Report identifies Anthropic as SpaceX's largest customer in third quarter

An independent report identified Anthropic as SpaceX’s unnamed Customer B, citing an unnamed person familiar with the matter. Neither company’s regulatory filing identifies Anthropic as Customer B.

If accurate, the identification would make Anthropic SpaceX’s largest disclosed customer in the third quarter. SpaceX said Customer B generated 34.5% of consolidated revenue in the three months ended Sept. 30 and 24.2% in the first nine months of 2026. Customer A accounted for 16.6% of quarterly revenue, and no other customer exceeded 10%. SpaceX reported $14.575 billion in total third-quarter revenue.

SpaceX said Customer B’s revenue related to its SI segment but did not name the customer. Anthropic, which made its public S-1 filing, separately disclosed several compute arrangements made between May and October with SpaceX.AI LLC, a wholly owned SpaceX subsidiary, for access to computing capacity powered by Nvidia graphics processors.

Anthropic said the arrangements covered aggregate spending of up to $120.5 billion through 2029. It expects fees of about $3.1 billion per month once all capacity is delivered, which it anticipated in December 2026. Fees differ during the ramp-up period.

The arrangements have initial non-cancelable periods ending in January and March 2027, Anthropic said. After those periods, either party may cancel an agreement with 90 days’ written notice.