stock index

Statistical indicator used in measurement and reporting of changes in the market value of a group of stocks/shares. Different stock indices (such as Dow Jones Industrial Average, Russell 1000, Standard And Poor's 500) track the market differently--depending on (1) which averaging method is used to establish the index, (2) whether the index is broad based or narrow based, and (3) whether the averaging method assigns weights on the basis of market price or market capitalization. Also called share index.