# Sharpe Ratio - definition & overview

Contents
Sharpe Ratio is the investment performance metric calculated as the average return in excess of the risk-free rate per unit of risk (standard deviation). Higher ratios indicate better risk-adjusted returns.

The Sharpe Ratio, named after its creator, Nobel laureate William F. Sharpe, is a measure used to understand the return of an investment compared to its risk. This ratio has become a cornerstone in the world of finance and investment, providing a mathematical approach to the risk-return trade-off. It's a vital tool for small businesses, particularly those in Australia, as it helps in making informed investment decisions.

Understanding the Sharpe Ratio can be a game-changer for small businesses. It can help you make better investment decisions, manage your risks more effectively, and ultimately, increase your profits. Let's delve into the world of Sharpe Ratio, exploring its definition, calculation, interpretation, and its importance in the context of small businesses.

## Definition of Sharpe Ratio

The Sharpe Ratio is a measure that indicates the average return minus the risk-free return divided by the standard deviation of return on an investment. In simpler terms, it's a measure that helps investors understand the return of an investment compared to its risk. The higher the Sharpe Ratio, the better the investment's return performance relative to the risk taken.

It's important to note that the Sharpe Ratio assumes that the returns are normally distributed, and it only considers the total risk of the investment. This means that it may not accurately represent the risk-return trade-off if the returns are not normally distributed or if there are specific risks associated with the investment.

### Components of Sharpe Ratio

The Sharpe Ratio is calculated using three main components: the expected return of the investment, the risk-free rate, and the standard deviation of the investment's return. The expected return is the profit that the investor anticipates to make from the investment. The risk-free rate is the return that could be earned on an investment that is considered risk-free, such as a government bond. The standard deviation is a measure of the investment's volatility, or how much the returns can vary from the expected return.

Each of these components plays a crucial role in the calculation of the Sharpe Ratio. The expected return provides an estimate of the potential profit, the risk-free rate provides a benchmark for comparison, and the standard deviation provides a measure of the investment's risk.

## Calculation of Sharpe Ratio

The Sharpe Ratio is calculated by subtracting the risk-free rate from the expected return of the investment and then dividing the result by the standard deviation of the investment's return. This formula provides a single number that represents the risk-adjusted return of the investment.

It's important to note that the Sharpe Ratio is a relative measure of risk-adjusted return. This means that it should be used to compare the performance of different investments or portfolios. A higher Sharpe Ratio indicates a better risk-adjusted return.

### Example of Sharpe Ratio Calculation

Let's consider an example to understand the calculation of the Sharpe Ratio. Suppose a small business in Australia has made an investment that is expected to return 15% per annum. The risk-free rate in Australia is 2%, and the standard deviation of the investment's return is 10%. The Sharpe Ratio of this investment would be (15% - 2%) / 10% = 1.3.

This means that for every unit of risk taken, the investment is expected to return 1.3 units of return above the risk-free rate. This is a relatively high Sharpe Ratio, indicating that the investment has a good risk-adjusted return.

## Interpretation of Sharpe Ratio

The Sharpe Ratio provides a measure of the risk-adjusted return of an investment. A higher Sharpe Ratio indicates a better risk-adjusted return, while a lower Sharpe Ratio indicates a worse risk-adjusted return. However, the interpretation of the Sharpe Ratio can be subjective and depends on the investor's risk tolerance.

Generally, a Sharpe Ratio of 1 or above is considered good, a Sharpe Ratio of 2 or above is considered very good, and a Sharpe Ratio of 3 or above is considered excellent. However, these are just general guidelines and the acceptable Sharpe Ratio can vary depending on the specific circumstances and the investor's risk tolerance.

### Limitations of Sharpe Ratio

While the Sharpe Ratio is a powerful tool for assessing the risk-adjusted return of an investment, it has its limitations. One of the main limitations is that it assumes that the returns are normally distributed. This means that it may not accurately represent the risk-return trade-off if the returns are not normally distributed.

Another limitation is that the Sharpe Ratio only considers the total risk of the investment and does not take into account the specific risks associated with the investment. This means that it may not accurately represent the risk-return trade-off if there are specific risks associated with the investment that are not captured by the standard deviation.

## Importance of Sharpe Ratio for Small Businesses

The Sharpe Ratio is an important tool for small businesses as it provides a measure of the risk-adjusted return of an investment. This can help small businesses make informed investment decisions and manage their risks more effectively.

By understanding the Sharpe Ratio, small businesses can compare the performance of different investments or portfolios and choose the ones that offer the best risk-adjusted return. This can help them maximise their profits and grow their business.

### Use of Sharpe Ratio in Investment Decision Making

The Sharpe Ratio can be used in investment decision making to compare the performance of different investments or portfolios. By comparing the Sharpe Ratios of different investments, small businesses can identify the investments that offer the best risk-adjusted return.

This can help them make informed investment decisions and allocate their resources more effectively. For example, if two investments have the same expected return but different Sharpe Ratios, the investment with the higher Sharpe Ratio would be the better choice as it offers a better risk-adjusted return.

### Use of Sharpe Ratio in Risk Management

The Sharpe Ratio can also be used in risk management to assess the risk of an investment. By understanding the Sharpe Ratio, small businesses can identify the investments that are more risky and take appropriate measures to manage the risk.

This can help them avoid unnecessary risks and protect their business from potential losses. For example, if an investment has a low Sharpe Ratio, it may be more risky and the business may need to take additional measures to manage the risk, such as diversifying the investment or setting aside a contingency fund.

## Conclusion

The Sharpe Ratio is a powerful tool that can help small businesses make informed investment decisions and manage their risks more effectively. By understanding the Sharpe Ratio, small businesses can maximise their profits, grow their business, and achieve their financial goals.

Remember, the journey to financial success is not about taking unnecessary risks, but about making informed decisions and managing risks effectively. The Sharpe Ratio is a tool that can help you on this journey, providing a measure of the risk-adjusted return of an investment and helping you make better investment decisions.