The Anthropic IPO Arrives With a $15 Billion Rent Bill: How the Four AI Labs Actually Compare
The Anthropic IPO will be the first look at what frontier AI costs to make. The company with the best margins rents its compute from a direct competitor for $15 billion a year, and Google just signed a lease with the same landlord.
Anthropic, OpenAI, SpaceXAI and Google sell the same product. The Anthropic IPO will be the first time one of them has to show what it costs to make. The company with the best numbers rents its computers from a competitor.
Disclosure: Impersonal research, not personal investment advice (see the disclaimer). Figures last refreshed 2026-08-17; sources linked inline.
Anthropic confidentially filed its IPO prospectus with the SEC on June 1. That was days after it closed a $65 billion Series H at a $965 billion valuation. CFO Krishna Rao has since started early meetings with public investors without naming a price.
When that prospectus goes public it will settle an argument the sector has been having in the dark. The four labs racing each other on model quality are not running the same business. They differ on one question: who pays for the data center.
The Setup: Four Labs, Four Ways to Pay for a Data Center
Anthropic rents. OpenAI rents at a scale that makes it the largest single tenant in cloud computing. Google builds its own, and has started renting on top. SpaceXAI built so much capacity that it now leases it to two of the other three.
Those four setups produce four different income statements. Anthropic's revenue run rate (the most recent month's revenue multiplied by twelve) topped $47 billion in May, up from $10 billion a year earlier. Its gross margin (what is left of a revenue dollar after paying for the compute that served it) went from 38% to 70% over the same stretch. The company was set to book roughly $10.9 billion of revenue in the second quarter with a projected $559 million operating profit. That would be its first profitable quarter.
OpenAI's run rate passed $40 billion after July revenue rose more than 20% in a single month, per Greg Brockman's note to staff. That is roughly double where CFO Sarah Friar said the company ended 2025. The two companies may not measure run rate the same way, so treat the gap as directional. The cost side is not in doubt. OpenAI's cash burn is tracking toward $27 billion this year and $63 billion next, with breakeven not expected until 2030. It has raised $122 billion to cover the gap. It has also committed to more than $500 billion of disclosed cloud capacity, including up to $250 billion with Azure. That single customer is roughly 45% of Microsoft's cloud backlog (backlog being contracted revenue not yet delivered).
The Map: Where the Revenue Actually Is
The SpaceX bar needs a footnote. Its AI segment reported $2.6 billion of revenue in the second quarter, up from $818 million in the first. That segment bundles X, Grok, and the data center rental business, so rent from Anthropic makes up a large share of the jump. Grok on its own was running near $500 million a year before the merger.
Alphabet is missing from the chart for a structural reason. It does not disclose AI revenue separately and never has to, because Gemini income arrives inside Google Cloud and inside Search. Cloud revenue grew 82% to $24.8 billion in the second quarter, with cloud backlog at $514 billion, up roughly $50 billion in three months. The subscriptions line reached $12.9 billion, and Google credited part of that to demand for its AI plans. The one clean AI figure in the release is a cost: $5.8 billion of Alphabet-level expenses, which the company says are mostly shared AI research and development. No analyst on the July call asked management to break the revenue out. The other three have to hand investors a number. Google gets to hand them a segment.
The $15 Billion Rent Bill
Anthropic, the revenue leader, buys a large share of the compute behind that revenue from a direct competitor.
In May the company agreed to pay xAI $1.25 billion every month through May 2029 for Colossus 1, the Memphis campus with more than 220,000 Nvidia processors drawing 300 megawatts. That is $15 billion a year and roughly $45 billion over the contract. The figure came out inside SpaceX's own S-1, not from Anthropic. Either party can walk on 90 days' notice.
Then Google signed up too. On June 5 Alphabet agreed to pay SpaceX $920 million a month from October 2026 through June 2029 for roughly 110,000 Nvidia GPUs at xAI's data centers, about $30 billion over the term. Same 90-day out after December 31. So the company with the largest in-house chip program of the four is also renting from Musk. Between the two leases SpaceX will collect about $2.2 billion a month in compute rent once the Google deal ramps.
SpaceXAI leased the capacity out because it was sitting there. xAI built Colossus to serve Grok, ended last year with over a million H100-equivalents across Colossus I and II, and never generated the model revenue to fill them. So the capacity went to the tenants who could use it, one of which is beating xAI in the market the campus was built to win. SpaceX acquired xAI in February in a $1.25 trillion deal and took the combined company public in June under $SPCX. It now books frontier-lab rent as recurring revenue.
The landlord business is not cheap to run. SpaceX's AI segment lost $1.3 billion in the second quarter and AI infrastructure took $15.8 billion of the quarter's $18.4 billion in capex. The stock fell about 10% on the print, to well under the $135 IPO price.
Follow the money one more hop and the trade resolves. Anthropic's $15 billion a year, and soon Google's $11 billion, land as revenue at a public company Elon Musk controls. The 300 megawatts behind Colossus 1 were sold as switchgear, busway, and thermal management by the vendors on the Data Center Index, with Vertiv the most direct beneficiary of a 300 MW single-campus load. The processors were an Nvidia order booked years before either lab's revenue existed. Whichever model wins, that equipment was sold once and gets serviced for the life of the site.
Capability Stopped Being the Differentiator
The benchmark race no longer separates the four on business quality. ChatGPT runs on GPT-5.6 Sol, which posts 88.8% on Terminal-Bench 2.1 (agentic command-line work). Gemini 3.1 Pro leads GPQA Diamond at 94.3% (graduate-level science questions). Different models own different corners.
OpenAI published the Sol launch without an Artificial Analysis Intelligence Index score and without a SWE-bench Verified number. Independent evaluator METR flagged the highest rate of benchmark-gaming it has recorded. A lab that leads with the one benchmark it shares with a rival and skips the two everyone uses to compare is telling you something.
Alphabet is shipping Gemini on a monthly cadence with Gemini 4 already in training. It raised 2026 capex guidance to $195 billion to $205 billion, from $180 billion to $190 billion. Shares fell on the increase. The public market has started charging for capex instead of applauding it. SpaceX got the same treatment two weeks later. That is the tape Anthropic is about to walk onto.
What to Watch
The public S-1. The confidential version is with the SEC now. When it flips public, read the contracted compute commitments footnote first. That line tells you whether the 70% gross margin survives a full disclosure schedule.
The 90-day exits. Both the Anthropic and Google leases with SpaceX carry a 90-day out. Anthropic paying a competitor $15 billion a year is a solved problem right up until Musk decides Grok needs the capacity back, or until Anthropic finds cheaper capacity elsewhere.
Alphabet's TPU revenue in 2027. Google has told investors that most revenue from existing TPU system sale agreements (TPUs being the AI chips Google designs in-house) gets recognized next year. That turns $GOOGL from a company that builds chips for itself into one that sells them. It also raises the question of why a company selling its own chips is renting 110,000 of Nvidia's from SpaceX.
OpenAI's 2027 burn. A $63 billion projected burn against a $40 billion revenue pace is a financing question. The July acceleration helps. It does not close the gap.
The View
Two of the four labs now pay rent to a third. The tenants have the revenue growth. The landlord has the capex bill and a stock under its IPO price. The vendors who built the buildings already got paid.
Anthropic is the best business of the four on the numbers we have, and the most exposed, because $15 billion a year buys capacity on someone else's terms and 90 days' notice is a short lease for a company worth close to a trillion dollars. The prospectus will show whether the margin holds once the rent is on the page.