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Jeremy Grantham warns AI stocks face a 70% crash, calls bitcoin 'nonsense', urges investing outside US markets.

Reported by Pluang
Jun 25, 2026· 3 min read
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Key Takeaways
  • • Jeremy Grantham, co-founder of GMO, warns that AI stocks face a potential 70% crash, characterizing the sector as a "classic investment bubble" similar to the dot-com and housing manias his firm successfully predicted.
  • • Grantham acknowledges AI technology is transformative ("it will change everything") but argues the market has priced in unrealistic valuations that diverge significantly from historical asset pricing norms, creating substantial downside risk.
  • • The veteran investor dismisses bitcoin as "nonsense," reflecting his broader skepticism toward speculative asset classes detached from fundamental value.
  • • Grantham advocates for investors to diversify away from concentrated US market exposure, positioning international and non-US equities as a more attractive risk-adjusted opportunity given current valuation extremes.
  • • GMO's track record of correctly identifying the late-1990s tech bubble, the 2008 housing crisis, and the 2020 pandemic market crash lends credibility to Grantham's current AI bubble thesis among institutional investors.
Summary
Jeremy Grantham, the legendary co-founder of Grantham, Mayo, & van Otterloo (GMO), has issued a stark warning to investors regarding AI-related equities, predicting a 70% decline in AI stocks as the sector represents a "classic investment bubble." Grantham's assessment is rooted in his firm's historical expertise in identifying speculative excess: GMO built its reputation by successfully predicting the dot-com mania of the late 1990s and the housing bubble of the mid-2000s. His current AI thesis extends this pattern recognition to present-day market conditions.

In recent commentary, Grantham acknowledges the genuine transformative potential of artificial intelligence technology, stating that "AI is serious" and "will change everything." However, he argues this fundamental technological significance does not justify the extreme valuations the market has assigned to AI-exposed equities. According to GMO's analytical framework, AI stocks represent a two-standard deviation divergence above historical pricing norms—the firm's formal definition of a bubble. This valuation disconnect, Grantham contends, creates significant downside risk for investors holding concentrated positions in the sector.

Beyond equity concerns, Grantham has also dismissed bitcoin and cryptocurrency markets as "nonsense," reflecting his broader skepticism toward speculative assets lacking intrinsic cash flow or fundamental value anchors. His critique extends to market concentration more broadly, with Grantham warning that US stocks are "about to be crushed" given current extremes. In response, he urges institutional and individual investors to reduce US equity exposure and reallocate capital toward international markets and non-US equities, where he identifies more attractive valuations and superior risk-adjusted opportunities.

Grantham's bubble-calling track record provides institutional investors with substantial context for evaluating his warnings. His firm's successful identification of the 2022 bear market as a correction phase and his earlier prediction of the 2020 pandemic crash demonstrate consistent pattern recognition in identifying inflection points. While the subsequent 2023-2025 equity rally tempered his near-term timing calls, Grantham maintains that structural AI valuation extremes remain unresolved, positioning his 70% decline forecast as a medium-term risk that warrants portfolio repositioning among sophisticated investors.

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Sources

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Pluang Jeremy Grantham warns AI stocks face a 70% crash, calls bitcoin 'nonsense', urges investing outside US markets.