This Exam FM sample reference tests Immunization and Asset-Liability Management. Asset and liability values coincide, their modified durations also coincide, and asset convexity is greater. These are exactly the three local conditions for Redington immunization, so choice E applies.
These notes identify the calculation error associated with each wrong letter when that error is reproducible.
AChoice A (Diversified) does not satisfy the defining value, duration, and convexity conditions for Redington immunization; no distinct standard one-step error is identifiable.
BChoice B (Fully immunized) does not satisfy the defining value, duration, and convexity conditions for Redington immunization; no distinct standard one-step error is identifiable.
CChoice C (Fully leveraged) does not satisfy the defining value, duration, and convexity conditions for Redington immunization; no distinct standard one-step error is identifiable.
DChoice D (Exactly matched) does not satisfy the defining value, duration, and convexity conditions for Redington immunization; no distinct standard one-step error is identifiable.
Original practice · fully worked
Original variant: missing curvature condition in a proposed immunization program
At a reference yield, an insurer's asset value equals its liability value and the two modified durations coincide, but asset convexity is lower than liability convexity. Which conclusion is correct about Redington immunization?
A The position is Redington immunized because value matching alone is sufficient.
B The position is Redington immunized because duration matching alone is sufficient.
C The position is fully cash-flow matched.
D The position is not Redington immunized because the convexity inequality has the wrong direction.
E The position is protected against every possible yield change.
Variant answer in brief
Value and duration matching remove the constant and first-order mismatch, but lower asset convexity makes the second-order surplus term unfavorable. The position is not Redington immunized, so choice D is correct.
Setup
Setup
The proposed position satisfies the value and first-order sensitivity conditions.
A(i0)=L(i0)
DA(i0)=DL(i0)
Model
Model
Redington immunization additionally requires asset convexity to exceed liability convexity.
CA(i0)>CL(i0)
Compute
Compute
Here the supplied inequality is reversed, so the local second-order surplus condition fails.
CA(i0)−CL(i0)<0
Answer
Answer
The position is not Redington immunized for the stated reason, selecting choice D.
The 2210-page Financial Mathematics Proof Manual reorganizes 461 verified Exam FM solutions by syllabus skill and adds formula proofs, error patterns, and original worked practice.