Where This Lesson Fits
The previous lesson introduced asset–liability management as the function responsible for coordinating the bank’s balance sheet structure and monitoring structural financial risks.
This lesson explores one of the most important sources of those risks: the timing differences between assets and liabilities.
When the timing of interest rate adjustments differs between what the bank owns and what it owes, the institution becomes exposed to changes in market interest rates.
Lesson Objective
By the end of this lesson, students should understand how duration mismatch and repricing gaps arise within banking balance sheets and why these mismatches create interest rate risk.
Lesson Overview
Banks operate by transforming deposits into loans and other earning assets. However, the timing of these financial instruments is rarely perfectly aligned.
Loans may have fixed interest rates for long periods, while deposits can reprice or leave much more quickly. Investments may mature years later, while short-term funding may reset in weeks or months.
These differences create structural mismatches that cause the bank’s earnings and financial value to respond to changes in market interest rates.
Understanding Duration
Duration is a measure of how sensitive a financial instrument is to changes in interest rates. It reflects how long it takes for the value of the instrument’s cash flows to be realized.
Assets with longer durations tend to react more strongly to interest rate changes because their cash flows occur further in the future.
Liabilities with shorter durations may adjust more quickly when market rates change.
Duration Mismatch
A duration mismatch occurs when the average duration of a bank’s assets differs significantly from the duration of its liabilities.
If assets have longer durations than liabilities, rising interest rates may increase funding costs faster than asset yields adjust.
If liabilities have longer durations than assets, falling interest rates may reduce asset yields faster than liability costs decline.
In both cases, the mismatch creates exposure to changing interest rate environments.
Repricing Behavior
Another important concept in asset–liability management is repricing.
Repricing refers to the moment when an instrument’s interest rate resets or adjusts based on current market conditions.
For example, adjustable-rate loans may reprice every year, while certificates of deposit may reset when they mature.
When many liabilities reprice sooner than assets, the bank may face higher funding costs before asset income adjusts.
The Repricing Gap
The repricing gap measures the difference between assets and liabilities that reprice during a given period.
If more liabilities than assets reprice in a short timeframe, the bank has a negative repricing gap. If more assets than liabilities reprice, the bank has a positive repricing gap.
These gaps help asset–liability managers estimate how changes in interest rates might affect net interest income.
How Rate Changes Affect Earnings
When interest rates rise, liabilities that reprice quickly may become more expensive. If asset yields do not adjust at the same speed, the bank’s interest margin can shrink.
When interest rates fall, assets may generate lower income while liability costs remain temporarily unchanged.
In both situations, mismatched repricing patterns can affect profitability.
Balance Sheet Sensitivity
Because banks hold many different financial products, each with its own maturity and repricing structure, the full balance sheet contains layers of interest rate sensitivity.
Asset–liability management uses repricing analysis and duration analysis to evaluate these patterns and estimate how the balance sheet will behave under different interest rate scenarios.
This helps management anticipate potential margin pressure before market conditions change.
Why Timing Differences Matter
Interest rate exposure does not arise simply because a bank holds loans and deposits. It arises because the timing and responsiveness of those instruments are different.
Without careful monitoring, small mismatches can accumulate into significant earnings volatility or valuation risk.
Asset–liability management therefore focuses on understanding these timing differences and ensuring they remain within acceptable limits.
What Good Basic Interpretation Looks Like
Students should understand that duration mismatch and repricing gaps arise naturally from the banking business model.
The purpose of asset–liability management is not to eliminate these mismatches completely, but to measure them, monitor them, and manage them within safe and sustainable levels.
Common Misunderstandings
Believing assets and liabilities adjust simultaneously
In reality, different financial instruments adjust at different times, creating exposure to interest rate changes.
Assuming duration only applies to investments
Duration concepts apply to loans, deposits, and funding instruments as well.
Thinking repricing gaps always produce losses
Gaps simply indicate sensitivity. Their effect depends on how interest rates move.
Practical Exercises
Exercise 1
Explain how a bank with long-term fixed-rate loans and short-term deposits might be affected if market interest rates rise sharply.
Exercise 2
Describe how repricing gaps help banks estimate changes in net interest income.
Exercise 3
Discuss why duration mismatch is a normal feature of banking but still requires active monitoring.
Key Terms
Duration — A measure of how sensitive a financial instrument’s value is to interest rate changes.
Duration Mismatch — A difference between the duration of assets and liabilities on a bank’s balance sheet.
Repricing — The moment when an instrument’s interest rate resets based on market conditions.
Repricing Gap — The difference between assets and liabilities that reprice within a given timeframe.
Interest Rate Risk — The possibility that changes in market rates will affect earnings or asset values.
Knowledge Check
Question 1
What is duration mismatch?
A. The difference between loan balances and deposit balances
B. A difference between the timing sensitivity of assets and liabilities
C. The elimination of interest rate exposure
D. A type of accounting error
Question 2
What does a repricing gap measure?
A. The number of loans issued by a bank
B. The difference between assets and liabilities that reprice within a certain period
C. Marketing performance metrics
D. Branch operating costs
Question 3
Why do repricing gaps matter?
A. They determine the design of bank buildings
B. They help estimate how interest rate changes could affect earnings
C. They eliminate funding costs
D. They reduce the number of loans issued
Lesson Summary
- Banks often hold assets and liabilities with different timing structures.
- Duration measures sensitivity to interest rate changes.
- Duration mismatch occurs when asset and liability timing differs.
- Repricing gaps measure how quickly instruments adjust to new rates.
- These mismatches create interest rate exposure that asset–liability management must monitor.
Next Lesson Preview
In the next lesson, students will examine how loans, deposits, and investment securities each respond differently to interest rate changes and how these behaviors shape overall bank exposure.
Continue to Lesson 36.3