A market-value weighted index of all common stocks listed on Nasdaq. The Nasdaq Composite dates back to 1971, which is when the Nasdaq exchange was first formalized. The index is used mainly to track technology stocks, and thus it is not a good indicator of the market as a whole. Unlike the Dow Jones Industrial Average (DJIA), the Nasdaq is market value-weighted, so it takes into account the total market capitalization of the companies it tracks and not just their share prices.