Proper bubbles involve people convincing themselves that a high-profit, low-inflation environment will be permanent

Periods of extreme valuation in the stock market don’t really happen very often. 

The basic driver has been much the same: the ability of investors to believe absolutely in something that always turns out to be impossible. 

This always ends badly. Think 1901, 1921, 1929, 1966, 2000, 2007, briefly 2020 and possibly right now. The only question is how fast it ends badly. 

Price-to-earnings ratio at about 40, more than double its long-term average.

Merryn Somerset Webb FT 28 Januay 2022

https://www.ft.com/content/0f763575-ac5f-4a20-a6a8-279e4613e048

 

US market is more overvalued than in 1929, 1973 and 2007 

Merryn Somerset Webb FT 28 December 2021

https://englundmacro.blogspot.com/2021/12/us-market-is-more-overvalued-than-in.html

 

Sommaren 1991 hälsade jag på min gamle gode vän Sven Rydenfelt. Vi talade om fastighetskrisen som då startat på allvar, och den tanklösa överbelåningen.
Ja, det är ju märkligt att människor inte tänker på vad som hände 1907, sa Rydenfelt

Nils-Eric Sandberg, DN 1996-10-18

https://internetional.se/nesrydenfelt.htm

 
In the fall of 1907, it took J.P. Morgan just eight weeks to resolve a credit crisis similar to ours. 

WSJ 29/9 2008

https://www.internetional.se/1907.htm