Banks earn money primarily by lending out the deposits you keep with them, charging interest on those loans, and collecting fees for services

When you deposit money into a bank account, that money does not sit in a vault with your name on it. The bank takes your deposit and lends it to other customers—for mortgages, car loans, credit cards, and business lines of credit. The borrower pays interest on that loan. The bank keeps the difference between the interest rate it pays you on your deposit and the interest rate it charges the borrower. That spread is the bank's primary source of profit.

A simple example: a bank might pay you 0.01% annual interest on a savings account, then lend that same money to a mortgage borrower at 6.5% interest. The bank keeps roughly 6.49% of that spread as profit. Multiply that across thousands of deposits and millions of dollars, and the numbers become substantial. This lending model is how banks have operated for centuries, and it remains their largest revenue stream.

Key Takeaways

  • Banks lend out customer deposits to borrowers and profit from the difference between what they pay depositors in interest and what they charge borrowers.
  • Monthly maintenance fees, overdraft fees, wire transfer fees, and ATM fees are secondary revenue sources that add up across millions of accounts.
  • Banks also earn money by investing deposits in bonds, stocks, and other securities, and by selling financial products like investment accounts and insurance.
  • The interest rate environment—set largely by the Federal Reserve—directly affects how much profit a bank can make from lending.
  • Banks must hold a portion of deposits in reserve and cannot lend out 100% of what customers deposit.

The interest rate spread: where most bank profit comes from

The interest rate spread is the gap between what a bank pays depositors and what it charges borrowers. When interest rates are high, banks can charge borrowers more while still paying depositors a competitive rate, widening the spread and increasing profit. When interest rates are low, the spread narrows, and banks make less money on lending.

The Federal Reserve influences this environment by setting the federal funds rate—the rate at which banks lend to each other overnight. Banks use this rate as a benchmark when deciding what to pay on savings accounts and what to charge on loans. When the Fed raises rates, banks typically raise both deposit rates and loan rates, but they often raise loan rates faster, widening their spread. When the Fed cuts rates, the opposite happens, and spreads compress.

A bank's profitability depends heavily on this spread. During periods of rising rates, banks often report record profits. During periods of falling rates or economic uncertainty, that profit shrinks. This is why you may notice your savings account interest rate changing—the bank is adjusting to maintain its margin.

Fees: the secondary revenue stream

Beyond lending, banks collect fees for services. These include monthly account maintenance fees (typically $10 to $15 for checking accounts), overdraft fees (often $25 to $35 per occurrence), wire transfer fees ($15 to $50 depending on domestic or international), ATM fees when you use an out-of-network machine, and fees for stopping payment on a check. Some banks charge fees for paper statements, account research, or closing an account early.

For a large bank with millions of accounts, these fees generate billions in annual revenue. A single overdraft fee charged to 100,000 customers in one month is $2.5 million in revenue. Overdraft fees alone have become controversial because they disproportionately affect lower-income customers who live paycheck to paycheck. Many banks have reduced or eliminated overdraft fees in recent years in response to regulatory pressure and customer complaints, but fees remain a significant part of bank revenue.

You can reduce the fees you pay by choosing a bank that offers no-fee checking, setting up overdraft protection (which links your checking account to a savings account or credit line), and using your bank's ATM network. Some online banks charge no monthly fees at all because they have lower overhead costs than brick-and-mortar branches.

Investment and securities trading

Banks also profit by investing customer deposits in bonds, Treasury securities, and other financial instruments. When a bank receives a deposit, it does not have to lend out 100% of it immediately. Some of that money sits in the bank's investment portfolio, earning returns. If a bank invests deposits in a Treasury bond yielding 4%, that is profit the bank keeps (minus what it pays the depositor).

Larger banks also have trading divisions that buy and sell securities, currencies, and derivatives on behalf of clients and for the bank's own account. These trading operations can generate substantial profits during volatile market periods, though they also carry risk. A major trading loss can significantly impact a bank's quarterly earnings.

Banks also earn fees by managing investment accounts for wealthy clients, offering brokerage services, and selling mutual funds and insurance products. These wealth management and advisory services generate commission-based revenue separate from the core lending business.

Reserve requirements and how they limit lending profit

Banks cannot lend out every dollar you deposit. The Federal Reserve requires banks to hold a minimum percentage of deposits in reserve—money that must stay in the bank and cannot be lent out. This reserve requirement varies by the size of the bank and the type of deposit, but it typically ranges from 0% to 10% of total deposits.

The reserve requirement exists to ensure banks have enough liquid cash to meet customer withdrawals and to maintain financial stability. It also limits how much profit a bank can extract from deposits. If a bank must hold 10% of deposits in reserve, it can only lend out 90%, which directly reduces the interest income it can generate.

During the COVID-19 pandemic, the Federal Reserve temporarily reduced reserve requirements to zero to encourage lending. Banks responded by increasing lending, which boosted their profits but also contributed to inflation. The Fed later raised reserve requirements again as part of its effort to control inflation.

How economic conditions affect bank profitability

Bank profits rise and fall with economic cycles. During economic expansion, borrowers are more likely to take out loans, default rates are low, and banks can charge higher interest rates. During recessions, loan demand drops, default rates rise (borrowers cannot repay), and banks must set aside more money to cover potential losses. This is called a loan loss reserve.

Interest rate changes also create winners and losers among banks. Banks that hold long-term fixed-rate loans on their books can suffer when interest rates rise suddenly, because the value of those loans decreases. Conversely, banks that lend at variable rates benefit when rates rise because they can immediately increase the interest they charge on new loans and adjustable-rate existing loans.

The 2023 banking crisis illustrated this dynamic. Several regional banks failed because they had invested heavily in long-term Treasury bonds when interest rates were low. When the Federal Reserve raised rates sharply, the value of those bonds plummeted, and depositors rushed to withdraw their money. The banks did not have enough liquid cash to meet the withdrawals and collapsed.

How deposit insurance affects bank operations

The Federal Deposit Insurance Corporation (FDIC) insures deposits up to $250,000 per depositor, per bank. This insurance protects you if the bank fails, but it also costs the bank money. Banks pay FDIC insurance premiums based on the size and risk profile of their deposits. A bank with riskier lending practices pays higher premiums than a conservative bank.

FDIC insurance creates a moral hazard: banks know that depositors are protected, so depositors have less incentive to monitor whether the bank is taking excessive risk. This can encourage banks to make riskier loans in pursuit of higher returns. Regulators try to offset this by requiring banks to maintain minimum capital levels and by conducting regular examinations.

Frequently Asked Questions

Why do banks pay almost no interest on savings accounts?

Banks pay low interest rates on savings because they can. When the Federal Reserve keeps interest rates low, banks have no competitive pressure to pay depositors more. They can borrow money cheaply (from you) and lend it out at higher rates, keeping a wide spread. When the Fed raises rates, banks gradually raise savings rates too, but usually with a lag.

Do banks make money when I use my debit card?

Yes, indirectly. When you swipe a debit card, the merchant's bank pays your bank a small fee called an interchange fee, typically 0.5% to 2% of the transaction amount. Your bank also earns money by holding the cash from that transaction for a day or two before it clears, investing it briefly in short-term securities. These amounts are small per transaction but add up across billions of debit card swipes annually.

What happens to my money if the bank invests it and loses?

Your deposit is protected up to $250,000 by FDIC insurance, regardless of whether the bank's investments lose money. The bank absorbs investment losses from its own capital and profits. If losses are severe enough to wipe out the bank's capital, the FDIC takes over the bank, pays off insured deposits, and sells the bank's assets to recover what it can.

Can I make money by keeping a large deposit in a bank account?

Not significantly. Even high-yield savings accounts currently pay 4% to 5% annual interest, which barely keeps pace with inflation. The bank is making far more money lending out your deposit than it is paying you. If you want to earn more, you would need to invest in bonds, stocks, or other securities, which carry more risk than a bank deposit.

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

Banks that charge overdraft fees rely on that revenue to offset lower interest margins and higher operating costs. Online banks and credit unions often eliminate overdraft fees because they have lower overhead and can afford to compete on service rather than fees. Traditional banks with physical branches need more revenue per account to cover rent, staff, and technology.