The topic of this article is the answer to the following question: what is the formula for stock beta calculation?First, let’s talk about the purpose of stock beta calculation.Stock beta calculation has to do with variability.The variability of a stock is essentially its risk.How risky is the stock?If the stock market drops, will the stock drop the same amount about as the stock market, or will it drop more?Or will it drop less?How safe will your money be in this stock?This is the variability of a stock, or its risk.
Some analysts and theorists of the stock market believe that investors should consider the risk of a particular stock before investing in it.To this particular end, they have come up with a number of different highly technical mathematical models in order to measure the risk of a stock.Stock beta measurement is used in the capital asset pricing model, or the CAPM.The stock’s variability is measured in relation to the variability of the overall stock market.If the beta measurement is just about one, this means that the stock will move up and down at about the same rate as the overall market.So if the market drops 2% on a particular day, then the stock will probably drop about 2% on the same day.If the beta measurement of a stock is 2, then if the stock market drops 2%, then this particular stock will drop about 4%.This stock is considered to have greater risk than other stocks.While you can potentially lose a lot of money on it, it also will probably have a greater yield on your investment.If a beta measurement of a stock is 0.5, then if the stock market drops 4% on one day, then this stock will probably drop about 2%.Your money will probably be safer with this stock.However, the return on your investment will not be as immediately high as on a stock with a higher beta measurement. If you are more of a long term investment style, or you are a value investor, then beta measurement don’t really mean all that much to you.However, if you are interested in growth investment style, or you are interested in working with high yield stocks, then beta measurement can be very important for you.However, beta measurement definitely has its drawbacks.The major drawbacks come from the fact that the beta measurement is entirely based on the history of the stock.It is an accurate measure of the history, but not necessarily the future of the stock. Furthermore, the beta measurement does not take account of any new developments in the company.
The formula for the stock beta calculation is highly technical.Here it is for an asset within a portfolio:
,
rais a measurement of the rate of return of the asset. rp is a measurement of the rate of the return of your portfolio.When you look at the total CAPM, then any rp terms that are in the formula are taken over by rm.This is the rate of the return of the overall market.
This particular formula of calculation, the stock beta measurement, come from linear regression analysis.After the beta measurement is calculated, then it is linked to the regression analysis of a portfolio’s returns during a specific period.These are compared to the returns of an individual asset.Then the regression line is renamed and called the Security Characteristic Line:
Pretty complicated, right?Fortunately, you are not the one who really needs to calculate all of this.It is calculated instead by economists and market analysts, and you simply need to decide what beta measurement you are comfortable with when deciding what kinds of stocks that you want to invest in.