SORTINO RATIO

Summary

The Sortino Ratio is a risk-adjusted performance measure that improves upon the Sharpe Ratio by focusing only on harmful volatility. While the Sharpe Ratio penalizes all volatility (both upside and downside), the Sortino Ratio only considers downside deviation - the volatility of negative returns below a target return (often the risk-free rate). This makes it more intuitive since investors typically don't mind upward price movements. The formula is (Portfolio Return - Target Return) / Downside Deviation. A higher Sortino Ratio indicates better risk-adjusted performance, as it shows the excess return earned per unit of downside risk taken.

Usage Context

Understanding this term is crucial when evaluating investment performance and comparing different investment strategies or portfolios. It's particularly important in portfolio management, risk assessment, and when studying alternative performance measures that better reflect investor preferences for asymmetric risk.

Common Confusions

• Confusing it with the Sharpe Ratio - students often don't understand the key difference in risk measurement
• Thinking that higher volatility always means higher Sortino Ratio
• Not understanding why upside volatility shouldn't be penalized
• Confusion about what constitutes the 'target return' in the formula
• Misunderstanding that downside deviation only includes returns below the target