A bank is a business that holds your money, lends it out, and charges fees for both

A bank takes deposits from customers, keeps some of that money in a vault or reserve, lends the rest to borrowers (mortgages, car loans, credit lines), and makes profit on the difference between what it pays you in interest and what it charges borrowers. You give the bank permission to use your money this way when you open an account. In return, the bank keeps your balance safe, processes your payments, and lets you withdraw cash whenever you need it.

Banks are regulated by federal and state authorities—the Federal Deposit Insurance Corporation (FDIC) insures deposits up to $250,000 per account holder per bank, which means if the bank fails, you get your money back. This insurance is automatic; you do not have to sign up for it. Banks must follow rules about how much cash they keep on hand, who they can lend to, and how they report their finances.

Not all financial institutions that look like banks are banks. Credit unions are member-owned nonprofits that work similarly but are insured by the National Credit Union Administration (NCUA), also up to $250,000. Online banks are banks too—they just have no physical branches. Money market accounts and savings accounts at banks are different products from checking accounts, and each has different rules about how often you can withdraw.

Key Takeaways

  • Banks profit by borrowing your deposits at low interest rates and lending that money to others at higher rates, so they have a financial incentive to keep you as a customer.
  • The FDIC insures bank deposits up to $250,000 per person per bank, meaning your money is protected even if the bank fails.
  • Banks are required to keep a percentage of deposits in reserve and follow federal rules about lending and reporting, which limits how recklessly they can operate.
  • Credit unions and online banks work the same way as traditional banks but may have different fee structures, interest rates, and membership requirements.

How banks make money from your account

When you deposit $1,000 into a checking account, the bank does not lock that money in a box with your name on it. It uses your money (and deposits from thousands of other customers) to make loans. A bank might pay you 0.01% interest on your checking balance while charging a borrower 6% on a car loan. That 5.99% difference is the bank's profit margin.

Banks also charge you directly: monthly maintenance fees, overdraft fees (when you spend more than your balance), ATM fees if you use another bank's machine, wire transfer fees, and fees for stopping a check. Some banks waive these fees if you keep a minimum balance or set up direct deposit. The fee structure varies widely between banks, which is why comparing accounts before opening one matters.

Interest rates on savings accounts and money market accounts fluctuate with the federal funds rate, which the Federal Reserve adjusts several times a year. When the Fed raises rates, banks eventually raise what they pay you on savings—but usually not as much as they raise what they charge borrowers. When the Fed cuts rates, banks cut what they pay you faster than they cut what they charge borrowers.

What happens to your money when you deposit it

Your deposit does not sit in a vault labeled with your name. The bank pools deposits from all customers and uses that pool to fund loans, buy securities, and cover operating costs. The bank keeps a reserve requirement—a percentage of deposits it must hold in cash or at the Federal Reserve—but this percentage is small. As of 2023, the Federal Reserve eliminated the reserve requirement for most banks, though banks still hold reserves voluntarily to manage risk.

When you swipe your debit card, the transaction goes through a payment network (Visa, Mastercard, or your bank's own network), not directly from your account to the merchant. The merchant's bank receives the payment, the networks take a small cut, and your bank deducts the amount from your balance. This process usually settles within one to three business days, which is why a transaction might show as "pending" before it fully clears.

If you write a check, the recipient deposits it at their bank, which sends it through the Federal Reserve's check-clearing system or a private clearing house. The check physically or digitally moves between banks, and your account is debited once the receiving bank confirms the check is valid. This can take three to five business days, which is why checks are slower than electronic transfers.

The difference between banks, credit unions, and online banks

A credit union is owned by its members (the people who bank there) rather than by shareholders. Credit unions typically offer lower fees and higher interest rates on savings because they are nonprofits—any profit goes back to members as better rates or lower fees. Credit unions are insured by the NCUA up to $250,000, the same as FDIC insurance. The trade-off is that credit unions have fewer branches and ATMs than large banks, though most credit unions belong to shared branching networks that let you use other credit unions' ATMs.

An online bank is a real bank with FDIC insurance, but it has no physical branches. You manage your account through a website or app, deposit checks by photographing them, and withdraw cash at ATMs or by transferring to another bank's account. Online banks have lower overhead costs than brick-and-mortar banks, so they often pay higher interest on savings and charge lower fees. The downside is you cannot walk into a branch to resolve problems in person, though most online banks have phone and chat support.

A traditional bank with branches offers in-person service, which costs money. You pay for that convenience through higher fees and lower interest rates on savings. Some traditional banks now offer online accounts with better rates alongside their branch accounts, letting you choose which product fits your needs.

How banks protect your money and what FDIC insurance actually covers

The FDIC (Federal Deposit Insurance Corporation) insures deposits at member banks up to $250,000 per depositor per bank. This means if your bank fails, the FDIC pays you back up to $250,000. The insurance is automatic—you do not need to sign up or pay for it. If you have $500,000 at one bank, only $250,000 is insured; the rest is at risk if the bank fails.

FDIC insurance covers checking accounts, savings accounts, money market accounts, and certificates of deposit (CDs). It does not cover stocks, bonds, mutual funds, or other investments held at the bank. If you buy a stock through your bank's brokerage arm, that stock is not FDIC-insured; it is protected by SIPC (Securities Investor Protection Corporation) insurance instead, which covers up to $500,000 per account.

If you have multiple accounts at the same bank—a checking account and a savings account, for example—the FDIC insures each account type separately up to $250,000. So you could have $250,000 in checking and $250,000 in savings at the same bank and be fully insured for both. If you are married and both spouses have accounts at the same bank, each spouse's accounts are insured separately up to $250,000.

Banks also protect your account from fraud through encryption, fraud monitoring software, and liability limits. If someone steals your debit card number and makes unauthorized purchases, federal law limits your liability to $50 if you report it within two business days, and $0 if you report it before any fraudulent charges post. Report fraud to your bank immediately—the faster you act, the better your protection.

Why banks charge fees and how to avoid them

Banks charge fees because they are businesses with costs: employee salaries, branch rent, technology infrastructure, and regulatory compliance. Fees also discourage behavior that costs the bank money—overdraft fees discourage spending more than you have, ATM fees discourage using competitors' machines, and wire transfer fees cover the cost of moving money between banks.

Common fees include monthly maintenance fees ($5 to $15 per month), overdraft fees ($25 to $35 per transaction), insufficient funds fees (similar to overdraft fees), ATM fees ($2 to $3 per withdrawal at another bank's ATM), wire transfer fees ($15 to $30), and stop payment fees ($25 to $35). Some banks charge fees for paper statements, cashier's checks, or account closures within a certain timeframe.

To avoid fees, compare accounts before opening one and choose a bank whose fee structure matches your habits. If you rarely overdraft, overdraft protection might not matter. If you use cash frequently, choose a bank with a large ATM network or no ATM fees. Many banks waive monthly fees if you maintain a minimum balance (often $500 to $2,500), set up direct deposit, or keep a certain number of transactions per month. Online banks typically charge fewer fees because they have lower overhead.

How bank accounts connect to the broader payment system

Your bank account is the foundation of the payment system. When you set up direct deposit, your employer's bank sends money to your bank through the ACH (Automated Clearing House) network, which is a batch system that processes millions of transactions overnight. When you pay a bill online, you are usually sending an ACH transfer. When you use your debit card, you are using a real-time payment network run by Visa or Mastercard.

Banks also connect to wire transfer networks like SWIFT (for international transfers) and Fedwire (for domestic transfers between banks). These are faster than ACH but more expensive. When you send money to another person's bank account, you are using one of these networks, and your bank is the intermediary that verifies you have the money and that the receiving bank exists.

Your bank account also connects to credit reporting. When you open a bank account, the bank may check ChexSystems, a banking history report similar to a credit report. If you have a history of overdrafts, bounced checks, or fraud, some banks will deny you an account. Your banking history stays in ChexSystems for five years, so past problems can affect your ability to open new accounts.

Frequently Asked Questions

What happens if a bank fails?

The FDIC takes over the bank, sells its assets, and pays depositors up to $250,000 per account. This process usually takes a few days. You keep access to your money through the FDIC's insurance payout, not through the bank itself. Banks fail rarely in the United States because of federal regulation and reserve requirements.

Can a bank refuse to give me my money?

A bank can freeze your account if it suspects fraud, if you have an outstanding debt to the bank, or if a court orders it. The bank must notify you and give you a chance to dispute the freeze. If the freeze is due to suspected fraud, the bank can hold your money while it investigates, usually for up to 10 business days. If you believe the freeze is wrong, contact the bank's customer service or file a complaint with your state's banking regulator.

Is my money safer at a big bank or a small bank?

Safety depends on FDIC insurance, not bank size. Both big and small banks are FDIC-insured up to $250,000 per account. A small bank might offer better customer service and lower fees, while a big bank might offer more branches and ATMs. The FDIC insurance level is the same either way.

Why do banks take so long to process transfers?

ACH transfers batch process overnight, so a transfer sent at 3 p.m. on Monday might not arrive until Wednesday morning. Wire transfers are faster (usually same-day) but cost more. Real-time payment networks like Zelle and FedNow are newer and faster, but not all banks offer them yet. The timeline depends on which network your bank uses and when you send the transfer.

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

A debit card pulls money directly from your bank account. A credit card borrows money from the card issuer, and you pay it back later (with interest if you do not pay the full balance). Debit cards offer less fraud protection than credit cards under federal law, and credit cards build credit history while debit cards do not. Both are connected to your bank account in different ways.