Not investment advice. Educational reading. See Disclaimer.
L.13 · BEGINNER · 2 MIN
Bank Capital, Tier 1 Ratios, and Stress Tests
Bank capital is the equity cushion that absorbs losses before depositors and bondholders take a hit. Regulators express it as a ratio: capital divided by risk-weighted assets. The higher the ratio, the more the bank can lose before it becomes insolvent. Stress tests are the regulators' way of asking 'how would your capital ratio hold up if everything went wrong at once?' — and investors should understand both what those tests measure and what they cannot.
Bank capital is the equity cushion that decides whether credit keeps flowing when losses hit. For a macro reader this matters at the system level: when capital ratios thin out across the banking sector, banks pull back lending to protect their ratios, and that credit contraction amplifies a downturn. Watching aggregate bank capital and stress-test headroom is watching the banking system's capacity to keep lending through a recession.
§ 02Where the full mechanics live
So far
The mechanics — CET1 and the tiers of capital, risk-weighted assets, CCAR and DFAST stress tests, and how to read a bank's loss-absorption headroom — get their full treatment in Reading a Bank's Numbers › Is the Bank Safe? Capital and the Call Report.
§ 03How much loss a bank could actually absorb
A bank reports CET1 at 11 percent — well above the 4.5 percent regulatory floor — but the latest stress test shows its CET1 would fall to 6 percent under severely adverse conditions. What does the gap tell you about how the bank is positioned for a recession?
Check your understanding
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Sit with the ideas.
A large US bank passes its annual CCAR stress test with a stressed CET1 minimum of 7.2 percent — comfortably above the 4.5 percent regulatory floor and the bank's stress capital buffer. Press coverage calls the result a 'clean pass.' What does that actually prove about the bank's safety?
