A bank bailout occurs when a government or financial authority provides financial support to a struggling bank to prevent its collapse. This support can come in the form of loans, capital injections, or guarantees, aimed at stabilizing the financial system and protecting depositors. Bailouts are often controversial, as they can lead to moral hazard, where banks take excessive risks knowing they might be rescued. Notable examples include the 2008 bailout of major banks during the financial crisis and the assistance provided to Citigroup and Bank of America.