Which metric is often used to measure market risk?

Beta is a widely recognized metric for measuring market risk, specifically the risk of a security or portfolio in relation to the overall market. It quantifies the sensitivity of the asset's returns to changes in the returns of a benchmark market index, such as the S&P 500. A beta of 1 indicates that the asset's price will move with the market, while a beta less than 1 suggests the asset is less volatile than the market, and a beta greater than 1 indicates higher volatility.

Understanding beta is crucial for investors and risk managers because it helps assess the market-related risk that cannot be diversified away. It provides insight into how much systematic risk the investor is taking by holding a particular asset compared to the market as a whole.

In contrast, the other metrics, while useful for evaluating different aspects of performance or risk, do not directly measure market risk. Alpha is related to the performance of an asset relative to a benchmark, the Sharpe ratio assesses risk-adjusted returns, and the information ratio measures the consistency of excess return relative to a benchmark. Therefore, these measures serve different purposes and do not focus specifically on the intrinsic market risk associated with an investment.