Open-Economy Macroeconomics: In-Depth Notes

Key Concepts of Open-Economy Macroeconomics

  • Closed Economy

    • Does not interact with other economies.
    • Limited to domestic trade.

  • Open Economy

    • Interacts freely with other economies.
    • Engages in international trade and investment.

International Flows of Goods and Capital

  • Exports and Imports

    • Exports: Goods/services produced domestically and sold abroad.
    • Imports: Goods/services produced abroad and sold domestically.
    • Net Exports (NX):
    • Formula:
      NX = ext{Value of Exports} - ext{Value of Imports}

  • International Trade In Goods and Capital

    • Increases consumption possibilities beyond production capabilities.
    • Affects overall GDP due to openness to trade

Trade Balances and Trade Negotiations

  • Trade Surplus:

    • NX > 0, exports exceed imports.
    • Indicates national prosperity in trade.

  • Trade Deficit:

    • NX < 0, imports exceed exports.
    • May indicate reliance on foreign goods.

  • Balanced Trade:

    • NX = 0, exports equal imports.

Net Capital Outflow (NCO)

  • Definition:
    • NCO = Purchase of foreign assets by domestic residents - Purchase of domestic assets by foreigners.
  • Types of Capital Outflow:
    • Foreign Direct Investment: Actively managed foreign investment.
    • Foreign Portfolio Investment: Purchase of foreign stocks/bonds.
  • NCO and NX Equality:
    • NCO = NX, indicating every transaction affects both variables equally.

Saving and Investment Relationships

  • Key Relationships:
    • Y = C + I + G + NX
    • where Y = national income, C = consumption, I = investment, G = government spending, and NX = net exports.
    • National saving, S = Y - C - G, which links to investment and net capital outflow:
    • S = I + NCO

Exchange Rates

  • Nominal Exchange Rate:

    • Rate at which one currency can be exchanged for another.
    • Example: 1 USD = 105 JPY.

  • Real Exchange Rate:

    • Measures the relative price of goods/services between countries.
    • Formula:
      ext{Real exchange rate} = rac{e imes P}{P^*}
      where:
    • e = nominal exchange rate, P = domestic price, P* = foreign price.

  • Appreciation and Depreciation:

    • Appreciation: Currency increases in value (buys more of a foreign currency).
    • Depreciation: Currency decreases in value (buys less of a foreign currency).

Purchasing-Power Parity (PPP)

  • Definition:

    • A theory suggesting equal purchasing power across countries (a good should cost the same globally).
    • Based on the ‘Law of One Price’ and arbitrage principles.

  • Limitations:

    • Does not always hold due to many goods being non-traded or imperfect substitutes,
    • Nominal exchange rates can fluctuate without relation to actual purchasing power.

Summary of Important Formulas and Relationships

  • NX = ext{Exports} - ext{Imports}

  • NCO = ext{Purchase of Foreign Assets} - ext{Purchase of Domestic Assets}

  • S = I + NCO

  • Trade Relations:

    • Trade surplus allows for capital outflow, while trade deficits involve capital inflow。

  • Exchange Rate Movement:

    • Nominal and real exchange rates influence export/import levels based on currency valuation changes.

  • Concluding Insights:

    • Recognize the interconnectedness of global economies and how policy decisions can enhance welfare by improving trade balance.