The S&P 500 (Standard & Poor's 500 Index) is a market-cap weighted index of 500 major U.S. companies—an essential benchmark ...

Indexes aren’t just important for index funds. By creating a virtual portfolio that represents the “market” (or a specific style of sector), they also establish a “typical” return and risk level that ...

Sometimes it pays to think long-term. There's no clearer example of that than index funds. Investopedia defines an index fund as "a type of mutual fund or exchange-traded fund with a portfolio ...