Deposits fund a large share of bank assets, but not every deposit is equally likely to remain. A funding concentration exists when balances that appear separate could leave for the same reason or at the same time.
A concentration is more than one large account
One depositor can represent a material share of funding, but concentrations can also form across related companies, one industry, a geographic market, a product or a digital channel. Several accounts may behave like one source when they share an owner, cash-flow cycle or reason for choosing the bank.
A concentration is not automatically unsafe. The risk depends on its size, stability, contractual terms and relationship to the bank’s available liquidity and other funding sources.
Banks study how the balances may behave
Banks consider factors such as insurance coverage, account purpose, rate sensitivity, seasonality, maturity, transaction activity and the depth of the customer relationship. Operational balances used for payroll and collections may behave differently from excess cash placed mainly for yield.
Related accounts should be viewed together when appropriate. Good analysis avoids assuming that a familiar customer or a long account history guarantees that funds will remain under stress.
Stress scenarios turn the exposure into a cash-flow question
Liquidity testing estimates what could happen if a large depositor leaves, a group of similar customers withdraws together or market conditions make alternative funding more expensive. The assumptions should reflect the bank’s own products, customers and operating experience.
The purpose is not to predict one exact withdrawal date. It is to compare plausible outflows with usable cash, unencumbered liquid assets, borrowing capacity, collateral needs and other obligations over relevant time periods.
Diversification and liquidity provide different protections
A bank can reduce reliance on one source by cultivating a broader mix of customers, products, maturities and funding channels. Diversification takes time and should support the institution’s business model rather than encourage unstable deposits simply to improve a metric.
Liquid assets and tested borrowing arrangements provide a separate layer of protection if balances leave. A funding source is not truly available in stress merely because it appears on a list; access, collateral, capacity and timing need to be understood in advance.
Limits, escalation and contingency plans keep the risk visible
Management reporting can track large relationships, shared characteristics, uninsured or rate-sensitive balances and changes in deposit behavior. Limits and early-warning indicators identify when the exposure needs review before it becomes a liquidity event.
A contingency funding plan defines who decides, which sources may be used and how customer and operational impacts will be managed. Leaders should investigate the cause of a change instead of responding mechanically to every movement in deposits.
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