“In simple terms, bubbles are booms that went bad. Not all booms are bad.” – Proessor Goetzmann
GS’s Peter Oppenheimer published a very interesting research paper on Mar 22, 2021. I recommend everybody should read this. The link for this paper is at the end of this article. Oppenheimer is trying to present why the current market cycle is not a bubble… more precisely speaking, not a typical bubble.
Typical characteristics of historical bubbles.
While I agree with these characteristics of bubbles and some of his arguments, I think he tried too hard to justify the current elevated valuation of the stock market. The first principle of a good investment is always “buy low, sell high.”
By the way, I found this chart interesting. Apple is now nearly 7% of S&P 500, the highest level we haven’t seen after GM fell from the rank.
Global Strategy Paper – Bubble Puzzle – A guide to bubbles and why we're not in one