Concentration Risk in Banking
Concentration risk exists when a bank's exposures are clustered in ways that make it vulnerable to a single adverse development. A bank with 50% of its loans in office commercial real estate does not just have CRE exposure — it has a business that could be severely impaired by a single sector downturn. Concentration turns diversifiable risks into existential ones.
Loan Concentration
Loan concentration is the most closely monitored form. Regulatory guidance flags banks with CRE loans exceeding 300% of total risk-based capital, or construction and land development loans exceeding 100% of capital. These thresholds are not hard limits but trigger enhanced supervisory attention and expectations for stronger risk management.
Concentration can occur by loan type, industry, or individual borrower. A bank with 35% of loans in hospitality CRE is concentrated by both type and industry. A bank with its ten largest borrower relationships totaling 40% of total loans carries single-name concentration risk. Each form creates a scenario where a specific adverse event could generate losses that overwhelm the bank's earnings and capital.
The danger of loan concentration is correlation. When a concentrated sector turns, defaults do not occur randomly — they cluster. An office CRE downturn does not produce one bad loan; it produces dozens simultaneously as vacancy rates rise across the market, property values decline, and refinancing becomes difficult. The bank faces a wave of problem loans that exceeds its capacity to work through them individually.
Deposit Concentration
Deposit concentration received new attention after SVB's failure. SVB's deposits were heavily concentrated in venture capital-backed technology companies — a single industry with tightly connected participants who communicated rapidly and made withdrawal decisions in a correlated fashion. When confidence eroded, virtually the entire deposit base moved in the same direction at the same time.
Deposit concentration can occur by industry (all tech companies), by size (mostly large uninsured balances), by geography (single metro area), or by relationship type (all rate-sensitive CDs). Each form creates the possibility that an external event triggers correlated withdrawals that drain the bank's funding faster than it can replace it.
Evaluating deposit concentration requires looking beyond the aggregate deposit totals. The percentage of uninsured deposits, the industry composition of the depositor base, and the behavioral characteristics of different deposit segments all matter. A bank with $5 billion in deposits spread across 50,000 retail customers has fundamentally different concentration risk than one with $5 billion spread across 500 corporate accounts.
Geographic Concentration
Community and small regional banks inevitably operate in concentrated geographies. A bank serving three counties in central Florida is exposed to that region's economy in a way that a national bank is not. If the local employer closes, if a hurricane devastates the area, or if the housing market collapses, the bank faces simultaneous pressure on both its loan portfolio and its deposit base.
Geographic concentration is not inherently bad — it is the source of the local knowledge that gives community banks their lending advantage. The risk becomes problematic when the bank lacks sufficient capital to absorb a localized downturn. Investors should evaluate geographic concentration alongside capital levels: a well-capitalized bank in a concentrated market is positioned differently than a thinly capitalized one.
How Investors Identify Concentration
Call report data provides detailed loan composition by type. Compare CRE, C&I, residential, and consumer loan percentages to peers and to regulatory thresholds. The 10-K typically includes additional narrative about the bank's largest industry exposures and geographic markets.
Deposit concentration is harder to assess from public data but some banks disclose their top depositor concentrations, uninsured deposit percentages, and industry mix. If the bank does not disclose this information, that itself may be a red flag worth raising with management during earnings calls.
Revenue concentration matters too. A bank earning 80% of fee income from mortgage banking is concentrated in a cyclical, rate-sensitive business. One with 50% of non-interest income from a single wealth management relationship has key-person and client concentration risk.
The best protection against concentration risk is awareness. Banks that acknowledge their concentrations, monitor them actively, and maintain capital buffers proportional to the risk are managing it appropriately. Banks that grow into concentrations without recognizing the accumulating risk are the ones most likely to be surprised when conditions turn.
Related Articles
- Credit Risk in Banking — Concentration amplifies credit risk by correlating defaults across the loan portfolio
- Liquidity Risk in Banking — Deposit concentration creates correlated withdrawal risk that can trigger liquidity crises
Related Metrics
- Non-Performing Loans (NPL) Ratio — Concentrated portfolios can see NPL ratios spike rapidly when the concentrated sector deteriorates
- CET1 Capital Ratio — Capital adequacy must be evaluated in the context of portfolio concentration — more concentration requires more capital