Independent solution

How to solve this Duration and Convexity question

Setup

Setup

A ten-year zero has Macaulay duration ten, so its modified duration identifies the yield.

9.26=101+ii=0.07991369.26=\frac{10}{1+i}\Longrightarrow i=0.0799136

Model

Model

Use that yield to discount the ten annual annuity payments.

DM=t=110t(1+i)tt=110(1+i)tD_M=\frac{\sum_{t=1}^{10}t(1+i)^{-t}}{\sum_{t=1}^{10}(1+i)^{-t}}

Compute

Compute

The ratio of the time-weighted sum to the ordinary present-value sum is 4.87195.

DM=4.87195D_M=4.87195

Answer

Answer

The annuity Macaulay duration is 4.87 years, corresponding to choice D.

DM4.87 years(D)\boxed{D_M\approx4.87\text{ years}\quad\text{(D)}}