Independent solution

How to solve this Duration and Convexity question

Setup

Setup

Macaulay duration depends on relative present-value weights, not on the common scale of all cash flows.

DM=ttCtvttCtvtD_M=\frac{\sum_t tC_tv^t}{\sum_t C_tv^t}

Model

Model

Changing face value multiplies coupons and redemption by the same factor, which cancels from the duration ratio.

CtkCtDM unchangedC_t\mapsto kC_t\Longrightarrow D_M\ \text{unchanged}

Compute

Compute

Raising the coupon without changing maturity shifts a larger share of value from redemption to earlier dates.

higher coupongreater early-payment weightsDM\text{higher coupon}\Longrightarrow\text{greater early-payment weights}\Longrightarrow D_M\downarrow

Answer

Answer

Duration is unchanged by face value and decreases as coupon rate rises, so choice E is true.

face invariant; duration decreases with coupon(E)\boxed{\text{face invariant; duration decreases with coupon}\quad\text{(E)}}