# Sharpe Ratio

Source: https://www.yieldcurve.pro/learn/sharpe-ratio

The **Sharpe ratio** measures the excess return of an investment per unit of risk (volatility). It is the most widely used risk-adjusted performance metric in portfolio management.

*Sharpe Ratio = (Return - Risk-Free Rate) / Standard Deviation of Return*

A Sharpe ratio of 1.0 means the investment earned 1 unit of excess return for each unit of volatility. Higher is better.

In fixed-income contexts, Sharpe ratios are used to:

- **Compare maturities**: which sector of the curve delivers the best return per unit of interest rate risk
- **Evaluate strategies**: the Salomon Brothers yield curve primer (Part 3) shows that the Sharpe ratio of rolling 1-month strategies varies significantly across the maturity spectrum
- **Assess regime performance**: the blog post "Asset Returns During Various Yield Curve Regimes" computes Sharpe ratios for bond ETFs across bull/bear steep/flat regimes

Typical Sharpe ratios for Treasury sectors:

- **Short-term bills**: high Sharpe (low vol, modest return)
- **Intermediate notes (2-5Y)**: often the best Sharpe on the curve due to favorable carry-to-risk tradeoff
- **Long bonds (20-30Y)**: lower Sharpe due to high duration volatility

The Sharpe ratio has limitations — it penalizes upside volatility equally with downside, doesn't account for non-normal return distributions, and depends heavily on the measurement period. The Sortino ratio (which only penalizes downside deviation) is sometimes preferred.