Reviewed by
ROBERT C. KELLYUpdated Jul 19, 2021
What Is Dispersion?
Dispersion is a statistical term that describes the size of the distribution of values expected for a particular variable and can be measured by several different statistics, such as range, variance, and standard deviation. In finance and investing, dispersion usually refers to the range of possible returns on an investment. It can also be used to measure the risk inherent in a particular security or investment portfolio.
Understanding Dispersion
Dispersion is often interpreted as a measure of the degree of uncertainty, and thus risk, associated with a particular security or investment portfolio.
Investors have thousands of potential securities to invest in and many factors to consider in choosing where to invest. One factor high on their list of considerations is the risk profile of the investment. Dispersion is one of many statistical measures to give perspective.
Most funds will address their risk profile in their fact sheets or prospectuses, which can be readily found on the internet. Information on individual stocks, meanwhile, can be found on Morningstar and similar stock rating companies.
The dispersion of return on an asset shows the volatility and risk associated with holding that asset. The more variable the return on an asset, the more risky or volatile it is.
For example, an asset whose historical return in any given year ranges from +10% to -10% can be considered more volatile than an asset whose historical return ranges from +3% to -3% because its returns are more widely dispersed.
Measuring Dispersion
The primary risk measurement statistic, beta, measures the dispersion of a security's return relative to a particular benchmark or market index, most frequently the U.S. S&P 500 index. A beta measure of 1.0 indicates the investment moves in unison with the benchmark.
A beta greater than 1.0 indicates the security is likely to experience moves greater than the market as a whole—a stock with a beta of 1.3 could be expected to experience moves that are 1.3x the market, meaning if the market is up 10%, the beta stock of 1.3 climbs 13%. The flip side is that if the market goes down, that security will likely go down more than the market, though there are no guarantees of the magnitude of the moves.
A beta of less than 1.0 signifies a less dispersed return relative to the overall market. For example, a security with a beta of 0.87 will likely trail the overall market—if the market is up 10%, then the investment with the lower beta would be expected to rise only 8.7%.
Alpha is a statistic that measures a portfolio's risk-adjusted returns—that is, how much, more or less, did the investment return relative to the index or beta.
A return higher than the beta indicates a positive alpha, usually attributed to the success of the portfolio manager or model. A negative alpha, on the other hand, indicates the lack of success of the portfolio manager in beating the beta or, more broadly, the market.
Related Terms
Unlevered Beta Definition
Unlevered beta (or asset beta) measures the market risk of the company without the impact of debt. more
Systematic Risk Definition
Systematic risk, also known as market risk, is the risk that is inherent to the entire market, rather than a particular stock or industry sector. more
Volatility measures how much the price of a security, derivative, or index fluctuates. more
Positive Correlation Definition
Positive correlation is a relationship between two variables in which both variables move in tandem. more
How to Use Required Rate of Return (RRR) to Evaluate Stocks
The required rate of return (RRR) is the minimum return an investor will accept for an investment as compensation for a given level of risk. more
Beta Risk
Beta risk is the probability that a false null hypothesis will be accepted by a statistical test. more
Related Articles
How Investment Risk Is Quantified
Alpha Vs. Beta: What's the Difference?
Vanguard 500 Index Fund Investor Risk Statistics
Trading High-Beta Stocks
Difference Between a Sharpe Ratio and Treynor Ratio
How to Select and Build a Benchmark to Measure Portfolio Performance
About Us
Terms of Use
Editorial Policy
Privacy Policy
Contact Us
California Privacy Notice
Investopedia is part of the Dotdash publishing family.