Your bank does not keep your money in a vault, like some cartoon Scrooge McDuck. It borrows it from you, lends most of it out to somebody else at a higher rate, and keeps a fraction in reserve. That is not a loophole or a scandal. It is what banking is, it has worked this way for centuries, and it is the reason a bank can pay you interest at all.
This is the third piece in the Money Basics series. If you have not read the first two, start with how money actually works. This piece assumes it.
Where your money goes when you deposit it
Picture handing a twenty-dollar bill to a teller, or watching a paycheck land in your account. Something has clearly happened - the number in your account went up. The natural assumption is that the money went into a box somewhere with your name on it, waiting for you.
That is not what happens.
When you deposit money, you are not storing it. You are lending it to the bank, on terms that allow you to ask for it back at any time. In exchange for the use of your money, the bank pays you interest. On a checking account that interest is often near zero. On a savings account it is usually small.
The bank then takes that money and lends the great majority of it out again - as mortgages, car loans, business loans, credit card balances. It charges a higher rate on those loans than it pays you. That difference is how a bank makes its money. As well as fees, it is the whole business.
So the money you think is sitting in your account is, in the ordinary course of things, out in the world working for somebody else. Your balance is a record of what the bank owes you, not a description of cash in a drawer.
Why the bank can do this at all
Because not everyone asks for their money on the same day.
Thousands, maybe millions of customers have a balance, and on any normal day only a small fraction of them want cash out. The rest are leaving their money where it is. So the bank needs to keep only enough on hand to cover what people actually withdraw, and it can lend the rest.
This is not a loophole. It is how banking has worked for centuries, and it is the reason a bank can pay you interest at all. If your money were genuinely sitting in a vault, the bank would have to charge you rent for the space.
Banks used to be required to hold a set fraction of deposits in reserve. In the United States that requirement was cut to zero in 2020, and several countries never had one at all. What limits lending now is a different rule: the bank has to hold enough of its own capital to absorb losses if loans go bad. Either way the principle is the same - a bank keeps a small amount and lends out the rest.
Which brings us to the obvious question.
What happens if everyone asks at once
Then the bank has a problem, and so do you.
If enough depositors demand their money at the same time - because a rumor spread, or because a bank is genuinely in trouble - a bank cannot pay them all, because most of the money is not in the building. This is a run on the bank, and it is why bank failures happen suddenly rather than gradually.
Your account is protected against this up to a limit. In the United States, the Federal Deposit Insurance Corporation insures deposits up to a set amount per depositor, per bank, and most other western countries have an equivalent scheme. That protection is why a rumor alone rarely starts a run any more.
Two things follow from this, and both are practical: first, check what your country’s deposit protection limit is, and make sure you are inside it. Second, if you hold a large amount, holding it across two institutions is a way of staying inside the limit twice. That is not a trick. It is what the protection is designed for.
Where the interest you earn comes from
Now the numbers make more sense.
- The bank pays you interest because it is using your money.
- It charges a borrower more, because lending carries risk and because it has costs.
- The gap between the two is its profit.
- On a savings account paying you 2 percent while it lends at 7 percent, the bank is keeping the difference.
There is one more layer, and it explains why rates on savings and rates on loans move together. The central bank sets a base rate that influences everything else. If it raises it, and borrowing across the economy gets more expensive, savings rates tend to rise, and people spend a little less. Lower it and the reverse happens. That is the lever governments use to steer the economy, and it is why a decision made in a committee room shows up in your mortgage payment some months later.
What you actually own
What you hold in a bank account is not money in the physical sense. It is a claim - a promise from the bank that it will give you cash, or transfer it, when you ask. Most of the money in circulation exists this way, as records on bank computers rather than notes in wallets.
That sounds like a technicality. It is not, and it is the thing that makes the rest of this series make sense: most money is created when banks lend, not when governments print. When a bank issues a mortgage, it does not go and fetch the money from somewhere. It creates the deposit. The loan and the deposit appear together on the bank’s books.
That is not a trick or a conspiracy. It is ordinary banking, described plainly, and it is taught in every economics course - just not to the rest of us.
What to do with this
- Check your deposit protection limit for your country, and check your balances against it. If you are over it, that is worth knowing today rather than later.
- Look at what your savings account actually pays you compared with what the base rate is. If your bank is paying you close to nothing while lending at a healthy rate, you are allowed to move your money.
- Be suspicious of your own confidence. In the survey behind this series, the adults who rated their money knowledge highest were not the most accurate. Being unsure about banking is normal and fixable. Assuming you already know is the thing that costs money.
If you want the next piece in this series, sign up for the free guide. We are going through the money basics one at a time - where money comes from, why prices rise, what a market really is - in plain language, with no jargon and no sales pitch.