ECB researchers say a stock market correction is likely as AI valuations echo the dot-com era

Researchers at the European Central Bank (@ecb) have issued a stark warning about stretched equity markets, arguing that the AI-fuelled tech rally bears an uncomfortable resemblance to the dot-com boom of the late 1990s.

The blog post, titled "The AI boom: rational enthusiasm or the next dot-com bubble," examined whether current stock market valuations are justified by AI's potential or could lead to a correction similar to previous technology booms. The authors concluded the latter is more likely. "Economic research on past technological revolutions points to a worrisome conclusion: a correction of current stock market valuations is likely," the post said, though it does not necessarily reflect the ECB's official position.

The S&P 500's cyclically adjusted price-to-earnings ratio, known as the CAPE ratio, is nearing historical peaks. The warning builds on earlier signals from within the institution: ECB Vice President Luis de Guindos flagged in May 2026 that correction risk was "quite elevated."

Why a correction could happen even if AI succeeds

Even if the technology succeeds and profits rise, stocks may still fall because it is hard to fulfil markets' excessively optimistic profit growth bets. The researchers pointed to investor psychology as a compounding factor. Overly optimistic investors tend to bid up prices beyond fundamentals, and when optimism fades, prices tend to fall even more sharply than in a rational scenario.

Early in a tech boom, investors tend to view risk as firm-specific, worrying about whether individual companies can deliver on their promises. Over time, that risk perception broadens to become economy-wide, which is when conditions become more dangerous.

What it means for Europe

For Europe, a US market correction would be a question of financial stability, since households have a 440 billion euro exposure to so-called Magnificent Seven stocks, comprising Alphabet, Amazon, Apple, Meta Platforms, Microsoft, Nvidia and Tesla, while pension and insurance firms' exposure is roughly the same.

A sharp correction can force funds to sell assets to meet redemptions, first liquid holdings and then, if the correction persists, distressed assets, pushing valuations down further and triggering more redemptions.

Unlike during the dot-com episode, today's starting point leaves markedly less room to cut interest rates or use fiscal policy to cushion the fallout, making a Magnificent Seven correction that coincides with broader market instability a financial stability concern rather than a private one.

While European stock valuations appear more rational, market moves closely correlate with the US, so local equities would also take a hit. The exact timing of any correction, the blog noted, "is unknowable in advance."

Sources:
ECB Blog: The AI boom, rational enthusiasm or the next dot-com bubble (August 17, 2026)
RTE News: AI market correction is coming, ECB blog predicts
Business Standard: Why AI stocks could crash even if AI succeeds