A measure of the volatility, or systematic risk, of a security or a portfolio in comparison to the market as a whole.Beta is a very important measure that is used as a key input for Discounted Cash Flow or DCF valuations. In this article, we look at the nuts and bolts of CAPM Beta.If you have not heard of Beta yet, then worry not. this article explains you about Beta in most basic way.Let us take an example: when we invest in stocks, it is but human to pick stocks that have the highest possible returns. However, if one chases only returns, the other corresponding element is missed i.e. Risk.