Original practice · fully worked
Original variant: verifying a two-sided habitat-restoration reserve
A habitat trust owes a single amount whose present value is 1,000 and duration is 10 years. It holds a seven-year zero worth 400 today and a twelve-year zero worth 600 today. Do these assets meet the two-sided full-immunization conditions?
- A
No; asset value is 1,200. - B
No; asset duration is 9. - C
No; both assets mature before the liability. - D
Yes; value and duration match, and maturities straddle year 10. - E
Yes, but only because convexities are equal.
Answer and calculation
The asset value is 1,000 and its duration is 10; the two maturities straddle the liability, so choice D.
Setup
Setup
Current market values are the weights in the duration calculation for zero-coupon assets.
PVA=400+600=1000 Model
Model
Check equality of present value, equality of duration, and placement of one maturity on each side of the liability date.
DA=10007(400)+12(600)=10 Compute
Compute
The weighted maturity is exactly ten years, and the two asset maturities lie at seven and twelve years.
Answer
Answer
All stated two-sided conditions are met, giving choice D.
two-sided full immunization(D)