Stocks are considered to be long-term investments. This is, in part, because it's not unusual for stocks to drop 10% to 20% or more in value over a shorter period of time. Over a period of time, investors have the opportunity to ride out some of these highs and lows to generate a better long-term return. If we look back at stock market returns since the 1920s, individuals have never lost money investing in the S&P 500 for a 20-year time period. Even considering many of the setbacks, such as the Great Depression, Black Monday , the tech bubble, and the financial crisis, investors would have experienced gains if they had invested in the S&P 500 and held it uninterrupted for 20 years. While past results do not guarantee future returns, it does suggest to the investors that a long-term invest in stocks generally yields positive results, if given enough time. One of the inherent problems in investor behavior is the tendency to be emotional over their investment. Many of