Discount rate vs Add-on rate

Going through an example in regards to DR and AOR where BEY is required to calculate. Data given is below along with the solution but it looks a bit messy due to format.

Now the question is- why is PV calculation the first step using 100 as FV for DR whereby for AOR the first step would be calculate FV using 100 as PV?

A Discount Rate 360 4.33%

B Add-On Rate 360 4.35%

Solution A:

Use Equation 9 to get the price per 100 of par value, where FV = 100, Days = 180, Year = 360, and DR = 0.0433.

PV =100×⎛1−180×0.0433⎞=97.835 ⎜⎝ 360 ⎟⎠

Use Equation 12 to get the bond equivalent yield, where Year = 365, Days = 180, FV = 100, and PV = 97.835.

AOR = ⎛365⎞ × ⎛100 − 97.835⎞ = 0.04487 ⎜⎝180 ⎟⎠ ⎜⎝ 97.835 ⎟⎠

The bond equivalent yield for Bond A is 4.487%.

Solution B

First, determine the redemption amount per 100 of principal (PV = 100), where Days = 180, Year = 360, and AOR = 0.0435.

FV = 100 + ⎛100 × 180 × 0.0435⎞ = 102.175 ⎜⎝ 360

Use Equation 12 to get the bond equivalent yield, where Year = 365, Days = 180, FV = 102.175, and PV = 100.

AOR = ⎛365⎞ × ⎛102.175 − 100⎞ = 0.04410 ⎜⎝180 ⎟⎠ ⎜⎝ 100 ⎟⎠

The bond equivalent yield for Bond C is 4.410%.

Another way to get the bond equivalent yield for Bond C is to observe that the AOR of 4.35% for a 360-day year can be obtained using Equation 12 for Year = 360, Days = 180, FV = 102.175, and PV = 100.

AOR = ⎛360⎞ × ⎛102.175 − 100⎞ = 0.0435 ⎜⎝180 ⎟⎠ ⎜⎝ 100 ⎟⎠

Therefore, an add-on rate for a 360-day year only needs to be multiplied by the factor of 365/360 to get the 365-day year bond equivalent yield.

365/360× 0.0435 = 0.04410

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yup figured it out myself :slight_smile: