Sortino ratio in mutual fund performance
The Sortino ratio is a risk-adjusted return measure that computes excess return per unit of downside deviation (volatility of negative returns only), rather than total volatility as in the Sharpe ratio . The Sortino ratio is more intuitive for most investors because it penalises only “bad” volatility (drawdowns) and not “good” volatility (upside).
Formula
Sortino ratio = (Scheme return - Risk-free return) / Downside deviation
Where:
- Downside deviation: Standard deviation of only negative returns (or returns below a target threshold).
The downside deviation captures only the “loss volatility”, aligning with investor intuition that risk = potential loss.
Interpretation
| Sortino ratio | Interpretation |
|---|---|
| > 2 | Excellent downside-risk-adjusted return |
| 1 to 2 | Good |
| 0 to 1 | Acceptable |
| < 0 | Underperformed risk-free rate |
Sortino is typically higher than Sharpe for the same scheme (because downside deviation is typically smaller than total deviation).
Comparison with Sharpe ratio
| Dimension | Sharpe Ratio | Sortino Ratio |
|---|---|---|
| Volatility measure | Total | Downside only |
| Intuition | Penalises all volatility | Penalises only losses |
| Industry usage | Most common | Increasingly common |
| Typical magnitude | Lower | Higher |
For asymmetric return distributions (more upside than downside), Sortino can be significantly higher than Sharpe.
Use in mutual fund evaluation
Sortino is particularly useful for:
- Equity funds with positive skew: Where upside dominates downside.
- Hybrid funds with downside protection: Conservative or balanced advantage.
- Long-term performance assessment: Where short-term drawdowns matter.
See also
- Mutual funds in India
- Sharpe ratio
- Alpha mutual fund
- Beta mutual fund
- Treynor ratio
- Information ratio
- Max drawdown
- Std deviation MF
- Downside upside capture
External references
References
- Sortino, Frank A. and van der Meer, Robert. “Downside Risk.” 1991.
- CFA Institute curriculum.