Notes on Financial Intermediaries, Banking Regulation, and Liquidity/Maturity Transformation
Depository Institutions (DIs)
Purpose: Help surplus units (savers) overcome difficulties in understanding, monitoring, diversifying, and maintaining liquidity when lending or taking equity; provide long-term funding to borrowers.
Types: commercial banks, thrifts, credit unions.
Core activities: take deposits, make loans, and buy securities; earn money on the spread between assets returns and funding costs.
Commercial Banks: Structure and Balance Sheet
Primary activities: take deposits (and other forms of borrowing), make loans (and acquire other assets).
Profitability metric: Net Interest Margin = (loan rate − deposit rate); and more broadly, Return on Assets (ROA) and Return on Equity (ROE).
Implication: balance sheet composition drives risk, liquidity, and capital needs.
Key Concepts: ROA, ROE, and Leverage
Leverage = where A = assets and E = equity (borrowing via deposits, etc., to acquire assets).
ROA (Return on Assets) = ; depends on the rate earned on assets minus the rate paid on liabilities.
ROE (Return on Equity) = ; equals ROA times Leverage: .
Note: Leverage amplifies ROE when ROA > 0 but increases risk; if ROA < 0, higher leverage makes ROE more negative.
Notation used: A = assets, E = Equity, P = Profits.
Banking Concentration and Structure in the US
US banks are less concentrated than in many other countries but show a trend toward greater concentration through mergers and failures.
Interstate banking restrictions historically reduced concentration/diversification; removing some restrictions increases concentration but can reduce diversification and resilience.
Tradeoffs:
Benefits of concentration: economies of scale.
Costs: reduced competition, potential for moral hazard and banks becoming “too big to fail.”
Moral hazard: banks may take excessive risks when government would bail them out to prevent systemic meltdown.
Bank Holding Companies (BHCs) and Financial Holding Companies (FHCs)
BHCs own one or more banks (and possibly other firms).
Structure allows parent or non-bank subsidiaries to engage in activities banks themselves cannot (e.g., investment banking, asset management).
Financial Holding Company (FHC): a form of BHC that includes banks and nonbank financial services firms.
Maturity Transformation: Core Banking Function
Banks transform maturities: long-term, illiquid loans financed by short-term, liquid deposits.
Risks:
Run risk: if many depositors withdraw simultaneously, banks may need to liquidate loans or securities.
Funding risk: rising short-term rates relative to long-term asset yields squeeze profits (ROA falls).
Central question: why demand liquidity? Why do banks meet it? (Leads to Diamond-Dybvig framework below.)
Diamond–Dybvig Model (Three Periods)
Time periods: T = 0, 1, 2.
Consumer types:
T1: will need consumption at T = 1.
T2: will need consumption at T = 2.
At T = 0, individuals do not know their type.
Preferences: risk-averse; prefer a certain $100 over a gamble with $100 expected value.
Available asset: an illiquid asset invested into at T = 0, yielding at T = 2, and a payoff yielding r_1\left(<r_2\right) liquidated at T = 1.
This illiquid asset may not pay off enough if it needs to be consumed in T = 1, and consumer would like to insure against that riskby relying on financial intermediaries who can pool risks and provide liquidity. But, it’s not a publicly observable event like a hurricane.
Bank as Liquidity Provider (Deposit–Illiquid Asset Arrangement)
Bank offering: creates a liquid asset (a deposit) that pays off in T = 1 or T = 2, with higher payoff for early withdrawal than the illiquid asset would provide at T = 1, yet lower payoff at T = 2 than the illiquid asset if needed at T = 2.
Banks invest deposits in the illiquid asset; consumers prefer deposits due to liquidity and smoother consumption.
Key question: what deposit rates must banks offer to attract consumers while remaining profitable? Outcomes depend on:
consumer risk aversion
the relative mix of T1 vs T2 demand
An Example: 100 Consumers (Illustrative)
Composition: 25 want consumption at T = 1; 75 at T = 2; cannot know type at T = 0.
Utility: U(c) = 1 − 1/c; U'(c) > 0; U''(c) < 0 (diminishing marginal utility; risk aversion).
Consumer types (utility form):
Type 1: U(c1) = 1 − 1/c1
Type 2: U(c2) = 1 − 1/c2
Without insurance/deposit intermediary: expected utility of investing directly in the project vs. taking a deposit.
Deposit offer: a deposit paying $1.28 at T = 1 and $1.75 at T = 2.
Direct project investment (no deposit): expected utility is calculated from the outcomes; for this example:
Deposit utility:
Result: risk-averse consumers prefer the deposit (slightly higher expected utility).
Bank profitability: bank funds deposits and invests in the illiquid asset; example trace shows profitability through cash flows and liquidation strategy.
Example outcome (summary): Bank deposits $100 in the project; at T = 1, liquidates to obtain $32 while keeping $68 for T = 2; at T = 2, earns $2 imes 68$ and pays out $75 imes 1.75$; Profit ≈ $4.75$.
Profit math (outline):
T = 1 cash from project: $25 imes 1.28 = 32$; remaining liquid investment: 68.
T = 2 payoff from project: $2 imes 68$; deposit payouts: $75 imes 1.75$ to 75 depositors? (illustrative bookkeeping).
Profit:
Liquidity Creation and Maturity Transformation, and Related Risks
Benefits:
Depositors are better off than direct project investment due to liquidity and risk sharing.
Banks earn a profit and the project gets financed.
Determinants of deposit rates:
Degree of consumer risk aversion.
Degree of competition in banking.
Proportion of withdrawals in T = 1 (early withdrawals).
Early withdrawal risk specificity: what if more people withdraw early than anticipated?
The Problem of Early Withdrawal and Bank Runs
Let x be the number of depositors withdrawing in T = 1.
Profit when x depositors withdraw:
Break-even threshold: x ≈ 30.9; if x ≥ 31, bank profits fall to zero.
Insolvency threshold: x > 78.125 (i.e., 100/1.28); only the first 78 depositors get money at T = 1; 22 depositors lose out.
Bank runs are often self-fulfilling: if depositors expect others to withdraw early, they do too, potentially causing a solvent bank to fail because liquidity evaporates.
Historical context: common in the 19th century and the Great Depression; caused widespread dislocations, loan contractions, and bank failures.
Mechanisms to Prevent Bank Runs
Suspension of convertibility (temporary withdrawal limits).
Deposit insurance (FDIC-style) to reassure depositors.
Lender of last resort (central bank facilities) to provide liquidity.
Moral hazard concerns: deposits insurance and lender facilities can encourage risk-taking (especially when banks are perceived as ‘too big to fail’).
Result: increased regulation to mitigate moral hazard and stabilize the system.
Maturity Transformation’s Wider Impacts and Regulatory Implications
Maturity mismatch remains a core instability risk: short-term liabilities vs long-term assets.
Even with protection mechanisms (deposit insurance, lender facilities), mismatches create direct health risks for banks and potential systemic risk.
Historical episodes (e.g., savings and loan crisis in the 1980s) highlight regulatory attention to maturity mismatch and liquidity risk.
Ongoing regulatory aim: limit excessive maturity transformation while preserving the liquidity creation role of banks.
Deposit Insurance and Lender of Last Resort (FDIC and Federal Reserve)
FDIC Deposit Insurance: insured up to per account; funded by a levy on banks.
Federal Reserve: provides a discount window; banks can post collateral to borrow from the Fed to meet liquidity needs; reduces the need to liquidate loans.
Stigma concerns: use of liquidity facilities is often stigmatized; during crises (e.g., 2008, COVID), emergency facilities were expanded.
Government interventions in crises are designed to prevent systemic collapses but raise concerns about moral hazard and risk-taking.
Bank Regulation and Supervision: Chartering and Oversight
Chartering options: national banks obtain charters and are regulated by OCC, FDIC, and the Fed (if they are Fed members).
Bank holding companies must be Fed members; large banks are typically part of holding companies and thus subject to Fed regulation.
State banks: typically regulated by FDIC and state regulators; most are not Fed members.
CAMELS Rating System (Bank Health Monitoring)
CAMELS components:
Capital adequacy (C)
Asset quality (A)
Management (M)
Earnings (E)
Liquidity (L)
Sensitivity to risk (S)
Ratings scale: 1 (best) to 5 (most concerning); CAMELS ratings are confidential.
Basel Accords and Capital Regulation
Basel Committee on Bank Supervision (BCBS) issues recommendations; no direct legal authority but widely adopted.
Basel I (1988): risk-weighted assets (RWA) and capital requirements; different assets assigned risk weights.
Example Basel I weights: 0% for sovereign debt of advanced economies; 20% for US agency bonds and some municipals; 50% for mortgages; 100% for loans.
Simple illustration: if a bank has $10 in each category, RWA = 0.2×$10 + 0.5×$10 + 1×$10 = $17.
Basel II: update to risk-weighting and new approaches for estimating risk.
Basel III: post-2008 reforms; ongoing phasing in; aims to strengthen bank capital and liquidity buffers.
Capital, RWA, and Capital Ratios (Basel III Context)
Capital types:
Common Equity (permanent shareholder equity)
Tier 1 capital: common equity + reserves (retained earnings plus contingency reserves)
Tier 2 capital: includes preferred stock and subordinated debt (lower priority than debt but higher than common equity)
Risk-Weighted Assets (RWA): capital requirements scale with riskiness of assets.
Baseline capital ratio guidelines (as presented):
Common Equity / RWA ≥ 4.5%
Tier 1 Capital / RWA ≥ 6%
Tier 2 Capital / RWA ≥ 8%
Intuition: higher risk assets require more capital; higher capital reduces leverage and stabilizes ROE volatility.
Tradeoffs in Bank Regulation
Regulation, capital requirements, and moral hazard: aim to reduce crisis probability and impact, but may constrain credit supply and raise financing costs for households and businesses.
Post-GFC tightening led to a generally safer but less leveraged banking environment; some rules have since been eased, but overall framework remains tighter than pre-crisis.
Financial Reform Post-GFC (Dodd–Frank Act) and Related Tools
Dodd-Frank reforms introduced several components intended to reduce systemic risk:
Higher equity requirements for FIs
Contingent Convertible (CoCo) bonds to aid recapitalization during distress
Systemically Important Financial Institutions (SIFIs) designated with enhanced oversight
Supplementary Leverage Ratio (SLR) as an additional backstop
Liquidity Coverage Ratio (LCR) to ensure sufficient high-quality liquid assets during stress
Net Stable Funding Ratio (NSFR) to ensure stable long-term funding.
CoCo Bonds (Contingent Convertible Bonds)
Features: bonds that convert to equity when triggers are hit (e.g., Tier 1 ratio falls below threshold or share price falls below threshold).
Purpose: recapitalize the financial institution in distress without requiring a bailout.
Global use: more common in Europe; examples cited include Banco Popular episode where a CoCo downgrade occurred around a value event.
Practical note: no widely publicized triggering case widely, but used as a regulatory tool.
Systemically Important Financial Institutions (SIFIs)
Definition: any financial institution whose failure would trigger major ripple effects across the financial system.
Dodd-Frank designated many SIFIs (originally BHCs with >$50B assets; others designated by regulators).
Regulation: tighter capital and liquidity requirements, stress testing, dividend and buyback restrictions; FDIC has resolution authority for SIFIs.
Ongoing status: SIFI framework remains a core part of the post-crisis regulatory landscape.
Supplementary Leverage Ratio (SLR)
Purpose: additional capital adequacy measure, independent of risk weights.
Definition: traditional capital ratio uses risk-weighted assets as the denominator; SLR uses total exposure (non-risk-weighted) in the denominator.
Basel III baseline: SLR target around 3% for large banks; U.S. applied more stringent requirements, with 5% SLR for the largest (SIFI) banks.
Rationale: prevents excessive leverage across the balance sheet and limits balance-sheet expansion as a risk-control tool.
Liquidity Coverage Ratio (LCR) and Net Stable Funding Ratio (NSFR)
LCR: high-quality liquid assets (HQLA) divided by 30-day net cash outflows under stress; minimum 100%.
NSFR: requires funding to be stable over a longer horizon; supported by stable long-term funding and retail deposits.
Basel III and US implementation: LCR and NSFR are core liquidity risk mitigants.
Regulatory Rollback and Current Landscape
Post-2018–2019 adjustments: SIFI thresholds raised (to $100B, then $250B); some rules eased during COVID as a temporary response.
Overall trajectory: regulatory framework remains tighter than pre-crisis levels, with bank leverage and profitability still lower relative to pre-crisis levels.
Bank Lending: Types and Monitoring
Syndicated loans: provided by two or more banks to diversify risk.
Revolvers/lines of credit: facilities that can be drawn as needed, often used in stress periods (e.g., financial crises, COVID).
Leveraged loans: extended to relatively riskier borrowers.
Consumer loans: mortgages and autos; mortgages are the dominant asset for many thrifts.
Letters of credit: promises to make payment to exporters if goods are delivered; used in international trade.
Core monitoring role of banks: assess creditworthiness and monitor repayment; economies of scale and diversification improve monitoring efficiency over individuals.
Loan Covenants and Covenant-lite Phenomenon
Covenants restrict borrower actions and require maintenance of certain earnings or leverage.
Covenant-lite loans: loans with few covenants; declined after the crisis but re-emerged later; associated with higher risk.
Banks and the Money Supply; Payments System
Money creation via bank lending: when a bank makes a loan, it credits the borrower’s deposit account; deposits are a major portion of the money supply.
Simple illustration: a $100 loan increases deposits by $100; the asset (loan) increases and the corresponding liability (deposits) increases.
Payments system roles: deposits enable checks, electronic transfers, debit cards, ACH, Zelle, Venmo; large transfers use Fedwire.
Other payment considerations: credit cards and stored-value cards are part of the payments ecosystem; crypto is not a widely practical payment due to volatility; stablecoins aim to address this but have underlying risk concerns; regulatory developments (e.g., GENIUS act) could shape growth of stablecoins.
Central bank digital currencies (CBDCs) discussed as potential components of future payment infrastructure; currently shelved for the US.
Ethical, Philosophical, and Practical Implications
Moral hazard: deposit insurance and lender of last resort create incentives for banks to take on more risk, requiring careful regulation and oversight.
Regulatory balance: need to prevent crises without unduly constraining credit and financial innovation.
Systemic risk: SIFIs and “too big to fail” concepts require additional buffers and governance to minimize spillovers in crises.
Transparency and uncertainty: some regulatory design elements (like CAMELS ratings) are confidential, complicating competitive dynamics and external assessment.
Public policy objective: ensure liquidity creation and credit provision while maintaining stability and protecting consumers.
Connections to Foundational Principles
Time value of money and liquidity preference drive maturity transformation and deposit creation.
Risk management concepts underpin Basel risk weights, capital requirements, and liquidity standards.
Market discipline vs. government safety nets: design of insurance and lender facilities shapes bank behavior and systemic resilience.
Tradeoffs between efficiency (monitoring economies of scale) and competition (consumer welfare and pricing).
Summary of Key Formulas and Values (LaTeX)
Leverage:
ROA:
ROE:
Diamond–Dybvig deposit payoff comparison and illiquid asset payoff structure is described conceptually; no single closed-form formula beyond the deposit and project cash flows described above.
Early withdrawal profitability (example):
Break-even:
Insolvency threshold: x > \frac{100}{1.28} = 78.125
Basel I risk weights (illustrative):
Weights: 0%, 20%, 50%, 100% for specified asset classes; if a bank has $10 in each category, RWA = (in the same currency units as assets)
Capital adequacy targets (per slide):
Common Equity / RWA ≥
Tier 1 Capital / RWA ≥
Tier 2 Capital / RWA ≥
LCR:
NSFR: requires funding to be stable from long-term sources; Basel III implementation applies in the US.
SLR: Basel III backstop; general target ; largest banks (SIFIs) approximately in the US context.
Quick Connections to Real-World Relevance
The Diamond–Dybvig framework explains why banks provide liquidity and how runs arise, informing modern macroprudential tools (deposit insurance, lender of last resort).
Basel III and post-GFC reforms aim to dampen systemic risk by increasing capital, improving liquidity risk management, and constraining leverage.
Ongoing debates about regulation rollback, the balance between financial stability and credit availability, and the role of new instruments (CoCo bonds, SIFIs, CBDCs) in future financial systems.