Investment funds, or mutual funds, pools the money of several investors to invest it in various securities such as stocks, bonds, or money market instruments. There are several synonyms for the term investment funds, such as asset funds, equity funds, market funds, and index funds. Asset funds aim to generate income and capital appreciation by investing in a variety of securities. Equity funds focus on investing in shares of companies listed on stock exchanges while market funds invest in short-term debt instruments. Index funds track the performance of an index such as the S&P 500. Additionally, there are balanced funds that invest in a mix of stocks and bonds, and bond funds that concentrate on fixed-income securities.