ETF stands for “exchange-traded fund.” These funds trade on the stock exchange just like any stock. ETFs are no secret, but investment professionals such as brokers can’t earn fees from most of them, so they go ignored. Each ETF is a “basket” of stocks that represents a particular index. For example, if you wanted to own every stock in the S&P 500 Index, you would buy one of several ETFs that follow that index. One example is the State Street Global Advisers SPDR S&P 500 (the ticker is SPY). By owning one share of SPY, you own 500 stocks in one.
Mutual funds are six to 10 times more expensive than ETFs because they hire pros, who attempt to select a few stocks within the index that they believe will beat the entire index. By owning the ETFs we use—funds which are widely held and used by millions of investors every day—you get nearly the exact return of the index that fund tracks. Since computers manage the stock buying, rather than a highly paid fund manager, the fees are very low.