HOW BANKING WORKS · PAYMENTS AND SETTLEMENT 11
One commercial bank cannot settle finally with another by handing over more of its own promises
A customer deposit at Bank A is a claim on Bank A. That claim works beautifully for Bank A’s customers because Bank A promises to honour it under the account terms.
But when Bank A owes Bank B after a cross-bank payment, Bank B does not want final settlement to consist merely of another Bank A liability. That would replace one claim on Bank A with another claim on Bank A.
Domestic banking systems therefore commonly use central-bank money as the settlement asset between eligible institutions. The central bank sits above individual commercial banks in the monetary hierarchy, giving competing banks a common asset in which they can discharge obligations to one another.
This article continues Batch 03 of the How Banking Works authority spine.
Customer money and bank settlement money are not the same object
Most households and businesses use commercial-bank deposit money. Banks themselves also hold balances at the central bank, usually called reserves or settlement balances depending on the jurisdiction and system.
| Money form | Issuer | Typical holder | Main job |
|---|---|---|---|
| Commercial-bank deposit | Commercial bank | Households and firms | Everyday payments and saving |
| Central-bank reserve / settlement balance | Central bank | Eligible banks and institutions | Interbank settlement and liquidity management |
| Physical currency | Central bank/state framework | Public and businesses | Physical payment and store of value |
These forms can exchange at par in ordinary conditions, but they occupy different balance sheets. That difference is precisely what makes settlement possible.
A cross-bank transfer creates two customer changes and one interbank obligation
Suppose Maya sends S$50,000 from Bank A to a supplier at Bank B.
- Bank A reduces its deposit liability to Maya.
- Bank B increases its deposit liability to the supplier.
- Bank A owes Bank B settlement value.
- Bank A transfers central-bank money or uses the system’s designated settlement arrangement.
- The interbank claim is discharged according to the system’s rules.
The customer-level money changed banks because settlement value changed banks underneath it.
Why Bank B does not simply accept Bank A deposits as final settlement
If Bank B accepted a new Bank A deposit as final payment, Bank B would still be exposed to Bank A. The obligation would have changed form but not necessarily disappeared.
Using central-bank money removes that direct commercial-bank credit exposure from the final settlement step. Bank B receives an asset issued by the central bank rather than an additional promise issued by the bank that already owes it.
This is why central-bank money is often described as the ultimate domestic settlement asset for banks. It creates a neutral meeting point among competing private institutions.
The hierarchy of money
Modern money works partly because claims at lower levels are expected to convert into claims at higher levels at par.
customer deposit at Bank A → transferable at par → customer deposit at Bank B → banks settle the difference in central-bank money.
If people began to doubt that one bank’s deposit could convert reliably into another bank’s deposit or into currency, the unity of everyday money would weaken. The settlement layer helps keep many private bank monies functioning as one monetary system.
Why reserves are not “customer deposits kept at the central bank”
A common misconception imagines that each customer deposit is mirrored by an equal reserve balance with the customer’s name attached. That is not how modern banking balance sheets generally work.
Commercial banks manage aggregate reserves and settlement liquidity. Customer deposits are liabilities of the commercial bank; reserves are assets of the commercial bank and liabilities of the central bank. They are different claims used by different holders.
This is why the amount of reserves a bank needs for settlement is related to payment flows, liquidity rules and monetary arrangements—not a simple one-for-one storage mapping of every customer deposit.
Why a bank that creates deposits still needs reserves
Return to the loan-creation mechanism. Bank A can create a S$100,000 loan asset and matching customer deposit. But if the borrower spends the deposit to someone at Bank B, Bank A must settle the interbank outflow.
The ability to create a Bank A deposit does not create unlimited central-bank settlement balances. Bank A therefore needs liquidity management, incoming payments, market funding, eligible collateral or other routes to obtain the settlement resources it requires.
This is one of the cleanest constraints on careless interpretations of “banks create money.” They create their own deposit liabilities. They do not thereby create the settlement asset accepted by every other bank.
Where do central-bank reserves come from?
The precise operating framework varies by central bank. In broad terms, reserves enter and leave bank balance sheets through central-bank operations, payments involving government or central-bank counterparties, asset purchases or sales, lending facilities and the settlement of flows among banks.
A bank can obtain reserves from another bank through interbank markets, from the central bank through eligible facilities, or through incoming payment flows. What matters is that reserves are part of the central bank’s balance sheet, not something a commercial bank can independently manufacture.
Why central banks provide liquidity facilities
A bank can be solvent yet face a temporary shortage of settlement liquidity. Large payments may leave before incoming payments arrive. Depositors may withdraw unexpectedly. Markets may become temporarily impaired.
Central banks can provide liquidity under defined conditions, often against eligible collateral, to help keep the payment system functioning and prevent a temporary timing problem from becoming a wider crisis.
But liquidity support is not a magic repair for insolvency. If a bank’s assets are fundamentally worth less than its liabilities, lending more settlement money can change timing without creating the missing economic value.
Why intraday liquidity matters
Payments arrive throughout the day. A bank can expect a large incoming transfer at 4 p.m. and still need reserves at 10 a.m. to settle an outgoing payment.
This means settlement liquidity has a time dimension. A bank can finish the day with the same reserve balance it started with and still have needed substantial intraday liquidity in between.
Payment systems therefore need mechanisms for queues, collateral, intraday credit or other liquidity management depending on their design.
Central-bank money supports par convertibility
Customers normally expect S$1 at Bank A to transfer as S$1 at Bank B. That expectation seems obvious because it works so consistently.
Underneath is a large institutional achievement. Banks settle at par in a common settlement asset, are supervised, hold liquidity and capital, and participate in payment infrastructures with defined rules. These layers help separate the value of money from the creditworthiness of any single transfer counterparty in ordinary use.
What happens if banks lose confidence in one another?
Interbank markets can become stressed when institutions fear counterparty risk or liquidity shortages. Banks may hoard reserves, reduce unsecured lending or demand more collateral.
The payment system still has to function. This is one reason central-bank settlement and liquidity facilities are systemically important: they provide a common monetary anchor when private willingness to extend credit to other banks weakens.
The failure-mode owner remains How Banking Does Not Work; this article owns the normal settlement mechanism.
Central-bank money does not eliminate every payment risk
Using a high-quality settlement asset solves one important problem: the credit quality of the settlement asset itself. Other risks remain.
- Messages can be wrong.
- Fraud can produce an authorised-looking instruction.
- A bank can lack liquidity at the required time.
- Technology can fail.
- Participants can disagree about reconciliation.
- Legal or sanctions controls can interrupt a payment.
- Operational dependencies can delay access even after settlement.
Settlement assets are one layer of resilience, not the whole system.
Four misconceptions to remove
| Misconception | Better model |
|---|---|
| “Bank reserves are my deposit held at the central bank.” | Customer deposits and bank reserves are different claims on different balance sheets. |
| “A bank that creates deposits can create all the settlement money it needs.” | A commercial bank creates its own liabilities, not central-bank liabilities. |
| “Central-bank liquidity proves a bank is solvent.” | Liquidity support addresses timing; solvency depends on asset value and capital. |
| “Central-bank money is only about monetary policy.” | It is also central to interbank settlement and payment-system functioning. |
A mastery test
- Why does Bank B prefer central-bank money to a new Bank A promise for final settlement?
- Whose liability is a customer deposit?
- Whose liability is a reserve balance?
- Why can a bank create deposits and still need settlement liquidity?
- Why can central-bank liquidity solve a timing problem without solving insolvency?
If those answers connect, central-bank reserves stop looking like an obscure technical account. They become the common settlement language that lets many commercial banks operate as one payment system.