Anthropic and SpaceX Data Centre Deal: Is It a Six-Month Lease or a Multi-Year Agreement?

Earlier this month, xAI secured a major compute arrangement with Anthropic, committing billions of dollars per month for access to the Company's Colossus computing cluster. The agreement was viewed as a significant win for both organisations, providing xAI with a substantial revenue stream while giving Anthropic additional computing capacity in the increasingly competitive AI race.

However, comments from Elon Musk on X have raised questions about the deal's actual duration.

Responding to a user, Musk stated that SpaceX had not committed to leasing Colossus for multiple years.

"SpaceX has not committed to leasing Colossus for years, although that may be what happens," Musk wrote. "This is a 180-day lease with 90-day notice mutual cancellation thereafter. The short term was our request, not Anthropic's. We won't leave them hanging and will provide a reasonable off-ramp, but if compute gets super tight, I said we might need it back at some point."

The statement appears to conflict with details outlined in SpaceX's recently filed S-1 registration document, which describes the arrangement as extending through May 2029 and acknowledges a standard 90-day termination clause.

According to page F-62 of the filing:

"On May 3, 2026, the Company entered into a cloud service agreement with Anthropic PBC, an AI research and development public benefit corporation, with respect to access to compute capacity. Pursuant to this agreement, the customer has agreed to pay a monthly fee through May 2029, with capacity ramping in May 2026 at a reduced fee. Either party may terminate the agreement upon 90 days' notice. The customer will retain ownership and intellectual property rights in its content, AI models, and related data."

The filing's language appears straightforward, indicating that Anthropic has agreed to make monthly payments through May 2029. Similar wording appears elsewhere in the document, including references stating that the customer has agreed to pay approximately $1.25 billion per month through that date.

As a result, the discrepancy between Musk's comments and the filing has prompted questions about how the arrangement is structured. One interpretation could be that Anthropic has agreed to payments over three years while both parties still retain the right to terminate the agreement with advance notice. However, the exact terms remain unclear.

Neither SpaceX nor Anthropic has publicly provided additional details on the agreement's duration, and xAI did not respond to requests for clarification.

Without access to the full contract, it is difficult to determine precisely how the arrangement is structured. Public announcements from both companies have largely focused on the strategic importance of the deal rather than its specific contractual terms.

The differing descriptions have nevertheless attracted attention because statements in public filings are generally expected to reflect material agreements accurately. Investors and industry observers will likely be watching closely for any further clarification regarding the compute partnership and its long-term implications for both companies.

Sean O'Kane contributed reporting to this story.