Anthropic's IPO Filing Says It Could Spend Up to $120.5 Billion on SpaceX Compute. It Can Also Walk Away on 90 Days' Notice After Early 2027.

Honest fence (read first): This is about one paragraph in Anthropic's IPO filing and what it tells us about SpaceX's AI rental business. It isn't a stock call. Our Oct 16 investing post covered the earlier $1.25 billion-a-month figure, and yesterday's post covered SpaceX's separate $40 billion GPU lease. This post covers only the new disclosure from Monday, Oct 26.

Editorial Thesis

For months, the SpaceX to Anthropic compute deal was a monthly number with no end date in public. On Monday, Oct 26, Anthropic filed its S-1 to go public, and one paragraph filled in the rest:

"Under the SpaceXAI Arrangements, we agreed to spend an aggregate of up to $120.5 billion over terms extending into 2029, consisting of approximately $3.1 billion in the aggregate per month once all capacity has been delivered, which we expect in December 2026, with different fees during capacity ramping periods."

That's the headline. The next sentence is the fence: "Following initial non-cancelable periods ending in January 2027 and March 2027 under the respective agreements, each agreement may be cancelled by either party upon 90 days' advance written notice."

So the filing shows two things. SpaceX's AI unit has signed one of the biggest GPU rental contracts anywhere, and that contract is much easier to exit than Anthropic's other big compute deals.

Honest Verdict

Proven (Anthropic's S-1, a sworn SEC filing): several agreements with SpaceX SI signed and amended between May and October 2026; NVIDIA GPU compute; spending of up to $120.5 billion over terms into 2029; about $3.1 billion a month at full capacity, expected in December 2026; non-cancelable periods ending January and March 2027; after that, 90 days' notice by either side. Not proven: that Anthropic will spend anywhere near $120.5 billion. "Up to" is a ceiling. The filing doesn't name the data centers, the GPU count or the price per GPU. Our read: it's a big, real revenue line for SpaceX's SI segment, and a short leash for both sides.

What changed since the last number

In our Oct 16 post, the public figure was $1.25 billion a month through May 2029, cancellable on 90 days' notice. The S-1 now says about $3.1 billion a month once all capacity is delivered. That's roughly 2.5 times the earlier number (our math). The Memphis Business Journal's headline on Oct 27 put it as "nearly triples."

Yahoo Finance noted on Oct 26 that "it was not known how long the deal would last or the possible total outlay" until the filing. Now we know the ceiling and the exit door.

How it compares with Anthropic's other compute deals

The same section of the S-1 lists Anthropic's other big providers. The wording is very different:

Google, Amazon and Microsoft have floors: Anthropic pays at least that much "regardless of actual usage." SpaceX's deal has a ceiling and a cancellation clause. On paper it's the biggest single number in the list, and it's also the easiest to walk away from.

That cuts both ways. Anthropic can leave if it finds cheaper chips. SpaceX can also leave, and its CFO has talked about steering compute to whatever pays best. Yahoo Finance quoted Bret Johnsen: "We expect to have additional new customers in future deals and will continuously evaluate the highest-margin usage for our compute assets across both new and existing cloud service agreements, including serving inference for our own SI products."

How big is $3.1 billion a month for SpaceX?

Our math, labelled as ours:

• $3.1 billion x 12 about $37 billion a year at full capacity.
• $3.1 billion x 3 about $9.3 billion a quarter. SpaceX's whole Super Intelligence segment brought in about $7.56 billion in Q3 (company results, Oct 20).

SpaceX's own 10-Q (filed Oct 22) shows how concentrated the segment already is. An unnamed "Customer B," whose revenue "relates to the SI segment," was 34.5% of SpaceX's total Q3 revenue. The 10-Q doesn't name Customer B, so we won't guess. It does show that one SI customer can move the whole company's numbers.

The same 10-Q puts SpaceX's nameplate compute at 1.7 gigawatts on Sep 30. SpaceX defines that as installed capacity, not power actually used.

What the filing doesn't tell you

• Which data centers. The S-1 says "compute powered by NVIDIA GPUs." It doesn't say Colossus 1, Colossus 2 or anywhere else.
• Price per GPU or per watt. No unit pricing.
• Ramp fees. "Different fees during capacity ramping periods," with no numbers.
• When notice can be given. The filing says the agreements can be cancelled after the non-cancelable periods. It doesn't say whether notice can be served before those periods end. If notice came right at the end, our math puts the earliest exits around April 2027 and June 2027.
• How much is spent. A ceiling of $120.5 billion is not a forecast of $120.5 billion.

Why the exit clause matters

Elon Musk wrote on Oct 25 that debt markets have "almost entirely shut off access to money for any company that doesn't have substantial revenue independent of AI data centers." Part of his point: SpaceX has Starlink and launch revenue behind it, so it can still borrow.

A 90-day exit clause is the other side of that. If GPU rental prices fall or Anthropic's own chips come online, a big customer can leave quickly. If prices rise, SpaceX can move the capacity to a customer who pays more, or to Grok. The S-1 shows the contract is built for a market both companies expect to change fast.

The video

We embed TBPN's interview with investor Gavin Baker (Oct 27, 41 minutes). It covers Anthropic's S-1, GPU prices and SpaceX. We couldn't play it on our research machine, so every number in this post comes from the filings and articles linked below, not the video. CNBC's Oct 26 report on the S-1 is an alternate.

Bottom line

The proof is a sworn filing: up to $120.5 billion, about $3.1 billion a month from December, and SpaceX's AI unit named as a core NVIDIA GPU provider for one of the biggest AI labs. The fence is in the same paragraph: "up to," and cancellable on 90 days' notice once early 2027 passes. It's a big contract, but it isn't locked in the way Anthropic's Google and Amazon deals are.