Anthropic, the company behind the Claude chatbot, will use all of the computing capacity at Colossus 1, the Memphis supercomputer that xAI built to train Grok. Anthropic announced the agreement with SpaceX, which now owns xAI, on Wednesday, May 6, at its developer conference in San Francisco.

The key facts

• Capacity: more than 300 megawatts of AI computing power.
• Chips: more than 220,000 Nvidia GPUs, including H100, H200 and GB200 accelerators.
• Timing: Anthropic said it expects access within the month.
• Money: financial terms and the length of the contract were not disclosed.

Anthropic said the extra capacity will let it raise usage limits for Claude Pro and Max subscribers, including for its Claude Code tool, and lift API rate limits on its Opus models, which had been held back by a shortage of computing power. The deal comes on top of recent capacity agreements with Amazon, Google, Microsoft and Nvidia.

Why SpaceX is renting it out

Colossus 1 was built by xAI in 2024 and was where Grok was trained. Elon Musk said SpaceX was comfortable leasing it because its AI unit has already moved its training work to Colossus 2, a much larger site nearby. Renting out the older cluster turns an asset that would otherwise sit partly idle into a source of revenue.

Musk wrote on X that he had spent the past week with senior Anthropic staff and found them highly competent. He also said SpaceX keeps the right to take the computing power back if Anthropic's AI "engages in actions that harm humanity". SpaceX added that Anthropic has expressed interest in working with it on AI data centers in orbit, though no agreement on that was announced.

A rival as a customer

The arrangement is striking because Grok and Claude compete for the same users and business customers. It shows that, for now, computing power is so scarce that even competitors are willing to buy it from each other. For SpaceX, it is an early sign that its AI business can sell capacity, not only chatbot subscriptions.

The Memphis sites also carry baggage. xAI faces legal disputes over gas turbines used to power Colossus 1 and Colossus 2, which residents say have worsened air pollution in Memphis and nearby Southaven, Mississippi.

The Tesla link

There are three connections to Tesla:

• Batteries: Tesla has sold Megapack batteries to xAI since 2024 to help power and stabilise its Memphis area data centers. More demand for computing power at these sites is, indirectly, more demand for Tesla storage.
• Ownership: Tesla invested $2 billion in xAI in January 2026. When SpaceX took over xAI weeks later, that stake became a small holding in SpaceX, so Tesla shareholders have a small indirect interest in deals like this one.
• Grok in the car: Grok is the voice assistant in Tesla vehicles. Leasing out Colossus 1 does not change that, but it shows that SpaceX now treats its data centers as a business in their own right, alongside the models that end up in Tesla cars.

What to watch next

• Whether Anthropic's capacity comes online within the promised month.
• Any follow-up deal on orbital data centers.
• Other outside customers for SpaceX's computing capacity, and how that is reported in SpaceX's planned IPO filing.