Banks lend out most of the money you deposit, and keep the difference between what they pay you in interest and what borrowers pay them

When you deposit money into a checking or savings account, the bank does not lock it in a vault with your name on it. Instead, the bank uses that money to make loans to other customers — mortgages, car loans, business loans, credit cards. You earn a small amount of interest on your deposit. The borrower pays a larger amount of interest on the loan. The bank keeps the spread between those two rates as profit.

This is the core business model of retail banking. A bank that takes in $100 million in deposits might pay depositors an average of 0.5% interest per year — $500,000 total. That same bank might lend out $80 million of those deposits at an average rate of 6% per year — $4.8 million in interest income. The difference, minus operating costs, is the bank's profit.

Banks do not lend out 100% of deposits because they must keep a portion on hand to cover withdrawals, and because federal regulators require them to maintain a minimum reserve. The Federal Reserve sets the reserve requirement, which varies but is typically around 10% for large banks. This means a bank that receives $100 in deposits must keep roughly $10 available and can lend out the remaining $90.

Key Takeaways

  • Banks earn money by lending out deposits at higher interest rates than they pay depositors, keeping the difference as profit.
  • The Federal Reserve requires banks to hold a minimum reserve of deposits and not lend out all customer money at once.
  • Banks also earn income from fees on accounts, overdrafts, wire transfers, and other services beyond the interest spread.
  • Interest rates on deposits and loans change based on what the Federal Reserve charges banks to borrow, economic conditions, and competition.
  • Your deposits are insured up to $250,000 per account by the FDIC, so the bank's lending activity does not put your money at direct risk.

The interest rate spread is where most bank profit comes from

The gap between the rate a bank pays you and the rate it charges borrowers is called the net interest margin. This is the primary source of revenue for most banks. A bank with a wider margin makes more money per dollar of deposits. A bank with a narrow margin must either take in more deposits or cut costs to stay profitable.

The size of this spread depends on several factors. When the Federal Reserve raises its benchmark interest rate, banks can charge borrowers more, which widens the margin. When the Fed lowers rates, the margin often shrinks because banks must lower what they pay depositors to stay competitive, but they cannot lower loan rates as much without losing borrowers. Banks also adjust their margins based on how much competition they face — in a market with many banks, margins tend to be tighter because banks compete for deposits by offering higher interest rates.

Economic conditions matter too. During a recession, banks may widen their margins to compensate for higher loan losses when borrowers default. During strong economic growth, margins may narrow because borrowers are more reliable and banks compete harder for deposits.

Banks earn additional income from fees and services

Interest on loans is not the only way banks make money from your account. Most banks charge fees for specific services: monthly maintenance fees on checking accounts, overdraft fees when you spend more than your balance, wire transfer fees, ATM fees at out-of-network machines, and fees for stopping payment on a check. Some banks charge fees for paper statements or for closing an account early.

Credit card companies, which are often owned by banks, earn money from interchange fees — a small percentage of every transaction that the merchant's bank pays to the card issuer. A bank that issues a credit card earns money both from the interest cardholders pay on balances and from these per-transaction fees.

Investment services also generate income. Banks that manage investment accounts, sell mutual funds, or offer wealth management services earn commissions or advisory fees. Some banks earn money by selling customer data to third parties, though this practice is limited by privacy regulations.

How the Federal Reserve's interest rate affects what banks pay and charge

The Federal Funds Rate is the interest rate at which banks lend money to each other overnight to maintain their required reserves. The Federal Reserve does not set this rate directly, but it influences it through open market operations. When the Fed raises the Federal Funds Rate, banks face higher costs to borrow from each other, so they raise the rates they charge customers on loans and lower the rates they pay on deposits. When the Fed lowers the rate, the opposite usually happens.

This is why your savings account interest rate might jump or drop a few times per year — it follows changes in the Federal Funds Rate with a lag of a few weeks to a few months. Loan rates follow the same pattern, though some loans like mortgages are also influenced by longer-term bond market rates.

Banks do not pass along Fed rate changes equally to all customers. A bank might raise loan rates quickly when the Fed raises rates but delay lowering deposit rates, widening its margin. Conversely, when the Fed cuts rates, banks may lower deposit rates immediately but keep loan rates higher for longer. This behavior is one reason why the spread between deposit and loan rates can vary widely even when Fed policy stays the same.

Why banks must hold reserves and cannot lend out all deposits

Federal regulators require banks to keep a portion of deposits on hand at all times. This reserve requirement serves two purposes: it ensures banks can cover customer withdrawals without delay, and it gives regulators a tool to control how much money banks can lend into the economy.

The reserve requirement is not the only limit on lending. Banks must also meet capital requirements, which means they must hold a certain amount of shareholder equity relative to the size of their loan portfolio. A bank with $1 billion in deposits might be required to hold $50 million in capital. These rules prevent banks from over-leveraging and reduce the risk that a bank will fail if loans go bad.

During the 2008 financial crisis, many banks had lent too aggressively and did not hold enough capital to absorb losses when borrowers defaulted. Regulators tightened capital requirements after the crisis, which is why modern banks hold larger reserves than they did before 2008.

Your deposits are insured even though banks lend them out

The Federal Deposit Insurance Corporation (FDIC) insures deposits up to $250,000 per depositor, per bank, per account type. This means if a bank fails and cannot repay deposits, the FDIC will pay you back up to that limit. Your money is not at risk because the bank lends it out — the FDIC may provide covers it regardless.

The FDIC maintains an insurance fund by charging banks a small premium based on the size and risk profile of their deposits. This fund has paid out billions of dollars to depositors when banks have failed, though bank failures are rare in modern times because of stricter regulation and oversight.

If you have more than $250,000 to deposit, you can spread it across multiple banks or multiple account types at the same bank to keep all of it insured. For example, a checking account and a savings account at the same bank are insured separately, so you could have $250,000 in each and both would be fully covered.

How competition and market conditions change what banks offer depositors

Banks compete for deposits by offering higher interest rates, especially when deposits are scarce or when the Federal Reserve has raised rates. During periods when the Fed keeps rates very low, deposit rates stay low too because banks have no incentive to pay more — they can lend money at low rates and still make a profit. When the Fed raises rates, banks must raise deposit rates to keep customers from moving money to competitors.

Online banks typically offer higher deposit rates than traditional brick-and-mortar banks because they have lower operating costs — no branch buildings, fewer employees, lower overhead. A traditional bank might pay 0.01% on a savings account while an online bank pays 4% or 5% on the same type of account. The online bank can afford to pay more because it spends less on operations.

Market conditions also matter. When loan demand is weak, banks have fewer places to put deposits to work, so they lower deposit rates. When loan demand is strong, banks compete harder for deposits to fund more loans, so they raise deposit rates. This is why deposit rates tend to rise during economic booms and fall during recessions.

Frequently Asked Questions

What happens to my money if the bank lends it out and the borrower does not pay back?

Your deposit is insured by the FDIC up to $250,000, so you are protected regardless of whether the bank's loans go bad. The bank absorbs the loss on defaulted loans through its capital and reserves. If losses are severe enough to wipe out the bank's capital, the FDIC steps in and pays depositors from its insurance fund.

Do all banks lend out deposits the same way?

No. Investment banks and commercial banks operate differently. A traditional commercial bank takes deposits and makes loans. An investment bank does not take deposits and instead raises money by issuing bonds or taking capital from investors. Credit unions, which are member-owned, operate on a non-profit basis and return profits to members as dividends or lower loan rates rather than to shareholders.

Why do some banks pay almost no interest on savings accounts?

Banks pay low rates when they do not need more deposits — either because they have plenty of money to lend or because loan demand is weak. When the Federal Reserve keeps rates very low, all banks pay low rates because there is little incentive to compete. Online banks and credit unions often pay higher rates because they need deposits more or operate with lower costs.

Can a bank run out of money and not be able to pay me back?

A bank can fail if losses on loans exceed its capital, but your deposits are insured by the FDIC up to $250,000. Even if the bank collapses, the FDIC will pay you back. Bank failures are rare because regulators monitor banks closely and require them to maintain minimum capital levels.

How much of my deposit does the bank actually lend out?

Banks typically lend out 80% to 90% of deposits after setting aside reserves and capital. The exact percentage varies by bank size, market conditions, and loan demand. Large banks with access to other funding sources may lend out a higher percentage. Banks facing weak loan demand may lend out less.