Bank capital is the accounting equity and qualifying regulatory capital available to absorb losses, support lending, and meet prudential requirements.
Bank capital is the financial interest and qualifying instruments available to absorb losses and support a bank’s continued operation or orderly resolution. In accounting, equity is the residual amount after liabilities are subtracted from assets. In regulation, capital includes only components recognized after eligibility tests, deductions, adjustments, limits, and consolidation rules.
Accounting equity, tangible common equity, Common Equity Tier 1, Tier 1 capital, and total regulatory capital are related but not interchangeable. The word capital should therefore be tied to a definition, reporting entity, date, and denominator before a bank is compared or judged.
The basic balance-sheet identity is:
Accounting equity = Total assets - Total liabilities
Suppose a bank reports:
Its accounting equity is:
$500 billion - $470 billion = $30 billion
If the value of assets falls by $8 billion and liabilities do not change, equity falls to $22 billion. Equity absorbs the loss because liability claims remain fixed before shareholder claims are paid.
Accounting equity depends on recognition and measurement rules. Loan-loss allowances, fair-value changes, accumulated other comprehensive income, goodwill, deferred tax assets, pension items, minority interests, and consolidation can affect reported equity or its composition.
Regulatory Capital is the amount supervisors recognize for prudential purposes after applying the relevant rule. It is not simply the equity total printed on the balance sheet.
Under the Basel structure:
| Component | General role | Main boundary |
|---|---|---|
| Common Equity Tier 1 | Highest-quality going-concern capital | Common equity elements after regulatory adjustments |
| Additional Tier 1 | Other qualifying going-concern instruments | Must satisfy strict permanence and loss-absorption criteria |
| Tier 1 Capital | CET1 plus eligible Additional Tier 1 | Going-concern regulatory capital |
| Tier 2 Capital | Qualifying gone-concern capital | Intended to absorb losses at nonviability or resolution |
| Total regulatory capital | Tier 1 plus eligible Tier 2 | Net of applicable adjustments and limits |
An ordinary subordinated bond is not Tier 2 merely because it ranks below senior debt. The instrument must satisfy the applicable eligibility criteria, and regulatory recognition can decline as maturity approaches.
Regulators adjust accounting amounts because not every recognized asset or equity component is equally available to absorb losses. Depending on the rule, adjustments can address:
The direction is not always obvious from a single balance-sheet line. Reconcile the bank’s regulatory disclosure rather than estimating CET1 by subtracting all intangible assets from equity.
Common formulas are:
CET1 ratio = CET1 capital / Risk-weighted assets
Tier 1 capital ratio = Tier 1 capital / Risk-weighted assets
Total capital ratio = Total regulatory capital / Risk-weighted assets
Risk-Weighted Assets reflect prescribed treatment for credit, market, operational, and certain off-balance-sheet risks. They are not the same as total accounting assets.
A regulatory leverage ratio divides Tier 1 capital by a non-risk-weighted denominator defined by the applicable framework. See Tier 1 Leverage Ratio.
The leverage ratio is a backstop to risk-based measures. A bank can report a strong risk-based ratio because its assets receive low risk weights while still operating with substantial total exposure.
Assume Bank C reports:
Its regulatory capital amounts are:
Tier 1 capital = $24 billion + $3 billion = $27 billion
Total capital = $27 billion + $5 billion = $32 billion
The risk-based ratios are:
| Ratio | Calculation | Result |
|---|---|---|
| CET1 ratio | $24 billion / $250 billion | 9.6% |
| Tier 1 capital ratio | $27 billion / $250 billion | 10.8% |
| Total capital ratio | $32 billion / $250 billion | 12.8% |
Accounting equity is $30 billion, while total regulatory capital is $32 billion. Total regulatory capital can include eligible Tier 2 instruments and, depending on their accounting classification, Additional Tier 1 instruments; regulatory deductions separately reduce CET1. This is why the regulatory total need not equal the accounting equity line.
Now suppose the bank recognizes a $6 billion after-tax credit loss that reduces retained earnings and CET1 by the same amount, with no immediate RWA change:
18 / 250 = 7.2%.This simplified example assumes no tax, provision, RWA, AOCI, deduction, or balance-sheet interaction beyond the stated loss. Real regulatory reporting can change both numerator and denominator.
Capital can increase through:
Capital can decline through:
Raising deposits or borrowing money increases funding but does not ordinarily create capital. Issuing debt creates regulatory capital only if the instrument qualifies for recognition.
| Concept | Main purpose | Why it is not the same as capital |
|---|---|---|
| Liquidity | Meet cash outflows when due | Cash and liquid assets do not necessarily absorb losses |
| Loan-loss allowance | Reflect expected credit losses under accounting rules | Treatment in regulatory capital is prescribed and limited |
| Deposits | Fund assets and provide payment services | Deposits are liabilities owed to customers |
| Net Stable Funding Ratio | Promote stable one-year funding structure | ASF is a funding measure, not a capital amount |
| Liquidity Coverage Ratio | Cover standardized 30-day net cash outflows | HQLA is a liquidity buffer, not loss-absorbing equity |
A bank can be well capitalized and illiquid, or liquid and undercapitalized. See Liquidity vs. Capital.
Risk weights standardize capital requirements but do not perfectly measure economic risk. Models, classifications, collateral, guarantees, and regulatory approaches matter.
Capital depends on when losses, gains, and valuation changes enter earnings, equity, or regulatory adjustments.
Capital reported at a parent or foreign subsidiary may not be freely available to another legal entity because of law, regulation, tax, or creditor claims.
A bank can remain above a headline minimum while facing restrictions on dividends, buybacks, bonuses, growth, or other actions because effective requirements and supervisory expectations are higher.
Different capital instruments absorb losses at different stages and ranks. A security labeled capital can still expose its investor to conversion, write-down, missed distributions, or resolution losses.
capital.This article provides general financial education, not regulatory, accounting, banking, deposit, legal, or investment advice. Capital definitions, eligibility, ratios, buffers, and consequences depend on the current rule, reporting entity, instruments, exposures, and supervisory treatment.