On Bubble Watch

On the 25th anniversary of his bubble.com memo, Howard Marks examined whether today's markets show signs of speculative excess. He argued that bubbles are fundamentally psychological phenomena—marked by "irrational exuberance," "FOMO," and the conviction that "there's no price too high"—rather than purely valuation-driven events. Marks noted that the seven largest S&P 500 stocks now represent 32–33% of the index, roughly double their share five years ago and approaching the 22% peak during the 2000 TMT bubble. He observed that U.S. stocks comprise over 70% of the MSCI World Index, the highest share since 1970. While acknowledging that today's leaders—particularly Nvidia, trading at a forward P/E in the low 30s—are superior to past market darlings, he cautioned that persistence in high-tech is rare: only six of the top twenty S&P 500 companies from 2000 remain in that tier today, and only Microsoft of the Magnificent Seven ranked in the top twenty then. Marks identified several cautionary signs: sustained market optimism since late 2022, above-average S&P valuations relative to global peers, enthusiasm for AI potentially spreading to other high-tech areas, and the assumption that the top seven will remain dominant. He also flagged Bitcoin's 465% two-year surge as a sign of diminished caution. A J.P. Morgan chart showed that when the S&P 500 traded at today's forward P/E of 22, subsequent ten-year annualized returns ranged between +2% and −2%. Recent bank projections for ten-year S&P returns sit in the low- to mid-single digits, consistent with that historical relationship. Marks stopped short of declaring a bubble, noting he does not hear "there's no price too high" rhetoric and the markets do not feel "nutty" to him. However, he warned that if multiple compression occurs rapidly rather than gradually, stock prices could decline sharply, as in 1973–74 and 2000–02.