Too big to fail.

In plain English

Too big to fail describes an expectation, not a legal status, and the expectation itself changes behavior, because a firm that believes it will be rescued has less reason to limit its risk. Economists call that moral hazard, and it can show up as cheaper funding, since lenders who expect a backstop demand less compensation for risk. Post-crisis rules attacked the problem from two sides, making failure less likely through capital and liquidity requirements, and making failure survivable through resolution planning and loss-absorbing debt. Size is only part of it, since a smaller firm sitting at the center of a critical market can matter more than a larger one at the edge. Whether the expectation has actually been broken is still argued.

01Why it matters

If lenders price a firm's debt as though the government stands behind it, that firm can borrow more cheaply than its competitors, which quietly shifts a real subsidy onto the public balance sheet.

02The math, step by step

Say two banks are equally risky on paper. The one markets assume would be rescued borrows at 4.2 percent while the other pays 4.7 percent. On $100 billion of debt, that half point is a $500 million a year funding advantage that comes from the expectation alone.

Illustrative example. The amounts here are hypothetical, chosen to show how the math works, not real quoted rates or figures.

03What this is NOT

04Receipts

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