An index designed to reflect the movement of the market as a whole. (For example, the S&P 100, the S&P 500, and the AMEX Major Market Index).
See Also:
Broad-Based: Generally referring to an index, it indicates that the index is composed of a sufficient number of stocks or of stocks in a variety of industry groups.
Index: A compilation of the prices of several common entities (stocks) into a single number. An index is a group of stocks which can be traded as one portfolio, such as the S&P 500. Broad-based indexes cover a wide range of industries and companies and narrow-based indexes cover stocks in one industry or economic sector.