# 1 Index funds are mutual funds.
# 2 An S&P 500 index fund DOES NOT return around 10%. In the PAST it has returned around 10%. This is VERY DIFFERENT FROM "returning around 10%." This isn't a bank savings account depositing 10% into your account every year.
Index funds are mutual funds that track the market they are designed to track, such as the US Stock Market, the Japanese stock market, Value Stocks, Real estate stocks etc.
The reason index funds beat 55-95% of their actively managed peers over the long run is cost. For example, if an actively managed fund costs an expense ratio of 1.0 and an index fund costs an expense ratio of 0.2, then the actively managed fund not only has to beat the index (hard in and of itself) but it has to beat it by 0.8%, which is even harder. They also have to overcome the cost of high turnover, which affects not only bid-ask spreads but also tax-efficiency. Every year, some of the funds do it, but as the years go by, fewer and fewer stay ahead of the index.
The tricky thing is to pick a fund that will beat the index over a long period of time a priori. That is nearly impossible. But if you wish to try, do NOT look at the past performance of the fund. Look at the COST (and the turnover which affects not only the cost, but also the tax-efficiency) of the fund. The lower the hurdle that the manager has to "clear," the better chance he has of doing it.
ETF suggests that index funds are for "beginners." Let me refer you to a forum where a high percentage of the investors are millionaires who got that way mainly by investing in index funds. Index funds may be "simple," but they are also sophisticated.
http://diehards.org/