The difference between interest-sensitive assets and interest-sensitive liabilities
Income Gap Analysis
1. Classify assets and liabilities according to maturity/repricing time buckets
2. Calculate the gap (RSA - RSL) in each bucket
3. Multiply the gap by the change in interest rate to get the change in net interest income
Income Gap Analysis
Provides a picture of overall balance sheet mismatches
Ignores market value effects of interest rate changes
Ignores effects of changes in interest rates on off-balance sheet instruments
Duration Analysis
Measures the sensitivity of the market value of an asset or liability to changes in interest rates
Duration Measures
Macaulay Duration
Modified Duration
Duration Gap
Income Gap Analysis is a book value accounting cash flow analysis, while Duration Analysis is a market value-based model
If interest rates decrease
Net interest income decreases due to liabilities repricing faster than assets
If interest rates increase
Net interest income increases due to assets repricing faster than liabilities
Income Gap Analysis ignores the market value effects of interest rate changes
Income Gap Analysis ignores the rate-sensitive component of rate-insensitive assets and liabilities
Income Gap Analysis ignores the effects of changes in interest rates on off-balance sheet instruments
Despite its limitations, Income Gap Analysis is still used by banks, but in conjunction with other risk management tools
Under the income gap analysis (maturity approach), banks report the gap in each maturity bucket, calculated as the difference between rate-sensitive assets (RSA) and rate-sensitive liability (RSL) on their balance sheets. GAP = RSA – RSL
A positive GAP implies sensitive assets > sensitive liabilities. The rise in interest rates will cause a bank to have interest revenue rising faster than interest costs; thus the net interest margin and income will increase.
The decline in interest rates will increase liabilities costs faster than assets returns; as a consequence the net interest margin and income will decrease.
Bank managers can calculate the income exposure to changes in interest rates in different maturity buckets, by multiplying GAP times the change in the interest rate: ΔI= GAP * Δi
3 main problems associated with income gap analysis
It ignores market value effects of interest rates changes
Even rate-insensitive assets & liabilities (whose interest rates are not re-priced) actually have a component that is rate sensitive (i.e a runoff cash flow)
It ignores the effects of the changes in interest rates on off balance sheet instruments
Macaulay duration
Measures the average financial life of an asset or liability
Modified duration
Expresses the interest sensitivity of an asset or liability's value
If the durations of designated assets and liabilities are matched (DURgap=0), then the duration gap on that part of the balance sheet is said to be 'immunised against unexpected changes in interest rates'
Duration gap can be used to calculate the change in the market value of net worth (DNW) as a percentage of total assets induced by a change in interest rates
The formula for the calculation of the Macaulay duration of any fixed-rate security is: D = ∑CFt x DFt x t / ∑CFt x DFt
Dividend
$150 next year with dividend growth expected to be 2.5% per annum thereafter
US corporate bond
Annual coupon rate of 5%, par (face) value of $1000, and maturity in 2 years time
Required return on similar US equities is 10%
Required return on similar US bonds is 7%
Macaulay duration calculation
1. ∑CFt x DFt x t = ∑PVt x t
2. ∑CFt x DFt
3. ∑PVt
Macaulay duration of a portfolio is the weighted average of the durations of the individual securities, with the weights reflecting the proportion of the portfolio invested in each security
Duration of a zero coupon bond is its maturity
Macaulay duration of a 4-year 5% coupon bond with market interest rate of 4% and par value of $1000 is 3.7 years
Investor constructs a bond portfolio of $10,000 in the 4-year 5% coupon bond and $30,000 in a 3-year zero coupon bond
Macaulay duration increases with the maturity of a bond
Macaulay duration decreases as market interest rate increases
Macaulay duration decreases as coupon interest rate increases
Modified duration
Direct measure of the interest rate sensitivity of an asset or liability
The larger the Macaulay duration, the more the price of an asset (or liability) is sensitive to changes in market interest rates