The NASDAQ Composite is a stock market index that includes almost all stocks listed on the Nasdaq stock exchange. Along with the Dow Jones Industrial Average and S&P 500, it is one of the three most-followed stock market indices in the United States. The composition of the NASDAQ Composite is heavily weighted towards companies in the information technology sector. The Nasdaq-100, which includes 100 of the largest non-financial companies in the Nasdaq Composite, accounts for about 80% of the index weighting of the Nasdaq Composite.