A bank is a business that holds your money, lends it out, and charges fees or pays interest for the service

When you open a checking or savings account, you are giving a bank permission to hold your cash. The bank then uses that money—along with deposits from thousands of other customers—to make loans to businesses and individuals. The bank keeps the difference between what it pays you in interest (if anything) and what it charges borrowers. That spread is how banks make money. You are not a customer buying a product; you are a depositor whose funds become part of the bank's operating capital.

Banks are regulated by federal and state authorities. In the United States, most banks are insured by the Federal Deposit Insurance Corporation (FDIC), which means if the bank fails, your deposits up to $250,000 per account type are protected. Credit unions—which operate similarly but are member-owned rather than shareholder-owned—are insured by the National Credit Union Administration (NCUA) instead. Understanding which regulator backs your institution matters when something goes wrong, because the insurance claim process differs between them.

Key Takeaways

  • Banks hold deposits, lend money out, and profit from the difference between interest paid to depositors and interest charged to borrowers.
  • FDIC insurance protects up to $250,000 per account type at most banks, and NCUA insurance does the same at credit unions.
  • Banks charge fees for services like overdrafts, wire transfers, and account maintenance, which vary widely between institutions.
  • When you dispute a transaction or suspect fraud, the bank's dispute resolution process and timeline depend on whether the transaction was debit, credit, or ACH.

How banks make money from your account

Banks earn revenue in three main ways. First, they pay you little or no interest on savings while charging borrowers 5 to 10 percent or more on loans and credit cards. Second, they charge you fees—overdraft fees (typically $25 to $35 per incident), monthly maintenance fees, wire transfer fees, and ATM fees if you use another bank's machine. Third, they invest deposits in securities and other financial instruments and keep the returns.

The interest rate you earn on a savings account is set by the bank and can change at any time. As of 2024, most traditional banks pay between 0.01 and 0.5 percent annual interest on savings, while online banks and high-yield savings accounts may pay 4 to 5 percent. The difference is real money over time. A $10,000 deposit earning 0.01 percent yields $1 per year; the same deposit at 4.5 percent yields $450. Banks count on most customers not shopping around, so comparing rates before opening an account is worth the ten minutes it takes.

What happens when you deposit money

When you deposit cash or a check, the bank credits your account when ready (or within one business day for checks). That money is now the bank's property, not yours—you own a claim against the bank for that amount, but the bank owns the physical cash. This distinction matters during a bank failure: you are a creditor, not an owner of the vault contents.

The bank then holds a fraction of deposits in reserve (required by federal law) and lends out the rest. If you deposit $1,000 and the reserve requirement is 10 percent, the bank keeps $100 on hand and lends $900 to someone else. That borrower spends the $900, which ends up in another account at the same bank or a different one. The second bank lends out 90 percent of that $900, and the cycle continues. This is how the money supply expands. It also means that if many depositors try to withdraw cash at once—a "bank run"—the bank cannot pay everyone when ready because most of the money is already lent out.

Checking accounts versus savings accounts

A checking account is designed for frequent transactions. You can write checks, use a debit card, set up automatic bill payments, and transfer money in and out without limit. Most checking accounts pay zero interest. Banks make money on checking accounts through overdraft fees, monthly maintenance fees, and by lending out your balance.

A savings account is designed to discourage frequent withdrawals. Federal law once limited you to six withdrawals per month, though that rule was suspended in 2020 and has not been formally reinstated. Savings accounts pay interest, though the rate is usually low. Some banks charge monthly fees on savings accounts if your balance falls below a minimum (often $300 to $500). Money market accounts sit between the two: they pay interest like savings accounts but allow limited check-writing and debit card use.

How disputes and fraud claims work

If you notice an unauthorized charge on your account, the process depends on the type of transaction. For debit card fraud, you have up to 60 days to report it to the bank. If you report within two business days, your liability is capped at $50; if you wait longer, it can rise to $500. The bank then investigates and typically issues a provisional credit within 10 business days while the investigation continues.

For credit card fraud, your liability is capped at $50 by federal law, and most card issuers waive it entirely. The process is faster because credit card companies are motivated to resolve disputes quickly. For ACH transfers and wire transfers (money moved electronically between accounts), the rules are different and less protective. Once an ACH transfer clears, reversing it is difficult. Wire transfers are nearly impossible to reverse. If you authorize a transfer to a scammer, the bank is not liable, even if the scammer misrepresented themselves.

The bank's dispute team will ask for documentation: the transaction date, amount, merchant name, and any communication with the merchant. If the merchant disputes your claim (called a "chargeback"), the bank may side with them if you cannot prove the charge was unauthorized. Keep receipts, emails, and screenshots of any communication about the transaction.

What FDIC insurance actually covers

The FDIC insures deposits up to $250,000 per depositor, per bank, per account type. "Per account type" is the key phrase. If you have a checking account and a savings account at the same bank, each is insured separately up to $250,000. If you have a joint account with your spouse, that is a separate account type and is also insured up to $250,000. If you have a payable-on-death account (where you name a beneficiary), that is another separate category.

FDIC insurance does not cover investment products like stocks, bonds, or mutual funds, even if you buy them through the bank. It does not cover safe deposit boxes or their contents. It does not cover money you lend to another person. If your bank fails, the FDIC pays out insured deposits within a few business days, usually by transferring your account to another bank or issuing a check.

Different types of banks and what they mean for you

A national bank is chartered by the federal government and regulated by the Office of the Comptroller of the Currency (OCC). A state bank is chartered by a state and regulated by that state's banking authority, though it may also be federally insured. The difference matters mainly for regulatory oversight and which agency handles complaints, but both types are FDIC-insured if they choose to be (most do).

A credit union is a member-owned cooperative, not a for-profit corporation. Credit unions often charge lower fees and pay higher interest rates on savings because they return profits to members rather than shareholders. They are regulated differently and insured by the NCUA instead of the FDIC, but the coverage limits are the same: $250,000 per account type. An online bank has no physical branches and operates entirely through a website or app. Online banks typically pay higher interest rates on savings because they have lower overhead costs, but they offer no in-person service.

Frequently Asked Questions

What happens to my money if the bank fails?

If your bank is FDIC-insured and your balance is under $250,000 per account type, the FDIC pays you in full, usually within a few business days. The FDIC either transfers your account to another bank or sends you a check. If your balance exceeds $250,000, the amount over the limit is not covered and you become a general creditor in the bank's bankruptcy proceedings, which can take years.

Can a bank freeze my account without warning?

Yes. Banks can freeze accounts if they suspect fraud, money laundering, or other illegal activity. They can also freeze accounts to collect on a debt or if a court orders it. The bank must notify you, but "notification" can happen after the freeze. If you believe the freeze is an error, contact the bank's compliance department when ready and ask for the reason in writing.

Why do some banks charge overdraft fees and others don't?

Overdraft fees are optional—banks choose whether to charge them. Some banks offer overdraft protection, which links your checking account to a savings account or credit line and automatically transfers money if you overspend. Others straightforward decline the transaction. Compare banks' overdraft policies before opening an account if you want to avoid these fees.

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

Safety depends on FDIC insurance, not bank size. Both large and small banks are FDIC-insured (if they choose to be), so your deposits are equally protected up to $250,000. Large banks may have more resources to fight fraud, but small banks and credit unions often have better customer service and lower fees.

What's the difference between a bank and a credit union?

Credit unions are member-owned cooperatives; banks are for-profit corporations. Credit unions typically offer lower fees, higher interest rates, and more personalized service. Banks offer more branches, more ATMs, and more online features. Both are insured by their respective agencies (FDIC for banks, NCUA for credit unions) up to $250,000 per account type.