A bank holds your money and moves it where you tell it to go

A bank is a business that takes deposits from customers, keeps those deposits safe, and lends money to other customers. When you put money in a bank account, the bank becomes responsible for that money. They don't lock it in a vault with your name on it. Instead, they use deposits from all their customers to make loans — to people buying homes, to businesses buying equipment, to other banks that need cash. You earn interest on your deposit because the bank is using your money to make money. In return, the bank guarantees they will give your money back when you ask for it.

The second purpose of a bank is to move money between accounts. When you write a check, set up a direct deposit, or send money to someone else's account, the bank processes that instruction. They deduct the amount from your account and add it to someone else's account — either at the same bank or at a different bank through a network of clearing systems. This is how paychecks reach your account, how you pay bills, and how money moves in the modern economy. Without banks, you would have to hand cash to every person you owe money to.

Key Takeaways

  • Banks hold your deposits and lend that money to borrowers, which is how they make profit and how you earn interest on savings.
  • Banks process payments on your behalf — checks, direct deposits, transfers — moving money between accounts at the same bank or different banks.
  • The Federal Deposit Insurance Corporation (FDIC) insures deposits up to $250,000 per account holder per bank, so your money is protected if the bank fails.
  • Banks charge fees for services like overdrafts, monthly maintenance, or wire transfers, which is another way they generate revenue.
  • A bank's main obligation is to return your money on demand, which is why they cannot lend out 100 percent of deposits and must keep reserves.

How banks use your deposits to make loans

When you deposit $5,000 into a checking account, that money does not sit in a physical vault. The bank records that you own $5,000 and they owe it back to you. Simultaneously, they lend portions of customer deposits to other customers. A homebuyer borrows $300,000 at 6 percent interest. A small business borrows $50,000 at 8 percent interest. The bank collects those interest payments and uses them to pay you interest on your deposit (usually much less), pay their employees, maintain their buildings, and keep profit.

This system works because not every customer withdraws their money at the same time. The bank knows from historical data that on any given day, only a small percentage of deposits will be withdrawn. They keep enough cash on hand to cover those daily withdrawals — this is called a reserve requirement. The Federal Reserve sets a minimum reserve ratio that banks must maintain. The rest of the deposits are lent out. If a bank lends too aggressively and cannot cover withdrawals, they fail. If they lend too conservatively, they make little profit and may not survive competition from other banks.

The payment and transfer systems banks operate

Banks are the infrastructure that moves money between people and businesses. When your employer deposits your paycheck, they send an electronic instruction to their bank, which sends it through the Automated Clearing House (ACH) network. The ACH is a system operated by the Federal Reserve and private clearing houses that matches payment instructions from one bank to another. Your employer's bank debits their account, the ACH records the transaction, and your bank credits your account. This usually takes one to two business days.

When you write a check, you are writing an instruction to your bank to pay someone from your account. The recipient deposits the check at their bank. That bank sends the check image and payment instruction through the Check 21 system (which replaced physical check clearing). Your bank verifies you have the funds, deducts the amount, and the transaction settles. Wire transfers work differently — they are faster and more expensive because they move money the same day through the Federal Reserve's wire network (Fedwire) or through SWIFT for international payments. Banks charge fees for wire transfers because they tie up staff and require when ready settlement.

Why banks charge fees and what they cover

Banks charge fees because moving money, storing records, and managing risk costs money. An overdraft fee occurs when you spend more than your balance and the bank covers the difference — they are lending you money for a few days and charging you for it. A monthly maintenance fee covers the cost of the account itself: the servers storing your balance, the staff processing your transactions, the fraud monitoring systems. A wire transfer fee covers the cost of using the Federal Reserve's wire network and the staff who process the instruction.

Some fees are negotiable. Banks often waive monthly maintenance fees if you maintain a minimum balance or set up direct deposit. Some banks charge no overdraft fees. Others charge per transaction. The fee structure varies by bank and by account type. Checking accounts typically have lower fees than savings accounts because banks expect more activity and more opportunity to lend the money. High-yield savings accounts often have no monthly fees because the interest rate is the bank's main cost.

How the FDIC protects your deposits

The Federal Deposit Insurance Corporation (FDIC) is a government agency that insures bank deposits. If a bank fails — meaning it cannot return customer deposits — the FDIC steps in and pays depositors up to $250,000 per account holder per bank. This limit applies per account category. A checking account and a savings account at the same bank are separate for insurance purposes, so you are covered up to $250,000 in each. If you have accounts at two different banks, each bank's deposits are insured separately.

This insurance exists because banks fail. When a bank makes bad loans or loses money on investments, their capital shrinks. If losses exceed their reserves, they cannot cover withdrawals. The FDIC takes over the bank, sells its assets, and pays depositors. The FDIC has a fund built from premiums that banks pay. Since the FDIC was created in 1933, no depositor has lost money on insured deposits. This is why the bank you choose matters less than whether it is FDIC-insured — your money is protected either way.

The difference between banks and other financial institutions

Banks are not the only places to store money. Credit unions are member-owned cooperatives that offer similar services — checking accounts, savings accounts, loans — but they are insured by the National Credit Union Administration (NCUA) instead of the FDIC. The insurance limit is the same: $250,000 per account holder per institution. Credit unions often charge lower fees and offer better interest rates because they are nonprofit and return profits to members.

Investment firms, brokerages, and money market funds are not banks. They do not take deposits in the traditional sense. When you buy a stock through a brokerage, you own the stock, not a deposit. If the brokerage fails, your stocks are still yours — they are held in your name. Money market funds are investment products, not bank accounts, and they are not FDIC-insured. The tradeoff is that they may offer higher returns but carry more risk. For everyday spending and savings, a bank or credit union is the standard choice because your money is insured and accessible.

What happens when you borrow from a bank

When you take out a loan, the bank lends you money and you agree to repay it with interest over time. The bank assesses your creditworthiness — your credit score, income, debt-to-income ratio — to decide whether to lend and at what interest rate. A borrower with a 750 credit score might get a mortgage at 6 percent. A borrower with a 600 credit score might be offered 8 percent or denied entirely. The interest rate reflects the bank's assessment of risk. Higher risk means higher interest.

The bank holds collateral for secured loans. A mortgage is secured by the house — if you stop paying, the bank forecloses and sells the house to recover their money. A car loan is secured by the car. An unsecured loan like a credit card or personal loan has no collateral, so the interest rate is higher to compensate for the risk. The bank's profit on a loan comes from the difference between the interest rate they charge you and the interest rate they pay depositors. If they lend at 6 percent and pay depositors 0.5 percent, they keep 5.5 percent as profit (minus operating costs).

Frequently Asked Questions

Where does a bank keep the physical cash from deposits?

Banks keep some cash in their vaults and in ATMs, but most deposits exist only as electronic records. When you deposit a check, the bank scans it and sends the image through clearing systems. The physical check is destroyed or archived. Your balance is a number in their computer system. The bank keeps enough physical cash on hand to cover daily withdrawals, but the rest is lent out or invested.

Can a bank lose my money?

A bank can fail, but your deposits up to $250,000 are insured by the FDIC. If the bank fails, the FDIC pays you. If you have more than $250,000 at one bank, the amount over $250,000 is at risk. To protect large deposits, spread them across multiple banks or use different account categories (checking, savings, money market) at the same bank, each insured separately.

Why do banks pay interest on savings accounts but charge interest on loans?

Banks pay interest on savings because they are borrowing your money — they use it to make loans to other customers. They charge interest on loans because they are lending money to you. The difference between the two rates is the bank's profit margin. In a low-interest environment, savings rates drop because banks have less demand for deposits and fewer profitable lending opportunities.

What is the difference between a debit card and a credit card at a bank?

A debit card draws from your deposit account — the money is yours and you are spending it. A credit card is a loan. You spend the bank's money and agree to repay it. The bank charges interest if you do not pay the full balance. Debit cards have no interest because no borrowing occurs. Credit cards build credit history because the bank reports your payment behavior to credit bureaus.

Do all banks have the same FDIC insurance?

All FDIC-insured banks have the same $250,000 coverage limit per account holder per bank. The coverage applies the same way regardless of the bank's size or reputation. However, not all banks are FDIC-insured — some are state-chartered and insured by state agencies instead. Before opening an account, confirm the bank displays the FDIC logo or check the FDIC's bank search tool online.