Jean-Philippe Bouchaud: “Black Was Right: Price Is Within a Factor 2 of Value”

Jean-Philippe Bouchaud (see book and podcast) offers new research. Excerpt:

“We provide further evidence that markets trend on the medium term (months) and mean-revert on the long term (several years). Our results bolster Black’s intuition that prices tend to be off roughly by a factor of 2, and take years to equilibrate. The story behind these results fits well with the existence of two types of behaviour in financial markets: “chartists”, who act as trend followers, and “fundamentalists”, who set in when the price is clearly out of line. Mean-reversion is a self-correcting mechanism, tempering (albeit only weakly) the exuberance of financial markets.”


Jean-Philippe Bouchaud
Jean-Philippe Bouchaud

The Author