Open Market Operations: How the Central Bank Moves Liquidity

An open market operation is a central bank buying or selling securities in order to change how much money the banking system is holding. A purchase puts money in and takes securities out, and a sale does the reverse. The operation matters because announcing a rate does not by itself make anybody trade at that rate. The operation is what makes the announced rate true.

Every rate, balance and operation below belongs to the Republic of Sankhya, an invented country with an overnight band of 5.75, 6.00 and 6.25 per cent. Real institutions appear by name where they issue something a reader can consult at source.

Underneath the answer sits one fact that most readers find harder to accept than to understand. A central bank does not need to have money before it spends money. When it buys something, it pays by increasing a number in an account that it keeps and controls, and that increase is the payment. Nothing was taken from somewhere else to fund it. Paying by raising a number is not a trick and not a controversy. The mechanics are ordinary and daily, and they belong to an institution whose liabilities are the money everybody else settles in.

Everything needed is already in place. The policy rateThe one interest rate a central bank puts out as the level it wants very short term money trading around. What it is and who settles it came earlier in this reading. and who decides it came earlier, and so did the list of instruments a central bank has to work with. The open market operation is one instrument on that list. Two subjects sit outside the operation. A rate decision came earlier, and so did the corridorThe band of rates a central bank puts around its policy rate by standing ready to take deposits at the bottom and lend at the top. It is worked through in detail later in this reading. the rate sits inside comes later. The operation stops firmly at the bank's balance at the central bank.

What exactly happens when a central bank buys a security?

Three steps make up the whole mechanism. Readers routinely talk themselves out of the correct answer on this subject, and the reason is that three steps seem too small to be the whole of it.

Step one: the central bank agrees to buy a securityA tradable financial claim that can be bought and sold, such as a government bond or a treasury bill. What kinds exist and how they are priced belong with the fixed income material, not here. from a bank in the market, at an agreed price. Step two: the central bank pays. The payment is an increase in the number in that bank's account at the central bank. Step three: the bank now has a larger balance at the central bank, and the security has moved across.

Money the banking system holds at the central bank comes into existence at the moment the central bank agrees to pay it out, so the increase in that account is both the payment and the creation. Nothing was printed. No notes moved. No taxpayer was charged and no saver was drawn down. The central bank did not first go and find Rs 5,000 crore somewhere in order to have it available.

The everyday parallel is nearer than it sounds. Put the mechanism in ordinary terms. Imagine the record keeper of a large housing society, the person who maintains the ledger of what every flat has paid in and owes. If that record keeper buys something from a resident and settles it by writing a credit against that resident's line in the society ledger, the resident's balance genuinely rises. No cash crossed a table. In a society the arrangement is limited. The society ledger settles obligations only among its own flats. The reason the central bank version is powerful is that the ledger it keeps is the one every bank in the country settles in.

A reader who wants this to be more complicated will invent complications that are not there. There is no fourth step in which the money is fetched from a vault, no fifth step in which somebody's savings are reduced, and no hidden press running somewhere. A reader still hunting for the missing piece has already passed it: an entry was made in an account, and in this particular account an entry is money.

What does liquidity mean here, and what does it not mean?

One word is doing three jobs in finance, and most confusion about open market operations actually starts there. The confusion is not about central banking but about vocabulary, and the only defence is to name each of the three jobs.

In an open market operation, liquidity means one thing: the quantity of central bank money the banking system is holding, the sum of the balances every bank keeps in its account at the central bank. The quantity is measurable, it goes up when the central bank buys and down when it sells, and it is the only quantity an open market operation moves directly.

The second sense is the liquidity of a market, meaning how easily a large trade goes through without shifting the price much. A share that trades in size all day is liquid in that sense; a plot of land in a small town is not. Market depth and trading answer that question, and they are covered with the material on how markets are structured.

The third sense is the liquidity of a company, meaning whether the business can meet the bills falling due over the next few months out of what it can turn into cash. Working capital and short term solvency answer that question, and they are covered with the material on reading a set of accounts.

The three senses are unrelated in almost every way that matters. A banking system can be flush with central bank money in the first sense on a morning when a particular bond market is barely trading in the second sense, and a single company can be short of cash in the third sense in either case. When a sentence uses the word without saying which sense it means, the honest response is to ask. A reader who guesses will be right about a third of the time.

Why operate at all, when the rate has already been announced?

The question separates a reader who has memorised the tools from a reader who understands them, and the answer is one sentence long. The announced rate is a target, not a fact, and the operation is what turns the target into the rate at which money actually changes hands.

Think about what an announcement actually is. A committee meets, decides that short term money should trade at 6.00 per cent, and says so. Nobody in the money marketWhere very short term funds change hands, usually between banks and other big institutions, on terms the two sides negotiate rather than terms anybody sets for them. is under instruction. The next morning, a few hundred institutions with surplus balances and a few hundred short of balances negotiate with each other, and whatever they agree is the rate. If the announcement were self-executing, no central bank would need a trading desk at all.

Quantity is what decides where those negotiations land. If the banking system is holding more central bank money than it has any use for, the lenders in that market are competing with each other to place it, and competing lenders push the rate down. If the system is short, the borrowers are competing instead, and the rate goes up. The competition is ordinary supply and demand, applied to a thing that happens to be money.

So the operation is aimed at the quantity, and the quantity is aimed at the rate. The desk adds balances when the market rate is drifting above the announced level and drains them when it is drifting below, in whatever size the drift calls for. The announcement and the operation are two halves of one act, and a central bank that did only the first half would be publishing an opinion rather than setting a rate.

Notice what this makes of the corridor. The floor and the ceiling stop the drift becoming unbounded. A bank that cannot place money anywhere can always place it with the central bank at 5.75 per cent, and will never lend below that. A bank short of money can always borrow from the central bank at 6.25 per cent, and will never pay above it. Inside that band the operation does the fine work. How the band itself is built is a separate matter, taken up later in this reading.

What does one purchase look like on both sides of the trade?

The claim that money was created and nothing was destroyed is exactly the kind of claim that should be checked rather than believed. Walk it through with numbers.

Set the scene. The Sankhya banking system is holding Rs 20,000 crore in its accounts at the central bank, and money is trading at 6.10 per cent, 10 basis pointsA hundredth of a percentage point, so the step from 6.00 to 6.10 per cent is ten of them. Small rate moves get quoted this way to keep the decimals unambiguous. above the announced 6.00 per cent. The system is a little short. The desk buys Rs 5,000 crore of securities. Here is what each side is holding before and after.

Read the two tables against each other and the whole claim is visible. The banking system holds Rs 80,000 crore before and Rs 80,000 crore after: it swapped one asset for another and is no richer and no poorer for having done so. The central bank holds Rs 3,30,000 crore of assets before and Rs 3,35,000 crore after, and owes Rs 3,30,000 crore before and Rs 3,35,000 crore after. Nothing anywhere was destroyed, and the Rs 5,000 crore of new money exists as an extra liability of the central bank matched by the extra security it now holds.

Now the rate consequence. The rate is the reason anybody bothered. The system was holding Rs 20,000 crore and is now holding Rs 25,000 crore. On the working assumption used throughout, Rs 25,000 crore is the level at which Sankhya money trades at the announced 6.00 per cent, so the operation was sized precisely to close a 10 basis point gap and no more. Had the desk bought Rs 17,500 crore instead, balances would have reached Rs 37,500 crore, and the competition to place all of it would have driven the overnight rate down to the floor of 5.75 per cent, where it would stop. A sale of Rs 7,500 crore would push it the other way to the ceiling of 6.25 per cent, and stop there too.

What separates a temporary operation from a permanent one?

Two operations can be the same size, the same instrument and the same direction, and be completely different acts. The difference is one line in the announcement: whether the money comes back, and on what date.

A temporary operation is a repurchase arrangement. The central bank buys the security and the bank agrees to buy it back on a stated date, one day away or two weeks away. Balances go up today and come down again on that date. Nothing about the level of money in the system has been changed beyond the window. The instrument exists to smooth a squeeze that has a beginning and an end, such as a week when a large tax payment pulls money out of the banks.

A permanent operation is an outright purchase. The central bank buys the security and keeps it. There is no return date and no return. Balances go up and stay up until some other operation changes them. An outright purchase changes the level rather than smoothing a bump, and the intention is different entirely.

On day one the two look identical, and after the stated date they have nothing in common. The return date is the only part of the announcement that settles what kind of act it is. The calculator above shows it happening: an operation set to temporary, seen on day one and then on day fifteen, has its balances back exactly where they started.

A second term is worth naming, and it turns up often. When a central bank does one operation to offset the effect of something else and leave the net quantity of money where it was, the operation is said to steriliseTo pair an operation with an offsetting one so the net quantity of money in the system does not change, usually because the first movement was a side effect of something the central bank was doing for another reason. the first movement. The mechanics are the ones set out above; only the intention is different.

Where does an open market operation stop working?

Here is the honest boundary of the tool, and it is narrower than most descriptions of central banking suggest. An operation moves the quantity of money the banking system is holding at the central bank. The operation does that, and the operation does only that.

Whether that quantity goes anywhere depends on two decisions that no operation can make. A bank has to choose to lend against the larger balance, and a borrower has to choose to borrow. Either link can fail. A bank with a bigger balance and no lending it considers worth doing will simply sit on the balance, and a bank willing to lend into a country where nobody wants to borrow gets the same result.

Money added to the banking system and not lent on has changed a number in the banking system and nothing else, and saying so is not a criticism of the tool but a description of where it ends.

The household version is exact. Suppose the withdrawal limit on a household's bank card rises from twenty thousand rupees to fifty thousand. Its capacity to spend has genuinely increased. Whether anything happens next depends on whether the household wants to buy anything, and whether the limit was the reason it was not buying. A household holding back out of worry about a job finds nothing at all changed about its week. A number has changed and nothing else.

The next stretch of this reading takes up what happens after the balance rises, how a bank decides to lend against it and how far a rate move actually travels toward a borrower. An open market operation stops at the balance.

What does an open market operation not do?

Three things are worth ruling out by name, because each is a reasonable guess that a reader can make from the mechanism and each is wrong.

An open market operation does not decide who gets credit. The central bank buys a security from whichever counterparty is on the other side of the trade, and the balance lands there. Which businesses or households are then lent to is decided by banks applying their own tests, one borrower at a time. The operation changes how much money the banking system holds and has nothing to say about where any of it should go.

An open market operation does not fund government spending. The operation is a purchase of an existing security in the market at a market price, in exchange for money, and the party on the other side is whoever was holding the security. How a government finances itself, and how that differs from what a central bank does, is a different lever taken up later in this reading where the two are set side by side.

An open market operation does not make anybody creditworthy. A borrower who could not service a loan before the operation is in exactly the same position after it. The collateralAn asset pledged to a lender that the lender can take if the borrower fails to pay. What counts as acceptable collateral, and how much it is discounted, sits with the lending material rather than here. a bank asks for, the tests it applies and the price it charges are its own decisions and are covered separately.

Why does a treasurer watch the operations rather than the announcements?

Take somebody with a real job. The treasurer of a mid sized manufacturer borrows short term money most weeks to bridge the gap between paying for material and being paid by customers. The treasurer needs to know what tomorrow morning's funding will cost, and the announced policy rate is not that number.

The number the treasurer pays is set in the money market, by whatever the rate does that morning. When the system is short, that rate sits above the announced level and short term funding is dearer than the headline suggests. When the system is flush, the opposite. Over a year of weekly borrowing, 10 basis points of drift on Rs 50 crore of rolling short term funding is real money, and it never appeared in any announcement.

So the treasurer watches two things the general reader ignores. The first is what the desk actually did today and in what size. The size of today's operation is what moves the rate tomorrow. The second is whether the operation carries a return date. An operation returning on day fifteen tells the treasurer that funding gets tighter again on day fifteen, a fact worth knowing when deciding whether to borrow for a week or for a month.

The announcement states where the central bank intends the rate to be, and the operation shows where the rate is going to be tomorrow morning. The second number is the one a person paying the rate cares about. A lender does the same arithmetic from the other side, and an analyst covering banks watches the same operations to understand what happened to short term funding costs in a quarter.

The Republic of Sankhya and its central bank are invented.
Educational material. Not advice on any investment, tax, budget or market position.