What is the S&P 500 and how is it used by investors?

• A. It is a market-cap-weighted index of 500 large U.S. companies used as a benchmark for overall U.S. stock market performance.
• B. It tracks the performance of 50 small-cap international companies.
• C. It is a price-weighted index of 2000 global stocks.
• D. It is a mutual fund that aims to beat the market.

Answer: (A)

The S&P 500 is a market-capitalization weighted index that represents 500 large U.S. companies. Because it uses market cap, bigger companies move the index more, so the overall performance reflects how the largest players in the U.S. stock market are doing. Investors use it as a benchmark to judge how their portfolios perform relative to the broad market. Many funds aim to match its returns by holding the same 500 companies in similar proportions through index funds or ETFs. It isn’t a collection of international or small-cap stocks, it isn’t price-weighted, and it isn’t a mutual fund itself—it's an index that funds can replicate.