SpaceX's largest single customer revealed: Anthropic pays over $3 billion per month, accounting for more than one-third of Q3 revenue

SpaceX's AI business is reshaping the rocket company's revenue structure at an unprecedented pace, and behind this transformation, the wager of an AI startup plays a crucial role.

According to Bloomberg, citing a source familiar with the matter, AI firm Anthropic PBC is currently SpaceX's largest single client, contributing over one-third of SpaceX’s revenue in the third quarter this year. This news means that the company, originally built on rockets and satellite services, now relies more heavily on a single AI computing client than it does on the United States federal government.

Last week, SpaceX disclosed in a filing that about 34.5% of third-quarter revenue came from a single client of its AI division (now renamed Super Intelligence), which was referred to in the document as "Client B".

The mentioned insider confirmed that "Client B" is Anthropic, but declined to be named due to the confidential nature of the information. This exposure has sparked doubts in the market about SpaceX's revenue stability—Anthropic could exercise its right to withdraw from the contract as early as next year.

SpaceX shares closed down 0.92% on Thursday. As of press time, shares dropped a further 1.7% after hours.

Anthropic’s payments to SpaceX originate from a contract the two parties signed earlier this year, in which Anthropic would utilize SpaceX’s computing resources at its Memphis, Tennessee data center.

Elon Musk is gradually pivoting SpaceX’s AI business toward a so-called “neocloud” model, leasing data center computing resources to clients such as Anthropic and Alphabet’s Google.

This wager began to pay off earlier this quarter: SpaceX’s AI business achieved its first profit, supporting Musk’s vision to “reach $100 billion in annualized revenue by the end of 2026.”

However, the strong performance of the AI computing power business also means SpaceX is highly dependent on a single client, precisely at a time when Wall Street’s confidence in the neocloud sector is cooling.

According to Anthropic's IPO filing, the company has committed to paying SpaceX up to $120.5 billion over the contract term (through 2029), which equates to about $3.1 billion per month starting December this year.

However, the contract includes explicit exit windows: Anthropic can terminate the contract with 90 days’ notice after January 2027 and March 2027, respectively.

In addition, Anthropic has also signed agreements with other neocloud vendors including Nscale and Lambda, further highlighting its intention to maintain a diversified supplier strategy for computing power, and indicating SpaceX is not its only option.

Amid pressure in the neocloud sector, Musk has spoken out frequently on his social platform X in recent weeks—X is now under SpaceX’s umbrella. He commented on CoreWeave's high-yield bond situation and strongly emphasized SpaceX’s differentiation from other neocloud competitors.

“The debt market has basically closed off funding for any company lacking substantial revenue outside of AI data centers,” Musk said, noting that SpaceX has Starlink and rocket launch services as revenue pillars.

“This means that over 200 neocloud companies will face shrimp-sized death and consolidation, with some surviving but not many.”

The fact that Anthropic now accounts for a higher share of revenue than the U.S. federal government reflects SpaceX's profound transformation in less than a year. Since SpaceX acquired Elon Musk’s AI company xAI, the company—long reliant on contracts from NASA and the Department of Defense—has rapidly shifted toward becoming an AI computing service provider.

According to SpaceX documents, only two customers contributed more than 10% of total revenue in the third quarter.

Aside from Anthropic, another client (possibly aggregate payments from multiple government agencies) accounted for just 16.6% of revenue in the third quarter, and this share is around one-fifth for 2025.

Musk also predicted that NASA, once one of SpaceX’s most important partners, would account for less than 5% of company revenue by 2026.