An index fund is a type of mutual fund or exchange traded fund (ETF) that is constructed to mimic the components of a market index, such as the S&P 500. Index funds are used to achieve broad market exposure, in an effort to reduce risk specific to a particular industry or stock. Index funds allow investors to capture the performance of the stock market in aggregate, instead having to go through the research and guesswork of investing in an individual stocks or industries.
Due to the fact that index fund investments require less effort on behalf of its manager, fees are typically less than more actively managed funds. While index fund expense ratios sit around 0.05% to 0.07%, actively managed funds typically see fees within the 1% to 3% range.*
Source: https://www.thestreet.com/investing/index-funds-vs-mutual-funds-14836608
