TL;DR:

The co-founder of the institutional investment firm GMO projects that artificial intelligence stocks could suffer a drop of up to 70% due to excess speculation.
Metrics gathered by the investor show that emerging markets recorded a 65% gain over the last 12 months, outperforming the 25% reported by the S&P 500 index.
Current data places the U.S. market valuation at between 35 and 40 times its earnings, a level considerably higher than normal historical averages.

Jeremy Grantham, renowned investor and co-founder of the firm GMO, issued a stark warning regarding global financial markets by labeling the artificial intelligence boom as the largest bubble in American economic history. During an interview published on June 25, 2026, the specialist categorically dismissed the utility of digital assets.

The financial markets veteran places current technological development at the same historical level as railroads or the birth of the internet. However, he clarified that the magnitude of the idea does not prevent its valuations from collapsing.

The Peak of Tech Speculation

A comparative analysis presented by the specialist details that major financial bubbles always form around humanity’s most transcendent innovations. Grantham’s projections suggest that the artificial intelligence market could follow a trajectory identical to the dot-com crash in the year 2000. In that period, leading firms experienced massive increases before recording pullbacks of over 90% in their commercial valuations.

According to the current trend, the aerospace company SpaceX stands out as the clearest symbol of speculative excess in private markets. The evaluated documentation indicates that the company defines its potential market as one-quarter of the global Gross Domestic Product. Grantham warned that the firm’s prospectus will be remembered in the coming decades in a similar fashion to the events of the historic South Sea Bubble.

The state of the international real estate market was also part of the technical evaluation presented by the financial analyst. The historical figures provided point out that in the United Kingdom, an average home sold for 3.4 times the household income in 1994, a ratio that later climbed above 10 times in various geographical regions. A 30% downward adjustment in residential property prices would still keep properties at high levels compared to records from previous decades.

Jeremy Grantham on Bitcoin – sounding the alarm on the AI bubble

Perspectives on Crypto-Assets and Portfolio Strategies

Regarding the digital currency environment, Grantham expressed a restrictive stance and noted that he does not hold any type of stake in these financial instruments. The investor described this sector as a tool designed primarily for capital speculation and devoid of the fundamental characteristics of a stable medium of commercial exchange. The specialist’s assertions suggest that the asset’s intrinsic volatility, exemplified by severe price fluctuations, nullifies its function as a long-term store of value.

Historical data from the U.S. equities market supports the firm’s caution regarding local stocks. Grantham recalled the precedent of the Japanese market, whose benchmark index reached a peak of 65 times its earnings in 1989 before entering a continuous 20-year bear market cycle.

Grantham’s operational suggestions for wealth management propose an allocation where 60% of the capital is assigned to equity indices outside the United States. This strategy includes exposure to markets in Europe, Japan, Canada, Australia, and emerging economies. The remaining capital could be distributed in a diversified manner among government fixed-income instruments, precious metals, and real estate to mitigate volatility risks in the American market.

The implementation of the European MiCA regulation on July 1, 2026, will mark the beginning of the new global regulatory order for digital financial service providers.