Calculating the Sharpe Ratio for a Portfolio

In evaluating the performance of an investment portfolio, risk-adjusted performance measures help investors understand how much return is generated for each unit of risk taken. One commonly used metric is the Sharpe Ratio, which is calculated by subtracting the risk-free rate from the portfolio return and dividing the result by the standard deviation of the portfolio's returns.

Imagine a portfolio that has an expected return of 12%, a risk-free rate of 3%, and a standard deviation of returns of 9%. What is the Sharpe Ratio for this portfolio?