The **Bond Equivalent Yield** (BEY) is used to calculate the yield of a bond that is traded at a discount. Formula: \[ \text{BEY} = \frac{100 \times (\text{Face Value} – \text{Purchase Price})}{\text{Purchase Price}} \times \frac{365}{\text{Days to Maturity}} \] This formula adjusts for the time to maturity and provides an annualized return rate.