A group of securities that exhibit similar characteristics, behave similarly in the marketplace, and are subject to the same laws and regulations. The three main asset classes are equities (stocks), fixed-income (bonds) and cash equivalents (money market instruments).

It should be noted that in addition to the three main asset classes, some investment professionals would add real estate and commodities, and possibly other types of investments, to the asset class mix. Whatever the asset class line-up, each one is expected to reflect different risk and return investment characteristics, and will perform differently in any given market environment.

Asset classes and asset class categories are often mixed together. In other words, describing large-cap stocks or short-term bonds asset classes is incorrect. These investment vehicles are asset class categories, and are used for diversification purposes.