Saturday Quiz – May 8, 2010 – answers and discussion

Here are the answers with discussion for yesterday’s quiz. The information provided should help you work out why you missed a question or three! If you haven’t already done the Quiz from yesterday then have a go at it before you read the answers. I hope this helps you develop an understanding of modern monetary theory (MMT) and its application to macroeconomic thinking. Comments as usual welcome, especially if I have made an error.

Question 1:

Under current institutional arrangements, the change in the ratio of public debt to GDP will exactly equal the primary deficit plus the interest service payments on the outstanding stock of debt both expressed as ratios to GDP.

The answer is True.

Note that after a few hours of being available I added the phrase at the end of the question “both expressed as ratios to GDP” in response to a question from Sergei. His point was absolutely correct and I had left that phrase off in my haste to compile the quiz before I travelled to Sydney yesterday. So if you had have answered false given the former wording you would have been correct.

But in the guise that I intended and which is now reflected in the current wording the answer is true as long as you note the caveat “under current institutional arrangements”. What are the institutional arrangements that are applicable here? I am referring, of-course, to the voluntary choice by governments around the world to issue debt into the private bond markets to match $-for-$ their net spending flows in each period. A sovereign government within a fiat currency system does not have to issue any debt and could run continuous budget deficits (that is, forever) with a zero public debt.

The reason they is covered in the following blogs – On voluntary constraints that undermine public purpose.

So given they are intent on holding onto these gold standard/convertible currency relics the answer is true.

The framework for considering this question is provided by the accounting relationship linking the budget flows (spending, taxation and interest servicing) with relevant stocks (base money and government bonds).

This framework has been interpreted by the mainstream macroeconommists as constituting an a priori financial constraint on government spending (more on this soon) and by proponents of Modern Monetary Theory (MMT) as an ex post accounting relationship that has to be true in a stock-flow consistent macro model but which carries no particular import other than to measure the changes in stocks between periods. These changes are also not particularly significant within MMT given that a sovereign government is never revenue constrained because it is the monopoly issuer of the currency.

To understand the difference in viewpoint we might usefully start with the mainstream view. The way the mainstream macroeconomics textbooks build this narrative is to draw an analogy between the household and the sovereign government and to assert that the microeconomic constraints that are imposed on individual or household choices apply equally without qualification to the government. The framework for analysing these choices has been called the government budget constraint (GBC) in the literature.

The GBC is in fact an accounting statement relating government spending and taxation to stocks of debt and high powered money. However, the accounting character is downplayed and instead it is presented by mainstream economists as an a priori financial constraint that has to be obeyed. So immediately they shift, without explanation, from an ex post sum that has to be true because it is an accounting identity, to an alleged behavioural constraint on government action.

The GBC is always true ex post but never represents an a priori financial constraint for a sovereign government running a flexible-exchange rate non-convertible currency. That is, the parity between its currency and other currencies floats and the the government does not guarantee to convert the unit of account (the currency) into anything else of value (like gold or silver).

This literature emerged in the 1960s during a period when the neo-classical microeconomists were trying to gain control of the macroeconomic policy agenda by undermining the theoretical validity of the, then, dominant Keynesian macroeconomics. There was nothing particularly progressive about the macroeconomics of the day which is known as Keynesian although as I explain in this blog – Those bad Keynesians are to blame – that is a bit of a misnomer.

This is because the essential insights of Keynes were lost in the early 1940s after being kidnapped by what became known as the neo-classical synthesis characterised by the Hicksian IS-LM model. I cannot explain all that here so for non-economists I would say this issue is not particularly important in order to develop a comprehension of the rest of this answer and the issues at stake.

The neo-classical attack was centred on the so-called lack of microfoundations (read: contrived optimisation and rationality assertions that are the hallmark of mainstream microeconomics but which fail to stand scrutiny by, for example, behavioural economists). I also won’t go into this issue because it is very complicated and would occupy about 3 (at least) separate blogs by the time I had explained what it was all about.

For the non-economists, once again I ask for some slack. Take it from me – it was total nonsense and reflected the desire of the mainstream microeconomists to represent the government as a household and to “prove” analytically that its presence within the economy was largely damaging to income and wealth generation. The attack was pioneered, for example, by Milton Friedman in the 1950s – so that should give you an idea of what the ideological agenda was.

Anyway, just as an individual or a household is conceived in orthodox microeconomic theory to maximise utility (real income) subject to their budget constraints, this emerging approach also constructed the government as being constrained by a budget or “financing” constraint. Accordingly, they developed an analytical framework whereby the budget deficits had stock implications – this is the so-called GBC.

So within this model, taxes are conceived as providing the funds to the government to allow it to spend. Further, this approach asserts that any excess in government spending over taxation receipts then has to be “financed” in two ways: (a) by borrowing from the public; and (b) by printing money.

You can see that the approach is a gold standard approach where the quantity of “money” in circulation is proportional (via a fixed exchange price) to the stock of gold that a nation holds at any point in time. So if the government wants to spend more it has to take money off the non-government sector either via taxation of bond-issuance.

However, in a fiat currency system, the mainstream analogy between the household and the government is flawed at the most elemental level. The household must work out the financing before it can spend. The household cannot spend first. The government can spend first and ultimately does not have to worry about financing such expenditure.

From a policy perspective, they believed (via the flawed Quantity Theory of Money) that “printing money” would be inflationary (even though governments do not spend by printing money anyway. So they recommended that deficits be covered by debt-issuance, which they then claimed would increase interest rates by increasing demand for scarce savings and crowd out private investment. All sorts of variations on this nonsense has appeared ranging from the moderate Keynesians (and some Post Keynesians) who claim the “financial crowding out” (via interest rate increases) is moderate to the extreme conservatives who say it is 100 per cent (that is, no output increase accompanies government spending).

So the GBC is the mainstream macroeconomics framework for analysing these “financing” choices and it says that the budget deficit in year t is equal to the change in government debt (ΔB) over year t plus the change in high powered money (ΔH) over year t. If we think of this in real terms (rather than monetary terms), the mathematical expression of this is written as:

which you can read in English as saying that Budget deficit (BD) = Government spending (G) – Tax receipts (T) + Government interest payments (rB_t-1), all in real terms.

However, this is merely an accounting statement. It has to be true if things have been added and subtracted properly in accounting for the dealings between the government and non-government sectors.

In mainstream economics, money creation is erroneously depicted as the government asking the central bank to buy treasury bonds which the central bank in return then prints money. The government then spends this money. This is called debt monetisation and we have shown in the Deficits 101 series how this conception is incorrect. Anyway, the mainstream claims that if the government is willing to increase the money growth rate it can finance a growing deficit but also inflation because there will be too much money chasing too few goods! But an economy constrained by deficient demand (defined as demand below the full employment level) responds to a nominal impulse by expanding real output not prices.

But because they believe that inflation is inevitable if “printing money” occurs, mainstream economists recommend that governments use debt issuance to “finance” their deficits. But then they scream that this will merely require higher future taxes. Why should taxes have to be increased?

Well the textbooks are full of elaborate models of debt pay-back, debt stabilisation etc which all “prove” (not!) that the legacy of past deficits is higher debt and to stabilise the debt, the government must eliminate the deficit which means it must then run a primary surplus equal to interest payments on the existing debt.

Nothing is included about the swings and roundabouts provided by the automatic stabilisers as the results of the deficits stimulate private activity and welfare spending drops and tax revenue rises automatically in line with the increased economic growth. Most orthodox models are based on the assumption of full employment anyway, which makes them nonsensical depictions of the real world.

More sophisticated mainstream analyses focus on the ratio of debt to GDP rather than the level of debt per se. They come up with the following equation – nothing that they now disregard the obvious opportunity presented to the government via ΔH. So in the following model all net public spending is covered by new debt-issuance (even though in a fiat currency system no such financing is required). Accordingly, the change in the public debt ratio is:

So the change in the debt ratio is the sum of two terms on the right-hand side: (a) the difference between the real interest rate (r) and the GDP growth rate (g) times the initial debt ratio; and (b) the ratio of the primary deficit (G-T) to GDP.

A growing economy can absorb more debt and keep the debt ratio constant. For example, if the primary deficit is zero, debt increases at a rate r but the debt ratio increases at r – g.

Thus, if we ignore the possibilities presented by the ΔH option (which is what I meant by current institutional arrangements), the proposition is true but largely irrelevant.

You may be interested in reading these blogs which have further information on this topic:

• On voluntary constraints that undermine public purpose
• Deficits 101 series
• Questions and answers 1
• Will we really pay higher taxes?
• Will we really pay higher interest rates?

Question 2:

The public debt ratio will always fall when economic growth is positive because the primary deficit falls due to the automatic stabilisers (more tax revenue, less welfare spending) and the denominator GDP rises.

The answer is False.

This answer is derived from the reasoning presented for Question 1. There are two false statements in the proposition. First, the use of the word always makes the proposition false per se. Second, the primary deficit may not fall when economic growth is positive if discretionary policy changes offset the declining net spending as tax revenue increases and welfare payments fall (the automatic stabilisation).

Using the framework developed and explained above:

We saw that a change in the change in the debt ratio is the sum of two terms on the right-hand side: (a) the difference between the real interest rate (r) and the GDP growth rate (g) times the initial debt ratio; and (b) the ratio of the primary deficit (G-T) to GDP.

As we noted a growing economy can absorb more debt and keep the debt ratio constant. For example, if the primary deficit is zero, debt increases at a rate r but the debt ratio increases at r – g.

Consider the following table which simulates two different scenarios. Case A shows a real interest rate of zero and a steadily increasing annual GDP growth rate across 10 years. The initial public debt ratio is 100 per cent (so well over the level Reinhart and Rogoff claim is the point of no return and insolvency is pending). The budget deficit is also simulated to be 5 per cent of GDP then reduces as the GDP growth induce the automatic stabilisers. It then reaches a steady 2 per cent per annum which might be sufficient to support the saving intentions of the non-government sector while still promoting steady economic growth.

You can see that the even with a continuous deficit, the public debt ratio declines steadily and would continue to do so as the growth continued. The central bank could of-course cut the nominal interest rate to speed the contraction in the debt ratio although I would not undertake that policy change for that reason.

In Case B we assume that the government stops issuing debt with everything else the same. The public debt ratio drops very quickly under this scenario.

However, should the real interest rate exceed the economic growth rate, then unless the primary budget balance offsets the rising interest payments as percent of GDP, then the public debt ratio will rise.

The only concern I would have in this situation does not relate to the rising ratio. Focusing on the cause should be the policy concern. If the real economy is faltering because interest rates are too high or more likely because the primary budget deficit is too low then the rising public debt ratio is just telling us that the central bank should drop interest rates or the treasury should increase the discretionary component of the budget.

In general though, the public debt ratio is a relatively uninteresting macroeconomic figure and should be disregarded. If the government is intent on promoting growth, then the primary deficit ratio and the public debt ratio will take care of themselves.

Question 3:

It would be impossible for the Reserve Bank of Australia to directly purchase Australian Treasury debt to facilitate the federal government’s budget deficit while still targeting its policy rate of 4.5 per cent.

The answer is Maybe.

The conditionality relates to whether the central bank decided to offer a support rate. In the Australian case, the RBA does offer a support payment on overnight reserves which is 25 basis points below the current target rate. So if this policy was maintained then the answer would be true. If the policy was revised such that the support rate was set equal to the current target rate then the answer would be false.

So what is the explanation?

The central bank conducts what are called liquidity management operations for two reasons. First, it has to ensure that all private cheques (that are funded) clear and other interbank transactions occur smoothly as part of its role of maintaining financial stability. Second, it must maintain aggregate bank reserves at a level that is consistent with its target policy setting given the relationship between the two.

So operating factors link the level of reserves to the monetary policy setting under certain circumstances. These circumstances require that the return on “excess” reserves held by the banks is below the monetary policy target rate. In addition to setting a lending rate (discount rate), the central bank also sets a support rate which is paid on commercial bank reserves held by the central bank.

Commercial banks maintain accounts with the central bank which permit reserves to be managed and also the clearing system to operate smoothly. In addition to setting a lending rate (discount rate), the central bank also can set a support rate which is paid on commercial bank reserves held by the central bank (which might be zero).

Many countries (such as Australia, Canada and zones such as the European Monetary Union) maintain a default return on surplus reserve accounts (for example, the Reserve Bank of Australia pays a default return equal to 25 basis points less than the overnight rate on surplus Exchange Settlement accounts). Other countries like Japan and the US have typically not offered a return on reserves until the onset of the current crisis.

If the support rate is zero then persistent excess liquidity in the cash system (excess reserves) will instigate dynamic forces which would drive the short-term interest rate to zero unless the government sells bonds (or raises taxes). This support rate becomes the interest-rate floor for the economy.

The short-run or operational target interest rate, which represents the current monetary policy stance, is set by the central bank between the discount and support rate. This effectively creates a corridor or a spread within which the short-term interest rates can fluctuate with liquidity variability. It is this spread that the central bank manages in its daily operations.

In most nations, commercial banks by law have to maintain positive reserve balances at the central bank, accumulated over some specified period. At the end of each day commercial banks have to appraise the status of their reserve accounts. Those that are in deficit can borrow the required funds from the central bank at the discount rate.

Alternatively banks with excess reserves are faced with earning the support rate which is below the current market rate of interest on overnight funds if they do nothing. Clearly it is profitable for banks with excess funds to lend to banks with deficits at market rates. Competition between banks with excess reserves for custom puts downward pressure on the short-term interest rate (overnight funds rate) and depending on the state of overall liquidity may drive the interbank rate down below the operational target interest rate. When the system is in surplus overall this competition would drive the rate down to the support rate.

The main instrument of this liquidity management is through open market operations, that is, buying and selling government debt. When the competitive pressures in the overnight funds market drives the interbank rate below the desired target rate, the central bank drains liquidity by selling government debt. This open market intervention therefore will result in a higher value for the overnight rate. Importantly, we characterise the debt-issuance as a monetary policy operation designed to provide interest-rate maintenance. This is in stark contrast to orthodox theory which asserts that debt-issuance is an aspect of fiscal policy and is required to finance deficit spending.

So the fundamental principles that arise in a fiat monetary system are as follows.

• The central bank sets the short-term interest rate based on its policy aspirations.
• Government spending is independent of borrowing which the latter best thought of as coming after spending.
• Government spending provides the net financial assets (bank reserves) which ultimately represent the funds used by the non-government agents to purchase the debt.
• Budget deficits put downward pressure on interest rates contrary to the myths that appear in macroeconomic textbooks about ‘crowding out’.
• The “penalty for not borrowing” is that the interest rate will fall to the bottom of the “corridor” prevailing in the country which may be zero if the central bank does not offer a return on reserves.
• Government debt-issuance is a “monetary policy” operation rather than being intrinsic to fiscal policy, although in a modern monetary paradigm the distinctions between monetary and fiscal policy as traditionally defined are moot.

Accordingly, debt is issued as an interest-maintenance strategy by the central bank. It has no correspondence with any need to fund government spending. Debt might also be issued if the government wants the private sector to have less purchasing power.

Further, the idea that governments would simply get the central bank to “monetise” treasury debt (which is seen orthodox economists as the alternative “financing” method for government spending) is highly misleading. Debt monetisation is usually referred to as a process whereby the central bank buys government bonds directly from the treasury.

In other words, the federal government borrows money from the central bank rather than the public. Debt monetisation is the process usually implied when a government is said to be printing money. Debt monetisation, all else equal, is said to increase the money supply and can lead to severe inflation.

However, as long as the central bank has a mandate to maintain a target short-term interest rate, the size of its purchases and sales of government debt are not discretionary. Once the central bank sets a short-term interest rate target, its portfolio of government securities changes only because of the transactions that are required to support the target interest rate.

The central bank’s lack of control over the quantity of reserves underscores the impossibility of debt monetisation. The central bank is unable to monetise the federal debt by purchasing government securities at will because to do so would cause the short-term target rate to fall to zero or to the support rate. If the central bank purchased securities directly from the treasury and the treasury then spent the money, its expenditures would be excess reserves in the banking system. The central bank would be forced to sell an equal amount of securities to support the target interest rate.

The central bank would act only as an intermediary. The central bank would be buying securities from the treasury and selling them to the public. No monetisation would occur.

However, the central bank may agree to pay the short-term interest rate to banks who hold excess overnight reserves. This would eliminate the need by the commercial banks to access the interbank market to get rid of any excess reserves and would allow the central bank to maintain its target interest rate without issuing debt.

The following blogs may be of further interest to you:

• Saturday Quiz – May 1, 2010 – answers and discussion
• Understanding central bank operations
• Building bank reserves will not expand credit
• Building bank reserves is not inflationary
• Deficit spending 101 – Part 1
• Deficit spending 101 – Part 2
• Deficit spending 101 – Part 3

Question 4:

One important lesson to be drawn from Modern Monetary Theory (MMT), which is overlooked in the public call for austerity programs, is that when economic growth resumes, the automatic stabilisers work in a counter-cyclical fashion and ensure that the government budget balance returns to its appropriate level.

The answer is False.

The factual statement in the proposition is that the automatic stabilisers do operate in a counter-cyclical fashion when economic growth resumes. This is because tax revenue improves given it is typically tied to income generation in some way. Further, most governments provide transfer payment relief to workers (unemployment benefits) and this increases when there is an economic slowdown.

The question is false though because this process while important may not ensure that the government budget balance returns to its appropriate level.

The automatic stabilisers just push the budget balance towards deficit, into deficit, or into a larger deficit when GDP growth declines and vice versa when GDP growth increases. These movements in aggregate demand play an important counter-cyclical attenuating role. So when GDP is declining due to falling aggregate demand, the automatic stabilisers work to add demand (falling taxes and rising welfare payments). When GDP growth is rising, the automatic stabilisers start to pull demand back as the economy adjusts (rising taxes and falling welfare payments).

We also measure the automatic stabiliser impact against some benchmark or “full capacity” or potential level of output, so that we can decompose the budget balance into that component which is due to specific discretionary fiscal policy choices made by the government and that which arises because the cycle takes the economy away from the potential level of output.

This decomposition provides (in modern terminology) the structural (discretionary) and cyclical budget balances. The budget components are adjusted to what they would be at the potential or full capacity level of output.

So if the economy is operating below capacity then tax revenue would be below its potential level and welfare spending would be above. In other words, the budget balance would be smaller at potential output relative to its current value if the economy was operating below full capacity. The adjustments would work in reverse should the economy be operating above full capacity.

If the budget is in deficit when computed at the “full employment” or potential output level, then we call this a structural deficit and it means that the overall impact of discretionary fiscal policy is expansionary irrespective of what the actual budget outcome is presently. If it is in surplus, then we have a structural surplus and it means that the overall impact of discretionary fiscal policy is contractionary irrespective of what the actual budget outcome is presently.

So you could have a downturn which drives the budget into a deficit but the underlying structural position could be contractionary (that is, a surplus). And vice versa.

The difference between the actual budget outcome and the structural component is then considered to be the cyclical budget outcome and it arises because the economy is deviating from its potential.

In some of the blogs listed below I go into the measurement issues involved in this decomposition in more detail. However for this question it these issues are less important to discuss.

The point is that structural budget balance has to be sufficient to ensure there is full employment. The only sensible reason for accepting the authority of a national government and ceding currency control to such an entity is that it can work for all of us to advance public purpose.

In this context, one of the most important elements of public purpose that the state has to maximise is employment. Once the private sector has made its spending (and saving decisions) based on its expectations of the future, the government has to render those private decisions consistent with the objective of full employment.

Given the non-government sector will typically desire to net save (accumulate financial assets in the currency of issue) over the course of a business cycle this means that there will be, on average, a spending gap over the course of the same cycle that can only be filled by the national government. There is no escaping that.

So then the national government has a choice – maintain full employment by ensuring there is no spending gap which means that the necessary deficit is defined by this political goal. It will be whatever is required to close the spending gap. However, it is also possible that the political goals may be to maintain some slack in the economy (persistent unemployment and underemployment) which means that the government deficit will be somewhat smaller and perhaps even, for a time, a budget surplus will be possible.

But the second option would introduce fiscal drag (deflationary forces) into the economy which will ultimately cause firms to reduce production and income and drive the budget outcome towards increasing deficits.

Ultimately, the spending gap is closed by the automatic stabilisers because falling national income ensures that that the leakages (saving, taxation and imports) equal the injections (investment, government spending and exports) so that the sectoral balances hold (being accounting constructs). But at that point, the economy will support lower employment levels and rising unemployment. The budget will also be in deficit – but in this situation, the deficits will be what I call “bad” deficits. Deficits driven by a declining economy and rising unemployment.

So fiscal sustainability requires that the government fills the spending gap with “good” deficits at levels of economic activity consistent with full employment – which I define as 2 per cent unemployment and zero underemployment.

Fiscal sustainability cannot be defined independently of full employment. Once the link between full employment and the conduct of fiscal policy is abandoned, we are effectively admitting that we do not want government to take responsibility of full employment (and the equity advantages that accompany that end).

So it will not always be the case that the dynamics of the automatic stabilisers will leave a structural deficit sufficient to finance the saving desire of the non-government sector at an output level consistent with full utilisation of resources.

The following blogs may be of further interest to you:

• A modern monetary theory lullaby
• Saturday Quiz – April 24, 2010 – answers and discussion
• The dreaded NAIRU is still about!
• Structural deficits – the great con job!
• Structural deficits and automatic stabilisers
• Another economics department to close

Question 5:

The money multiplier concept suggests that changes in the monetary base are transmitted by commercial bank lending in multiplied changes in the money supply. The fact is that in a modern monetary economy the monetary base adjusts to the changes in the money supply.

The answer is True.

Mainstream macroeconomics textbooks are completely wrong when they discuss the credit-creation capacity of commercial banks. They star act is the concept of the money multiplier.

They posit that the multiplier m transmits changes in the so-called monetary base (MB) (the sum of bank reserves and currency at issue) into changes in the money supply (M). The chapters on money usually present some arcane algebra which is deliberately designed to impart a sense of gravitas or authority to the students who then mindlessly ape what is in the textbook.

They rehearse several times in their undergraduate courses (introductory and intermediate macroeconomics; money and banking; monetary economics etc) the mantra that the money multiplier is usually expressed as the inverse of the required reserve ratio plus some other novelties relating to preferences for cash versus deposits by the public.

Accordingly, the students learn that if the central bank told private banks that they had to keep 10 per cent of total deposits as reserves then the required reserve ratio (RRR) would be 0.10 and m would equal 1/0.10 = 10. More complicated formulae are derived when you consider that people also will want to hold some of their deposits as cash. But these complications do not add anything to the story.

The formula for the determination of the money supply is: M = m x MB. So if a $1 is newly deposited in a bank, the money supply will rise (be multiplied) by $10 (if the RRR = 0.10). The way this multiplier is alleged to work is explained as follows (assuming the bank is required to hold 10 per cent of all deposits as reserves):

• A person deposits say $100 in a bank.
• To make money, the bank then loans the remaining $90 to a customer.
• They spend the money and the recipient of the funds deposits it with their bank.
• That bank then lends 0.9 times $90 = $81 (keeping 0.10 in reserve as required).
• And so on until the loans become so small that they dissolve to zero

None of this is remotely accurate in terms of depicting how the banks make loans. It is an important device for the mainstream because it implies that banks take deposits to get funds which they can then on-lend. But prudential regulations require they keep a little in reserve. So we get this credit creation process ballooning out due to the fractional reserve requirements.

The money multiplier myth also leads students to think that as the central bank can control the monetary base then it can control the money supply. Further, given that inflation is allegedly the result of the money supply growing too fast then the blame is sheeted home to the “government”. This leads to claims that if the government runs a budget deficit then it has to issue bonds to avoid causing hyperinflation. Nothing could be further from the truth.

That is nothing like the way the banking system operates in the real world. The idea that the monetary base (the sum of bank reserves and currency) leads to a change in the money supply via some multiple is not a valid representation of the way the monetary system operates.

First, the central bank does not have the capacity to control the money supply in a modern monetary system. In the world we live in, bank loans create deposits and are made without reference to the reserve positions of the banks. The bank then ensures its reserve positions are legally compliant as a separate process knowing that it can always get the reserves from the central bank. The only way that the central bank can influence credit creation in this setting is via the price of the reserves it provides on demand to the commercial banks.

Second, this suggests that the decisions by banks to lend may be influenced by the price of reserves rather than whether they have sufficient reserves. They can always get the reserves that are required at any point in time at a price, which may be prohibitive.

Third, the money multiplier story has the central bank manipulating the money supply via open market operations. So they would argue that the central bank might buy bonds to the public to increase the money base and then allow the fractional reserve system to expand the money supply. But a moment’s thought will lead you to conclude this would be futile unless (as in Question 3 a support rate on excess reserves equal to the current policy rate was being paid).

Why? The open market purchase would increase bank reserves and the commercial banks, in lieu of any market return on the overnight funds, would try to place them in the interbank market. Of-course, any transactions at this level (they are horizontal) net to zero so all that happens is that the excess reserve position of the system is shuffled between banks. But in the process the interbank return would start to fall and if the process was left to resolve, the overnight rate would fall to zero and the central bank would lose control of its monetary policy position (unless it was targetting a zero interest rate).

In lieu of a support rate equal to the target rate, the central bank would have to sell bonds to drain the excess reserves. The same futility would occur if the central bank attempted to reduce the money supply by instigating an open market sale of bonds.

In all cases, the central bank cannot influence the money supply in this way.

Fourth, given that the central bank adds reserves on demand to maintain financial stability and this process is driven by changes in the money supply as banks make loans which create deposits.

So the operational reality is that the dynamics of the monetary base (MB) are driven by the changes in the money supply which is exactly the reverse of the causality presented by the monetary multiplier.

So in fact we might write MB = M/m.

You might like to read these blogs for further information:

• Teaching macroeconomics students the facts
• Lost in a macroeconomics textbook again
• Lending is capital- not reserve-constrained
• Oh no … Bernanke is loose and those greenbacks are everywhere
• Building bank reserves will not expand credit
• Building bank reserves is not inflationary
• 100-percent reserve banking and state banks
• Money multiplier and other myths