Deposit Concentration Risk

Judge a bank's funding fragility by the correlation-adjusted effective depositor count rather than the headline number — coupled depositors collapse toward one bet, voiding the law-of-large-numbers smoothing a large base seems to guarantee.

Core Idea

Deposit concentration risk is the funding fragility arising when a bank's deposit base is dominated by a few large depositors, or by many whose withdrawal decisions are correlated — sharing an industry, an advisor network, or an information event. The bank looks diversified by count but not by exposure: when the correlation activates, the nominally many behave as one, and funding leaves faster than assets liquidate at par. The 2023 SVB failure is the canonical case.

Scope of Application

Deposit concentration risk lives within banking, finance, and prudential regulation, across deposit-taking and funding settings sharing its substrate.

• Commercial banking — the home turf: single-large-depositor or industry-vertical concentration (SVB).
• Prudential supervision — Basel III LCR/NSFR penalties, top-20 depositor lists, uninsured-deposit ratios.
• Money-market funds — institutional flows highly correlated and concentrated.
• Non-bank deposit-takers — credit unions and fintech accounts via partner banks.
• Stablecoin reserves — concentration in the reserve bank becoming concentration in the coin.
• DeFi liquidity pools — pools dominated by a few large providers whose exit breaks the pool.

Clarity

Naming the risk makes legible the difference between diversification by count and by exposure. The protective smoothing a large base seems to guarantee is an artifact of the law of large numbers, which requires independence; a shared cause voids it. The question sharpens from "how many depositors?" to "what is the correlation structure, and the effective count once it is applied?"

Manages Complexity

The sprawl is the unbounded variety of couplings — industry, region, advisor, insurance status — each suggesting its own ad hoc story. The concept collapses that variety onto one quantity: the effective depositor count under correlation, read against the nominal count. The insured/uninsured split is the branch: insured balances drain slowly, uninsured balances are mutually informative and self-accelerating.

Abstract Reasoning

The concept licenses diagnostic reasoning (computing the effective count behind the nominal one), predictive reasoning (the effective count and insurance split fixing the run mode), order-of-events reading of a trigger through a correlated population, interventionist reasoning (diversify against the cause, not the count), and boundary-drawing on the broken independence assumption and the substrate edge.

Knowledge Transfer

Within banking the mechanism transfers in full across every deposit-taking and funding structure, the SVB case instructive throughout. Beyond it is a strong shared-mechanism case: the parent concentration_risk/correlated_exposure (with run_dynamics/contagion and liquidity_under_stress) recurs in customer, supplier, and counterparty concentration, where the same effective-count diagnostic and diversify-against-the-cause remedy apply literally. The deposit-specific flavor stays home.

Relationships to Other Abstractions

Current abstraction Deposit Concentration Risk Domain-specific

Parents (3) — more general patterns this builds on

• Deposit Concentration Risk is a kind of Funding Fragility Domain-specific

  Deposit concentration risk is funding fragility caused by concentrated or correlated withdrawal-capable funding claims.

• Deposit Concentration Risk is a decomposition of, conditional Apparent Variety Masks Shared Driver Prime

  In the nominally broad but correlated-depositor branch, stripping banking reveals surface multiplicity coupled by a hidden driver and an effective count that collapses under stress.

• Deposit Concentration Risk is a decomposition of Dependency Distribution Concentration Prime

  Removing deposits, insurance, run dynamics, and asset-liquidity framing leaves dependency weight concentrated across funding providers, with fragility governed by effective rather than nominal provider count.

Hierarchy paths (12) — routes to 9 parentless roots

• Deposit Concentration Risk → Funding Fragility → Coordination Problem and Equilibrium Selection → Coordination → Concurrency

Show alternative paths (11)

Neighborhood in Abstraction Space

Deposit Concentration Risk sits in a sparse region of the domain-specific corpus (74^th percentile for distinctiveness): few abstractions share its structure, so a faithful description tends to retrieve it precisely.

Family — Monetary Mechanics & Macro Trilemmas (7 abstractions)

Nearest neighbors

• Wholesale-Funding Run — 0.86
• Flight to Quality — 0.83
• Concentration Illusion — 0.82
• Money Multiplier — 0.82
• Modigliani–Miller theorem — 0.82

Computed from structural-signature embeddings · 2026-07-12