Look at what Alphabet, Microsoft, Amazon, Meta, and Oracle officially owe, and the numbers seem large but manageable. Look off the books, and a second, bigger pile of debt appears.

A Nikkei study put that hidden figure at $1.65 trillion, up roughly eightfold in four years. It is more than the $1.35 trillion the five report outright.

The Enron echo

The money is tied up in off-balance-sheet vehicles, the same kind of structure Enron used to hide debt before it collapsed 25 years ago. Back then it was fraud. Now, tightened rules and fuller disclosures make it legal.

The tools are still there, though. “Enron's crime wasn't having special purpose vehicles,” analyst Gil Luria told Bloomberg Law. “Enron's crime was hiding them.”

How it works

The mechanics are simple. A company packages the debt for chips, servers, and power into a separate legal entity, often a joint venture, so the cost never flows through its own accounts.

Take Meta's Hyperion data centre in Louisiana. Meta and Blue Owl Capital both put equity into a separate structure that took on $27 billion in debt. Meta is the sole tenant, yet argues it does not have to record that debt, because it is not the one who must find replacement tenants.

Oracle has $260 billion of future lease commitments that will eventually land on its books. Nvidia carries $119 billion in purchase obligations. Alphabet and Microsoft keep their vehicles off-book too.

The numbers behind the boom

The scale is the story. Meta's off-balance-sheet debt alone is about $420 billion, nearly triple its reported debt. Oracle's has grown roughly thirtyfold in four years.

It is all in service of the same race. The industry is expected to spend more than $3 trillion through 2028 building and equipping AI data centres, much of it financed against the chips inside them.

Why it matters now

The timing is awkward. Four of the five report earnings in the next two weeks, and the reported debt will look tidy. The $1.65 trillion sitting in the footnotes will not make the headlines.

The catch is what happens later. When a data centre goes live, its lease rolls onto the balance sheet at once. If AI demand falls short, the facility is marked down, and the loss lands on the lenders and insurers who funded it.

Some already see the risk. S&P has cut Oracle's credit rating over stretched leverage, and both Morgan Stanley and Moody's have flagged the wider issue. “What if one of these companies was a house of cards,” asked accounting consultant Tom Selling, “and was propping itself up with this accounting treatment?”

The honest version

None of this is illegal, and the companies insist future earnings will more than cover the bills. The disclosures exist, buried in the footnotes, for anyone willing to dig.

But it means investors reading this week's results are seeing less than half the leverage. In a year of loud bubble talk, the quiet number is the one hiding off the page.