ECO349H5 Chap.9 Bank Competition, Regulation and Stability
Bank Competition, Regulation and Stability
Access and stability on different margins
Competition among banks can improve borrower access and reduce lending margins, yet its effect on stability depends on how banks respond. A quantity-setting model provides one benchmark: each bank chooses lending while taking rivals’ quantities as given. More competitors can raise total lending even when lending by each individual bank falls.
Report both quantities because they answer different policy questions.
Solve the competitive benchmark
Write the inverse return or demand schedule facing the banking system and the bank’s funding or operating cost. A bank internalizes how its own lending changes the market return but treats rivals’ lending as fixed. Under symmetry, impose equal quantities only after deriving the first-order condition.
Solving too early can conceal which term represents the strategic effect.
Comparative statics should distinguish the extensive system outcome from the intensive bank outcome. Entry may expand aggregate credit and compress net interest margins. That can benefit borrowers and reduce rents.
It does not follow mechanically that every bank becomes safer or riskier; the next step is to identify how lower margins interact with portfolio choice, charter value and limited liability.
Connect margins to risk incentives
Equity holders receive gains after fixed claims are paid but can lose only their invested equity.
This payoff shape can encourage a bank to prefer a riskier asset when upside accrues to owners and part of the downside falls on depositors, insurers or creditors. Margin compression may strengthen a search-for-yield channel, while competition can also improve discipline in other settings. State the model mechanism rather than claiming a universal sign.
Expected asset return and tail risk are not interchangeable.
A portfolio can offer the same mean with a greater probability of a severe loss. Evaluate the distribution of outcomes, the funding promise and the equity cushion.
Deposit guarantees can prevent destabilizing withdrawals while also weakening depositor monitoring, so their stabilizing and incentive effects belong in separate parts of the answer.
Read the balance sheet correctly
Reserves are liquid assets held to meet payments and withdrawals. Capital is the residual claim equal to assets minus liabilities and absorbs losses.
A reserve requirement and a capital requirement therefore target different vulnerabilities. More reserves improve immediate liquidity; more capital increases the loss-absorbing buffer. Neither ratio should be substituted for the other in a calculation.
Leverage magnifies the effect of an asset-value change on equity.
Compute the dollar loss on assets, subtract it from initial equity and then divide by initial equity if an equity return is requested. A modest percentage loss on total assets can erase a large share of a thin capital cushion.
Keep assets, deposits and equity in levels before converting to ratios.
Match policy to the externality
Capital regulation makes owners fund more of the balance sheet and can reduce risk shifting, but it may change lending cost or quantity. Liquidity regulation increases the stock of readily available assets but can lower maturity-transformation returns.
Supervision and disclosure address information and enforcement. Resolution rules determine how losses are allocated after failure. A defensible proposal identifies the targeted problem and one trade-off.
Policy evaluation should track borrower access, bank margins, portfolio risk, expected public losses and the distribution of credit.
More lending is not automatically efficient if standards deteriorate, and fewer failures are not automatically costless if productive credit disappears. Use the competition model for quantity, the limited-liability model for risk and the balance sheet for resilience, then connect them explicitly.
Structure an exam answer
First solve per-bank and system lending. Second describe the margin effect.
Third introduce the risk-choice channel and state its assumptions. Fourth calculate reserves or capital using the correct balance-sheet side. End by matching a regulatory instrument to liquidity, loss absorption or incentives. This layered response avoids jumping from a Cournot formula directly to a policy conclusion that the model alone cannot establish.
What this chapter covers
- 01
Cournot competition
- 02
Net interest margin
- 03
Portfolio risk
- 04
Reserve ratio
- 05
Capital adequacy
Worked example · free
How competition changes per-bank lending
- 2Insert market size, funding cost, slope terms and bank count into the symmetric expression.
- 2Multiply the individual optimum by the number of banks to recover aggregate credit.
Key terms
- Cournot Competition
- Cournot Competition has firms choose quantities while treating rivals’ quantities as given.
- Charter Value
- Charter Value is the future franchise value lost when a bank closes.
Bank Competition, Regulation and Stability FAQ
Why can more banks increase risk taking?
Entry compresses net margins in the model, reducing the value preserved by a successful safer portfolio. The marginal cost of risk falls relative to its upside, though the result depends on the specified payoff and liability structure.
How do reserve and capital requirements differ?
Reserve requirements protect near-term payment capacity with liquid assets. Capital requirements place owner-funded loss absorption behind assets. Each targets a different balance-sheet margin and can change lending incentives.
Does concentration guarantee stability?
No. Concentration can preserve margins or charter value but may create market power and large-system exposure. Empirical comparisons also mix regulation, funding, portfolio composition and history, so the model tradeoff needs evidence.
Exam move
Solve per-bank and total lending, trace the margin-risk channel, then match each safeguard to liquidity, loss absorption or coordination.
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