中级宏观经济学讲义9

IntermediateMacroeconomics91TheOpenEconomyWhydocountriestradewitheachother?“Nonationwaseverruinedbytrade.”---BenjaminFranklinMorevarieties;higherquality;cheaperprice2TheOpenEconomyMerchandisetradeasa%ofGDP(2005)

MerchandiseTrade(%ofGDP)Highincome43.6Uppermiddleincome66.7Middleincome62.2Lowermiddleincome58.8Lowincome41.13TheOpenEconomy

ArgentinaChinaEthiopiaFranceGermanyHongKongIndiaMexicoU.KU.S.MerchandiseTrade(%ofGDP)37.563.844.945.362.7333.728.25840.121.24TheOpenEconomyTheinternationalflowsofcapital&goodsFactorsaffectingCA(savingsandinvestment)ExchangeratesFactorsaffectingex-rate5InternationalFlowsofK&GoodsCapitalaccount¤taccount6InternationalFlowsofK&Goods(I-S)+NX=0 or KA+CA=0NX≡TB=CA(S-I)≡NFI=-KA7InternationalFlowsofK&GoodsS–I=NX(-KA=CA)IfS–I>0(KA<0)境内储蓄多于境内投资部分储蓄投资到国外(资本净流出)外国人用这部分资金购买我国商品(商品净流出)NX>0;TB>0;CA>0;KA<08InternationalFlowsofK&Goods经常项目顺差：既定时期，一国居民向外国居民的贷出大于借入，从而对外净资产增加。：本国的净对外资产余额因此，t时点一国净对外资产余额是过去经常项目盈余或赤字的结果。

9投资于本国：I或净对外投资：InternationalFlowsofK&Goods10InternationalFlowsofK&GoodsNX=CA=-KA?我们借来的钱是否可以全被用于购买别国的商品服务?外国人借的人民币是否可全被用于购买我国的商品服务?No！Wepay/earninterestif(S–I)<>011InternationalFlowsofK&Goods通常情况下,相对于贸易余额,国外的净要素支付很小。因此,经常项目余额和贸易余额几乎相等。Mankiw的假设CA=TB=-KA正是基于此12InternationalFlowsofK&Goods经常项目包括：贸易余额利息/股息其他商品劳务和收入（旅游，工人汇款…）单边转让官方转让其他13InternationalFlowsofK&Goods经常项目余额部分构成（2005年）（亿美元）中国美国日本巴西商品贸易590-6，6201，321337服务贸易-97450-379-48要素收入-36-241857-205数据来源：IMF2006报告14InternationalFlowsofK&Goods2005ChinaCA:USD160.8billion数据来源：中国外汇管理局15InternationalFlowsofK&Goods项

目差额一.经常项目1608.183

A.货物和服务1247.977

a.货物1341.891

b.服务-93.9139

B.收益106.3514

1.职工报酬15.19648

2.投资收益91.15491

C.经常转移253.8547

1.各级政府-1.76234

2.其它部门255.61716InternationalFlowsofK&Goods项

目差额

b.服务-93.9139

1.运输-130.21

2.旅游75.3693

3.通讯服务-1.18173

4.建筑服务9.73567

5.保险服务-66.5014

6.金融服务-0.14244

7.计算机和信息服务2.17676

8.专有权利使用费和特许费-51.6385

9.咨询-8.61408

10.广告、宣传3.60521

11.电影、音像-0.20096

12.其它商业服务74.97029

13.别处未提及的政府服务-1.2817517OtherInterpretations如何评价CA>0(S–I>0)？是好是坏？(S–I)>0国外比国内更好的投资机会？量入为出的自律？18两期国家跨时预算约束

C1>Q1TB赤字C1<Q1TB盈余

无投资。仅选择消费或储蓄

19两期国家跨时预算约束第一期消费大于产出则第二期消费必小于产出若第一期贸易逆差,则第二期的贸易必为顺差

20两期国家跨时预算约束

贸易逆差或经常项目逆差本身并不说明好坏，只是一国跨时选择的结果。现在逆差将来必须实现顺差，现在顺差将来必然享受逆差。21多期国家跨时预算约束

若为有限期，预算约束可得出与两期模型相同结论：如果有些时期出现贸易（经常项目）顺差，必然有另外的时期是贸易（经常项目）逆差。22但是，对于每个国家，时限可以被假设是无穷的，如何约束？可不可能永远是逆差或者顺差？甚至借新债还旧债无限举债（PonziScheme）？多期国家跨时预算约束23多期国家跨时预算约束美国会不会是Ponzi？2004：CA赤字0.67万亿占GDP11.67万亿的 5.7%2005：CA赤字0.79万亿占GDP12.5万亿的 6.3%2006：CA赤字0.85万亿占GDP14.98万亿的 5.7%美国的净外债约占GDP的25％即使CA赤字稳定在GDP的5％，2020年净外债也会>GDP的60％24FactorsaffectingCA

---SmallOpenEconomyWhatmakesacountry“small”?---thescaleoftheeconomyissosmallthatitcannotaffecttheworldpricelevelPricetaker---takeworldrealinterestrate25FactorsaffectingCA

---SmallOpenEconomyr=r*Domestic&foreignbondsareperfectsubstitutesCapitalisperfectlymobile26FactorsaffectingCA

---SmallOpenEconomyModel27FactorsaffectingCA

---SmallOpenEconomyWorldreali-rateandCAKA=-CA=I–Srr*S,ICAISCA(r*)28FactorsaffectingCA

---SmallOpenEconomyI↑rtendsto↑$flowsintillr=r*NFI↓CA↓rS,IISEr*S=II’>S’=SCA=0CA<0

Shocktoinvestment(betterinfrastructure)29FactorsaffectingCA

---SmallOpenEconomyY↓S=(Y–C–G)↓rtendsto↑$flowsintillr=r*NFI↓CA↓rS,IISEr*Hurricane(temporaryshocktoproduction)S=I,CA=0S’<I’=ICA<030FactorsaffectingCA

---SmallOpenEconomyAsYconsistently↑,C↑Swouldnot↑asmuchAlso,investmentmay↑rS,IISEr*Technologicalimprovement(permanentshocktoproduction)temp.shock31FactorsaffectingCA

---SmallOpenEconomyTemporarytradesanctiononIraqTemporaryshocktoTermsofTrade(TOT)toChinaTOT↓Cwouldnot↓muchS↓rtendsto↑$flowsouttillr=r*NFI↓CA↓rS,IISES’<I’=ICA<032FactorsaffectingCA

---SmallOpenEconomyAlargeportionofoilfieldsinIraqweredestroyedduringthewaronTerrorismTOT↓permanentlypeoplewouldadjusttheirCSwouldnotdecreaseasmuch(orevengoesbacktoitsinitiallevel)CAdeficitmaydisappearfinally33FactorsaffectingCA

---SmallOpenEconomyFinancingfortemporaryshocks,adjustingforpersistent(permanent)shocks---IMFCompensatoryFinancingFacility(CFF)Acountrycouldaskforloanswhenitsincomefromexportsisinsufficientandtheinsufficientistemporary.34FactorsaffectingCA

---SmallOpenEconomyInfluenceofhomeexpansionaryfiscalpoliciesG↑orT↓S↓Iunchanged(S-I)↓NFI↓&NX↓(CA<0)rS,IISEI’<S’=SCA<035FactorsaffectingCA

---SmallOpenEconomyInaSOE,anexpansionaryfiscalpolicy(G↑orT↓)squeezesouttheNXHigherbudgetdeficitathomeleadstohighertradedeficit(currentaccountdeficit)---TheTwinDeficits36FactorsaffectingCA

---SmallOpenEconomyInfluenceofforeignfiscalpolicies(large)