Anthropic is reportedly responsible for 34.5% of SpaceX’s revenue, which makes it the SpaceX biggest customer and puts it ahead of the US government. Bloomberg reported Thursday, citing a person familiar with the matter, that Anthropic is the unnamed “Customer B” in SpaceX’s latest filing. Neither company has confirmed it. The 34.5% figure comes from the filing itself, but the name behind it rests on one anonymous source.
The filing shows Customer B bought computing power from SpaceX’s AI unit, now called Super Intelligence, in the quarter ended Sept. 30. According to TeslaNorth’s read of the filing, “Customer A” came in at 16.6%.
Quarterly revenue was about $14.6 billion. So Customer B’s share works out to roughly $5 billion for the quarter, or about $1.7 billion a month. That is TeslaNorth’s math, and it checks out.
The ranking is the real story. Anthropic’s payments have now passed those of the US federal government, which used to be SpaceX’s largest single customer. Meanwhile, SpaceX’s revenue rose 161%, and the AI unit turned a profit for the first time.
Inside the Anthropic SpaceX deal: the bill is about to get bigger
Today’s $1.7 billion a month is only the start. Anthropic’s own IPO paperwork describes agreements for Nvidia GPU-based compute from SpaceX worth up to $120.5 billion through 2029.
Anthropic expects to pay about $3.1 billion a month once all that capacity is delivered, per ShiftDelete’s summary. Full delivery is due in December 2026, so the monthly bill could nearly double within weeks.
That timeline also explains why the Customer B story fits so neatly. In May, Anthropic and SpaceX announced that Anthropic would use all the compute at Colossus 1 in Memphis, more than 300 megawatts.
The chip appetite behind it is just as wild elsewhere, as China’s giants ordering more Nvidia cards than Nvidia can build shows.
Why the SpaceX top customer holds a short-notice exit
That $120.5 billion is a ceiling, not a guarantee. Anthropic can terminate with 90 days’ notice beginning in early 2027. Musk has also said the Colossus deal was first structured as a six-month arrangement.
Think of it as the biggest tenant in the building holding a short-notice exit clause. When one customer is about a third of your revenue, the lease language matters more than the press release.
And Anthropic isn’t putting every chip in one basket. Its prospectus reportedly lists $417 billion in total compute obligations, with SpaceX as one of several suppliers. Big tech is hedging the same way on silicon, too: Microsoft built its own chip to need Nvidia less.
The clause that decides what comes next
Confirmation of the Customer B link may come any day, and December’s full-capacity delivery will show whether the bill really jumps toward $3.1 billion. Neither matters as much as early 2027, when that 90-day exit option opens. A third of SpaceX’s money now comes from one AI customer, and that customer has a door it can walk through.
