Aussi, thank you for sharing your research on the question of whether pre- and post-1990 CAPE are comparable. Even if they are not directly comparable, the data after 1990 (though a relatively short 36 years) still shows a bubble which is comparable to the dot-com bubble in 1999. Even more concerning, the speculative excess spending on infrastructure that would not pay off profitably for many years (fiber optics in 1999, data centers in 2026) is very similar. This pattern also drove the 1929 bubble and the earlier bubbles which are described in the book "Manias, Panics and Crashes."

It's very concerning that the rapid increase in the S&P500 over the past couple of years has been driven by a handful of tech companies which are now taking on immense debts to build data centers and whose profits are largely from sales to each other, rather than to paying end-users.

multpl.com - Shiller pe

Wendy