Indexes and Benchmarks
S&P 500
A stock market index that tracks 500 of the largest publicly traded U.S. companies.
Also called: Standard & Poor's 500, SP500, S and P 500
What it means
The S&P 500 is a widely followed stock market index made up of 500 large public companies in the United States. It is often used as a quick way to describe how the overall U.S. stock market is doing, even though it does not include every company.
Why it matters
People often compare investment performance to the S&P 500. It also helps beginners understand whether the market as a whole has been rising or falling.