Aman: Index is just a group of individual stocks. You'll need to look at the corelation between the stocks and the index. For example, QQQQ which is composed of the 100 tech stocks will have more of a positive corelation to INTC than to SIGA. If an index is down, it could be because majority of the stocks in the index are down or some of the stocks that are weighted heavily are down huge. I usually track the index because it tells me how on average nist of the stocks are doing, Then I can drill down and find individual stocks to buy or sell. It is said that 75% of the stocks go up or down with the market. So, in a bull market if you were to buy 4 stocks just by random chance 3 of the 4 will go up. In a bear market a company could be relly good and still not go up in price because of the general conditions.