The numbers describing America's artificial intelligence buildout have long since left the realm of ordinary corporate spending. A landmark study published last month puts the total investment in AI data centres and related infrastructure at $10.3 trillion between 2025 and 2032 — a sum that would make it the largest investment boom in American history relative to the size of the economy, dwarfing the railroads, the interstate highways, and the electrification of the continent. Now, the Financial Times reports, that boom is starting to fray: financing is tightening, investors are questioning whether the revenues will ever justify the debts, and the physical and financial strains of building at this speed are showing everywhere at once.
The biggest bet in American economic history
The figure comes from economist Stijn van Nieuwerburgh of Columbia Business School, in a paper presented at a Brookings Institution conference in late September and reported by The Wall Street Journal. His central estimate: $10.3 trillion of spending on data-centre buildings, power systems, networking, specialised chips, and related equipment over eight years — an annual average equivalent to about 3.6 per cent of US gross domestic product.
To grasp the scale, compare it with the great buildouts of the past. The railroad boom of the late 1800s — the previous record — absorbed roughly 2.2 per cent of GDP per year. The interstate highway system took about 1.1 per cent from the 1950s onward. The telecoms and fibre expansion of the mid-1990s took a similar share, and nationwide electrification a mere 0.5 per cent. The AI buildout, at 3.6 per cent, is in a different league — and it demands roughly 183 gigawatts of new data-centre capacity against about 57 gigawatts installed today. Van Nieuwerburgh described the financial arrangements knitting the boom together — AI firms, Big Tech, banks, private credit lenders, and real-estate companies — as fiendishly complicated, and warned that the combination of unprecedented scale, unproven revenue streams, and layered debt had created the conditions for a serious downturn.
Real money — and real debt
This is not a story of frothy equity alone. The five big hyperscalers — Alphabet, Amazon, Meta, Microsoft, and Oracle — are expected by FactSet estimates to spend $4.2 trillion in capital expenditure over the four years through the end of 2029, and a growing share of it is being funded with borrowed money. Hyperscaler capital spending has surged from roughly $97 billion in 2020 to more than $400 billion in 2025, and firms are now leaning heavily on bond markets, bank loans, and private credit.
At least $1.3 trillion of debt has already been committed to the data-centre boom, with more capital flowing in from insurers and pension funds — often through special-purpose vehicles and private credit deals that obscure exactly who holds the risk. Morgan Stanley data cited by the FT puts global AI-related debt issuance at $450 billion from January through early September 2026, more than double the total for the whole of 2025, with companies raising an estimated $466 billion in AI-linked debt so far this year against $101 billion in the same period last year. Track how credit markets are pricing this risk on our markets page.
Where the fraying shows
The FT's macro analysis finds the strain in three places: financing pressure, investor scepticism, and execution risk. On financing, the pace of new borrowing has already cracked. AI-related debt issuance collapsed from a record $113 billion in June to just $23 billion in September, as lenders grew more selective about which projects deserve funding. Morgan Stanley attributes part of the drop to the sheer volume already raised earlier in the year — but the FT also reports deepening investor doubt about whether the spending will ever pay off.
That doubt has a number attached. Gartner forecasts that AI providers will spend $7 trillion on infrastructure through 2030 while data-centre-attributable AI revenue reaches no more than $3.6 trillion over the same period — leaving more than $4 trillion of asset value exposed to write-downs through 2032 if the current pace holds. Investor Michael Burry has warned that roughly $3 trillion of firm commitments by top tech firms could force asset write-downs in 2028–2029 if demand lags supply, and Gartner predicts more than 80 per cent of specialised AI cloud providers — the so-called neoclouds — will cease operating independently by 2030. Allianz chief investment officer Ludovic Subran captured the mood by calling this a “Darwinian moment” for data-centre debt, in which weaker projects face a fight for survival.
Equity markets are voting too. In mid-October, shares of debt-heavy AI firms tumbled as bets on further US interest-rate rises intensified: neoclouds Nebius and CoreWeave fell 15.1 and 9.5 per cent in a single session, Oracle dropped 7.2 per cent, and the cost of insuring AI-company debt against default surged to record highs. Higher rates are poison for a buildout funded on borrowed money.
The financial plumbing nobody fully understands
What worries regulators most is not the headline debt but the plumbing underneath it. The Bank of England's Financial Policy Committee concluded at its September meeting that surging AI-related borrowing had spread loss exposure across capital markets: as a widening circle of investors funds the boom, exposure to any disappointment in earnings expectations spreads with it — and could reinforce sell-offs in a self-accelerating loop, as happened during July's sharp slide in AI and semiconductor shares.
Particularly troubling are the guarantees greasing the machine. The FT reported that residual value guarantees provided by Big Tech companies over the preceding year to support AI infrastructure investment amounted to as much as $300 billion. These arrangements underpin borrowing by special-purpose vehicles holding chips or data centres by guaranteeing the assets' future value stays above an agreed level. The Bank of England warned that the opacity of such financing — combined with what it called “circular trading” between companies — could amplify losses if returns disappoint. When the ultimate risk-bearer is hidden three layers deep in an SPV, nobody can price the system accurately, including the people running it.
Physics gets a vote
Even if the financing held, the physical world is pushing back. Data centres devour electricity, water, and land, and communities are increasingly reluctant hosts. Electrician wages are climbing, electricity prices are rising, and chip and equipment costs are being bid up by insatiable demand. In some regions, manufacturing projects have begun competing directly with data centres for power, workers, and land — a contest the factories, with their thinner margins, are losing.




