Summary
Economists at the European Central Bank have set out why a correction in equity valuations appears likely, arguing that historical research on technological revolutions shows booms fueled by enthusiasm for new technologies such as artificial intelligence commonly end in marked downturns. In their post, the authors say U.S. valuations, as measured by the cyclically adjusted price-to-earnings (CAPE) ratio, sit close to their historical high, while euro zone equity valuations have also risen but to a lesser degree.
Two complementary channels for a correction
The ECB economists present two frameworks from economic research that together point to the risk of a correction.
- Rational view - High valuations can be rational when a new technology creates substantial uncertainty about future productivity. But as adoption widens beyond a narrow sector, that uncertainty transfers to the wider economy. Investors then require a higher risk premium, and that rise in required returns can more than offset the cash-flow benefits from technology adoption.
- Behavioural view - Investor psychology can push prices beyond what fundamentals justify. Overconfidence and excessive optimism can elevate valuations, and when that sentiment wanes prices can fall even more sharply than in the rational scenario.
The economists who authored the post are Malin Andersson, Johannes Breckenfelder, Stefano Corradin, Kalin Nikolov and Maria Antonietta Viola.
Potential transmission to the euro zone
A sharp correction in U.S. technology shares would reach the euro zone through at least two channels, the post argues. First, direct exposure by euro zone investors to the seven largest U.S. technology companies - referred to as the 'Magnificent Seven' - could transmit losses. Those companies are Alphabet, Amazon, Apple, Tesla, Meta Platforms, Microsoft and Nvidia.
Second, the extent of exuberance within euro zone equity markets matters. While euro zone price-to-earnings ratios remain considerably lower than in the United States, and the region s stock markets are dominated by older-economy firms that show less of the AI-driven excitement seen in the Magnificent Seven, a U.S. correction could still spill over because of the historically high correlation between the two regions' markets.
Household and institutional exposures
The ECB economists estimate euro zone households have roughly c440 billion of exposure to U.S. technology equities, largely held via low-cost exchange-traded funds. The post notes that households may not fully appreciate the concentration risk implicit in those holdings.
Insurance companies and pension funds also carry material exposure to the Magnificent Seven, mainly through investment funds rather than via direct stock ownership. That ownership structure can amplify market moves: if a correction forces investment funds to meet redemptions by selling assets, those sales can depress valuations further and prompt additional redemptions.
Policy constraints and systemic concerns
The economists highlight a key difference from the dot-com era: there is today substantially less scope to cut interest rates or deploy fiscal policy to soften the blow of a market correction. As a result, a significant decline in the Magnificent Seven that coincides with broader market stress becomes a financial stability concern rather than a problem limited to private investors.
Conclusion
Although the euro zone's lower valuation levels and sector composition reduce the chance of a domestically driven equity crash, the combination of concentrated exposures to U.S. mega-cap technology firms, the fund-based ownership structure of many institutional investors, and the limited room for policy easing means a pronounced correction in U.S. tech shares could carry sizeable spillovers to the euro zone.
Key points
- US equity valuations by the CAPE measure are close to historical highs; euro zone valuations have risen but remain lower.
- Two mechanisms could drive a correction: a rational shift in required risk premia as uncertainty spreads, and a behavioural drop as investor overconfidence fades.
- Major affected sectors include technology, asset management and financial intermediaries, as well as household wealth through ETF exposures.
Risks and uncertainties
- Concentrated exposure to the Magnificent Seven could transmit a US correction to euro zone households, insurers and pension funds.
- Fund structures create a potential amplification channel - forced sales to meet redemptions could deepen price declines.
- Limited monetary and fiscal policy room relative to the dot-com period reduces the ability to cushion a broad-based market shock, raising financial stability concerns.