SpaceX's S-1 filing with the SEC this week revealed a striking figure: Anthropic will pay $1.25 billion per month to lease compute capacity from the Colossus cluster.
The contract runs through May 2029, covering 36 months. Annualized, that's $15 billion; total value is $45 billion.
How Big Is This Deal?
SpaceX's annual revenue is around $18 billion. Anthropic's compute payments alone will account for nearly 8% of that total.
More telling is SpaceX's own language in the filing:
"Allows us to monetize unused compute capacity in our infrastructure."
In plain terms: SpaceX has idle compute capacity and is selling it. The Colossus data center, under Elon Musk's xAI, was originally built for Grok. But Grok's user growth has slowed over the past six months, leaving capacity free. SpaceX and xAI merged their compute assets earlier this year, so SpaceX now contracts with large clients like Anthropic.
Key Contract Details
- Compute scale: 300 MW total power across Colossus 1 and the expanding Colossus 2
- GPU configuration: Nvidia GB200 clusters (Blackwell Ultra generation)
- Ramp discount: Proportional discounts in May and June as Colossus 2 is still being installed
- Exit clause: Either party can terminate with 90 days' notice, making the $45 billion a "renewable" floating commitment
Anthropic's compute chief Tom Brown stated directly:
"We're expanding our partnership with SpaceX, and will be scaling up on (Nvidia) GB200 capacity in Colossus 2 throughout June."
The GB200 is Nvidia's flagship Blackwell Ultra chip, offering more than double the inference performance per card compared to the H100. With these chips, Anthropic's Claude Opus series will see improved inference speed and reduced cost pressure.
Why Doesn't Anthropic Build Its Own Data Centers?
Many wonder: why spend $45 billion renting when you could build your own? The problem is Anthropic doesn't have three years to wait for a data center to be built.
The company reported Q1 revenue of $4.8 billion and expects Q2 revenue of $10.9 billion, doubling quarter over quarter. Dario Amodei has said that while they planned for 10x growth, they encountered 80x. At that pace, building a data center from scratch—land, power, installation, commissioning—takes at least 18 to 24 months. Anthropic can't afford that window.
| Option | Time to Live | Control | Cash Pressure |
|---|---|---|---|
| Rent SpaceX's existing capacity | Immediate | Low | $1.25B/month |
| 10-year commitment with AWS | Available now | Medium | Spread over 10 years |
| Build own data center | 18-24 months | High | Massive upfront capex |
Anthropic is pursuing all three paths simultaneously: contracts with AWS, Google, and SpaceX. The SpaceX deal is the fastest to go live.
Musk's Calculus
On the surface, it seems contradictory: Musk is suing OpenAI for unfair competition while supplying compute to Anthropic. But from SpaceX's financial perspective, this is a straightforward wholesale compute deal. xAI invested billions in the data center, but Grok didn't attract enough users. Excess capacity would either depreciate or be sold. Naturally, they sell it.
This practice of AI companies renting compute to each other has a new name: neocloud. The logic is simple:
- Top AI firms are all building their own compute (OpenAI with Oracle, Anthropic with AWS)
- But building too much leads to waste; building too little leads to shortage
- A secondary market emerges: today I rent my excess to you; tomorrow you rent yours to me
xAI (now under SpaceX) is a standard neocloud seller. In a year or two, if Grok takes off, the 90-day termination clause could be triggered to reclaim capacity for internal use.
Who Gives Way?
The 90-day exit clause is Anthropic's safety net. If SpaceX adjusts pricing or needs to reclaim the data center for itself, Anthropic isn't locked in. But SpaceX can use the same clause: if Grok truly takes off and needs the capacity, it can give Anthropic 90 days' notice to vacate.
So the $45 billion figure is more of a "maximum expected" amount, not a fixed final sum.
Conclusion
The $45 billion buys not just compute, but time. Anthropic is paying for the ability to run models now. Whether it's worth it—compare that to Anthropic's expected operating profit of $559 million. Monthly payments of $1.25 billion versus quarterly profit of $559 million. How long that profit line holds will become clear in the second half of the year.
Sources: Anthropic Will Pay xAI $1.25B Per Month for Compute (TechCrunch); CocoLoop; Anthropic is Paying SpaceX $15 Billion Per Year (Axios); SpaceX Discloses $1.25 Billion Monthly AI Compute Deal With Anthropic in IPO Filing (BigGo Finance)