Bad news, investors. Some of you must fail. Not probably, or unfortunately, but must. Professional, amateur. Hedge fund manager, day trader, indexer, 401(k) saver. Some of you must fail. It's a necessity of how markets work. According to Dalbar and other research groups, the average U.S. stock investor has underperformed the market by between three and seven percentage points per year during the last 30 years, depending on how it's calculated. Most of this is due to what New York Times columnist Carl Richards calls the behavior gap: a parade of dumb decisions where the average investor buys high and sells low. This ... (full story)