Bank Capital Ratios Explained: Tiers, Buffers, and Thresholds

Bank capital ratios measure how much of a bank’s own money stands behind its assets to absorb losses before depositors or the deposit insurance fund take a hit. U.S. regulators track four of them: the Common Equity Tier 1 (CET1) ratio, the Tier 1 capital ratio, the total capital ratio, and the leverage ratio. Three divide a form of bank capital by risk-weighted assets; the fourth divides Tier 1 capital by average total assets with no risk adjustment. Minimum levels are set by federal rule, and a bank that falls below them faces escalating restrictions that can end in receivership.

The Four Ratios and How They Are Calculated

Each ratio uses a different slice of capital in the numerator. Three share the same denominator; one does not.

CET1 Ratio

CET1 capital ÷ risk-weighted assets. This is the most closely watched ratio because it reflects only the highest-quality capital.¹ A bank with a CET1 ratio of 12 percent has twelve cents of common equity backing every dollar of risk-adjusted lending.

Tier 1 Capital Ratio

Tier 1 capital (CET1 plus Additional Tier 1) ÷ risk-weighted assets. By adding qualifying preferred stock and hybrid instruments to common equity, this ratio captures a broader set of loss-absorbing funds. It will always be equal to or higher than the CET1 ratio for the same bank.

Total Capital Ratio

Total capital (Tier 1 plus Tier 2) ÷ risk-weighted assets. This is the most comprehensive risk-based measure, adding subordinated debt and loan loss reserves into the numerator. A declining trend over time is often an early warning that a bank is expanding its risk profile faster than its equity base can support.

Leverage Ratio

Tier 1 capital ÷ average total consolidated assets. Unlike the three above, the leverage ratio ignores risk weighting.² It acts as a backstop: without it, a bank could pile into low-risk-weight assets and lever up far beyond what its equity could actually support.

What Counts as Capital

Capital is split into tiers based on how reliably each instrument can absorb losses.

Common Equity Tier 1 (CET1) is the strongest form. It consists primarily of common stock and retained earnings — profits the bank kept instead of paying out as dividends.³ These funds have no maturity, no mandatory repayment schedule, and no contractual payout obligation. If assets lose value, CET1 absorbs the hit first.

Additional Tier 1 (AT1) capital includes non-cumulative perpetual preferred stock and certain hybrid securities that can absorb losses while the bank is still operating. These rank below common equity because they sometimes carry dividend obligations or other features that make them less flexible. CET1 plus AT1 equals total Tier 1.

Tier 2 capital acts as a secondary cushion. It includes subordinated debt with an original maturity of at least five years, loan loss reserves up to 1.25 percent of risk-weighted assets, and certain preferred stock that doesn’t qualify for Tier 1. These instruments are less permanent than equity but still protect depositors and senior creditors.³

Not everything on the balance sheet counts. Regulators require banks to deduct certain items from CET1 because they couldn’t realistically be converted to cash during a crisis:

Goodwill and other intangible assets, which have no liquidation value if the bank itself is failing.
Deferred tax assets arising from temporary differences that exceed 25 percent of CET1 capital, since they depend on future profitability.⁴
Accounting gains that arise when a bank’s own creditworthiness deteriorates, which regulators strip out so the bank isn’t rewarded for becoming riskier.⁴

Risk-Weighted Assets

Three of the four ratios use risk-weighted assets (RWA) rather than total assets in the denominator. The idea is that a dollar lent to the U.S. government is far safer than a dollar lent to an unsecured consumer borrower, so each should require a different amount of capital backing.

Under the standardized approach, each asset class carries a fixed risk weight:

0 percent: cash in vaults, deposits at central banks, and sovereign debt from the highest-rated governments.⁵
50 percent: first-lien residential mortgages that are current, owner-occupied or rented, and prudently underwritten.⁵
100 percent: corporate loans and unsecured consumer credit.⁵
150 percent: high-volatility commercial real estate loans and any non-sovereign exposure that is 90 or more days past due or on nonaccrual status.⁶

Shift a portfolio toward high-interest personal loans and risk-weighted assets climb even if the total asset figure barely moves. The ratios drop. Load up on Treasuries instead and the balance sheet can grow with little effect on the ratios. That is the incentive regulators intended.

Minimum Thresholds

Under the Prompt Corrective Action (PCA) framework created by the Federal Deposit Insurance Act, every insured bank is sorted into one of five categories based on its ratios.

To be “well capitalized,” a bank must meet all four of these at once:⁷

CET1 ratio of 6.5 percent or greater
Tier 1 ratio of 8.0 percent or greater
Total capital ratio of 10.0 percent or greater
Leverage ratio of 5.0 percent or greater

“Adequately capitalized” means a CET1 ratio of 4.5 percent, a Tier 1 ratio of 6.0 percent, a total capital ratio of 8.0 percent, and a leverage ratio of 4.0 percent.⁷ Falling below any one of those puts the bank into undercapitalized territory, which triggers mandatory corrective action.

A bank is “significantly undercapitalized” if its total capital ratio is under 6.0 percent, its Tier 1 ratio is under 4.0 percent, its CET1 ratio is under 3.0 percent, or its leverage ratio is under 3.0 percent. The most severe category, “critically undercapitalized,” applies when tangible equity falls to 2.0 percent or less of total assets.⁷ That final threshold uses tangible equity over total assets, not the risk-based total capital ratio, which matters because tangible equity strips out intangibles like goodwill.

Buffers on Top of the Minimums

Meeting the floors alone isn’t enough. Banks must hold several CET1 buffers that stack on top of the minimum ratios.

Capital Conservation Buffer

Every bank must hold an additional 2.5 percent of risk-weighted assets in CET1 above the minimums.⁸ Dipping into the buffer doesn’t trigger receivership, but it does trigger escalating caps on dividends and discretionary bonuses:

Buffer above 2.5 percent: no payout restrictions.
Buffer between 1.875 percent and 2.5 percent: payouts limited to 60 percent of eligible retained income.
Buffer between 1.25 percent and 1.875 percent: payouts limited to 40 percent.
Buffer between 0.625 percent and 1.25 percent: payouts limited to 20 percent.
Buffer at or below 0.625 percent: no dividends or bonuses allowed.⁸

Stress Capital Buffer

For large bank holding companies, the Federal Reserve replaces the standard 2.5 percent buffer with a firm-specific Stress Capital Buffer determined by annual stress tests. The SCB equals the greater of 2.5 percent or the decline in the bank’s CET1 ratio under the Fed’s severely adverse scenario, plus four quarters of planned dividend payments.⁹ A bank whose ratio would plummet under stress gets a higher buffer; a bank whose models show resilience operates closer to the 2.5 percent floor.

Countercyclical Capital Buffer

This buffer can range from 0 to 2.5 percent of risk-weighted assets. The Federal Reserve has kept the U.S. countercyclical buffer at 0 percent since its introduction but retains authority to raise it if systemic risk indicators warrant.⁸

Extra Requirements for the Largest Banks

The eight U.S. Global Systemically Important Banks (G-SIBs) face layers above everything described so far.

Each G-SIB holds a G-SIB surcharge of CET1 capital determined by its systemic footprint, including size, interconnectedness, cross-border activity, and difficulty of substitution. The surcharge currently starts at 1.0 percent and rises with the bank’s systemic risk score. Under a 2026 proposal, the calculation would become more granular, adjusting in increments of 0.1 percentage points for each 20-basis-point increase in the risk score above the baseline.¹⁰

Banks subject to Category I through III capital standards must also maintain a supplementary leverage ratio (SLR) of at least 3 percent.¹¹ The SLR uses a broader denominator called total leverage exposure, which includes off-balance-sheet items like derivatives, securities financing transactions, and credit commitments. That closes a gap the basic leverage ratio leaves open: a bank with enormous derivatives positions could appear well-capitalized under the simpler measure while carrying real hidden exposure.

G-SIBs face a higher bar. Under a final rule effective April 1, 2026, each G-SIB must hold an enhanced SLR buffer equal to 50 percent of its G-SIB surcharge on top of the 3 percent minimum. Their subsidiary depository institutions face the same calculation, capped at 1 percent.¹¹

A Simpler Path for Community Banks

Institutions with less than $10 billion in total consolidated assets can opt into the Community Bank Leverage Ratio (CBLR) framework and skip risk-based calculations entirely. As of July 1, 2026, a qualifying community bank that maintains a leverage ratio of at least 8 percent is automatically considered well capitalized for all PCA purposes.¹² That is down from the previous 9 percent threshold.

A CBLR bank that slips below 8 percent gets a grace period of up to four consecutive quarters to climb back above the threshold, double the previous two-quarter window. Fall to 7 percent or below and the grace period disappears; the bank must immediately comply with the full risk-based framework.¹²

Consequences of Falling Short

An undercapitalized bank must submit a capital restoration plan to its primary regulator and faces restrictions on asset growth, new business lines, and acquisitions. Dividend payments and management fees become subject to regulatory approval.¹³

A significantly undercapitalized bank faces those same restrictions plus mandatory limits on executive compensation. Senior officers can be removed, and regulators may require the bank to raise capital, merge, or sell assets.¹³

Once a bank is critically undercapitalized, with tangible equity at 2 percent or less of total assets, the appropriate federal banking agency must appoint a receiver or conservator within 90 days, unless the agency determines with FDIC concurrence that an alternative action would better protect depositors and the insurance fund.¹⁴ That clock is short, and a bank in this position is either finding a buyer, raising capital at desperate terms, or preparing to be taken over.

Where to Find a Bank’s Ratios

Banks report their capital ratios to regulators each quarter through Consolidated Reports of Condition and Income, known as Call Reports. The capital disclosures appear on Schedule RC-R, which breaks out each component of regulatory capital and every ratio described above.¹⁵ These filings are public, so depositors, investors, and analysts can see for themselves whether a bank is comfortably above its minimums or drifting toward trouble.

1
Office of the Superintendent of Financial Institutions. Common Equity Tier 1 (CET1)
2
Federal Deposit Insurance Corporation. Community Bank Leverage Ratio Framework
3
Federal Deposit Insurance Corporation. Risk Management Manual of Examination Policies – Section 2.1 Capital
4
Federal Register. Regulatory Capital Rules: Regulatory Capital and Standardized Approach for Risk-Weighted Assets
5
eCFR. 12 CFR Part 3 Subpart D – Risk-Weighted Assets, Standardized Approach
6
eCFR. 12 CFR 3.32 – General Risk Weights
7
eCFR. 12 CFR 208.43 – Capital Measures and Capital Category Definitions
8
eCFR. 12 CFR 217.11 – Capital Conservation Buffer, Countercyclical Capital Buffer Amount, and GSIB Surcharge
9
eCFR. 12 CFR 238.170 – Capital Planning and Stress Capital Buffer Requirement
10
Federal Register. Regulatory Capital Rule (Regulation Q): Risk-Based Capital Surcharges for Global Systemically Important Bank Holding Companies
11
Federal Register. Regulatory Capital Rule: Modifications to the Enhanced Supplementary Leverage Ratio Standards
12
Federal Reserve. Final Rule to Modify the Community Bank Leverage Ratio
13
eCFR. 12 CFR Part 208 – Membership of State Banking Institutions in the Federal Reserve System, Subpart D
14
Federal Deposit Insurance Corporation. Section 38 – Prompt Corrective Action
15
Federal Financial Institutions Examination Council. Instructions for Preparation of Consolidated Reports of Condition and Income