IBE303 Lecture 10

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Lecture 10September 13th, 2010

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Economic Policy in the Open Economy Under Fixed Exchange Rates

Targets, Instruments, and Policy: A Model•“External balance”

▫Any decrease in the interest rate (e.g., because of expansionary monetary policy) will cause a decrease in short-term capital inflows or an increase in short-term capital outflows and a BOP deficit.

▫Expansionary fiscal policy (by increasing Y and M) also leads to a BOP deficit.

•“Internal balance”▫Expansionary monetary policy lowers

interest rates and increases I; this will be inflationary unless fiscal policy offsets it.

Targets, Instruments, and Policy: A Model•Recalled , there are four situations when

there are internal and external imbalances:▫Case I: BOP deficit; unacceptably rapid

inflation,▫Case II: BOP surplus; unacceptably high

unemployment,▫Case III: BOP deficit; unacceptably high

unemployment, and▫Case IV: BOP surplus; unacceptably rapid

inflation.

The Mundell-Fleming Diagram

External Balance

Internal Balance

IIITo achieve internal and external balance, fiscal and monetary policy must both be used.

General Equilibrium in the Open Economy: the IS/LM/BP Model

▫To understand the effects of policies on the open economy, we need to use a general equilibrium model.

▫The IS/LM/BP model is built around three sorts of equilibria: money market equilibrium (the LM curve), real sector equilibrium (the IS curve), and BOP equilibrium (the BP curve).

Money Market Equilibrium

Money Market Equilibrium: the LM Curve•The LM curve comprises all combinations

of the interest rate (i) and income (Y) such that money supply and money demand are equal.

Money Market Equilibrium: the LM Curve

▫Money supply is assumed to equal money demand.

▫Money supply is fixed.▫Money demand depends inversely on the

interest rate (i) and positively on income (Y). As interest rates rise, the opportunity cost of

holding money rises, and so the quantity demanded of money decreases.

As income rises demand for money increases.

L = f(i,Y)

At i1, Ms>Md: people will buy bonds, reducing i.

At i2, Ms<Md: people will sell bonds, increasing i.

▫If income rises, money demand will exceed money supply,

and interest rates will rise.▫Therefore, the LM curve is the positive

relationship between the interest rate and income (Y).

▫Points to the left of the LM curve mean there is an excess supply of money; points to the right imply an excess demand.

▫Increases in Ms or decreases in Md will shift LM to the right.

▫Decreases in Ms or increases in Md will shift LM to the left.

income

Real Sector Equilibrium

Real Sector Equilibrium: the IS Curve

•The IS curve comprises all combinations of the interest rate (i) and income (Y) such that the real sector of the economy is in equilibrium.

▫Investment should depend inversely on the interest rate (i). As interest rates rise, the cost of borrowing

rises, so I falls.▫As before, consumption (C) depends

positively on income (Y).▫Also, exports (X) and government spending

(G) are fixed.

▫The IS curve is the relationship between the interest rate and Y. As the interest rate falls, investment

increases, thereby increasing Y. As the interest rate rises, investment

decreases, thereby decreasing Y.▫Therefore, the IS curve is downward-

sloping.

▫Increases in autonomous I, X, G or decreases in T will shift IS to the right.

▫Decreases in autonomous I, X, G or increases in T will shift IS to the left.

income

Balance Of Payment Equilibrium

BOP Equilibrium: the BP Curve•The BP curve comprises all combinations

of the interest rate (i) and income (Y) such that the balance of payments is in equilibrium.

BOP Equilibrium: the BP Curve▫The BP curve is the relationship between

the interest rate and Y. If Y increases and i is unchanged

M will increase BOP deficit will open.

To return to BOP balance, i must rise. This would trigger net short-term capital inflows.

▫Therefore, the BP curve is upward- sloping.

BOP Equilibrium: the BP Curve▫Points to the left of the BP curve imply a

BOP surplus.▫Points to the right of the BP curve imply a

BOP deficit.

income

BPBOP deficit

BOP surplus

BOP Equilibrium: the Slope of the BP Curve

▫The slope of the BP curve depends on how responsive short-term private capital flows are to changes in the interest rate.

▫Points to the right of the BP curve represent BOP deficits, triggering an increase in i, which would cause in increase in capital inflows.

▫If capital inflows are very responsive, a small Δi will bring us back to BOP equilibrium (that is, a relatively flat BP curve).

▫The typical upward slope of the BP curve results from impediments to capital flows or when the country is large enough to influence international interest rates.

▫The upward-sloping BP represents “imperfect capital mobility.”

▫Capital could be perfectly mobile.▫This would occur if any deviation of the

domestic i away from the international rate immediately triggered capital flows that brought interest rates back in line.

▫When capital is perfectly mobile, the BP curve is a horizontal line.

▫Capital could be perfectly immobile.▫If a country fixes its exchange rate, it

typically maintains strict foreign exchange controls.

▫When capital is perfectly immobile, the BP curve is a vertical line.

BOP Equilibrium: the BP Curve▫A depreciation of the home currency, an

autonomous increase in exports, or an autonomous decrease in imports will shift BP to the right.

▫An appreciation of the home currency, an autonomous decrease in exports, or an autonomous increase in imports will shift BP to the left.

income

Equilibrium in the Open Economy

income

Only at point E is the economy in full equilibrium.

Equilibrium in the Open Economy: Adjustments

▫Suppose exchange rates are fixed.▫How does the system adjust to a “shock”

such as an increase in foreign income? This should increase exports Shifting BP rightwards to BP′.

income

▫The IS curve will shift rightwards to IS′.

income

▫The IS curve will shift rightwards to IS′.▫To maintain the fixed exchange rate, the

central bank must purchase the surplus foreign currency; this shifts LM rightwards to LM′.

▫Eventually, a new equilibrium is reached at E''.

income

Fiscal Policy Under Fixed Exchange Rate

Fiscal Policy Under Fixed Exchange Rates

▫With perfect capital immobility Fiscal stimulus initially increases Y and M

(and also i) Because capital is immobile, a BOP deficit

emerges,

income

Perfect capital immobility

▫With perfect capital immobility Fiscal stimulus initially increases Y and M

(and also i) Because capital is immobile, a BOP deficit

emerges, Decreasing the money supply Increasing i further.

▫In the end, Y returns to its original level The fiscal stimulus completely crowds out

domestic investment (I).

income

▫With perfect capital mobility, any fiscal stimulus increases Y and M i does not rise due to capital inflows.

income

Perfect capital mobility

▫With perfect capital mobility, any fiscal stimulus increases Y and M i does not rise due to capital inflows.

▫To maintain the fixed exchange rate, the central bank must increase the domestic money supply.

▫In the end, Y rises, but i stays the same.

income

▫The bottom line: When capital is relatively mobile,

Fiscal policy is more effective at increasing national income.

When capital is relatively immobile Fiscal policy is less effective at increasing

national income.

Monetary Policy Under Fixed Exchange Rates

▫With perfect capital immobility Monetary stimulus initially increases Y and M

(and lowers i) Because capital is immobile, a BOP deficit

emerges.▫The central bank must sell foreign

exchange (decreasing the money supply) to maintain the fixed exchange rate.

▫In the end, the LM curve returns to its original place The monetary stimulus doesn’t change Y.

income

▫With perfect capital mobility Monetary stimulus increases Y and M But i does not fall due to capital inflows.

▫Again, to maintain the fixed exchange rate, the central bank must decrease the domestic money supply.

▫In the end, the LM curve returns to its original place The monetary stimulus doesn’t change Y.

income

▫The bottom line: When capital is relatively mobile

Monetary policy is ineffective at increasing national income.

When capital is relatively immobile Monetary policy is ineffective at increasing

national income.▫Maintaining a fixed exchange rate system

means losing monetary policy as an effective tool.

Effects of Official Changes in the Exchange Rate System

▫To maintain a fixed exchange rate system, A country would not want to devalue or

revalue the currency often.▫However, such policy actions are

occasionally required: what will be the effects?

▫If the home country’s exchange rate is devalued Exports rise and imports fall.

▫This shifts both the IS and BP curves rightward.

▫The money supply must be expanded Central bank must buy foreign exchange.

▫This means the LM curve also shifts rightward.

▫The devaluation increases Y.

▫The bottom line: When capital is relatively immobile

Devaluation increases national income. When capital is relatively mobile

Devaluation increases national income to an even greater extent.

IBE303 Lecture 10

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