Monetary Policy and Bank Regulation

This is Unit Twelve of Principles of Macroeconomics, part two of two. Part one built the institution and its tools. This part asks what happens when those tools reach their limits. Carry the unit's idea to its payoff. Contractionary policy always bites and expansionary policy may not, and that asymmetry is the most useful single thing in this unit. Draining reserves forces lending down, because a bank short of them has to act. Adding reserves only offers the chance to lend, and a bank may decline it. By the end you will trace a policy along the transmission chain, identify the right action against inflation and say why each alternative fails, compute velocity and solve the equation of exchange, compute a real rate at the zero lower bound, and say how the two regimes differ.

Three entries on what a central bank does with no room left to cut, and the chain its actions travel along.

With no room to cut.

MAC 1125 Quantitative Easing

When short-term rates reach zero there is no room to cut, so the central bank buys long-term bonds and mortgage-backed securities instead, which is quantitative easing. Central bank assets rose from about four trillion dollars in February twenty twenty to over eight trillion by late twenty twenty-one. Its effectiveness is disputed, and the anchor rates later rounds below the first.

How any of this reaches output.

MAC 1126 The Transmission Chain

Monetary policy reaches the economy along one chain: central bank action, then reserves or the rate paid on them, then the federal funds rate, then investment and durable consumption, then aggregate demand, then real GDP and the price level. Every link is a place the chain can weaken. Net exports belong in it too, through the exchange rate.

Tracing one all the way.

MAC 1127 Tracing a Policy Through to Output and Prices

Take one action and follow it to the end of the chain, naming the direction at every link, because most errors happen at a middle link and a skipped link cannot be checked. The economy sits in a recessionary gap, so the central bank buys bonds. Reserves rise. The federal funds rate falls and other rates follow it down. Cheaper borrowing raises investment and purchases of durable goods. The lower rate also makes domestic assets less attractive, so the currency falls and net exports rise. Aggregate demand shifts right by the multiplier times those initial changes, and with the economy below potential, output rises and the price level rises a little. Contract instead and every link reverses. How much of the movement lands on output and how much on the price level depends on where the economy sits against potential, which is unit eight's zones: monetary policy shifts aggregate demand, and does not by itself decide what that shift produces.

Two entries naming the two stances, and working the case the exam asks most often.

Naming the two stances.

MAC 1128 Expansionary and Contractionary Stances

Expansionary policy, also called loose, adds reserves and lowers rates to shift aggregate demand right. Contractionary policy, also called tight, does the reverse to hold down inflation, and policy should lean against the cycle. The same tool serves both, and only the direction changes. Whether a central bank should target inflation alone or weigh unemployment too is disputed and unsettled.

The exam's version of that choice.

MAC 1129 Fighting Inflation: Which Action

Given inflation as the problem, identify the correct action and say why each alternative fails. The rule is short: fighting inflation means contracting, and contracting means reducing the money supply. Test every option by asking which way it moves aggregate demand. Reducing the money supply is contractionary and correct. Buying bonds adds reserves and is expansionary, so it worsens inflation. Lowering the discount rate encourages borrowing and is expansionary. Lowering the required reserve ratio would leave banks more to lend and is expansionary, and that ratio has stood at zero since March twenty twenty, so the option names a lever already at its limit. Three of the four alternatives fail for the same reason. Sorting by direction beats memorising a list, because the exam can name a tool in either direction: ask what the action does to reserves or to their price, then to the federal funds rate, then which way aggregate demand shifts.

Four entries linking money to prices, and saying where that link holds and where it does not.

The equation that links them.

MAC 1130 Velocity and the Equation of Exchange

Velocity is how many times the money supply is spent in a period: nominal GDP divided by the money supply. Rearranged, money times velocity equals the price level times real output — M times V equals P times Y, where Y is real output. The anchor writes that last term as Q. It is the same quantity under a different letter.

Computing with it.

MAC 1131 Computing Velocity and Solving the Equation

Compute velocity from the data, then solve the equation for a missing term. It holds by definition, so it can be rearranged freely, but the units must survive the rearrangement: real output is a quantity of goods, not a sum of money. Take a money supply of ten thousand billion, a price level of one point two five and real output of sixteen thousand billion in base-year terms. Nominal GDP is twenty thousand billion, so velocity is two — the money supply was spent twice. Now hold velocity at two and the money supply at ten thousand, and let the price level rise to one point three. Real output is twenty thousand divided by one point three, about fifteen thousand three hundred and eighty-five billion in base-year terms. That answer is a quantity of output in base-year dollars, not a sum of current money, and the difference from sixteen thousand is a fall in real output of about six hundred and fifteen billion in those terms. The anchor's own worked version solves for real output and then reports the change as plain dollars, which loses the distinction unit three spent a whole unit building.

What it says over long periods.

MAC 1132 The Quantity Theory in the Long Run

In growth rates, money growth plus velocity growth equals inflation plus output growth. With velocity stable over long periods and output at potential, inflation equals money growth minus potential output growth. This is unit ten's long-run result, now derived rather than asserted. The relationship holds best where inflation is high, and loosely below ten percent.

Why it fails over short periods.

MAC 1133 Why Velocity Is Not Stable in the Short Run

Velocity is the reciprocal of how much money people hold relative to income, so anything that shifts money demand shifts velocity: interest rates, expected inflation and transfer costs all move it. Expecting inflation, people hold money more briefly, so velocity rises. A rise in the money supply therefore need not raise nominal GDP by the same percentage.

One entry on the rate that matters when prices fall, and why falling prices tighten policy.

The rate that matters when prices fall.

MAC 1134 Real Rates and the Zero Lower Bound

Compute the real interest rate from the nominal rate and inflation, then apply it to deflation. Unit six gave the relationship: the real rate is the nominal rate minus inflation. A nominal rate of three percent with inflation of one percent gives a real rate of two percent, and cutting the nominal rate to one percent brings the real rate to zero, which is stimulative. Now let prices fall by two percent a year with the nominal rate already at zero. The real rate is zero minus negative two, which is positive two percent: the central bank has cut as far as it can and the real rate has risen, so holding cash earns two percent in real terms for doing nothing. This is the zero lower bound, and it inverts the usual picture — the more prices fall, the tighter policy becomes, however loose it looks. Nominal rates stop at zero because nobody lends ten dollars to get back less than ten. Deflation is not automatically catastrophic, and the United States grew through a long deflation in the late nineteenth century, but deflation with a nominal rate already at zero disables the main tool.

Two entries to close the unit: why expansion can fail where contraction cannot, and the two regimes held at once.

Why expansion can fail.

MAC 1135 Why Expansionary Monetary Policy Can Fail

Here the unit's governing idea is at work. Contractionary policy always bites and expansionary policy may not, and the asymmetry is the unit's most useful single lesson. Draining reserves forces lending down, because a bank short of required or desired reserves must act. Adding reserves only offers the chance to lend, and a bank may decline. The old description is that contraction is pulling on a rope while expansion is pushing on a string: pull and the far end follows, push and the rope buckles. There are four routes to failure and they can operate together. Lags, with monetary policy's own impact lag running from about six months to two years, so a remedy can arrive after the problem has passed. Excess reserves, which banks hold more of in recessions, exactly when lending is wanted, and paying interest on reserves gives them a further reason. The zero lower bound, where the nominal rate cannot fall and deflation raises the real rate anyway. And unstable velocity, so a given increase in money need not raise spending. Put all four together: a central bank cuts to near zero, buys bonds heavily, reserves rise, but firms are pessimistic and do not borrow while banks prefer to hold. Lending barely moves, so the money supply barely moves. Households expecting further price falls delay purchases, so velocity falls. Prices drift down, raising the real rate while the nominal sits at zero. Every link in the chain is intact and each transmits almost nothing. Three cautions. This is about what monetary policy alone can do, and it is a standard reason for combining it with fiscal policy, which is unit fourteen's subject rather than a verdict here. Central banks responded with quantitative easing and by extending credit more widely, and the evidence is genuinely mixed. And none of this shows expansionary policy never works: its effect depends on conditions the central bank does not control.

The two regimes held at once.

MAC 1136 Two Regimes, One Institution

This unit has taught two accounts of how a central bank works, and they are not a contradiction. In the limited-reserves regime, reserves are scarce and earn nothing: the central bank changes their quantity, banks shed any excess because holding it is costly, lending expands or contracts, and unit eleven's money multiplier describes the result. In the ample-reserves regime, reserves are abundant and they pay interest: changing their quantity by a little does nothing, because there is already far more than banks need, and a bank has no reason to shed reserves that earn a return. So the central bank sets the rate it pays on reserves, and the federal funds rate tracks it. The first steers a quantity, the second a price. What changed was not the theory but the conditions it assumed, and it changed for a reason — reserves grew from about fifteen billion dollars in two thousand and seven to trillions, and interest began to be paid on them in two thousand and eight. Take the same action under both. The central bank buys two hundred of bonds from unit eleven's bank. Under limited reserves, reserves rise above the level the bank wants, and because they earn nothing it lends the excess, so loans and deposits rise and the money supply expands by a multiple. Under ample reserves, the bank already held far more than it needed and the reserves pay the policy rate, so it may keep them and loans need not move at all. The identical transaction gives a multiplied expansion in one regime and possibly nothing in the other. Three cautions. The limited-reserves model is still examinable, so learn it, and learn it labelled. With the required ratio at zero, one divided by the ratio has no finite value, which signals that the binding constraints are now a bank's capital, its risk judgement, and what it is paid to hold reserves. And regimes change again, so what to carry forward is the habit of asking what a model assumes about scarcity and about what an asset earns.

Look at what you can now do. You can trace a policy along the transmission chain, naming the direction at every link rather than skipping to the end. You can identify the right action against inflation, and say why each alternative fails by sorting on direction. You can compute velocity and solve the equation of exchange, keeping real output as a quantity of goods rather than a sum of money. You can compute a real rate at the zero lower bound, and say why falling prices tighten policy however loose it looks. And you can say why expansion can fail where contraction cannot, and what separates the two regimes. Unit thirteen turns to the price of one currency in another.