In todays world lots of companies are very secretive about there dealings, i.e Murges, Sell off's etc. How and Where do the guys on the stock market learn the goings on before it actually happens??
There are sectors in the capital market whose stocks are very expensive and whose market value is more like to appreciate than depreciate. Examples are shares of banks and oil companies. So, it is usually simple to forecast the future market value of such shares. The common Forecasting tool used is time series analysis. Apart from that, past stock market information is used to predict future market capitalisation of companies