The Dow Jones Industrial Average, often referred to as the DOW, is a stock market index that tracks the performance of 30 large companies listed on the New York Stock Exchange and the NASDAQ. It is one of the most widely followed indices in the world and is often used as a benchmark for the overall performance of the US stock market. The Wall Street Index, or WSI, is a broader index that includes all stocks traded on the New York Stock Exchange, the NASDAQ, and the American Stock Exchange. It is considered to be a more comprehensive measure of the US stock market than the DOW.