《曼昆《经济学原理》32macroeconomic.ppt

32 A Macroeconomic Theory of the Open Economy Open Economies An open economy is one that interacts freely with other economies around the world. Key Macroeconomic Variables in an Open Economy The important macroeconomic variables of an open economy include: net exports net foreign investment nominal exchange rates real exchange rates Basic Assumptions of a Macroeconomic Model of an Open Economy The model takes the economy’s GDP as given. The model takes the economy’s price level as given. SUPPLY AND DEMAND FOR LOANABLE FUNDS AND FOR FOREIGN-CURRENCY EXCHANGE The Market for Loanable Funds S = I + NCO At the equilibrium interest rate, the amount that people want to save exactly balances the desired quantities of investment and net capital outflows. The Market for Loanable Funds The supply of loanable funds comes from national saving (S). The demand for loanable funds comes from domestic investment (I) and net capital outflows (NCO). The Market for Loanable Funds The supply and demand for loanable funds depend on the real interest rate. A higher real interest rate encourages people to save and raises the quantity of loanable funds supplied. The interest rate adjusts to bring the supply and demand for loanable funds into balance. Figure 1 The Market for Loanable Funds The Market for Loanable Funds At the equilibrium interest rate, the amount that people want to save exactly balances the desired quantities of domestic investment and net foreign investment. The Market for Foreign-Currency Exchange The two sides of the foreign-currency exchange market are represented by NCO and NX. NCO represents the imbalance between the purchases and sales of capital assets. NX represents the imbalance between exports and imports of goods and services. The Market for Foreign-Currency Exchange In the market for foreign-currency exchange, U.S. dollars are traded for foreign currencies. For an economy as a whole, NCO and NX must balance each other out, or: NCO = NX The Market for Forei