Index fund

An index fund (also index tracker) can be defined as a mutual fund or exchange-traded fund (ETF) with specific rules of construction that are adhered to regardless of market conditions. An index fund’s rules of construction clearly identify the type of companies suitable for the fund. The most commonly known index fund, the S&P 500 Index Fund, is based on the rules established by S&P Dow Jones Indices for their S&P 500 Index. Equity index funds would include groups of stocks with similar characteristics such as the size, value, profitability and/or the geographic location of the companies. A group of stocks may include companies from the United States, Non-US Developed, Emerging Market or Frontier Market countries. Additional index funds within these geographic markets may include indexes of companies that include rules based on company characteristics or factors, such as companies that are small, mid-sized, large, small value, large value, small growth, large growth, the level of gross profitability or investment capital, real estate, or indexes based on commodities and fixed-income. Index funds have also been designed to include rules that screen for social and sustainable criteria. Companies are purchased and held within the index fund when they meet the specific index rules or parameters and are sold when they move outside of those rules or parameters. Think of an index fund as an investment utilizing rules-based investing. Those rules may also include trading or implementation rules, such as tax-management, tracking error minimization, large block trading or patient/flexible trading strategies that allows for greater tracking error, but lower market impact costs. Some index providers announce changes of the companies in their index before the change date and other index providers do not make such announcements.