What Is the Sharpe Ratio?

Written by True Tamplin, BSc, CEPF®

Reviewed by Editorial Team

Updated on March 11, 2023

Sharpe Ratio Definition

The Sharpe Ratio is a mathematical formula which measures the performance of an asset or a group of assets relative to their assumed risk.

Formulaically, the Sharpe Ratio is the expected returns of an asset, minus the risk-free rate, divided by the standard deviation of excess returns, which is a measure of volatility.

In other words, this formula helps an investor determine the performance of returns attributable to risk when compared to its riskiness.

Example of the Sharpe Ratio

For example, Mr. Sharpe anticipates a 13% return on his portfolio in the coming year. He also knows the One-year US Treasury yield, which can be considered a risk-free investment, is 1.55%.

He also calculates the volatility of his portfolio as 9%. Using these figures, he calculates a Sharpe ratio of 127%.

Now Mr. Sharpe is considering a risky investment which is projected to raise his portfolio return to 22% and volatility to 29%.

Using the same risk-free rate, the Sharpe Ratio will be 70%.

Mr. Sharpe should not make the investment because his return relative to the risk assumed is nearly half of what it was.

Stated another way, a higher Sharpe Ratio will indicate a greater return proportional to the risk taken on.

A Drawback of the Sharpe Ratio

The Sharpe Ratio is one of the most widely used efficiency ratios in modern investing due to its simplicity and usefulness in comparing investment with differing characteristics.

A drawback of using the Sharpe Ratio is that volatility, which is used in the denominator of the calculation does not necessarily equate to risk.

Therefore, an investor should consider volatility as well as other qualitative factors indicative of an investment's risk in order to create a more accurate picture of an investment's risk-reward profile.

Sharpe Ratio FAQs

About the Author

True Tamplin, BSc, CEPF®

True Tamplin is a published author, public speaker, CEO of UpDigital, and founder of Finance Strategists.

True is a Certified Educator in Personal Finance (CEPF®), author of The Handy Financial Ratios Guide, a member of the Society for Advancing Business Editing and Writing, contributes to his financial education site, Finance Strategists, and has spoken to various financial communities such as the CFA Institute, as well as university students like his Alma mater, Biola University, where he received a bachelor of science in business and data analytics.

To learn more about True, visit his personal website, view his author profile on Amazon, or check out his speaker profile on the CFA Institute website.

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