A fund's past performance is not as important as you might think. Advertisements, rankings, and ratings often emphasize how well a fund has performed in the past. But studies show that the future is often different. This year's "number one" fund can easily become next year's below average fund.

Be sure to find out how long the fund has been in existence. Newly created or small funds sometimes have excellent short-term performance records. Because these funds may invest in only a small number of stocks, a few successful stocks can have a large impact on their performance. But as these funds grow larger and increase the number of stocks they own, each stock has less impact on performance. This may make it more difficult to sustain initial results.

While past performance does not necessarily predict future returns, it can tell you how volatile (or stable) a fund has been over a period of time. Generally, the more volatile a fund, the higher the investment risk. If you'll need your money to meet a financial goal in the near-term, you probably can't afford the risk of investing in a fund with a volatile history because you will not have enough time to ride out any declines in the stock market.