How Banks Actually Make Money
Banks pay savers less than they charge borrowers. Learn how that spread works and how to compare banks, credit unions, and online institutions.
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What this means
Most people picture a bank as a vault with their money sitting in it. That picture is wrong in an important way, and correcting it explains almost everything banks do.
When you deposit money, the bank records that it owes you that amount. Then it lends most of the money out. A person buying a car, a family buying a house, and a small business buying equipment are all borrowing money that other customers deposited. Your savings and their loan are the same dollars.
The borrower pays interest to the bank. The bank pays interest to you. And the rate it charges borrowers is always higher than the rate it pays depositors. That gap has a name: the spread. The spread is where the bank's income comes from, along with fees.
The gap is usually much wider than people expect. A savings account might pay a small fraction of a percent while a credit card charges well over twenty percent, and a mortgage sits somewhere in between. Go look up the actual numbers at a real institution and the difference will be more striking than any figure printed here.
Not every institution is built the same. A bank is a for-profit company with outside owners. A credit union is a not-for-profit cooperative owned by its members, which is why credit unions often pay somewhat better rates on savings and charge somewhat less on loans. There are also online-only institutions with no branches, which have lower operating costs and often pass some of that along to savers, in exchange for no place to walk into.
They all offer overlapping products: checking accounts, savings accounts, certificates of deposit, loans, credit cards, and increasingly a phone app that does most of it. The right choice depends on what you need, not on which is objectively best.
Why it matters
Once you know about the spread, you stop reading a bank as a helpful institution or a villain and start reading it as a business with a model. That makes you a better customer. You will notice that the same institution advertises its loan rates and its savings rates very differently, and you will understand why.
It also explains why banks are so eager for deposits. Deposits are their raw material. That eagerness is your leverage: you can compare, negotiate, and move. Many people never move their account from the bank their parents used, which is exactly the outcome the bank is counting on.
Real-world example
Pull up any single financial institution's website and look at two pages: the savings account page and the credit card page. The same company, on the same day, will show you what it pays you for your money and what it charges you for its money. The two numbers are usually not close. Neither page mentions the other, and that is the point.
Try it
- Draw the money flow for a single institution. Show depositors, the institution, and borrowers, with arrows for deposits, loans, interest paid, and interest received. Label which arrow is larger.
- Pick one real financial institution. On its website, find the rate it currently pays on a basic savings account. Record the rate and the date.
- At the same institution, find the rates it charges on three kinds of borrowing: a credit card, an auto loan, and a personal loan or mortgage. Record all three with the date.
- Compute the spread for each pair. Write a sentence describing how much more the institution charges than it pays.
- Now repeat steps 2 through 4 at a credit union. Compare the two sets of numbers. Which one pays savers more? Which one charges borrowers less? Does anything surprise you?
- Build a comparison table of three institution types: a large national bank, a local credit union, and an online-only institution. For each, record ownership structure, number of physical branches, savings rate, monthly fees, minimum balance, ATM access, and the range of products offered.
- Write a recommendation for two different people: someone who wants the highest savings rate and rarely needs in-person help, and someone who needs to deposit cash from a job every week and wants a person to talk to. They should get different answers.
- Answer in a paragraph: where does the money come from that a bank uses to pay you interest? Trace it back at least two steps.
Teacher note
Step 8 is the assessment for the third learning outcome, and it is the one students get wrong most often. The common wrong answer is "the bank has money" or "the bank makes money." Require two steps: the bank pays you from what it earns, and it earns it primarily from borrowers who are borrowing depositors' money. When a student traces it back to other customers, the loop is closed.
The vault misconception is worth attacking head-on. Ask what happens if every depositor asks for their money on the same day. This is a legitimate and historically important question, and it sets up deposit insurance in the next benchmark. You do not need to teach fractional reserve mechanics at this level; you need students to know that deposits are lent out, not stored.
Steps 3 through 5 produce the memorable moment. Students are genuinely startled by how much wider the credit card gap is than they expected. Let them find it themselves rather than telling them; a number you announce is forgotten, a number they looked up is not.
Do not put current rates in your materials. They change, and students will carry a stale number for years. The date-stamping in steps 2 and 3 is a habit worth building.
Watch for students concluding that credit unions are always better. They often pay more on savings, but they may have membership requirements, fewer branches, weaker apps, or a smaller ATM network. Step 7 exists to prevent a single-winner conclusion. A student has it when they can explain the spread in their own words and defend two different institution choices for two different people.
Check yourself
Where does a bank get the money it uses to pay interest to savers?
A bank pays 1% on savings and charges 9% on auto loans. What is the 8-point difference called, and what is it for?
What is the key structural difference between a bank and a credit union?
Why might an online-only institution offer savers a better rate than a bank with many branches?
Your deposit is somebody else's loan, and the gap between what the bank charges them and pays you is the whole business.