US large-cap equities show epic speculation that recalls the 2000 bubble. Margin debt is up 50% year over year to $1.5T and equals 4.6% of GDP, versus 3% at the dot-com top in 2000. Comparing it with market cap misleads when market cap itself is grossly inflated, the same argument bulls made wrongly in 1999-2000. The circular AI flywheel resembles 2000's vendor financing, which ultimately led to disaster. x.com x.com x.com