This Exam FM sample reference tests Duration and Convexity. The portfolio Macaulay duration is the price-weighted value 10.829; solving 105,000 = 100,000(1.0432/(1+i))¹⁰·⁸²⁹ gives i = 3.85%, choice C.
These notes identify the calculation error associated with each wrong letter when that error is reproducible.
AChoice A is inconsistent with the weighted portfolio duration and inverted yield-factor estimate; no distinct standard single-step error producing it is identifiable.
BChoice B is inconsistent with the weighted portfolio duration and inverted yield-factor estimate; no distinct standard single-step error producing it is identifiable.
DChoice D is inconsistent with the weighted portfolio duration and inverted yield-factor estimate; no distinct standard single-step error producing it is identifiable.
EChoice E is inconsistent with the weighted portfolio duration and inverted yield-factor estimate; no distinct standard single-step error producing it is identifiable.
Original practice · fully worked
Original variant: yield inferred from an estimated arts-bond portfolio value
An arts portfolio contains a 40,000 bond of Macaulay duration 5 and a 60,000 bond of duration 9, both valued at 4% yield. Using the Macaulay approximation, a new portfolio value of 105,000 implies what annual yield?
A 2.80%
B 3.00%
C 3.32%
D 3.60%
E 4.20%
Variant answer in brief
Portfolio duration is 7.4; inverting the 1.05 value ratio gives yield 3.32%, choice C.
Setup
Setup
Market-value weights 40% and 60% produce the portfolio duration.
DP=0.4(5)+0.6(9)=7.4
Model
Model
A five-percent estimated value increase implies a yield below the original 4%, and the yield-factor ratio can be inverted.
1.05=(1+i1.04)7.4
Compute
Compute
Taking the 7.4th root gives an implied yield of 0.0331656.
i=1.051/7.41.04−1=0.0331656
Answer
Answer
The estimated annual yield is 3.32%, corresponding to choice C.
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