A mutual fund that invests in money-market instruments.

A type of mutual fund that invests in stable, short-term securities. Money-market funds are easily convertible into cash and usually maintain an unchanged value of $1 a share, but aren't insured by the federal government. There are various types of money-market funds based on the type of securities they buy, but the most important distinction is whether your dividends are taxable or tax-free.

Investment fund that invests its assets by the majority in short-term, fixed-income securities (term to maturity less than one year).