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1、宏观经济理论和政策：L5,开放经济,国际商品和资本流动名义汇率真实汇率蒙代尔弗莱明模型：固定汇率与资本完全流动资本完全流动与可变汇率,开放经济贸易联系资本联系为什么有国际贸易？谁受益？,国际商品流动,贸易贸易盈余NX0贸易赤字NX0贸易平衡NX=0,Percent,of GDP,0,5,10,15,1950,1955,1960,1965,1970,1975,1980,1990,1985,2000,1995,Exports,Imports,Copyright 2004 South-Western,国际商品流动,什么决定国际贸易NX汇率国内与国际相对价格国内和国外的收入水平运输费用贸易政策,国际商
2、品流动,根据中国与美国的国际贸易发展，贸易有何好处？中国和美国的开放程度如何？自由贸易的利弊？1966年通信技术只能使北美与欧洲之间的138人同时通话！贸易比今天困难的多。,国际资本流动,净资本流出或者叫做净国外资产（购买外国资产）FDI，中国企业在美国投资外商证券投资FPI，楼继伟购买黑石股票决定因素国内利率，名义利率还是真实？国外利率经济与政治风险政府政策,净资本流出=净出口,恒等式NCO=NX，为什么比如，中国ABC公司出口衣服1亿美元到美国，中国出口商给美国出口商1亿美元的衣服，美国的进口商支付1亿美元给中国的出口商中国出口商的销售，增加了中国的出口（NX)。中国出口商获得了1亿美元外
3、国资产（美元）也许ABC公司不愿意持有美元，在外汇市场换成了RMB，但是买走美元的也许是中石油，他想在海外钻探石油，购买海外的资产。在这个例子里，ABC的净出口等于中石油资本流出 外汇储备增加，破坏了NCO=NX吗？,储蓄，投资和国际资本流动,净出口是GDP的一部分:Y=C+I+G+NX国民储蓄等于S=S(P)+S(G)=(Y-T-C)+(T-G)=Y-C-GS=Y-C-G=I+NX,Saving,Investment,and Their Relationship to the International Flows,国民储蓄 S=Y-C-G so:S=I+NXor,收入大于支出会怎样？YC+
4、I+GSI外国资产？收入小于支出呢,1980年以前，比较平衡1980年代主要因为储蓄减少，主要是政府赤字增加1990年代，高科技投资带动的投资增加2000年以后，小布什的赤字又增加了,中国的资本流出,图2：中国国际收支年度顺差（2001 2007），单位：亿美元,数据来源：国家外汇管理局网页,其中，2007年数据为估算，根据国家统计局公布的2007年上半年的相应数值乘以2而得。,千美元,名义汇率,名义汇率 1美元=7RMB贬值升值法定贬值法定升值,真实汇率,例子中国汉堡10RMB美国汉堡2$美国的汉堡价格用rmb表示2$7RMB/$=14RMB14RMB/10RMB=1.4什么意思？美国的价格
5、额是中国的1.4倍真实汇率=,名义汇率外国价格,本国价格,真实汇率=,名义汇率外国价格,本国价格,购买力平价,一价定律一个相同的商品必须卖相同的价格刚才的例子里，你可以做什么来牟利？,真实汇率=1=,EP*,P,1,P*,1美元在美国的购买力,E,P,1美元可以兑换成E元RMB，E元RMB的购买力等于E/P,这二者应该相等，为什么？,货币，价格，和汇率：德国超级通胀期间,10,000,000,000,1,000,000,000,000,000,100,000,1,.00001,.0000000001,1921,1922,1923,1924,Exchange rate,Money supply,
6、Price level,1925,指数,(Jan.1921,5,100),图3：中国外汇储备（2004.12007.9），单位：亿美元,数据来源：国家外汇管理局网页,关于汇率的短期理论,可贷资金市场,均衡数量,均衡利率,可贷资金供给，来自国内储蓄,可贷资金需求，用于国内投资和净出口,外汇市场,真实汇率,用于兑换美元的人民币数量,人民币需求，用于净出口,人民币供给，来自资本净流出,美国作为债务帝国2004年5000亿美元美国增长很快4%你怎么看美国的前途？资本外逃短短10年前，资本外逃是中国关注的问题。现在没人关心了资本会逃离美国吗？,汇率制度,定义：以一种通货表示的另外一种通货的价格表示方法：
7、7.3RMB/$固定汇率中央银行的干预浮动汇率清洁浮动与肮脏浮动,1995年，一个愚蠢的众议员说，要让美国历史上第一次拖欠债务。后果是美国政府债券利率上升了0.1个百分点，汇率下降。美国还敢试吗？KRUGMAN说，外国信任美国，是基于美国的领袖不会干蠢事。如果美国不负责任的财政赤字持续的话，投资者最终会得出结论，美国中最要变成第三世界国家，并开始像那些国家一样威胁投资者。这对美国的经济后果并不妙。,图4：人民币对美元月度汇率（2005.12007.12）,数据来源：国家外汇管理局网页,商品贸易与贸易均衡,本国居民的支出=A=C+I+G对国内商品的支出=A+NX=C+I+G+NX=A+NX回忆A
8、=A(Y,i),净出口,NX=X(Yf,R)-Q(Y,R)=NX(Y,Yf,R)边际进口倾向IS曲线：Y=A(Y,i)+NX(Y,Yf,R)例子，美国收入降低国内支出增加对收入和净出口的影响？国外收入增加对收入和净出口的影响实际贬值呢？,资本的流动性,资本逐利我们先分析资本完全流动的情况国际收支与资本流动BP=NX(Y,Yf,R)+CF(i-if)内部平衡与外部平衡,蒙代尔弗莱明模型,在固定汇率下，和资本完全流动，一国无法采取独立的货币政策利率无法背离世界市场上通行的利率水平。实施独立的货币政策会导致资本流动，并且需要干预，直至利率回到与世界市场的利率水平一致为止,紧缩货币提高利率资本流入，国
9、际收支盈余货币升值的压力通过卖出本国货币，买进外币来干预干预扩张了货币，降低了利率回到原先的利率和货币存量和国际收支水平,固定汇率使得货币存量外生化,资本的完全流动与可变汇率,在完全可变汇率下，没有干预意味着国际收支余额为0.任何经常项目赤字，必须由私人资本流入来加以解决，经常项目盈余由资本流出来平衡。汇率的调整保证经常项目与资本项目之和为0i=if贬值，IS曲线右移，？,货币存量的调整,非常有效贬值政策输出失业竞争性贬值,The Mundell-Fleming model,Key assumption:Small open economy with perfect capital mobil
10、ity.r=r*Goods market equilibrium the IS*curve:,where e=nominal exchange rate=foreign currency per unit domestic currency,The IS*curve:Goods market eqm,The IS*curve is drawn for a given value of r*.Intuition for the slope:,The LM*curve:Money market eqm,The LM*curveis drawn for a given value of r*.is
11、vertical because:given r*,there is only one value of Y that equates money demand with supply,regardless of e.,Equilibrium in the Mundell-Fleming model,equilibriumexchangerate,equilibriumlevel ofincome,Floating&fixed exchange rates,In a system of floating exchange rates,e is allowed to fluctuate in r
12、esponse to changing economic conditions.In contrast,under fixed exchange rates,the central bank trades domestic for foreign currency at a predetermined price.Next,policy analysis first,in a floating exchange rate systemthen,in a fixed exchange rate system,Fiscal policy under floating exchange rates,
13、Y1,At any given value of e,a fiscal expansion increases Y,shifting IS*to the right.,Results:e 0,Y=0,Lessons about fiscal policy,In a small open economy with perfect capital mobility,fiscal policy cannot affect real GDP.“Crowding out”closed economy:Fiscal policy crowds out investment by causing the i
14、nterest rate to rise.small open economy:Fiscal policy crowds out net exports by causing the exchange rate to appreciate.,Monetary policy under floating exchange rates,Y2,An increase in M shifts LM*right because Y must rise to restore eqm in the money market.,Results:e 0,Lessons about monetary policy
15、,Monetary policy affects output by affecting the components of aggregate demand:closed economy:M r I Ysmall open economy:M e NX YExpansionary mon.policy does not raise world agg.demand,it merely shifts demand from foreign to domestic products.So,the increases in domestic income and employment are at
16、 the expense of losses abroad.,Trade policy under floating exchange rates,At any given value of e,a tariff or quota reduces imports,increases NX,and shifts IS*to the right.,Results:e 0,Y=0,Lessons about trade policy,Import restrictions cannot reduce a trade deficit.Even though NX is unchanged,there
17、is less trade:the trade restriction reduces imports.the exchange rate appreciation reduces exports.Less trade means fewer“gains from trade.”,Lessons about trade policy,cont.,Import restrictions on specific products save jobs in the domestic industries that produce those products,but destroy jobs in
18、export-producing sectors.Hence,import restrictions fail to increase total employment.Also,import restrictions create“sectoral shifts,”which cause frictional unemployment.,Fixed exchange rates,Under fixed exchange rates,the central bank stands ready to buy or sell the domestic currency for foreign cu
19、rrency at a predetermined rate.In the Mundell-Fleming model,the central bank shifts the LM*curve as required to keep e at its preannounced rate.This system fixes the nominal exchange rate.In the long run,when prices are flexible,the real exchange rate can move even if the nominal rate is fixed.,Fisc
20、al policy under fixed exchange rates,Y1,Under floating rates,a fiscal expansion would raise e.,Results:e=0,Y 0,Y2,To keep e from rising,the central bank must sell domestic currency,which increases M and shifts LM*right.,Under floating rates,fiscal policy is ineffective at changing output.Under fixed
21、 rates,fiscal policy is very effective at changing output.,Monetary policy under fixed exchange rates,An increase in M would shift LM*right and reduce e.,To prevent the fall in e,the central bank must buy domestic currency,which reduces M and shifts LM*back left.,Results:e=0,Y=0,Under floating rates
22、,monetary policy is very effective at changing output.Under fixed rates,monetary policy cannot be used to affect output.,Trade policy under fixed exchange rates,A restriction on imports puts upward pressure on e.,Results:e=0,Y 0,Y2,To keep e from rising,the central bank must sell domestic currency,w
23、hich increases M and shifts LM*right.,Under floating rates,import restrictions do not affect Y or NX.Under fixed rates,import restrictions increase Y and NX.But,these gains come at the expense of other countries:the policy merely shifts demand from foreign to domestic goods.,Summary of policy effect
24、s in the Mundell-Fleming model,Interest-rate differentials,Two reasons why r may differ from r*country risk:The risk that the countrys borrowers will default on their loan repayments because of political or economic turmoil.Lenders require a higher interest rate to compensate them for this risk.expe
25、cted exchange rate changes:If a countrys exchange rate is expected to fall,then its borrowers must pay a higher interest rate to compensate lenders for the expected currency depreciation.,Differentials in the M-F model,where(Greek letter“theta”)is a risk premium,assumed exogenous.Substitute the expr
26、ession for r into the IS*and LM*equations:,The effects of an increase in,IS*shifts left,because r I,LM*shifts right,because r(M/P)d,so Y must rise to restore money market eqm.,Results:e 0,Y2,The fall in e is intuitive:An increase in country risk or an expected depreciation makes holding the countrys
27、 currency less attractive.Note:an expected depreciation is a self-fulfilling prophecy.The increase in Y occurs because the boost in NX(from the depreciation)is greater than the fall in I(from the rise in r).,The effects of an increase in,Why income might not rise,The central bank may try to prevent
28、the depreciation by reducing the money supply.The depreciation might boost the price of imports enough to increase the price level(which would reduce the real money supply).Consumers might respond to the increased risk by holding more money.Each of the above would shift LM*leftward.,CASE STUDY:The M
29、exican peso crisis,CASE STUDY:The Mexican peso crisis,The Peso crisis didnt just hurt Mexico,U.S.goods more expensive to MexicansU.S.firms lost revenueHundreds of bankruptcies along U.S.-Mexican borderMexican assets worth less in dollarsReduced wealth of millions of U.S.citizens,Understanding the cr
30、isis,In the early 1990s,Mexico was an attractive place for foreign investment.During 1994,political developments caused an increase in Mexicos risk premium():peasant uprising in Chiapas assassination of leading presidential candidateAnother factor:The Federal Reserve raised U.S.interest rates severa
31、l times during 1994 to prevent U.S.inflation.(r*0),Understanding the crisis,These events put downward pressure on the peso.Mexicos central bank had repeatedly promised foreign investors that it would not allow the pesos value to fall,so it bought pesos and sold dollars to“prop up”the peso exchange r
32、ate.Doing this requires that Mexicos central bank have adequate reserves of dollars.Did it?,Dollar reserves of Mexicos central bank,December 1993$28 billionAugust 17,1994$17 billionDecember 1,1994$9 billionDecember 15,1994$7 billion,During 1994,Mexicos central bank hid the fact that its reserves wer
33、e being depleted.,the disaster,Dec.20:Mexico devalues the peso by 13%(fixes e at 25 cents instead of 29 cents)Investors are SHOCKED!they had no idea Mexico was running out of reserves.,investors dump their Mexican assets and pull their capital out of Mexico.Dec.22:central banks reserves nearly gone.
34、It abandons the fixed rate and lets e float.In a week,e falls another 30%.,The rescue package,1995:U.S.&IMF set up$50b line of credit to provide loan guarantees to Mexicos govt.This helped restore confidence in Mexico,reduced the risk premium.After a hard recession in 1995,Mexico began a strong reco
35、very from the crisis.,CASE STUDY:The Southeast Asian crisis 1997-98,Problems in the banking system eroded international confidence in SE Asian economies.Risk premiums and interest rates rose.Stock prices fell as foreign investors sold assets and pulled their capital out.Falling stock prices reduced
36、the value of collateral used for bank loans,increasing default rates,which exacerbated the crisis.Capital outflows depressed exchange rates.,Data on the SE Asian crisis,Floating vs.fixed exchange rates,Argument for floating rates:allows monetary policy to be used to pursue other goals(stable growth,
37、low inflation).Arguments for fixed rates:avoids uncertainty and volatility,making international transactions easier.disciplines monetary policy to prevent excessive money growth&hyperinflation.,The Impossible Trinity,A nation cannot have free capital flows,independent monetary policy,and a fixed exc
38、hange rate simultaneously.A nation must choose one side of this triangle and give up the opposite corner.,Option 1(U.S.),Option 3(China),Option 2(Hong Kong),CASE STUDY:The Chinese Currency Controversy,1995-2005:China fixed its exchange rate at 8.28 yuan per dollar,and restricted capital flows.Many o
39、bservers believed that the yuan was significantly undervalued,as China was accumulating large dollar reserves.U.S.producers complained that Chinas cheap yuan gave Chinese producers an unfair advantage.President Bush asked China to let its currency float;Others in the U.S.wanted tariffs on Chinese go
40、ods.,CASE STUDY:The Chinese Currency Controversy,If China lets the yuan float,it may indeed appreciate.However,if China also allows greater capital mobility,then Chinese citizens may start moving their savings abroad.Such capital outflows could cause the yuan to depreciate rather than appreciate.,Mu
41、ndell-Fleming and the AD curve,So far in M-F model,P has been fixed.Next:to derive the AD curve,consider the impact of a change in P in the M-F model.We now write the M-F equations as:,(Earlier in this chapter,P was fixed,so we could write NX as a function of e instead of.),Y1,Y2,Deriving the AD cur
42、ve,AD,Y2,Y1,Why AD curve has negative slope:,P,LM shifts left,NX,Y,(M/P),From the short run to the long run,then there is downward pressure on prices.,Over time,P will move down,causing(M/P)NX Y,Large:Between small and closed,Many countries including the U.S.are neither closed nor small open economi
43、es.A large open economy is between the polar cases of closed&small open.Consider a monetary expansion:Like in a closed economy,M 0 r I(though not as much)Like in a small open economy,M 0 NX(though not as much),Chapter Summary,1.Mundell-Fleming modelthe IS-LM model for a small open economy.takes P as
44、 given.can show how policies and shocks affect income and the exchange rate.2.Fiscal policyaffects income under fixed exchange rates,but not under floating exchange rates.,CHAPTER 12 The Open Economy Revisited,slide 90,Chapter Summary,3.Monetary policyaffects income under floating exchange rates.und
45、er fixed exchange rates,monetary policy is not available to affect output.4.Interest rate differentialsexist if investors require a risk premium to hold a countrys assets.An increase in this risk premium raises domestic interest rates and causes the countrys exchange rate to depreciate.,CHAPTER 12 T
46、he Open Economy Revisited,slide 91,Chapter Summary,5.Fixed vs.floating exchange ratesUnder floating rates,monetary policy is available for can purposes other than maintaining exchange rate stability.Fixed exchange rates reduce some of the uncertainty in international transactions.,CHAPTER 12 The Open Economy Revisited,slide 92,
