# The regulatory architecture that governs every bank decision
A borrower in Ohio gets a $400,000 mortgage approved in eight minutes. What they never see: that single loan just touched three separate regulators, two capital rules, one liquidity test, and a licensing regime that could shut the bank down entirely. Let's trace it.
When the bank says "yes" to that mortgage, it triggers obligations under a divided system. In the US and Europe, no single body governs a bank. Power is deliberately split so that one failure does not blind everyone.
Three questions get asked about that loan, each by a different authority:
Prudential regulation means rules that keep a bank solvent, focused on capital and risk. When our Ohio bank books the mortgage, it must hold capital (the bank's own money, shareholder funds and retained profit) against it as a buffer against losses.
The core rulebook is Basel III, an international standard set by the Basel Committee on Banking Supervision (a global body of central banks and supervisors based in Switzerland). Basel is not law by itself. Each region turns it into binding rules.
Here is the concrete link to our mortgage. Under Basel III's standardized approach, a residential mortgage does not require capital against its full value. It gets a risk weight based on loan-to-value. A prudent, well-collateralized mortgage often carries a risk weight around 35% or lower (illustrative, per Basel standardized ranges; exact figures depend on jurisdiction and LTVLTVLifetime Value: the total revenue (or profit) a customer generates throughout their entire relationship with your business.View full definition →).
A worked example:
Loan amount: $400,000
Risk weight: 35%
Risk-weighted assets: $400,000 x 0.35 = $140,000
Minimum capital ratio
(Basel III common equity
tier 1, illustrative): ~7% (4.5% minimum + 2.5% buffer)
Capital the bank must hold:
$140,000 x 0.07 = $9,800So issuing a $400,000 mortgage forces the bank to set aside roughly $9,800 of its own equity. Multiply across a $10 billion loan book and you see why capital rules shape every lending decision. Riskier assets (an unsecured business loan) carry a 100% risk weight, so they consume far more capital per dollar lent.
Capital keeps a bank solvent. Liquidity keeps it alive day to day. A bank can be perfectly solvent on paper and still collapse if depositors withdraw faster than it can raise cash. That is exactly what happened to Silicon Valley Bank in March 2023: a solvency problem became a fatal liquidity run within 48 hours.
Basel III added two liquidity rules:
Our mortgage matters here too. A 30-year mortgage is a long-term, illiquid asset funded partly by short-term deposits. That mismatch is precisely what the NSFR polices.
Now the second question. Prudential regulators do not care whether the borrower was overcharged. Conduct regulation does. It governs fairness, disclosure and consumer protection.
This is the key architectural point: capital and conduct sit under different watchdogs on purpose. The Fed can find your capital ratios flawless while the CFPB fines you $100 million for deceptive fee disclosure. Both can be true on the same loan.
You can see the CFPB's actual consumer-facing mortgage rules here: CFPB mortgage resources.
This is where the architecture gets teeth. Different bodies hold different kill switches.
A bank cannot operate without a charter or license. In the US, the OCC charters national banks; state regulators charter state banks. Revoke the charter, and the bank ceases to exist as a bank. This is the nuclear option.
When a bank fails, the FDIC in the US steps in as receiver. It can seize the bank, protect insured deposits (up to $250,000 per depositor per bank, as of 2026), and sell the assets. When SVB failed, the FDIC took control within a day.
In the EU, the Single Resolution Board (SRB) performs this role for major banks, using the Bank Recovery and Resolution Directive (BRRD). A key tool is bail-in: forcing losses onto shareholders and certain creditors instead of taxpayers.
Long before shutdown, regulators exert control through supervision: on-site examinations, stress tests, and enforcement actions. The Fed's annual CCAR/stress test models whether big banks survive a severe recession. Fail it, and the regulator can block dividends and share buybacks. That is a powerful lever short of closure.
The design is not bureaucratic accident. It follows a logic:
Knowledge check
1. Why is regulatory power over banks deliberately split among multiple authorities rather than concentrated in a single body?
2. A bank asks whether a loan is 'safe for the bank' and how much capital it must hold against potential losses. Which regulatory layer does this concern fall under?
3. Basel III is described as an international standard but 'not law by itself.' What does this imply about how it takes effect?
4. Select ALL correct answers about the three core questions that different authorities ask about a single loan.
Select all the correct answers.
5. Select ALL correct answers about how prudential rules are enforced in the US and EU.
Select all the correct answers.
If you are assessing a bank (as an investor, counterparty, or partner), the regulatory architecture gives you a checklist. You are reverse-engineering which watchdog is worried.
1. Capital adequacy. Find the bank's CET1 ratio (Common Equity Tier 1 capital divided by risk-weighted assets). A large bank sitting near the regulatory minimum has no cushion. Well-capitalized US and EU banks often report CET1 ratios in the low-to-mid teens (bank-specific; check the latest filings). A ratio drifting down is an early warning.
2. Liquidity. Check LCR and NSFR disclosures. Both should sit comfortably above 100%. A bank barely clearing 100% LCR is one bad week from stress.
3. Enforcement history. Search the CFPB, FCA, and Fed enforcement databases. A pattern of conduct fines signals cultural problems that prudential ratios will not show.
4. Concentration. SVB failed partly because its depositors were concentrated in one sector (tech startups) and its assets in long-duration bonds. Ask: is funding diversified? Is the loan book concentrated in one region or industry?
5. Charter and jurisdiction. Know which regulator holds the license. A bank operating across borders answers to multiple authorities, which raises complexity and cost.