An open-end investment company is a type of investment firm that pools money from multiple investors to invest in a variety of securities. It is also known as a mutual fund or a unit trust. Synonyms for open-end investment company include investment fund, equity fund, stock fund, bond fund, income fund, growth fund, sector fund, index fund, and exchange-traded fund (ETF). Each of these terms refers to a specific type of mutual fund that invests in a different type of asset or industry. For instance, an equity fund invests primarily in stocks, while a bond fund invests in bonds. Regardless of the name, open-end investment companies offer investors the chance to diversify their portfolios and potentially generate higher returns than individual investments.