Anthropic is now SpaceX's largest customer, accounting for more than a third of the company's revenue in the third quarter. According to Bloomberg, citing people familiar with the matter, the unnamed "Customer B" represented 34.5% of quarterly income, exceeding the US government as SpaceX's primary client.

SpaceX disclosed this relationship in a recent filing, identifying the buyer only as "Customer B," which purchases computing power from its artificial intelligence unit, now branded as Super Intelligence. Anthropic rents this computing infrastructure at SpaceX data centers located in Memphis, Tennessee.

The financial exposure is significant. Anthropic's IPO filing indicates potential spending of up to $120.5 billion under contracts extending to 2029, averaging approximately $3.1 billion monthly starting in December. However, the agreement allows Anthropic to terminate the contract with 90 days' notice after early 2027, leaving SpaceX heavily dependent on a single client.

While SpaceX reported a 161% revenue increase last quarter, with its AI unit turning a profit for the first time, Elon Musk has emphasized that the company's Starlink and launch operations provide stability compared to other neocloud firms facing tighter credit markets. Google also rents computing power from SpaceX, paying roughly $920 million per month.

Neither Anthropic nor SpaceX commented directly on the arrangement when approached by Bloomberg.