曼昆《经济学原理》32macroeconomic.ppt

32 AMacroeconomicTheoryoftheOpenEconomy OpenEconomies Anopeneconomyisonethatinteractsfreelywithothereconomiesaroundtheworld KeyMacroeconomicVariablesinanOpenEconomy Theimportantmacroeconomicvariablesofanopeneconomyinclude netexportsnetforeigninvestmentnominalexchangeratesrealexchangerates BasicAssumptionsofaMacroeconomicModelofanOpenEconomy Themodeltakestheeconomy sGDPasgiven Themodeltakestheeconomy spricelevelasgiven SUPPLYANDDEMANDFORLOANABLEFUNDSANDFORFOREIGN CURRENCYEXCHANGE TheMarketforLoanableFundsS I NCOAttheequilibriuminterestrate theamountthatpeoplewanttosaveexactlybalancesthedesiredquantitiesofinvestmentandnetcapitaloutflows TheMarketforLoanableFunds Thesupplyofloanablefundscomesfromnationalsaving S Thedemandforloanablefundscomesfromdomesticinvestment I andnetcapitaloutflows NCO TheMarketforLoanableFunds Thesupplyanddemandforloanablefundsdependontherealinterestrate Ahigherrealinterestrateencouragespeopletosaveandraisesthequantityofloanablefundssupplied Theinterestrateadjuststobringthesupplyanddemandforloanablefundsintobalance Figure1TheMarketforLoanableFunds Copyright 2003Southwestern ThomsonLearning Quantityof LoanableFunds Real Interest Rate TheMarketforLoanableFunds Attheequilibriuminterestrate theamountthatpeoplewanttosaveexactlybalancesthedesiredquantitiesofdomesticinvestmentandnetforeigninvestment TheMarketforForeign CurrencyExchange Thetwosidesoftheforeign currencyexchangemarketarerepresentedbyNCOandNX NCOrepresentstheimbalancebetweenthepurchasesandsalesofcapitalassets NXrepresentstheimbalancebetweenexportsandimportsofgoodsandservices TheMarketforForeign CurrencyExchange Inthemarketforforeign currencyexchange U S dollarsaretradedforforeigncurrencies Foraneconomyasawhole NCOandNXmustbalanceeachotherout or NCO NX TheMarketforForeign CurrencyExchange Thepricethatbalancesthesupplyanddemandforforeign currencyistherealexchangerate TheMarketforForeign CurrencyExchange Thedemandcurveforforeigncurrencyisdownwardslopingbecauseahigherexchangeratemakesdomesticgoodsmoreexpensive Thesupplycurveisverticalbecausethequantityofdollarssuppliedfornetcapitaloutflowisunrelatedtotherealexchangerate Figure2TheMarketforForeign CurrencyExchange Copyright 2003Southwestern ThomsonLearning QuantityofDollarsExchanged intoForeignCurrency Real Exchange Rate TheMarketforForeign CurrencyExchange Therealexchangerateadjuststobalancethesupplyanddemandfordollars Attheequilibriumrealexchangerate thedemandfordollarstobuynetexportsexactlybalancesthesupplyofdollarstobeexchangedintoforeigncurrencytobuyassetsabroad EQUILIBRIUMINTHEOPENECONOMY Inthemarketforloanablefunds supplycomesfromnationalsavinganddemandcomesfromdomesticinvestmentandnetcapitaloutflow Inthemarketforforeign currencyexchange supplycomesfromnetcapitaloutflowanddemandcomesfromnetexports EQUILIBRIUMINTHEOPENECONOMY Netcapitaloutflowlinkstheloanablefundsmarketandtheforeign currencyexchangemarket Thekeydeterminantofnetcapitaloutflowistherealinterestrate Figure3HowNetCapitalOutflowDependsontheInterestRate Copyright 2003Southwestern ThomsonLearning 0 NetCapital Outflow Real Interest Rate EQUILIBRIUMINTHEOPENECONOMY Pricesintheloanablefundsmarketandtheforeign currencyexchangemarketadjustsimultaneouslytobalancesupplyanddemandinthesetwomarkets Astheydo theydeterminethemacroeconomicvariablesofnationalsaving domesticinvestment netforeigninvestment andnetexports Figure4TheRealEquilibriuminanOpenEconomy Copyright 2003Southwestern ThomsonLearning a TheMarketforLoanableFunds b NetCapitalOutflow Real Interest Rate Real Interest Rate c TheMarketforForeign CurrencyExchange Quantityof Dollars Quantityof LoanableFunds NetCapital Outflow Real Exchange Rate HOWPOLICIESANDEVENTSAFFECTANOPENECONOMY Themagnitudeandvariationinimportantmacroeconomicvariablesdependonthefollowing GovernmentbudgetdeficitsTradepoliciesPoliticalandeconomicstability GovernmentBudgetDeficits Inanopeneconomy governmentbudgetdeficits reducethesupplyofloanablefunds driveuptheinterestrate crowdoutdomesticinvestment causenetforeigninvestmenttofall Figure5TheEffectsofGovernmentBudgetDeficit Copyright 2003Southwestern ThomsonLearning a TheMarketforLoanableFunds b NetCapitalOutflow Real Interest Rate Real Interest Rate c TheMarketforForeign CurrencyExchange Quantityof Dollars Quantityof LoanableFunds NetCapital Outflow Real Exchange Rate Demand Demand NCO S S GovernmentBudgetDeficits EffectofBudgetDeficitsontheLoanableFundsMarketAgovernmentbudgetdeficitreducesnationalsaving which shiftsthesupplycurveforloanablefundstotheleft which raisesinterestrates GovernmentBudgetDeficits EffectofBudgetDeficitsonNetForeignInvestmentHigherinterestratesreducenetforeigninvestment GovernmentBudgetDeficits EffectontheForeign CurrencyExchangeMarketAdecreaseinnetforeigninvestmentreducesthesupplyofdollarstobeexchangedintoforeigncurrency Thiscausestherealexchangeratetoappreciate TradePolicy Atradepolicyisagovernmentpolicythatdirectlyinfluencesthequantityofgoodsandservicesthatacountryimportsorexports Tariff Ataxonanimportedgood Importquota Alimitonthequantityofagoodproducedabroadandsolddomestically TradePolicy Becausetheydonotchangenationalsavingordomesticinvestment tradepoliciesdonotaffectthetradebalance Foragivenlevelofnationalsavinganddomesticinvestment therealexchangerateadjuststokeepthetradebalancethesame Tradepolicieshaveagreatereffectonmicroeconomicthanonmacroeconomicmarkets TradePolicy EffectofanImportQuotaBecauseforeignersneeddollarstobuyU S netexports thereisanincreaseddemandfordollarsinthemarketforforeign currency Thisleadstoanappreciationoftherealexchangerate TradePolicy EffectofanImportQuotaThereisnochangeintheinterestratebecausenothinghappensintheloanablefundsmarket Therewillbenochangeinnetexports Thereisnochangeinnetforeigninvestmenteventhoughanimportquotareducesimports TradePolicy EffectofanImportQuotaAnappreciationofthedollarintheforeignexchangemarketencouragesimportsanddiscouragesexports Thisoffsetstheinitialincreaseinnetexportsduetoimportquota Figure6TheEffectsofanImportQuota Copyright 2003Southwestern ThomsonLearning a TheMarketforLoanableFunds b NetCapitalOutflow Real Interest Rate Real Interest Rate c TheMarketforForeign CurrencyExchange Quantityof Dollars Quantityof LoanableFunds NetCapital Outflow Real Exchange Rate Supply Supply Demand NCO D E TradePolicy EffectofanImportQuotaTradepoliciesdonotaffectthetradebalance PoliticalInstabilityandCapitalFlight Capitalflightisalargeandsuddenreductioninthedemandforassetslocatedinacountry PoliticalInstabilityandCapitalFlight Capitalflighthasitslargestimpactonthecountryfromwhichthecapitalisfleeing butitalsoaffectsothercountries Ifinvestorsbecomeconcernedaboutthesafetyoftheirinvestments capitalcanquicklyleaveaneconomy Interestratesincreaseandthedomesticcurrencydepreciates PoliticalInstabilityandCapitalFlight WheninvestorsaroundtheworldobservedpoliticalproblemsinMexicoin1994 theysoldsomeoftheirMexicanassetsandusedtheproceedstobuyassetsofothercountries PoliticalInstabilityandCapitalFlight ThisincreasedMexicannetcapitaloutflow Thedemandforloanablefundsintheloanablefundsmarketincreased whichincreasedtheinterestrate Thisincreasedthesupplyofpesosintheforeign currencyexchangemarket Figure7TheEffectsofCapitalFlight Copyright 2003Southwestern ThomsonLearning a TheMarketforLoanableFundsinMexico b MexicanNetCapitalOutflow Real Interest Rate Real Interest Rate c TheMarketforForeign CurrencyExchange Quantityof Pesos Quantityof LoanableFunds NetCapital Outflow Real Exchange Rate r1 r1 D1 Demand S Supply NCO1 Summary Toanalyzethemacroeconomicsofopeneconomies twomarketsarecentral themarketforloanablefundsandthemarketforforeign currencyexchange Inthemarketforloanablefunds theinterestrateadjuststobalancesupplyforloanablefunds fromnationalsaving anddemandforloanablefunds fromdomesticinvestmentandnetcapitaloutflow Summary Inthemarketforforeign currencyexchange therealexchangerateadjuststobalancethesupplyofdollars fornetcapitaloutfl