Macroeconomics in an Open Economy: Study Notes

Macroeconomics in an Open Economy

Introduction

This chapter explores how economies interact through trade and financial flows, focusing on the balance of payments, exchange rates, and the implications for macroeconomic policy. Understanding these linkages is essential for analyzing the effects of globalization and international events on national economies.

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

Definition and Structure

• Balance of Payments (BoP): A comprehensive record of a country's economic transactions with the rest of the world, including trade in goods and services, and financial flows.

• Current Account: Records net exports (exports minus imports), net income on investments, and net transfers.

• Financial Account: Records purchases of assets abroad and foreign purchases of domestic assets. Includes foreign portfolio investment (financial assets like stocks and bonds) and foreign direct investment (physical assets like factories).

• Capital Account: Records minor transactions such as migrants’ transfers and sales/purchases of nonproduced, nonfinancial assets (e.g., intellectual property).

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

Account	Component	Value
Current Account	Balance on current account	-971
Financial Account	Balance on financial account	741
Capital Account	Balance on capital account	-5
Statistical Discrepancy		252
Balance of payments		0

Additional info: The sum of the current, financial, and capital accounts (plus statistical discrepancy) must be zero, reflecting the double-entry nature of the BoP.

Open and Closed Economies

• Open Economy: Engages in international trade and financial transactions.

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

Trade Balance and Net Exports

• Trade Balance: Difference between the value of exports and imports of goods.

• Net Exports: Sum of the trade balance and the balance of services (exports minus imports of services).

• Net Income on Investments and Net Transfers are typically small for the U.S. and often omitted in simplified analysis.

Net Foreign Investment

• Net Foreign Investment (NFI): The difference between capital outflows and inflows; also equal to net foreign direct investment plus net foreign portfolio investment.

Why Is the Balance of Payments Always Zero?

• The sum of the current account, financial account, and capital account balances must be zero due to double-entry bookkeeping.

• If a country runs a current account deficit, it must be financed by a surplus in the financial account (e.g., by selling assets or borrowing).

The Foreign Exchange Market and Exchange Rates

Exchange Rate Concepts

• Nominal Exchange Rate: The value of one country’s currency in terms of another’s (e.g., $1 = ¥100).

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

Formula:

$\text{Real exchange rate} = \text{Nominal exchange rate} \times \frac{\text{Domestic price level}}{\text{Foreign price level}}$

Determination of Exchange Rates

• Exchange rates are determined by supply and demand in the foreign exchange market.

• Demand for U.S. dollars ($US): Comes from foreigners wanting to buy U.S. goods/services or invest in U.S. assets.

• Supply of $US: Comes from Americans wanting to buy foreign goods/services or invest abroad.

• The equilibrium exchange rate is where the quantity supplied equals the quantity demanded.

Shifts in Demand and Supply

• Factors shifting demand/supply include:

  • Changes in demand for domestic vs. foreign goods/services

  • Changes in investment attractiveness (interest rates)

  • Expectations about future currency values

Currency Speculation

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

• Speculation can increase volatility in exchange rates.

Exchange Rates, Imports, and Exports

• When the domestic currency appreciates:

  • Imports become cheaper

  • Exports become more expensive for foreigners

  • Net exports and aggregate demand decrease

• When the domestic currency depreciates, the opposite occurs.

Real Exchange Rates: Example

• Suppose $1 = £1$, U.S. and U.K. price levels are both 100:

$\text{Real exchange rate} = 1 \times \frac{100}{100} = 1$

• If $1 = £1.10$ and U.S. price level rises to 105:

$\text{Real exchange rate} = 1.1 \times \frac{105}{100} = 1.16$

This means U.S. goods are now 16% more expensive relative to British goods.

Purchasing Power Parity (PPP)

• Over the long run, exchange rates should adjust to equalize the purchasing power of different currencies.

• PPP is limited by non-tradable goods, differences in preferences, and trade barriers.

Example: If a candy bar costs £2 in the UK and $1 in the U.S., and the exchange rate is £1 = $1, arbitrage would occur until the exchange rate adjusts to reflect equal purchasing power.

Exchange Rate Systems

Types of Exchange Rate Systems

• Floating Exchange Rate: Determined by market forces (demand and supply).

• Fixed Exchange Rate: Government sets and maintains a specific exchange rate.

• Managed Float: Mostly market-determined, but with occasional government intervention.

Historical Systems

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

• Bretton Woods System: Post-WWII system where currencies were fixed to the U.S. dollar, which was convertible to gold.

The Euro and Pegging

• Many European countries adopted the euro, fixing exchange rates among themselves.

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

• Pegging can aid planning and credibility but limits monetary policy independence and can invite speculation.

The International Sector and National Saving and Investment

Saving and Investment Equation

• National Saving (S): The sum of private and public saving.

• Private Saving: $S_{private} = Y - C - T$

• Public Saving: $S_{public} = T - G$

• National Saving: $S = S_{private} + S_{public}$

• Saving and Investment Equation:

$S = I + NFI$

• Where $I$ is domestic investment and $NFI$ is net foreign investment (equal to net exports).

The Effect of a Government Budget Deficit on Investment

Budget Deficits and the Twin Deficits

• A government budget deficit reduces national saving.

• By the saving and investment equation, either domestic investment or net foreign investment (net exports) must fall.

• Higher interest rates from government borrowing can crowd out private investment and cause currency appreciation, reducing net exports.

• Twin Deficits: When a budget deficit is accompanied by a current account deficit.

Monetary Policy and Fiscal Policy in an Open Economy

Policy Effectiveness

• Monetary Policy: More effective in an open economy because lower interest rates can also depreciate the currency, boosting net exports and aggregate demand.

• Fiscal Policy: Less effective in an open economy because higher interest rates can appreciate the currency, reducing net exports and dampening the multiplier effect.

Appendix: The Gold Standard and the Bretton Woods System

The Gold Standard

• Under the gold standard, currencies were convertible to gold at fixed rates, determining exchange rates automatically.

• The system collapsed during the Great Depression due to inflexibility and excessive money printing.

The Bretton Woods System

• Established fixed exchange rates with the U.S. dollar as the anchor, convertible to gold at $35/ounce.

• Central banks intervened to maintain fixed rates, holding U.S. dollar reserves.

• The system collapsed in the early 1970s due to excessive dollar holdings and unwillingness of some countries to adjust their currencies.

Capital Controls and Speculation

• Relaxation of capital controls in the 1960s increased currency speculation, making fixed exchange rates harder to maintain.