You walk into a bank and deposit $100 in cash. Most people carry a rough mental picture of what happens next. The cash goes into a vault. It sits there, more or less, until you want it back. Some of it might get lent to somebody else in the meantime, which is why the bank can pay you a little interest.
That picture is wrong in a specific and interesting way. Not slightly wrong, not a simplification that mostly holds. Wrong about the direction the money moves, and wrong about where most money comes from in the first place.
The accurate version is stranger, and once you see it you cannot unsee it in the news. It changes what a central bank announcement means, what a credit crunch is, and why "the banks are not lending" is a sentence about the money supply rather than a complaint about customer service.
What actually happens when you deposit $100?
From an accounting perspective, two things happen at the same instant, and they are not the two things most people expect.
The bank receives your cash. That becomes an asset on its balance sheet, because the bank now owns those notes. Simultaneously, the bank creates a deposit in your name. That deposit is a liability, because the bank now owes you $100 on demand.
So the $100 in your account is not a box with your name on it. It is a legal claim you hold against the bank, recorded as a number. The bank owes you. You are, in the most literal sense, one of the bank's creditors.
Your balance is not money the bank is holding for you. It is money the bank owes you.
This distinction sounds pedantic until the moment it matters. It is precisely why deposit insurance exists. If your balance were cash in a vault with your name on it, a failing bank would be an inconvenience rather than a risk, because you would simply collect your box. Because your balance is a claim against an institution, a failing institution means a claim that might not be honoured. Deposit insurance exists to make that claim good regardless.
It also explains a phrase you have heard without unpacking: money exists primarily as a balance-sheet entry. Not as coins in a vault. Not as bills in a drawer. As a number on a ledger, matched by an offsetting number somewhere else.
Do banks lend out the money you deposited?
No. This is the part that surprises people, and it is not a fringe position.
In 2014 the Bank of England published a paper in its Quarterly Bulletin titled "Money creation in the modern economy." It stated plainly that the common description, in which banks act as intermediaries taking in deposits and lending them out, does not describe how money is actually created. The paper is unusually direct for a central bank document. It says the reality is the reverse of the textbook story: lending creates deposits, rather than deposits funding lending.
Read that again, because the order is the whole point. A bank does not need your $100 to make a $100 loan. It makes the loan, and the act of making it produces a new deposit.
What happens on the balance sheet when a bank makes a loan?
Say a bank approves a $200,000 mortgage. Here is what it does, mechanically.
It writes $200,000 as an asset, because the borrower now owes the bank that amount. A loan, from the bank's side, is something it owns: a stream of future repayments.
And it writes $200,000 as a liability, by crediting the borrower's account with $200,000 that the borrower can now spend.
Both entries appear at once. The balance sheet stays balanced, which is the whole trick. And the $200,000 sitting in the borrower's account did not come from anywhere. It was not moved from a saver. It was not taken from a vault. It was typed into existence as the matching half of a debt.
| Event | Bank's assets | Bank's liabilities | Money supply |
|---|---|---|---|
| You deposit $100 cash | +$100 cash | +$100 your deposit | Unchanged, cash became a deposit |
| Bank makes a $200,000 loan | +$200,000 loan owed to bank | +$200,000 borrower's deposit | +$200,000, newly created |
| Borrower repays $200,000 | -$200,000 loan | -$200,000 deposit | -$200,000, destroyed |
The overwhelming majority of money in a modern economy was created this way. Physical notes and coins are a small fraction of the total. The rest is commercial bank deposits, which is to say: the accounting shadow of outstanding loans.
How this is taught inside Astra Trainer
This exact mechanism is a lesson called Fractional Money Creation inside the Money Systems direction, one of five directions in the Business & Finance world. It takes about five minutes, it is written in plain language rather than balance-sheet notation, and a guide walks you through anything strange. Money Systems runs to twenty courses covering where money comes from, how banks create it from credit, and why the Federal Reserve moves the way it does.
Every lesson carries a discussion thread underneath it, which matters more on this topic than most. Almost everyone arrives holding the vault picture, and reading other people work through the same correction tends to be what makes it stick.
If banks can create money, what stops them?
This is the right question, and the honest answer is that several things do, none of which is a pile of cash in a basement.
Capital requirements
A bank must hold capital against its assets, and loans are assets. Capital here means the bank's own funds, shareholder equity and retained earnings, standing behind the lending as a buffer against losses. Make more loans and you need more capital behind them. This is a genuine, binding brake, and it is the reason regulators spend so much energy on capital ratios.
Funding and settlement
The borrower spends the new deposit, usually immediately, and usually at a different bank. When that happens, the first bank must settle with the second, in central bank reserves. So while a bank can create a deposit freely, it cannot avoid the consequence of that deposit walking out the door. It needs reserves, and reserves cost money to obtain. That cost disciplines lending.
Profitability and credit risk
A loan is only worth making if it is likely to be repaid at a rate above the bank's funding cost. Lending to people who will not repay does not create wealth, it creates losses. Banks are constrained by the supply of borrowers who are both creditworthy and willing.
Monetary policy
Central banks influence the price of reserves, which feeds through to the rates banks charge. Raise that price and lending becomes less attractive at the margin. This is the lever, and it works by changing incentives rather than by rationing a fixed quantity.
The common misreading. "Banks create money from nothing" is often deployed as though it proves banks are getting something for free. They are not. The newly created deposit is matched by a newly created liability of equal size. The bank has not gained $200,000. It has gained a claim on a borrower and an obligation to a depositor, and it earns the spread between them while carrying the risk that the loan sours. Money creation is not the same as profit.
What is the money multiplier, and why do economists argue about it?
The money multiplier is the model most people were taught, if they were taught anything. It goes like this. A bank must keep a fraction of deposits in reserve, say ten percent. It lends out the other ninety. That ninety gets deposited at another bank, which keeps ten percent and lends ninety percent of it. Repeat, and an initial deposit supports a predictable multiple of loans.
It is a tidy story, it is easy to draw, and it treats reserves as the binding constraint, with central banks controlling lending by controlling the quantity of reserves.
The dispute is over whether it describes reality. The Bank of England's 2014 paper argued that it does not, on the grounds that the causation runs the other way. Banks do not wait for reserves and then lend. They lend when they find profitable, creditworthy borrowers, and then obtain the reserves they need to settle. Reserves follow lending rather than limiting it.
Several things support this reading. Many jurisdictions have no reserve requirement at all, including Canada, the UK, and since March 2020 the United States, yet banks in those places did not lend without limit. If reserves were the binding constraint, removing the requirement should have removed the brake. It did not, because the brake was capital, funding cost and credit risk all along.
The large-scale asset purchases after 2008 point the same way. Central banks flooded the system with reserves, far beyond anything the multiplier model would require. Lending did not expand by the predicted multiple. Banks sat on the reserves, because the constraint was never a shortage of them.
It is worth being straight about the state of the argument. The multiplier is still taught, and some economists defend it as a serviceable approximation in particular regimes rather than a literal description. But the operational account, the one describing what a bank actually does when it books a loan, is the one central banks themselves publish. When a practitioner's description and a textbook's description diverge, it is usually worth knowing both and noticing which one the practitioners use.
Where does central bank money fit in?
There are two distinct kinds of money moving through the system, and conflating them is the source of a great deal of confusion.
Commercial bank money is what you and I use. Deposits. Created by commercial banks when they lend, as described above. This is the vast majority of the money supply.
Central bank money comes in two forms: physical notes and coins, and reserves held by commercial banks at the central bank. Ordinary people cannot hold reserves. They exist so banks can settle with each other, and they are created by the central bank.
The two circulate in separate layers. When you pay someone at another bank, your deposit falls and theirs rises in the commercial layer, while the two banks settle in the reserve layer underneath. Most people never see the lower layer, which is why it is easy to imagine it does not exist.
Locking it in rather than just reading it
Two layers of money, four balance-sheet entries and a live academic dispute is more than anyone retains from a single read. This is the specific problem the Business & Finance world is built around.
Each topic is followed by quizzes, and each course ends with a ten-question final exam. The daily Connections round and the 10x10 crossword are generated from that world's own lessons, so the terms you just met here, ledger, liquidity, supply, demand, come back as practice rather than revision. There is a fresh round every day.
You can also run it with other people. A Circle is a small group with a shared weekly goal and a chest that only opens when the group hits it together, plus live sessions where everyone races through the same lesson at once. Finance is a subject people quietly avoid admitting they find confusing, and a group of twelve working through fractional reserve mechanics at the same time removes most of that.
What destroys money?
Repayment. This is the symmetrical half of the story, and it is almost never mentioned.
When a borrower repays a loan, the deposit used to repay it disappears and the loan asset disappears with it. Both sides of the original creation are reversed. The money is not transferred to anyone. It ceases to exist.
This has a large consequence. If an economy is repaying debt faster than it is taking on new debt, the money supply contracts. Not because anyone decided to shrink it, but as the arithmetic result of millions of individual repayments outrunning new lending. That is what a credit contraction is, and it is why central banks watch net lending rather than gross.
It also reframes a familiar political sentence. "The banks are not lending" is usually heard as a complaint about institutional behaviour. Mechanically, it is a statement that the economy's main source of new money has slowed, which is a different and more serious claim.
What to take from this
Three things are worth carrying out of this.
First, a deposit is a claim, not a container. Once that lands, deposit insurance, bank runs and bank failure all stop being abstractions and start being obvious consequences of a specific legal relationship.
Second, lending creates deposits rather than deposits funding lending. The order matters. It is the difference between a system that rations a fixed quantity of money and one that expands and contracts with the demand for credit.
Third, the constraints are real but they are not the ones in the standard diagram. Capital, funding cost, credit risk and regulation do the work that reserves were supposed to do. Anyone telling you banks face no limits is as wrong as the textbook, in the opposite direction.
None of this requires a finance background, and none of it is investment advice. It is plumbing. But it is the plumbing underneath every headline about rates, credit and central banks, and reading those headlines without it is like following a match without knowing the offside rule.
Do banks really create money out of thin air?
They create deposits by writing matching entries, so yes in the sense that the deposit did not exist beforehand. But each new deposit is matched by an equal new liability, so the bank does not gain net wealth from the act. It earns the spread between what the borrower pays and what the funding costs, while carrying the risk of default.
If banks do not lend out deposits, why do they want my deposit?
Deposits are a comparatively cheap and stable source of funding for settling payments and meeting regulatory liquidity rules. A bank with a large retail deposit base pays less for funding than one relying on wholesale markets. Wanting deposits and lending out deposits are different things.
Is the money multiplier wrong?
It is disputed rather than settled. The Bank of England's 2014 paper argued the causation runs the opposite way, with reserves following lending rather than constraining it. Several jurisdictions have removed reserve requirements entirely without unlimited lending resulting, which supports that reading. Some economists still defend the multiplier as a rough approximation.
Does this mean inflation is caused by banks?
Bank lending expands the money supply, and the money supply is one input into inflation, but the relationship is not mechanical or immediate. Inflation also depends on supply conditions, demand, expectations and velocity. Treating bank lending as the single cause of inflation overstates what this mechanism explains.
Where can I learn this properly rather than in one article?
The Money Systems direction inside the Business & Finance world of Astra Trainer runs to twenty courses on exactly this, from where money comes from through to how the Federal Reserve operates. Lessons take about five minutes and the first one needs no card. You can see what is inside the world here.