Stock Price Charts

How is the stock index determined?

I mean what does it mean when the finance report says that the NASDQ is down 12 points.

Public Comments

1. Stock market index is generally a relative change in the market capitalization of the comprised companies with respect to base value. Market capitlization is the market value of a company. ie, mps * Number of shares outstanding(or floating as in case of floating market cap). when they say nasdaq is down by 12 ponts its a comparision with respect to yesterdays market value of the companies comprising of the index in nasdaq.