The US stock market is made up of thousands of publicly traded companies. These companies are primarily listed and traded on two major exchanges: the New York Stock Exchange (NYSE), which hosts most large traditional firms, and Nasdaq, which is dominated by technology and growth stocks. The overall performance of the US stock market is most commonly tracked through three key indices: the S&P 500 (representing the 500 largest companies), the Dow Jones Industrial Average (30 major blue-chip stocks), and the Nasdaq Composite (heavily weighted toward tech).