The information ratio is a financial metric used to assess the performance of an investment portfolio or strategy relative to a benchmark. It is widely recognized as a measure of the manager’s ability to generate excess returns (alpha) per unit of risk taken. The higher the information ratio, the more value the manager has added to the portfolio.

## Origin:

The concept of the information ratio was first introduced by William F. Sharpe, a Nobel laureate in economics, in the late 1960s. Sharpe aimed to devise a quantitative measure that could capture the skill of portfolio managers in utilizing available information to outperform the market. Over the years, the information ratio has become an essential tool in evaluating investment managers across various asset classes.

## Calculation:

To calculate the information ratio, two key components are required: the excess return of the portfolio and the variability of those returns. The excess return is the difference between the portfolio’s average return and the benchmark’s average return. The variability is typically measured using the standard deviation of the excess returns. The information ratio is then computed by dividing the excess return by the standard deviation of the excess return.

## Formula:

Information Ratio = (Portfolio Return – Benchmark Return) / Standard Deviation of Excess Returns

## Interpretation:

The information ratio provides investors with a quantitative measure to assess the skill and performance of a portfolio manager. A ratio greater than 1 generally indicates that the manager has generated more alpha relative to the risks taken, suggesting superior performance. Conversely, a ratio below 1 may suggest that the manager has failed to outperform the benchmark on a risk-adjusted basis.

## Limitations:

While the information ratio is a valuable metric, it is essential to consider its limitations when interpreting the results. Firstly, the ratio assumes that excess returns follow a normal distribution, which may not be the case in reality. Additionally, it does not account for non-linear risks or factors such as transaction costs, liquidity constraints, and market impact, which may heavily influence portfolio performance. Therefore, investors should use the information ratio in conjunction with other performance measures and qualitative analysis to gain a comprehensive understanding of a manager’s abilities.

## Practical Application:

The information ratio is widely utilized by institutional investors, fund managers, and consultants to evaluate the performance of investment portfolios and to compare the skill of different managers. It helps investors identify managers who consistently deliver alpha above a benchmark and navigate through periods of market volatility. By utilizing the information ratio, investors can distinguish between luck and skill in investment management.

In conclusion, the information ratio is a crucial tool for assessing the ability of investment managers to generate excess returns relative to a benchmark. Although it has its limitations, it remains a widely accepted measure for evaluating the performance of portfolio managers. By considering a manager’s information ratio along with other performance metrics, investors can make informed decisions when selecting and monitoring their investment portfolios.

## References:

– Sharpe, William F. Mutual Fund Performance. The Journal of Business, vol. 39, no. 1, 1965, pp. 119-138.

– Jobson, J. D., and Korkie, B. M. Performance Hypothesis Testing with the Sharpe and Treynor Measures. Journal of Finance, vol. 55, no. 3, 2000, pp. 1273-1291.

– Grinold, Richard C., and Khan, Ronald N. Active Portfolio Management: A Quantitative Approach for Producing Superior Returns and Controlling Risk, 2nd ed., McGraw-Hill, 2000.