Jeremy Grantham on How to Tell If a Bubble Is About to Burst

Jeremy Grantham on How to Tell If a Bubble Is About to Burst – Odd Lots

Market views

Bullish

MSFT— Microsoft has doubled revenue from $143B to $280B in five years (2020-2025), demonstrating massive real business growth that laps Wall Street forecasts year after year, unlike the speculative dot-com era.
NVDA— Nvidia's revenue grew over 10x from $11.7B in 2019 to $130B in 2025, demonstrating extraordinary real business growth. While Grantham attributes some success to luck (chips designed for gaming happened to be perfect for AI), the company has a significant head start worth substantial value.
AIMODELS— AI is described as a transformative technology comparable to railroads, the biggest idea in decades that will fundamentally change the world. Despite bubble concerns, the underlying technology is real and powerful.

Bearish

SPACEX— SpaceX at $2.7 trillion valuation on only $20B revenue represents a price-to-sales ratio over 100x, comparable to the South Sea Bubble. Grantham suggests this will be studied by market historians as an example of extreme speculation.
EQUITIES— Current market represents one of the highest priced markets in history. Grantham identifies a key bubble indicator: speculative leaders from 2021 (meme stocks, Cathie Wood portfolio, QuantumScape) declined 35-40% while the S&P powered ahead, a pattern that has only occurred four times since 1925 (1929, 1972, 2000, 2021) and preceded major bear markets each time.
TECH— The MAG-7 tech companies face a fundamental watershed moment: they previously dominated seven different monopolistic niches, but are now all competing aggressively in the same AI market with massive capital expenditures ($200B+ annually). This represents a shift from easy monopolies to a 'blood curdling' competitive dogfight where only one can dominate.
ARKK— Cathie Wood's portfolio declined 35-40% from peak by end of 2021 while the broader market continued rising, representing the type of speculative leader decline that has historically preceded major bear markets.

Not investment advice.