005Can markets fund the AI buildout?

Small next to Treasuries and mortgages

At the 2028 peak the need is $435B, about 1.3% of GDP. That is 22% of the $1.99T deficit the federal government ran in FY2026, and 21% of the $2.1T of mortgages lenders will write this year. Debt across every US borrower outside finance (households, businesses and governments) is growing about $4.4T a year, and the AI peak would be 10% of that. Even on stated targets, where SpaceX builds to 10 GW and 2027 reaches $755B, the peak is 38% of one year’s deficit.

Large next to what’s actually new

Those comparisons flatter it. Most mortgage lending and bond issuance replaces debt that already exists; the AI need is new money. With mortgage rates near 7%, US mortgage debt grew only $182B over the past year, so the 2028 peak is 2.4× the net growth in all US mortgage debt. If it were all borrowed, it would also be 39% of the $1.1T a year that all US nonfinancial businesses are adding in debt, and 68% on stated targets.

Hyperscalers are the easy part

The four need $438B over five years, peaking at $155B in 2027: 6.8% of a year of US investment-grade issuance at the 2026 pace. Hyperscalers as a group have gone from about 2% of that market in 2023–24 to 11% this year, by Vanguard’s count, including Amazon’s $54B sale in March, the largest corporate bond deal on record, and investment-grade spreads have barely moved: 84bp on October 15, 4bp wider than at the end of August. The need is counted before dividends and buybacks. If the four keep paying out, they raise more; if markets tighten, payouts are the first thing they can cut.

The strain is in three places

SpaceX on its stated targets. Building to about 10 GW by end-2027 needs about $370B in 2027 from one BBB-rated issuer. That is roughly what the whole US high-yield market raised in 2025, 6.9× the largest corporate bond deal ever, and 4.3× what SpaceX raised in its IPO, itself a record. On Street numbers it needs $80B that year. Either the build is slower than Musk has described, or chip vendors and partners finance most of it.

The neoclouds. They need $347B of new money plus $75B of GPU loans to roll, mostly through high-yield bonds, convertibles and private credit. At the 2027 peak that is about 12% of what those markets raise in a year, and convertibles alone carry up to $32B a year, 17% of US convertible issuance. Those markets are already straining. High-yield spreads have widened 60bp since the end of August, to 323bp, after the heaviest month of junk supply this year, while investment grade moved 4bp. CoreWeave’s bonds yield over 15%.

OpenAI. Its own plan burns $278B over 2026–30, $116B more than the cash it started the year with plus the $122B it raised in March. That has to come from private rounds and, eventually, an IPO that Altman says won’t happen in 2026. At the 2028 peak the need is 22% of what US IPOs and share sales raised at this year’s record pace, and two deals, SpaceX’s IPO and Alphabet’s raise, were about two-thirds of that. Anthropic is the opposite case: on its own figures it already funds itself, and its risk is $518B of mostly non-cancellable compute commitments that need its revenue to keep growing.

Issuance is already running ahead of the gap

Goldman counts nearly $600B of AI-linked debt priced this year, against a $259B gap for 2026 here. Part of the difference is issuers raising ahead of need: by Vanguard’s count, hyperscalers had sold about $132B of bonds by the end of July, against a 2026 gap here of $83B for the four, and Alphabet alone raised $85B in June. The rest is borrowers beyond these companies: data-center developers and the lease-backed vehicles that build sites and buy chips for the labs.

Some of the money goes in a circle

Since the start of 2025, at least $110B of the labs’ new equity has come from companies they buy compute from. Amazon alone put $39B into the two labs in the first half of 2026, close to its $45B capex gap for the whole year. That doesn’t change the total here. It moves part of the labs’ need onto their suppliers, whose gaps in pack 001 don’t include these investments.

Read the total as a floor

It excludes about $830B of data-center leases the four hyperscalers have signed but not started, which developers finance with their own debt; the debt partners and lessors raise to build and equip the labs’ capacity (almost $100B against OpenAI’s sites by late 2025, and more than $100B of packages this year for chips and sites serving Anthropic, among others); power and grid; and payouts. Broader estimates run higher: Morgan Stanley sees a $1.5T data-center financing gap for 2025–28, and JPMorgan expects more than $2.1T of data-center financing from investment-grade bonds alone over five years.

The telecom comparison

The last debt-funded network buildout is the obvious reference. Telecom companies raised about $1.3T of debt in the five years to 2001, by Cambridge Associates’ count, in an economy a third the size of today’s, and by 2001 telecom bonds were nearly a quarter of the US high-yield market. This one needs $1.54T over five years: more in dollars, far less relative to the economy. Where it rhymes is in who is stretching: the weakest borrowers, funded in high yield, selling to a few customers.

So the total is manageable. The risk is in its shape: a few issuers, the weakest credit markets, and revenue that traces back to two AI labs, one of which still has to raise another $116B.