A stock that has fallen out of favor with investors and, consequently, tends to trade at a low P/E. Also called orphan stock.
In general terms, a wallflower is somebody who remains on the sidelines of a social activity. The financial sense of the word is very similar. This type of stock is often neglected by research analysts and, as a result, doesn't get much attention from investors. For this reason, many believe that wallflowers are undiscovered bargains.