What Are the Dow, S&P, and NASDAQ?

There are about 15,000 U.S. stocks that change hands every day, but not even Wall Street professionals can keep constant track of them all. Instead, people talk about the performance of the “stock market” as a whole, and Wall Street has developed some gauges to give investors a clearer perspective on where “the market” is moving. These are the various averages or indices that people make such a big deal about when they talk about financial markets. Think of them as thermometers, except instead of measuring temperature, they tell you whether the stock market is heating up or cooling down.