AI bubble monitor: four indicators, two near and two far
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The AI Bubble Monitor compares the 2000 dot-com bubble with the 2026 AI market using four indicators, concluding that two are close and two are far off. According to the monitor, the Shiller CAPE was 40.9 at the end of September 2026, close to the December 1999 peak of 44.2; tech stocks accounted for 39.4% of S&P 500 market capitalization, higher than the nearly 35% in March 2000.
AI overview based on source reports · Updated 39 min ago
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- Hacker News AIDot Com Bubble vs. AI Bubble: 2000 and 2026 Compared
A comparison of the dot-com era and 2026 on four measures finds long-run valuations and market concentration at or near 2000 extremes, while the S&P 500's forward P/E was 18.7 on October 30, 2026 versus 24.4 in March 2000, and the Nasdaq's 6.8% decline from its October 6, 2026 record is far short of the 77.9% dot-com crash. Tech stocks were 39.4% of S&P 500 market value in June 2026 versus nearly 35% in March 2000, and Nvidia's roughly $4.99 trillion market value dwarfs Cisco's $579 billion peak. St. Louis Fed researchers estimated AI-related investment added 0.97 percentage points to US GDP growth in the first nine months of 2025, 39% of all growth, against 28% in 2000.
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