Anthropic’s $84.5 Billion SpaceX Deal Is a 90-Day Option

Anthropic may spend up to $84.5 billion on SpaceX compute through 2029, a ceiling it can largely cancel on 90 days’ notice. The figure landed in a confidential IPO prospectus reviewed this week, and it is almost double the monthly-rate math SpaceX put in its own spring filing.

Most of Anthropic’s other compute bills do not work that way. About 80% of a decade-long $518 billion stack is due whether the chips get used or not.

The $84.5 Billion Line Is an Option

The prospectus says Anthropic has agreements to pay SpaceX up to $84.5 billion through 2029 for Nvidia-based capacity. That is the new ceiling, not a invoice already earned. Final spend still depends on how much of Colossus Anthropic actually uses, and on whether either side keeps the contract alive.

SpaceX’s May registration statement described a different number. Anthropic had agreed to pay $1.25 billion a month through May 2029 for capacity at Colossus 1 and Colossus 2, with a cheaper ramp in May and June 2026. Twelve months at that rate is $15 billion. Thirty-six months is about $45 billion, the figure investors treated as the deal’s size until this week.

The two totals are not a fight over one bill. SpaceX disclosed a monthly rate on a stated term. Anthropic’s later papers disclose a higher cap across the SpaceX relationship, still mostly cancellable. After an initial three-month period, either party may end the cloud services agreements on 90 days’ written notice.

That exit is the hinge. A maximum that can be dropped in a quarter is spare capacity on call, which is a very different instrument from the Google, Amazon, Microsoft and Broadcom paper sitting beside it.

Musk Asked for the Short Lease

Elon Musk, SpaceX’s chief executive, made the flexibility explicit on May 28, while his company was in the quiet period after its own IPO filing. He was answering readers who had treated the May 2029 date as a locked three-year lease of the Memphis clusters.

SpaceX has not committed to leasing Colossus for years, although it’s possible that may be what happens. This is a 180 day lease with 90 day notice mutual cancellation thereafter. The short term was our request, not Anthropic’s.

Elon Musk, chief executive, SpaceX, on X, May 28, 2026

He added that SpaceX would not leave Anthropic hanging and would offer a reasonable off-ramp, but that the racks might be needed back “if compute gets super tight.” A person familiar with the contract later described a 180-day minimum that then runs open-ended unless someone serves notice.

SpaceX told the SEC the same logic in correspondence on the S-1. The cloud services agreements were ordinary-course deals, the company argued, because if they ended the capacity would easily be redeployed to other customers or pulled back for SpaceX’s own models. That, it said, is why it negotiated a 90-day termination either side can use without a penalty.

The short fuse is therefore not a gift Anthropic extracted. It is the term SpaceX wanted so Grok training, or another paying lab, can reclaim the same watts on a quarter’s notice.

$518 Billion, and Most of It Stays Locked

Anthropic told investors it expects to spend at least $518 billion over the next decade with six infrastructure partners. About 80% of that sum is non-cancellable, or payable even if usage falls short. Future demand for advanced systems, the company wrote, will be “limited principally by the availability of compute.”

The locked slice is the hyperscaler and chip-lease book. The SpaceX ceiling is the pressure valve.

ANTHROPIC’S COMPUTE BOOK BY PARTNER

On Google, the filing is blunt. “If our actual spend falls short, we must pay Google the difference,” Anthropic said, and it added that similar terms apply to Amazon. Microsoft’s contract survives unless Microsoft itself commits an uncured material breach. The Broadcom leases are equipment paper that survives anything short of a default.

Those four relationships are also tangled. Amazon, Google and Microsoft are investors, customers, cloud hosts, sales channels and competitors at once. “The interests they may pursue may not fully align with our interests,” Anthropic said. If third-party compute is cut, repriced or ended, “our business, financial condition, and results of operations could be adversely affected.”

That is why the company says it is moving off a cloud-only model toward dedicated halls and chips it leases itself. The SpaceX paper fits that shift, with the difference that it can still be torn up.

Memphis Racks Now Serve a Direct Rival

The hardware sits in Tennessee, not in orbit. In May, SpaceXAI offered Anthropic access to Colossus 1 in Memphis, the first of two clusters SpaceX now files as a single roughly 1.0 gigawatt campus, with extra power on site for the halls. xAI, the Grok lab Musk founded in 2023, was acquired by SpaceX in early 2026 and is the AI division running those floors.

Colossus 1 had already been described as more than 220,000 Nvidia GPUs and more than 300 megawatts. The May cloud services agreements go further. A SpaceX free-writing prospectus says the customer gets approximately 325,000 NVIDIA GPUs across Colossus and Colossus II, plus hyperscale CPUs, exabyte-scale storage and high-speed interconnects built for training loads. Anthropic keeps the IP in its models and data.

SpaceX’s own filing explains why a rival is even on the floor. Grok-5 was being trained at Colossus II. Renting the older hall, and some of the new one, lets SpaceX “monetize unused compute capacity in our infrastructure” while leaving room to snatch it back. Google has its own seat, at $920 million a month through June 2029. Reflection AI is also on the tenant list.

WHAT SPACEX PUT IN ITS S-1

• The chips: About 325,000 Nvidia GPUs across both Memphis clusters, on a $1.25 billion monthly rate through May 2029 after a cheaper May-June ramp.
• The build speed: The first Colossus cluster came up in 122 days in a reused factory shell; the first Colossus II cluster came up in 91 days, against an industry mark of about two years for a 100 megawatt greenfield hall.
• The dual use: The same campus trains Grok and sells spare watts to Anthropic, Google and other labs, with a 90-day path to reclaim them.

Anthropic co-founder and chief compute officer Tom Brown wrote in June that the lab was “scaling up on Nvidia GB200 capacity in Colossus 2 throughout June.” Claude usage limits rose when the first hall came on, including doubled five-hour caps on Claude Code. The customer-facing point of the lease was always extra tokens, not a merger of the two labs.

Musk had posted in 2025 that “winning was never in the set of possible outcomes for Anthropic.” After the compute deal, he said he had been “clearly wrong about Anthropic” and called the company “obviously currently the leader in AI.” The warmer line did not change the cancellation math.

What the IPO Filing Tells Investors

The $84.5 billion ceiling is one line in a still-private prospectus. Anthropic, a public-benefit corporation, confidentially submitted a draft registration statement on June 1, 2026. The full S-1 is not public. Anthropic declined to comment on the latest leak. Marketing could start as early as mid-October, with a listing discussed for after the November U.S. midterm elections, and a valuation talked about above $2 trillion.

On May 28 it raised $65 billion in Series H funding at a $965 billion post-money valuation. The IPO math, if it holds, would more than double that mark and top SpaceX’s June debut.

THE PATH FROM MAY LEASE TO SEPTEMBER CEILING

1. May 2026: SpaceX and Anthropic sign cloud services agreements covering Colossus and Colossus II at $1.25 billion a month through May 2029.
2. May 6, 2026: The companies announce the Colossus 1 partnership and Anthropic raises Claude usage limits.
3. May 28, 2026: Musk describes a 180-day lease with 90-day mutual cancellation after that.
4. June 1, 2026: Anthropic files a confidential Form S-1.
5. June 12, 2026: SpaceX lists under ticker SPCX at $135 a share, jumps 19% to $160, and is valued at $1.77 trillion.
6. Sept. 29, 2026: Anthropic’s prospectus shows an $84.5 billion SpaceX ceiling through 2029 and at least $518 billion of compute commitments, and SPCX closes at $149.24, up 2.59%.

The 2025 P&L shows why a flexible overflow hall matters. Revenue rose roughly twelvefold to nearly $4.6 billion. The operating loss was more than $8 billion. The net loss was about $42 billion, of which roughly $34 billion was an accounting charge on financing that may convert into stock. Total operating expenses hit $12.65 billion, and compute and infrastructure took $7.33 billion of that, more than half the opex line and about triple the 2024 compute spend.

Anthropic held $20.28 billion in cash, cash equivalents and short-term investments at the end of 2025. Two customers generated nearly a quarter of 2025 revenue, and many of the largest clients have no long-term contracts. The company is asking public investors to fund a compute book many times the cash on the balance sheet, on the view that tokens, not sales calls, are the binding constraint.

Idle GPUs Become SpaceX’s Fastest Business

For SpaceX, the Anthropic paper is a way to get paid while it scales a new line. The rocket company spent $12.7 billion of capital expenditure on AI in 2025, about 61% of total capex. Its AI division lost $6.3 billion on $3.2 billion of revenue that year. Group revenue was $18.7 billion, so a full year of Anthropic at $15 billion would have almost doubled that 2025 top line, if the lease had run the whole year at the headline rate, which it did not.

TD Cowen analyst John Blackledge initiated coverage of SpaceX on Sept. 29 with a $200 price target. He expects installed compute to rise from 2.1 gigawatts in 2026 to 6 gigawatts by the end of 2027, with leasing about 60% of company revenue next year.

The biggest near-term driver of SPCX revenue is leasing terrestrial AI compute capacity to frontier labs and other companies.

John Blackledge, analyst, TD Cowen, Sept. 29, 2026

SpaceX has already said it may sign more third-party compute contracts. Musk has also talked up orbital racks, and the May announcement said the two firms had expressed interest in multiple gigawatts of compute in space. That is not in the $84.5 billion terrestrial ceiling, and none of it is owed if someone sends a letter.

The prospectus still leaves the 2029 spend unfixed. Anthropic can keep filling Memphis, cut the order to a trickle, or leave. SpaceX can keep cashing $1.25 billion months, or take the GPUs back for Grok. Until one of those notices goes out, the $84.5 billion line is a cap on a rental, sitting next to hundreds of billions that do not come with a 90-day door.

Disclaimer: This article is news reporting and analysis of company filings, regulator correspondence and public statements, and it is for information only. It is not investment advice, a solicitation to buy or sell Anthropic, SpaceX or any other security, or a prediction of an IPO price, listing date or share move. Readers should consult a licensed financial adviser, and where needed a securities lawyer, before acting on any offering or listed-stock decision. Dollar figures, contract windows and cancellation rights reflect the cited papers and statements on the dates given and can change if Anthropic amends its prospectus, uses less capacity, or either party serves notice.