Macroeconomics in an Open Economy: Study Notes (Chapter 18)

Macroeconomics in an Open Economy

Introduction

This chapter explores how macroeconomic linkages between countries affect trade, investment, and policy outcomes. It covers the balance of payments, foreign exchange markets, exchange rate systems, and the impact of government policies in an open economy.

18.1 The Balance of Payments: Linking the United States to the International Economy

Open and Closed Economies

• Open economy: A country that interacts in trade or finance with other countries.

• Closed economy: No interactions in trade or finance with other countries (rare in practice).

• Most modern economies are open to some degree.

Balance of Payments (BoP)

The balance of payments is a record of a country's transactions with other countries in goods, services, and assets. It consists of three main accounts:

• Current account: Records net exports, net income on investments, and net transfers.

• Financial account: Records purchases of assets abroad and foreign purchases of domestic assets.

• Capital account: Records minor transactions such as migrants' transfers and sales/purchases of nonproduced, nonfinancial assets.

Table: U.S. Balance of Payments, 2020 (Billions of Dollars)

Account	Major Items	2020 Value (Billions)
Current Account	Exports of goods	1,429
	Imports of goods	-2,407
	Balance on goods	-978
	Exports of services	697
	Imports of services	-460
	Balance on services	237
	Net income on investments	149
	Net transfers	-141
	Balance on current account	-471
Financial Account	Increase in foreign holdings of U.S. assets	1,565
	Increase in U.S. holdings of foreign assets	-841
	Balance on financial account	741
Capital Account	Balance on capital account	-5
Statistical Discrepancy		-252
Total Balance of Payments		0

Why Is the Balance of Payments Always Zero?

• The sum of the current account, financial account, and capital account balances must be zero.

• If a country spends more on foreign goods/services than it receives, the difference is offset by financial flows (e.g., foreigners buying domestic assets).

18.2 The Foreign Exchange Market and Exchange Rates

Exchange Rates

• Nominal exchange rate: The value of one country's currency in terms of another's.

• Real exchange rate: Adjusts the nominal rate for differences in price levels between countries.

Formula:

$ext{Real exchange rate} = ext{Nominal exchange rate} imes rac{ ext{Domestic price level}}{ ext{Foreign price level}}$

Foreign Exchange Market Equilibrium

• Exchange rates are determined by supply and demand for currencies.

• Demand for $US: Foreigners buying U.S. goods/services or investing in U.S. assets.

• Supply of $US: Americans buying foreign goods/services or investing abroad.

• Equilibrium occurs where quantity supplied equals quantity demanded.

Shifts in Demand and Supply

• Factors shifting demand/supply curves include:

  • Relative demand for goods/services

  • Relative investment opportunities

  • Expectations about future currency values

• Example: Rising U.S. incomes increase demand for imports, shifting supply of $US right.

• Higher U.S. interest rates increase demand for $US, causing appreciation.

Currency Speculation

• Speculators buy/sell currencies to profit from expected changes in exchange rates.

• Speculation can increase volatility in currency markets.

• Example: Forward contracts to buy currency at a future date.

Exchange Rates, Imports, and Exports

• When $US appreciates:

  • U.S. exports become more expensive for foreigners (exports fall).

  • Imports become cheaper for Americans (imports rise).

  • Net exports decrease, reducing aggregate demand and real GDP.

• Example: If $1 = €1, a $200 iPhone costs €200. If $1 = €1.20, it costs €240 in Europe.

Real Exchange Rates

• Measures the price of domestic goods in terms of foreign goods.

• Formula: $ext{Real exchange rate} = ext{Nominal exchange rate} imes rac{ ext{Domestic price level}}{ ext{Foreign price level}}$

• Example: If $1 = £1, U.S. and UK price levels = 100, real exchange rate = 1 pound/dollar.

• If $US appreciates to $1 = £1.10 and U.S. price level rises to 105, real exchange rate = 1.1 × (105/100) = 1.16.

Purchasing Power Parity (PPP)

• In the long run, exchange rates should equalize the purchasing power of different currencies.

• PPP theory: Arbitrage opportunities (buying goods where cheaper, selling where expensive) should drive exchange rates toward parity.

• Limitations: Not all goods/services are tradable, consumer preferences differ, and trade barriers exist.

• Example: The Big Mac Index compares prices of Big Macs across countries as a lighthearted measure of PPP.

18.3 Exchange Rate Systems

Types of Exchange Rate Systems

• Floating exchange rate: Currency value determined by market forces (demand and supply).

• Managed float: Currency value mostly determined by market, but with occasional government intervention.

• Fixed exchange rate: Currency value set and maintained by government policy.

The Gold Standard and Bretton Woods System

• Gold standard: Currencies redeemable for fixed amounts of gold; exchange rates fixed by gold content.

• Bretton Woods system: Post-WWII system fixing exchange rates to the U.S. dollar, which was convertible to gold.

• System collapsed in the 1970s due to inability to maintain fixed rates and dollar convertibility.

The Euro and Pegging

• European countries adopted the euro to facilitate trade and economic integration.

• Some developing countries peg their currencies to the dollar or another major currency for stability.

• Advantages of pegging: Easier planning, credibility in fighting inflation.

• Disadvantages: Difficulty maintaining the peg, risk of destabilizing speculation, loss of independent monetary policy.

18.4 The International Sector and National Saving and Investment

Saving and Investment Equation

• When a country's spending exceeds its income, it finances the difference by selling assets or borrowing.

• Key identity: $ext{Current account balance} = - ext{Financial account balance}$ $ext{Net exports} = ext{Net foreign investment}$

• National saving: Sum of private and public saving.

• Formulas: $S = S_{private} + S_{public}$ $S_{private} = Y - C - T$ $S_{public} = T - G$

• Saving and investment equation: $S = I + NFI$ where $NFI$ is net foreign investment.

18.5 The Effect of a Government Budget Deficit on Investment

Government Budget Deficits and Investment

• Budget deficits reduce national saving.

• Lower saving leads to reduced domestic investment and/or net foreign investment.

• Deficits are often financed by selling government bonds, which can raise interest rates.

• Higher interest rates discourage private investment and attract foreign capital, causing currency appreciation and reduced net exports.

• Twin deficits: Simultaneous government budget and current account deficits.

18.6 Monetary Policy and Fiscal Policy in an Open Economy

Monetary Policy

• Expansionary monetary policy (lower interest rates) increases investment and consumption in both closed and open economies.

• In open economies, lower interest rates also depreciate the currency, boosting net exports and aggregate demand.

• Monetary policy is generally more effective in open economies due to this additional channel.

Fiscal Policy

• Expansionary fiscal policy (tax cuts or increased government spending) raises aggregate demand.

• May lead to higher interest rates, currency appreciation, and reduced net exports.

• Multiplier effect is lower in open economies, as some spending leaks to imports.

• Fiscal policy is less effective in open economies compared to closed economies.

Online Appendix: The Gold Standard and the Bretton Woods System

The Gold Standard

• Under the gold standard, coins and currency could be redeemed for gold at a fixed rate.

• Exchange rates were determined by the gold content of each currency.

• The system collapsed in the 1930s due to the Great Depression and excessive money printing.

The Bretton Woods System

• Established fixed exchange rates to the U.S. dollar, which was convertible to gold.

• Central banks held U.S. dollar reserves and could borrow from the IMF.

• System ended in the early 1970s due to inability to maintain fixed rates and dollar convertibility.

Table: Comparison of Exchange Rate Systems

System	How Rates Are Set	Advantages	Disadvantages
Floating	Market forces	Flexibility, automatic adjustment	Volatility
Fixed	Government policy	Stability, predictability	Risk of crises, loss of policy autonomy
Managed float	Market + intervention	Balance of flexibility and stability	Potential for uncertainty

Key Terms

• Balance of payments (BoP): Record of all economic transactions between residents of a country and the rest of the world.

• Current account: Net exports, net income on investments, net transfers.

• Financial account: Net capital flows (purchases of assets).

• Capital account: Minor transactions (e.g., migrants' transfers).

• Exchange rate: Price of one currency in terms of another.

• Purchasing power parity (PPP): Theory that exchange rates adjust to equalize the purchasing power of currencies.

• Net foreign investment (NFI): Difference between capital outflows and inflows.

• Managed float: Exchange rate system with market determination and occasional government intervention.

• Pegging: Fixing a currency's value to another currency.

Summary

This chapter provides a comprehensive overview of how open economies interact through trade, investment, and policy. Understanding the balance of payments, exchange rate determination, and the effects of government policies is essential for analyzing macroeconomic outcomes in a global context.