Anthropic SpaceX Deal: AI Lab Is Now SpaceX’s Largest Customer
Anthropic, the maker of the Claude AI models, is the unnamed “Customer B” that accounted for 34.5% of SpaceX’s third-quarter 2026 revenue, Bloomberg reported on Thursday, October 29, citing a person familiar with the matter. The Anthropic SpaceX compute deal makes the AI lab SpaceX’s largest single customer, ahead of the US government.
What the Anthropic SpaceX Filings Show
SpaceX’s quarterly report (Form 10-Q), filed with the SEC on October 22, lists two customers that each brought in more than 10% of revenue but does not name them. According to the filing:
- SpaceX reported Q3 2026 revenue of $14.575 billion, up from $5.576 billion a year earlier, and net income of $4.404 billion.
- “Customer B” made up 34.5% of Q3 revenue, which works out to roughly $5 billion. In the same quarter of 2025 it was below the 10% reporting threshold.
- All of Customer B’s revenue sits in SpaceX’s SI segment, the AI business that rents out data center capacity. That segment brought in $7.56 billion in the quarter.
- “Customer A”, which spans all three SpaceX segments, accounted for 16.6% of revenue.
The filing describes these cloud contracts as carrying a fixed monthly fee, with terms that typically run three years and can be ended by either party on 90 days’ notice.
Anthropic’s IPO Filing Points the Same Way
The report lines up with what Anthropic disclosed in its own IPO paperwork this week. As we covered when Anthropic filed for its Nasdaq IPO, the S-1 registration statement details agreements to buy Nvidia GPU-based computing capacity from SpaceX worth up to $120.5 billion through 2029. Anthropic expects to pay about $3.1 billion a month once all of that capacity is delivered.
That figure is a ceiling rather than a guaranteed payment. After initial periods that end in January and March 2027, either company can terminate the agreements with 90 days’ notice. Neither SpaceX nor Anthropic has publicly confirmed that Anthropic is Customer B.
Why It Matters
The disclosure shows how quickly AI compute has become a major business for SpaceX, which until recently earned most of its money from rocket launches and Starlink internet service. It also highlights how dependent SpaceX’s AI revenue now is on a single buyer whose contract can be cancelled after early 2027.
For Anthropic, the deal is one of several huge infrastructure commitments revealed in its prospectus, alongside multi-year cloud agreements with Google and Amazon. The company is racing to secure computing power and energy for Claude, including turning to natural gas to power its data centers. Its filing also lists the risks it sees in advanced AI.
Anthropic’s IPO has not been priced yet, and the S-1 remains a preliminary filing that can change before shares start trading.
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