A bank takes deposits, makes loans, and provides payment services. It is a business, but it is also a public trust. Deposits are insured by the government, and banks have access to central bank lending in emergencies. That safety net exists because banks are essential to the economy. When they fail, the damage spreads.

Banks make money on the spread. They pay depositors a low interest rate and charge borrowers a higher one. The difference covers operating costs and generates profit. They also earn fees for services: account maintenance, overdrafts, wire transfers, wealth management, and investment banking. The largest banks, like JPMorgan Chase and Bank of America, do all of this and more.

Banking is heavily regulated. In the United States, the Federal Reserve, the Office of the Comptroller of the Currency, the Federal Deposit Insurance Corporation, and state regulators all supervise banks. They set capital requirements, conduct stress tests, and examine lending practices. The rules are complex, and compliance is expensive. But the 2008 financial crisis showed what happens when regulation fails.

Most people interact with banks through checking accounts, savings accounts, debit cards, and mobile apps. The branch is becoming less important. But the bank itself is not going away. It is too central to how money moves.