Beta effectively describes the activity of a security's returns as it responds to swings in the market. A security's beta is calculated by dividing the product of the covariance of the security's returns and the market's returns by the variance of the market's returns over a specified period.
What is beta data & why is it important?
Beta data about an individual stock can only provide an investor with an approximation of how much risk the stock will add to a (presumably) diversified portfolio. For beta to be meaningful, the stock should be related to the benchmark that is used in the calculation. The S&P 500 has a beta of 1.0.
What is a beta index?
Beta (β) measures a stock's volatility or the degree to which its price fluctuates relative to the market as a whole. A benchmark index is chosen to represent the market in the beta calculation. An analyst will generally select an index most appropriate to compare with the chosen stock.
What is a beta coefficient?
A beta coefficient can measure the volatility of an individual stock compared to the systematic risk of the entire market. In statistical terms, beta represents the slope of the line through a regression of data points. In finance, each of these data points represents an individual stock's returns against those of the market as a whole.
