Investors gather and analyze vast amounts of information about security markets on a continual basis. Because this work can be both time consuming and data intensive, investors often use a single measure that consolidates this information and reflects the performance of an entire security market.
Security market indexes were first introduced as a simple measure to reflect the performance of the US stock market. Since then, security market indexes have evolved into important multi-purpose tools that help investors track the performance of various security markets, estimate risk, and evaluate the performance of investment managers. They also form the basis for new investment products.
in·dex, noun (pl. in·dex·es or in·di·ces) Latin indic-, index, from indicare to indicate: an indicator, sign, or measure of something.
ORIGIN OF MARKET INDEXES
Investors had access to regularly published data on individual security prices in London as early as 1698, but nearly 200 years passed before they had access to a simple indicator to reflect security market information.1 To give readers a sense of how the US stock market in general performed on a given day, publishers Charles H. Dow and Edward D. Jones introduced the Dow Jones Average, the world’s first security market index, in 1884.2 The index, which appeared in The Customers’ Afternoon Letter, consisted of the stocks of nine railroads and two industrial companies. It eventually became the Dow Jones Transportation Average.3Convinced that industrial companies, rather than railroads, would be “the great speculative market” of the future, Dow and Jones introduced a second index in May 1896—the Dow Jones Industrial Average (DJIA). It had an initial value of 40.94 and consisted of 12 stocks from major US industries.4,5 Today, investors can choose from among thousands of indexes to measure and monitor different security markets and asset classes.
This reading is organized as follows. Section 2 defines a security market index and explains how to calculate the price return and total return of an index for a single period and over multiple periods. Section 3 describes how indexes are constructed and managed. Section 4 discusses the use of market indexes. Sections 5, 6, and 7 discuss various types of indexes, and the final section summarizes the reading. Practice problems follow the conclusions and summary.