A money market fund is a kind of mutual fund that invests in highly liquid, near-term instruments. These instruments include cash, cash equivalent securities, and high-credit-rating, debt-based securities with a short-term maturity such as U.S. Treasuries. Money market funds are intended to offer investors high liquidity with a very low level of risk. Money market funds are also called money market mutual funds.While they sound similar in name, a money market fund is not the same as a money market account . A money market fund is an investment that is sponsored by an investment fund company. Therefore, it carries no guarantee of principal. A money market account is a type of interest-earning savings account. Money market accounts are offered by financial institutions. They are insured by the Federal Deposit Insurance Corporation and they typically have limited transaction privileges.