Calculate the beta coefficient of a stock to understand its correlation with market movements and risk profile.
Enter historical stock returns as percentages (e.g., 2.5, -1.2, 3.1)
Enter corresponding market returns as percentages (e.g., 1.8, -0.9, 2.2)
The stock moves in line with the market.
The beta coefficient is an indicator of the correlation of a stock (or a portfolio) compared to the overall market to which it belongs. Using a statistical approach, we analyze the historical returns of a company and the overall market to identify what happened with the stock when the market went up/down and consider it an indication for the future.
The risk of the market is represented by its volatility, meaning, tomorrow or any day, it can go up 10% or go down 10%. The beta coefficient indicates what happened in the past to the stock when such price fluctuations occurred. Did the stock go up when the market was up, both went down, or maybe the opposite?
The beta coefficient is calculated using the following formula:
β = Covariance(Stock Returns, Market Returns) / Variance(Market Returns)
Where:
Stock moves exactly with the market
Stock is more volatile than the market
Stock is less volatile than the market
Risk that affects the entire market and cannot be diversified away. This includes:
Beta measures this systematic risk.
Risk specific to individual companies that can be reduced through diversification:
This risk can be diversified away.
Let's calculate the beta for a stock with the following data:
| Period | Stock Return (%) | Market Return (%) |
|---|---|---|
| 1 | 2.5 | 1.8 |
| 2 | -1.2 | -0.9 |
| 3 | 3.1 | 2.2 |
| 4 | -0.8 | -0.5 |
| 5 | 1.9 | 1.5 |
Using our calculator, we find:
This means the stock is 20% more volatile than the market, indicating higher systematic risk.
Investors use beta to create diversified portfolios by combining high-beta and low-beta stocks to achieve desired risk levels.
Beta helps investors understand how much additional risk they're taking compared to the overall market.
Beta is a key component in the Capital Asset Pricing Model (CAPM) for calculating expected returns.
Conservative investors prefer low-beta stocks, while aggressive investors may seek high-beta stocks for higher potential returns.
Different sectors have characteristic beta ranges - utilities typically have low betas, while technology stocks often have high betas.
