Anthropic is in talks with U.K. neocloud Nscale for a second multibillion-dollar deal to lease computing capacity at a site in the U.S., a person familiar with the matter told CNBC.

The agreement would cover a second 460-megawatt data center at the same West Virginia site as the first deal, the person said. The person asked not to be named because they were not authorized to discuss the talks. The deal could be worth around $45 billion, the person said.

CNBC reported the first deal in August.

Bloomberg first reported that Anthropic and Nscale were in talks over a second deal. Anthropic declined to comment. Nscale has been approached for comment.

Nvidia-backed Nscale is one of several companies that have emerged in recent years to develop the infrastructure needed to power artificial intelligence. The company builds or leases data centers and sells computing capacity to hyperscalers and AI labs.

Rivals CoreWeave and Nebius have seen their shares drop 28% and 27%, respectively, in the past month, amid concerns over heavy borrowing.

Nscale has faced its own challenges. On Sunday, U.K. newspaper The Telegraph reported that Microsoft had pulled out of a deal to anchor an Nscale data center just outside London, amid delays connecting to the country's power grid.

An Nscale spokesperson told CNBC that it remained "committed" to the project and was "exploring alternative power sources for the site."

"Our relationship with Microsoft remains strong and long-term, and this unfortunate London-wide grid issue has no impact on our other contracts," the spokesperson added.

The U.K.-based company filed to go public on the New York Stock Exchange in September.

Anthropic said earlier this year that growing demand for its Claude AI models and products has caused "inevitable strain" on its infrastructure.

Since then, it has announced a flurry of deals with infrastructure partners to try and increase its computing capacity, including major agreements with Advanced Micro Devices, Elon Musk's SpaceX, Google and Broadcom.