HOW BANKING WORKS · BANKING AND TIME 31
A bank can expect plenty of money later and still need cash now
A bank knows that mortgages will repay over years, business loans will amortise, securities will mature and customers will continue depositing money. None of that guarantees enough cash at 10:00 tomorrow morning.
The banking liquidity gap is the difference between cash and cash-like inflows available over a chosen horizon and the outflows that must be met over that same horizon.
It is the operating expression of banking’s time mismatch: money needed today against money returning later.
This article continues Batch 08 under How Banking Works.
Liquidity is about timing, not just total value
Suppose a bank expects S$100 million of loan repayments over the next year. That sounds substantial. But if S$30 million of deposits and wholesale funding can leave this week while only S$5 million of contractual inflows arrive this week, the bank has a short-horizon gap.
The annual total does not solve the weekly problem.
liquidity is not “Do I own enough?” It is “Can I pay enough, at the time payment is required?”
Banks map cash flows into maturity buckets
A liquidity manager does not look only at one end date. Cash flows are grouped into horizons such as overnight, one week, one month, three months and longer periods.
| Possible inflow | Possible outflow |
|---|---|
| Loan principal and interest received | Deposit withdrawals |
| Maturing securities | Maturing wholesale funding |
| New customer deposits | Committed loan drawdowns |
| Secured borrowing | Payment and settlement obligations |
| Asset sales | Collateral or margin calls |
| Central-bank facilities where eligible | Operational, tax and other cash needs |
The result is a liquidity ladder showing where future gaps can appear.
Contractual cash flow is only the starting point
Customer behaviour changes the ladder. Deposits legally available on demand may remain stable. Credit lines not yet drawn can suddenly be used. Borrowers can prepay. Term deposits can roll over. Wholesale lenders can refuse renewal.
The bank therefore creates behavioural assumptions around contractual dates.
That improves realism but introduces model risk. A behaviour observed in ordinary years may change sharply in stress.
A positive cumulative gap does not make every earlier gap safe
Imagine the bank expects S$80 million of inflows and S$70 million of outflows over three months. The cumulative position looks positive by S$10 million.
But if S$40 million of those outflows occur in the first week while only S$10 million of inflows arrive, the bank needs a bridge for S$30 million before later cash arrives.
Liquidity management therefore cannot skip the path and look only at the ending balance.
A liquidity buffer closes the early gap
The bank holds cash, central-bank balances and assets that can be sold or pledged quickly enough under stress. Those resources provide immediate liquidity while slower inflows continue to arrive.
A strong buffer does three things:
- meets early cash outflows;
- reduces the need for distressed asset sales;
- buys management time to obtain more durable funding or shrink risk.
Liquidity is therefore a stock of cash-like capacity and a strategy for surviving until other cash flows return.
Not every asset is equally liquid
A central-bank balance is immediately useful for settlement. A high-quality security may be saleable or pledgeable quickly. A mortgage can be valuable but difficult to monetise at full value on short notice.
The bank therefore ranks assets by more than accounting value. It asks:
- How quickly can the asset become cash?
- What discount might be required?
- Can it be pledged for secured borrowing?
- Is it already encumbered?
- Will the market remain open under stress?
The relevant value is often cash available under the conditions that matter, not the latest normal-market price.
Unencumbered collateral is hidden liquidity capacity
An asset does not have to be sold to create liquidity. If eligible, it can sometimes be pledged in secured funding or central-bank operations.
But an asset already pledged elsewhere cannot generally be promised again without legal and contractual consequences. The bank therefore monitors how much collateral remains unencumbered.
Two banks with the same securities portfolio can have different liquidity capacity if one has already pledged most of it.
Committed credit lines create contingent outflows
A company may have a S$10 million revolving facility but only S$3 million currently drawn. The remaining S$7 million is not yet a funded loan, but the bank may be contractually required to provide it if conditions are met.
During stress, many customers can draw unused lines at once because they also want liquidity.
The bank therefore includes expected contingent drawdowns in liquidity stress tests.
Deposits can leave faster than history suggests
A deposit base that has been stable for years can become mobile when interest rates, technology or confidence changes. Corporate deposits can be especially concentrated. A few large customers can remove substantial funding quickly.
This is why the bank looks beyond average deposit duration toward concentration, insurance status, customer type and behavioural sensitivity.
Read Why Some Deposits Are More Stable Than Others for the deposit side of this gap.
Wholesale funding creates explicit maturity cliffs
A bond, interbank borrowing or other wholesale liability has a defined maturity. The bank must repay or refinance it at that time.
If a large amount matures in one month, the liquidity ladder shows a funding cliff. The bank can pre-fund, issue longer-term debt, retain additional liquid assets or reduce other uses of cash before the date arrives.
What looks like one future maturity today becomes today’s problem as the date approaches.
Stress widens the gap from both sides
Liquidity stress rarely changes only one line item.
- deposit withdrawals accelerate;
- wholesale funding stops rolling;
- committed credit lines are drawn;
- collateral calls increase;
- asset-sale discounts widen;
- some expected inflows arrive late;
- the bank’s credit rating can weaken and make new funding more expensive.
The gap therefore can widen exactly when the bank’s ability to close it is weakening.
A worked stress example
A bank begins with S$20 million of immediately available liquidity. It expects S$8 million of contractual inflows over the next week and S$12 million of ordinary outflows.
Under stress, deposit withdrawals increase by S$15 million and customers draw S$5 million of committed facilities. The weekly outflow becomes S$32 million against S$8 million of inflows.
The initial S$20 million buffer leaves a S$4 million residual gap. The bank must raise or release at least another S$4 million before allowing for additional safety margin.
The purpose of stress planning is to identify that need before the week begins.
A contingency funding plan turns analysis into action
A liquidity gap report says where the problem could appear. A contingency funding plan says what the bank will do about it.
- which assets can be sold or pledged;
- which funding markets can be accessed;
- who has authority to act;
- which customer or product actions are permitted;
- how collateral will be mobilised;
- how communications and escalation will work;
- which options disappear as stress becomes more severe.
Batch 10 will own contingency funding in depth. Here the key idea is simple: the gap matters only if the bank knows how to close it.
Liquidity can be expensive precisely when it is needed most
During calm markets, borrowing can be easy and cheap. During stress, lenders demand more collateral, higher rates or refuse to lend altogether.
This makes “we can always borrow” a weak liquidity strategy. Access that exists only in calm markets is not a reliable stress buffer.
Central-bank reserves have a special settlement role
A bank can hold valuable assets and still need the form of money accepted for final settlement between banks. Central-bank balances are therefore especially important for payment liquidity.
Read Why Banks Need Central-Bank Money to Settle With One Another for that boundary.
Liquidity gaps can become solvency problems
If a bank must sell good long-term assets at large discounts to meet urgent outflows, temporary liquidity pressure can crystallise permanent losses. Those losses reduce capital.
This is the dangerous transition:
cash shortage → forced sale → realised loss → capital damage → weaker confidence → larger cash shortage.
Liquidity and solvency are different, but stress can connect them quickly.
The safest liquidity is prepared before it is needed
A bank has the most options before markets become worried. It can lengthen funding, build liquid assets, reduce concentration, pre-position collateral and diversify counterparties.
Once confidence falls, those same actions become more expensive or impossible.
Liquidity management is therefore preventive rather than merely reactive.
Four misconceptions to remove
| Misconception | Better model |
|---|---|
| “If enough cash arrives eventually, liquidity is fine.” | The timing path matters; early outflows can create a gap before later inflows arrive. |
| “All assets count equally as liquidity.” | Speed, sale discount, collateral eligibility and encumbrance determine practical liquidity value. |
| “Unused credit lines do not affect liquidity until drawn.” | They are contingent obligations that can be drawn rapidly under stress. |
| “A bank can always borrow if it needs cash.” | Market access can become expensive or disappear precisely when confidence weakens. |
A mastery test
- What is a banking liquidity gap?
- Why can a positive three-month position still contain a dangerous one-week gap?
- How does encumbrance reduce usable liquidity?
- Why do committed credit lines matter in stress?
- How can a liquidity problem damage capital?
If those answers connect, bank liquidity stops looking like a pile of cash. It becomes a timed map of obligations, inflows, buffers and executable choices.