HOW BANKING WORKS · BANK FUNDING 33
A bank does not finance itself with one pool of money
A customer sees a savings account. A bond investor sees a security. Another bank sees an interbank placement. Treasury sees all of them as different funding claims supporting one balance sheet.
The two broad families are retail deposits and wholesale funding. Retail deposits come from households and smaller businesses through current, savings and term accounts. Wholesale funding comes from larger institutional markets through interbank borrowing, issued debt, secured funding and other market-based sources.
Neither family is automatically superior. They behave differently, cost differently and fail differently. A resilient bank understands those differences before it needs the money.
This article begins Batch 09 under How Banking Works: bank funding.
Retail deposits are customer relationships and bank liabilities at the same time
When a household leaves S$20,000 in a savings account, the customer owns a claim against the bank. The bank records a deposit liability. That liability is also funding because it helps support the bank’s assets over time.
Retail deposits are unusual because customers often choose them for more than yield. Salary crediting, payments, cards, standing instructions, convenience, digital access and trust all matter. This can make some balances less price-sensitive than market funding.
That relationship value is one reason retail deposits can be strategically important.
Wholesale funding is raised from larger financial counterparties and markets
Wholesale funding can include interbank borrowing, negotiable certificates, commercial paper, bonds, secured borrowing and other institutional sources. The bank may raise tens or hundreds of millions in one transaction rather than gathering the same amount from thousands of depositors.
That scale is useful. It can also create concentration. One market closure or one large maturity can matter much more than the behaviour of a typical retail depositor.
Retail deposits can be operationally stable without being contractually long-term
Many current and savings deposits are available on demand. Contractually, the customer can leave quickly. Behaviourally, however, large portions of the deposit base may remain for years.
Banks model this behavioural stability because maturity transformation depends on it. But they should never confuse historical stickiness with a legal lock.
Digital transfers, higher competing rates or loss of confidence can shorten behaviour dramatically.
Wholesale funding often has clearer contractual maturity
A six-month interbank loan matures in six months. A three-year bond matures in three years. This makes the timing explicit, which can help planning.
But contractual clarity does not remove rollover risk. If the bank expects to refinance a maturing instrument, it still depends on future market access.
Read Rollover Risk for the time boundary.
Why retail funding can be cheaper
Some retail customers value transactional services enough to accept lower interest than institutional investors would demand for a comparable unsecured exposure. A current account can therefore be relatively low-cost funding.
But cheap is not free. Retail banking requires branches or digital infrastructure, fraud prevention, customer service, payments, onboarding, compliance and deposit operations.
The true economic cost of retail funding includes the service platform that keeps the customer relationship alive.
Why wholesale funding can be more expensive but more precise
Wholesale investors typically compare yields across institutions and instruments. They may demand a spread reflecting the bank’s credit quality, maturity, collateral and market conditions.
The price can therefore be more sensitive to market stress. But wholesale funding can provide exact tenor, currency and size. A bank needing three-year US-dollar funding can target that need more precisely than by waiting for retail deposit flows to arrive organically.
A simplified comparison
| Funding source | Strength | Risk |
|---|---|---|
| Current and savings deposits | Often diversified and relationship-driven | Can leave rapidly under rate competition or confidence stress |
| Term deposits | Clearer contractual tenor | Can reprice sharply at renewal |
| Interbank borrowing | Fast, flexible institutional liquidity | Can disappear when banks become cautious about one another |
| Issued bonds | Can provide longer tenor and large size | Market access and refinancing price can deteriorate |
| Secured funding | Collateral can preserve access when unsecured markets weaken | Requires eligible, unencumbered collateral and tolerable haircuts |
Deposit concentration can make retail funding behave like wholesale funding
A bank with one million small household depositors has a different funding profile from a bank whose “deposits” are dominated by twenty large corporate customers.
Large corporate balances can move quickly in response to treasury decisions, ratings or yield. They can therefore behave more like market funding than traditional sticky retail deposits.
Funding labels matter less than actual behaviour.
Deposit insurance can change behaviour but not eliminate runs
Eligible insured deposits can be more stable because depositors know protection exists up to the applicable scheme rules and limits. Uninsured balances may be more sensitive to perceived bank weakness.
Insurance does not make every deposit stable. Customers can still move funds for convenience, yield, concentration management or uncertainty beyond the insured amount.
Wholesale investors tend to react faster to public risk signals
Institutional lenders monitor ratings, capital, liquidity, earnings, asset quality and market prices closely. A deteriorating signal can cause spreads to widen before ordinary retail customers notice anything.
This can make wholesale funding a valuable early-warning market signal—and a dangerous source of sudden pressure.
Retail deposits can reprice slowly, then suddenly
When market rates first rise, a bank may not need to increase savings rates by the full amount. Depositors remain because convenience matters. Over time competitors offer higher returns, customers notice, and deposit pricing catches up.
The bank can therefore enjoy cheap funding temporarily before deposit beta increases. Funding stability and pricing stability are related but not identical.
Wholesale funding can help manage currency mismatch
If a bank makes loans in a foreign currency, it needs funding and liquidity in that currency. Domestic retail deposits may not provide enough of it.
Wholesale markets can provide targeted foreign-currency funding. The bank must still manage exchange-rate, basis and rollover risk.
Matching currency is another reason funding diversification has a practical job beyond simple quantity.
Wholesale funding can help extend maturity
A bank can issue three-, five- or ten-year debt to reduce dependence on short-term deposits and money markets. Longer-term funding can therefore improve maturity structure even if it costs more.
The added cost buys time certainty. A bank should not optimise funding expense while ignoring the value of surviving a market closure.
Why wholesale funding can disappear exactly when assets are weakest
Investors lend when they believe repayment is safe. If asset quality weakens, funding becomes more expensive or unavailable. The bank therefore loses access to funding when it most wants additional liquidity.
This procyclicality is one reason excessive reliance on wholesale funding can amplify banking stress.
The funding mix changes bank strategy
A bank rich in stable deposits may be more comfortable holding longer-lived loans. A bank relying heavily on short market funding may need more liquid assets, tighter tenor limits and larger contingency capacity.
Funding is therefore not merely a treasury afterthought. It shapes what asset strategy the bank can safely support.
A worked miniature
Bank A funds 75 per cent of its balance sheet with diversified household and small-business deposits and 15 per cent with longer-term bonds. Bank B funds only 30 per cent with deposits and 50 per cent with short-term wholesale borrowing.
In normal markets, Bank B may enjoy cheaper marginal funding and faster growth. In a confidence shock, its large short-term market requirement can become a refinancing problem before Bank A faces the same pressure.
That does not prove Bank A is always safer. It shows why funding composition changes the path through stress.
The best funding source is the one that remains useful under the stress it is supposed to survive
A cheap deposit that leaves instantly is not cheap in a crisis. A long-term bond that costs more can be valuable because it does not mature during the stress window. Secured funding can preserve access but only if collateral remains available.
Funding quality therefore depends on price, maturity, concentration, currency, collateral and behaviour together.
Four misconceptions to remove
| Misconception | Better model |
|---|---|
| “Retail deposits are always stable.” | They can be sticky, but rate competition, concentration and confidence can change behaviour quickly. |
| “Wholesale funding is bad because it is market-based.” | It can provide scale, tenor and currency precision; the risk is overdependence and rollover sensitivity. |
| “The cheapest funding source is the best.” | Resilience depends on maturity, concentration, behaviour and stress availability as well as price. |
| “Funding mix does not affect lending strategy.” | The durability of liabilities helps determine which assets the bank can safely hold. |
A mastery test
- What makes retail deposits different from wholesale funding?
- Why can contractual and behavioural maturity differ?
- How can wholesale funding improve currency and tenor matching?
- Why can large corporate deposits behave like market funding?
- Why should a bank judge funding by stress behaviour rather than price alone?
If those answers connect, bank funding becomes visible as a portfolio of promises rather than one pool of money. The bank survives by knowing which promises remain available when the world becomes less convenient.