" Unlikely, but in theory if you were not willing to buy it at that price originally, you should be selling it once it gets to that price after already holding the security." A straw man - if it reaches that price after a pullback much may have changed in the company or the market - better earnings, for example.   The original article stated that the best measure of momentum is 12 months performance - interesting, and a cursory check seems to bear it out.