This index tracks the prices of all of the securities traded on the Nasdaq Stock Market (Nasdaq), which in one way makes it a broader measure of market activity than the Dow Jones Industrial Average (DJIA) or Standard & Poor's 500-stock Index (S&P 500). On the other hand, since so many computer, biotechnology, and telecommunications companies are listed on the Nasdaq, the movement of the index is heavily influenced by what's happening in those sectors. The index is market capitalization weighted, which means that companies whose market values are higher exert greater influence on the index. Market capitalization, or value, is computed by multiplying the total number of existing shares by the most recent sales price. The index is updated throughout the trading day.