銀行は、預けられたお金をすべて現金として保管しているわけではありません。

READING

Banks do not keep all deposited money in cash. Instead, they use part of those funds to make loans to households and businesses, while retaining enough liquid assets to meet normal withdrawals. This system supports economic activity, but it can create problems when confidence in a bank suddenly weakens. If rumors about financial trouble spread, many depositors may try to withdraw their money at the same time. Even a bank that is otherwise sound may then struggle to provide enough cash immediately, because much of its money is tied up in loans and other assets.

A bank run can have effects far beyond a single institution. If one bank fails, customers at other banks may begin to fear that their savings are also at risk and withdraw funds as a precaution. Financial institutions may respond by holding more cash and reducing lending in order to protect themselves. Businesses can then find it harder to obtain credit for investment, hiring, or daily operations, while households may also face tighter borrowing conditions. As confidence falls and lending contracts, economic activity can slow, turning a problem at one bank into a broader financial crisis.

To reduce this danger, many governments operate deposit insurance systems that guarantee customers will recover their savings up to a certain limit if a bank fails. This protection can reassure depositors and reduce the incentive to rush to withdraw money during periods of uncertainty. However, the system also has drawbacks. If banks and customers expect losses to be covered, they may pay less attention to financial risks than they otherwise would. In addition, the failure of a very large institution, or several banks at once, can create substantial costs for the public sector if insurance funds are insufficient to cover guaranteed deposits.