Debt-heavy AI companies face increased financing risk as bond yields spike, raising refinancing and expansion costs across the infrastructure buildout.

With Treasury yields climbing this week to their highest levels since 2007, companies reliant on debt are poised to see their borrowing costs rise. That means the AI infrastructure buildout, which has already reached historic levels, is about to get even more expensive.

JPMorgan Chase estimated in June that $4.1 trillion in AI-related debt will be issued through 2030 as data center companies and others tied to the artificial intelligence boom race to build capacity to meet what many industry experts view as insatiable demand for AI services. As borrowers return to the market, they now face a 10-year Treasury yield near 5.17%, up about 1 percentage point since the start of the year, forcing companies to offer more attractive rates to lure investors.

The market shows mixed signals. Shares of neocloud provider CoreWeave have risen almost 8% this week, while Oracle, which has relied on debt markets for AI expansion, has fallen 7% for the week and about 30% this year. Japan's SoftBank, a principal provider of capital for AI projects, raised $11.1 billion in a junk-bond sale this week at yields as high as 9.75% for the 7-year tranche.

"They basically are price insensitive to that raise, which means they're price takers," said Mark Malek, chief investment officer at Siebert Financial. "In my view, a lot of these companies need to be price insensitive. They need to get as much capital as possible to compete."

At the center of the AI craze are leading model developers OpenAI and Anthropic, each valued at close to $1 trillion in the private market. To provide infrastructure for their advanced models and services from other companies, tech's hyperscalers—Amazon, Google, Meta and Microsoft—have committed to hundreds of billions of dollars this year in capital expenditures, with expected increases in 2027. While much of that investment is funded through debt raises, these tech giants hold investment-grade credit ratings, providing cheaper access to capital. For smaller players, bigger challenges lie ahead.

A senior private credit investor told CNBC that neocloud deals will become more difficult to finance as companies have less cushion to absorb rising costs. Riley Thompson, a vice president at Mitsubishi HC Capital America, said lenders are growing pickier about projects they fund even when borrowers agree to higher rates. "Instead of a roster of 50 neoclouds, there's probably 20 that the market's truly interested in," Thompson said.

CoreWeave, which went public last year, warns in SEC filings that every 100-basis-point increase in rates could result in a $30 million jump in its interest expense based on outstanding floating-rate debt. An early warning sign emerged this week when Oracle's stock fell following reports that the company sent a "force majeure" notice tied to its New Mexico data center project to protect itself from higher expenses. Oracle is seeking to delay payment on the campus, dubbed Project Jupiter, if it fails to launch as expected in 2028, though the company said the project "remains on our planned schedule."

Rising interest rates are not the only headwind. Prior to this week's yield spike, the CEOs of Anthropic and OpenAI urged a slowdown in the pace of AI development after industry researchers raised concerns that advanced models risk spinning out of human control. A nationwide backlash against AI data centers has emerged as a major election issue, with 69% of respondents to a recent NBC News Decision Desk Poll opposing construction of such facilities in their local area. Texas Governor Greg Abbott, facing a tight reelection race, ordered a temporary halt to all data center-related environmental permits following a moratorium on grid approvals.

Still, demand for AI services is exploding. Meta's Muse personal assistant app, launched earlier in September, has rocketed in popularity with more than 2.5 million global downloads in its first two weeks, passing ChatGPT at the top of Apple's App Store. Evercore's Mark Mahaney told CNBC this week that Muse could reach 100 million users within six to 12 months.

Andrew Giudici, global head of corporate, project and infrastructure finance at credit rating agency KBRA, said that even as rising rates may affect future deals, he doesn't see major impact on borrower demand. "In a normal environment, people might take a step back and pause a bit," Giudici said. "But I don't think that's going to happen here. I think you're going to continue to see relatively large issuance."

Haim Zaltzman, vice chair of Latham & Watkins' emerging companies and growth practice, said there's no doubt that as costs rise, "somebody will have to absorb it." But absorbing higher costs in a demand environment where demand is so great is easier to manage.

For Bernie Margulies, CEO of American Compute, which advises on risk management for GPU financing, the equation is simpler. Borrowers are eager to secure financing even at higher costs, especially if they have commitments with OpenAI and Anthropic, which have been signing contracts to secure compute capacity years into the future. "If you have a deal with Anthropic, will 50 basis points really stop you?" Margulies said.