Stock Beta

What is Stock Beta?

Stock Beta is one of the statistical tools that quantify the volatility in the prices of a security or stock with reference to the market as a whole or any other benchmark used for comparing the performance of the security. It is actually a component of Capital Asset Pricing Model (CAPM)Capital Asset Pricing Model (CAPM)The Capital Asset Pricing Model (CAPM) defines the expected return from a portfolio of various securities with varying degrees of risk. It also considers the volatility of a particular security in relation to the market.read more which is used to calculate the expected returns of an asset based on the underlying Beta, risk-free rate and the risk premium.

Stock Beta formula

Stock’s Beta is calculated as the division of covariance of the stock’s returns and the benchmark’s returns by the variance of the benchmark’s returns over a predefined period.

Below is the formula to calculate stock Beta.

Stock Beta Formula = COV(Rs,RM) / VAR(Rm)

Here,

You are free to use this image on your website, templates etc, Please provide us with an attribution linkHow to Provide Attribution?Article Link to be Hyperlinked
For eg:
Source: Stock Beta (wallstreetmojo.com)

If we focus on the components that go into the calculation of Stock Beta, it would become much more evident that:

  • It helps in assessing the direction of movement of the stock with reference to the direction of the movement of the market or the benchmark used for the comparison.
  • How sensitive or volatile is the stock’s price movement with respect to the market or the benchmark?

One more important thing that is worth mentioning is that there should be some kind of relation between stock and the market or the benchmark used for the comparison as otherwise, the analysis would serve no purpose. For example, an oil company stock and an index weighted majorly by technology companies would not have much of a relationship as the businesses are too dissimilar to compare, and hence no practically useful insight may come out of the Beta calculationBeta CalculationThe beta coefficient reflects the change in the price of a security in relation to the movement in the market price. The Beta of the stock/security is also used for measuring the systematic risks associated with the specific investment.read more between the two.

Calculate Stock Beta of MakeMyTrip

Let us calculate the Stock Beta of a NASDAQ Listed company MakeMyTrip (MMTY).

The benchmark index is NASDAQ.

Steps to Calculate Stock Beta are as follows

  1. Download the stock prices and NASDAQ index prices for the past couple of years.


    For NASDAQ, download the dataset from Yahoo Finance.


    NASDAQ-Historical-Prices-Download

    Likewise, download the corresponding stock price data for the MakeMyTrip example from here.

  2. Sort the data in the requisite format.


    Please format the data as per the details provided below.


    Beta-Calculation-Step-2a

  3. Prepare an excel sheet with stock price data and NASDAQ data.


    Beta-Calculation-Step-3a

  4. Calculate the percentage change in Stock Prices and NASDAQ.


    Beta-Calculation-Step-4

  5. Calculate Stock Beta using the Variance/Covariance Formula.


    Beta-Calculation-using-Variance-Covariance

    Using the variance-covariance stock beta formula, we get the Beta as 0.9859 (Beta Coefficient)

What Does Stock Beta Imply?

It may look like an overly mathematical formula, but it does provide both qualitative and quantitative actionable information. The sign (positive or negative) indicates the direction of the movement of the stock in question with respect to that of the underlying market or benchmark against which the stock’s movement is assessed.

The Stock Beta can have three types of values:

  • Beta < 0: If the Beta is negative, then this implies an inverse relationship between the stock and the underlying market or the benchmark in comparison. Both stock and the market or the benchmark will move in the opposite direction.
  • Beta = 0: If the Beta is equal to zero, then this implies that there is no relation between the movement of the returns of the stock and the market or the benchmark, and hence both are too dissimilar to have any common pattern in price movements.
  • Beta > 0: If the Beta is greater than zero, then there is a strong direct relationship between the stock and the underlying market or the benchmark. Both stock and the market or the benchmark will move in the same direction. Some further insight is as follows:
    1. Beta between 0 and 1 implies that the stock is less volatile than the underlying market of the benchmark.
    2. Beta of 1 implies that the volatility of the stock is exactly the same as that of the underlying market or the index in both qualitative and quantitative terms.
    3. Beta of greater than 1 implies that the stock is more volatile than the underlying market or index.

A negative Beta is possible but highly unlikely. Most investors believe that gold and stock based on gold tend to perform better when the market dives. Whereas a Beta of zero is possible in the case of government bonds acting as risk-free securities providing a low yield to the investors. And a Beta of greater than zero is the most common scenario that we see in the investment world. Most of the stocks follow this pattern.

Conclusion

It is one single statistical tool that investors frequently use to assess the risk that the stock may add to their portfolio, allowing them to gauge the risk in both qualitative and quantitative terms and to assess the risk and rewards associated with the stock. Using their analysis of Beta and their market acumen, the investors can take action regarding the stock.

This article has been a guide to what is Stock Beta and its definition. Here we discuss the Stock Beta formula and calculate stock beta (step by step) along with practical examples. You can learn more about from the following articles –