宏观经济学（第十三版）课件：The Demand for Money

TheDemandforMoney

.IntroductionWhatismoney?Whydoesanyonewantit?Ineconomics,money=mediumofexchangeWhateverisacceptedinexchangeInU.S.,M1(currencyandcheckabledeposits)comesclosesttodefiningmeansofpaymentAttheendof2005,M1=$4,596perpersonDebatewhetherbroadermeasure,M2,mightbettermeetthedefinitionofmoneyinamodernpaymentsystemDemandformoneyreferstothestockofassetsheldascash,checkingaccounts,andcloselyrelatedassets,specificallynotgenericwealthorincome16-2ComponentsoftheMoneyStockTwomainmonetaryaggregatesinU.S.:M1andM2M1comprisesthoseclaimsthatcanbeuseddirectly,instantly,andwithoutrestrictions→LIQUIDM2includesM1,plussomelessliquidassets(ex.savingsaccountsandmoneymarketfunds)Asliquidityofanassetdecreases,theinterestyieldincreasesAtypicaleconomictradeoff:inordertogetmoreliquidity,assetholdershavetosacrificeyield

16-3TheFunctionsofMoneyTherearefourtraditionalfunctionsofmoney:MediumofexchangeMoneyisusedtopayforgoodsandservicesEliminatestheneedfora“doublecoincidenceofwants”StoreofvalueAnassetthatmaintainsvalueUnitofaccountTheunitinwhichpricesarequotedStandardofdeferredpaymentMoneyunitsareusedinlongtermtransactions(ex.loans)16-4TheDemandforMoney:TheoryThedemandformoneyisthedemandforrealmoneybalances→peopleholdmoneyforitspurchasingpowerTwoimplications:Realmoneydemandisunchangedwhenthepricelevelincreases,andallrealvariables,suchastheinterestrate,realincome,andrealwealth,remainunchangedEquivalently,nominalmoneydemandincreasesinproportiontotheincreaseinthepricelevel,giventherealvariablesjustspecified16-5TheDemandforMoney:TheoryThetheoriescoveredherecorrespondtoKeynes’sfamousthreemotivesforholdingmoney:Thetransactionsmotive,whichisthedemandformoneyarisingfromtheuseofmoneyinmakingregularpaymentsTheprecautionarymotive,whichisthedemandformoneytomeetunforeseencontingenciesThespeculativemotive,whicharisesfromuncertaintiesaboutthemoneyvalueofotherassetsthatanindividualcanholdTransactionandprecautionarymotives→mainlydiscussingM1Speculativemotive→

M2,aswellasnon-moneyassets16-6TransactionDemandThetransactiondemandformoneyarisesfromthelackofsynchronizationofreceiptsanddisbursementsKeepmoneyonhandtomakepurchasesbetweenpayperiodsTradeoffbetweenamountofinterestanindividualforgoesbyholdingmoneyandcostsofholdingasmallamountofmoneyBenefitsofkeepingsmallamountsofmoneyonhandisinterestearnedonmoneyleftinthebankCostofkeepingsmallamountsofmoneyisthecostandinconvenienceofmakingtripstothebanktowithdrawmore16-7TransactionDemandSupposethefollowing:Y=$1800/monthPersonspendstheYevenlyoverthemonth,atarateof$60/dayAlternative1:Personcouldkeeptheentire$1800incashandspend$60/dayCashbalancesfallssmoothlyfrom$1800to$0attheendofthemonthAveragebalanceofForgoneinterestof16-8TransactionDemandSupposethefollowing:Y=$1800/monthPersonspendstheYevenlyoverthemonth,atarateof$60/dayAlternative#2:Personcoulddepositentireamount,andeachdaytaketheneeded$60outofthebankEarninterestonmoneyleftinthebankoverthecourseofthemonthCashbalancesfallfrom$1800/30tozeroeverydayAveragebalanceofForgoneinterestof16-9Ingeneral:StartingincomeofYntripstothebank→TheaveragecashbalanceisEachtripscoststc→Thecombinedcostoftripsplusforgoneinterestis:Choosentominimizecostsandcomputetheaveragemoneyholdings

Baumol-Tobinformulaforthedemandformoney:

(1)

TransactionDemand16-10ThePrecautionaryMotiveTheBaumol-TobinmodelignoreduncertaintyPeopleuncertainaboutthepaymentstheymightwantorhavetomake→thereisdemandformoneyfortheseuncertaineventsThemoremoneyapersonholds,thelesslikelyheorsheistoincurthecostsofilliquidityThemoremoneyapersonholds,themoreinteresthe/shewillgiveup→similartradeoffencounteredwithtransactionsdemandformoneyTechnologyandthestructureofthefinancialsystemareimportantdeterminantsofprecautionarydemand16-11SpeculativeDemandforMoneySpeculativedemandformoneyfocusesonthestore-of-valuefunctionofmoney→concentratesonroleofmoneyintheinvestmentportfolioofanindividualWealthheldinspecificassets→

portfolioDuetouncertainty,unwisetoholdentireportfolioinasingleriskyasset→diversifyassetholdingsMoneyisasafeassetDemandformoneydependsupontheexpectedyieldsandriskinessoftheyieldsonotherassets(JamesTobin)IncreasedopportunitycostsofholdingmoneylowersmoneydemandIncreasedriskinessofreturnsonotherassetsincreasesmoneydemand16-12EmpiricalEstimatesFouressentialpropertiesofmoneydemand:Demandformoneybalancesrespondsnegativelytotherateofinterest.Demandformoneyincreaseswiththelevelofrealincome.Short-runresponsivenessofmoneydemandtochangesininterestratesandincomeisconsiderablylessthanthelong-runresponse.(thelong-runresponsesareestimatedtobeabout5timesthesizeoftheshort-runresponses)Demandfornominalmoneybalanceisproportionaltothepricelevel.Thereisnomoneyillusion;inotherwords,thedemandformoneyisademandforrealbalances.16-13TheIncomeVelocityTheincomevelocityofmoney:thenumberoftimesthestockofmoneyisturnedoverperyearinfinancingtheannualflowofincome.EqualtotheratioofnominalGDPtothenominalmoneystock,or:(2)CanalsobeinterpretedastheratioofnominalincometonominalmoneystockORtheratioofrealincometorealbalances16-14TheIncomeVelocityConceptofvelocityisimportantlargelybecauseitisaconvenientwayoftalkingaboutmoneydemandDemandforrealbalancesis:Substitutingintoequation(2),velocitycanbewrittenas:

Moneydemandcanbewrittenas:Velocityofmoneyis:16-15TheIncomeVelocityFigure16-1showsM2velocity(leftscale)andtheTreasurybillinterestrate(rightscale)M2isrelativelystableVelocityhasastrongtendencytoriseandfallwithmarketinterestrates16-16TheIncomeVelocityFigure16-1showsM2velocity(leftscale)andtheTreasurybillinterestrate(rightscale)M2velocityhasbecomemuchlessstableWhenmonetaryaggregatesrelativelyunstable,monetaryauthorityshouldusetheinterestrateratherthanmoneysupplyasthedirectoperatingtarget16-17TheQuantityTheoryThequantitytheoryofmoneyprovidessimplewaytothinkabouttherelationbetweenmoney,prices,andoutput: