We run a stock screen that we have named 'The Nosebleed' that filters for the most expensive or richly-priced stocks in the market. The purpose here is to find stocks that are priced so high up in the stands that the air is thin and investors could begin to experience a nasal hemorrhage metaphorically speaking. Of course, terms like expensive and cheap are subjective, but the stocks that filter in the nosebleed section of the market typically exhibit expectations exuberance with the share price bid up with an extreme and aggressive growth premium.
The difficulty