Asset-Liability Portfolio
Study guide: Exam FM-2
An asset-liability portfolio is the combined position of an institution's assets and the liabilities they are held to fund, valued together. Its surplus — the present value of the asset cash flows A_t less that of the liability cash flows L_t — is what asset-liability management protects against changes in the interest rate i.
S(i) = \sum_{t} v^t \left(A_t - L_t\right) = PV_A(i) - PV_L(i)
- Cash Flow Matching (dedication): choose assets whose cash flow on each date exactly equals the liability cash flow due that date, which protects the surplus against any movement in interest rates
- Redington Immunization: equal present values, equal modified durations (Duration Matching), and asset Convexity greater than liability convexity — all three are required; it protects against small changes in
i - Full Immunization (single liability): equal present values, equal durations, and one asset cash flow before and one after the liability — the surplus is positive for any immediate change in
i - Banks, insurers and pension funds manage their assets and liabilities together because their net worth — the surplus — fluctuates with the interest rate (Immunization is the general name for the duration-based strategies)
Simple ALM An insurer has a liability of
50{,}000due in exactly 4 years ati=5\%. Describe a cash-flow-matched portfolio.Answer Purchase a 4-year zero-coupon bond with face value
50{,}000at a cost of50{,}000(1.05)^{-4} = 41{,}135.12The bond's single cash flow exactly matches the liability, so the surplus is zero at every interest rate: the position carries no interest rate risk.