Anthropic, the company behind the AI assistant Claude, is the tenant in a roughly $28 billion lease of Riot Platforms' entire campus in Corsicana, Texas, a bitcoin mining site. Riot announced the 15-year lease on Nov. 4 and named the tenant only as a leading AI lab. Riot's quarterly report to U.S. regulators, out the same day, names the tenant as Anthropic PBC and says the lease was signed Oct. 28. Anthropic has not announced the lease itself.
The campus sits on 332 acres and is meant to supply 910 megawatts, or 910 million watts, of electric power for computing equipment. Riot expects to hand the space over in three stages: 400 megawatts in September 2027, 200 megawatts in January 2028 and 310 megawatts in July 2028. Each stage arrives in pieces, and Riot's quarterly report sets June 28, 2027 as the target for the first piece.
Riot is not the one putting in or running the computers. Under this kind of lease, Riot provides the land, the power equipment and the pads the equipment sits on, and it keeps owning and running the main power equipment. Anthropic will buy, install, own and run the computers, and it pays for the electricity they use, plus taxes and insurance. Rent is $130 a month per kilowatt (a thousandth of a megawatt) of power capacity, rising 3% a year. Riot says it is owed on the full 910 megawatts once delivered, whether or not Anthropic uses it all.
Riot puts the rent at about $1.8 billion a year on average. If Anthropic uses both of its options to extend the lease by five years each, Riot says the deal would be worth about $54 billion. Riot also agreed to repay Anthropic up to $4 million per megawatt toward the cost of the modular data center units Anthropic installs, if Riot can borrow the money on terms it accepts. If it can't, Riot's quarterly report says, Riot will pay that money back through rent discounts spread over the rest of the lease's first 15 years, plus 12% interest a year.
This is the second Riot site Anthropic has taken. Riot's quarterly report says Anthropic signed in August for 191 megawatts at Riot's other Texas site, in Rockdale, on a 20-year lease. Anthropic's updated paperwork for its planned stock market listing puts the purchases and leases it has agreed to at about $895 billion, almost all of it for computing power and the systems that run it. That paperwork does not say whether this lease is among them. Riot sold 20,264 bitcoin in the first nine months of this year, for about $1.5 billion, mostly to pay for building data centers.
The delivery dates are targets, and Riot's quarterly report names risks to them. Texas's grid operator has put the Corsicana site in a group with other large power users nearby, Riot says, and could cap or cut the site's power as those users draw more, even if the site's own use does not change. Riot says the operator has not yet started limiting the group. If Riot delivers more than 60 days late, Anthropic gets rent discounts, and if a stage is more than 270 days late, Anthropic can cancel that stage, according to the report. Riot would get 30 days to fix the delay first, and the deadline stretches for events beyond its control or delays Anthropic causes.