Money, Interest and Prices - WordPress.com · Prof George Alogoskoufis, Dynamic Macroeconomic...

Post on 04-Aug-2018

214 views 0 download

Transcript of Money, Interest and Prices - WordPress.com · Prof George Alogoskoufis, Dynamic Macroeconomic...

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015

Money,InterestandPrices

MoneyinGeneralEquilibriumModels,thePriceLevel,InterestRates

andInflation

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 2

Money,thePriceLevelandNominalVariables

• Money,theexistenceofwhichinamoderneconomyisusuallytakenforgranted,performsthreemainfuncJons.

• First,itisaunitofaccount,seconditisauniversallyacceptedmeansofpayment,andthirdly,itisastoreofvalue.

• WhileinmodelswithoutmoneyonecanonlyanalyzethedeterminaJonofrealvariables,suchasthequanJJesofgoodsandservicesproducedandconsumed,andtheirrela9veprices,inmodelswithmoneyonecanalsodeterminenominalvariablessuchasthepricelevel,nominalincome,thelevelofnominalwages,nominalinterestratesandinfla9on.Thesenominalvariablesareexpressedintermsofmoney.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 3

MoneyasaUnitofAccount• Inamonetaryeconomyallpricesaredeterminedandquotedintermsofthe

monetaryunit.Otherwise,economicagentswouldhavetocalculatealltherelaJvepricesofgoodsandservicesinordertoconducttheirtransacJons.

• InaneconomywithNgoodsplusmoney,thereareNmoneyprices.Withoutmoney,economicagentswouldneedtocalculateN(N+1)/2relaJvepricesinordertomaketheirtransacJons.Asthenumberofgoodsandservicesincreases,thenumberofrelaJvepricestobecalculatedgrowsexponenJally.Forexample,ifthereare5goodsandservices,therearefivemoneyprices,and15relaJvepricesofgoodsbetweenthem.With1000goodsandservices,thereare1000moneyprices,and500,500relaJvepricesbetweengoodsandprices.

• MoneythereforehelpstosimplifythecalculaJonofpricesandvalues,andthusfacilitateseconomictransacJonsthroughitsunitofaccountfuncJon.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 4

MoneyasaMeansofPayment• Beingacceptedbyall,moneygreatlyfacilitateseconomictransacJons

anddrasJcallyreducestheircosts.

• Withoutmoney,inordertocompleteatransacJonthesellerofaproductorservicewouldhavetofindabuyerwhowouldbepreparedtoofferinreturnanothergoodorservicethatthesellerwishestoacquire.ThisrequiresthatthereisadoublecoincidenceofwantsinalleconomictransacJons.TransacJonsorthiskindarecalledbarter,whichimplieshugecostsonthepartofeconomicagentsinordertofindsuitablecounter-parJestotheirtransacJons.

• AmoderneconomywouldimmediatelyceasefuncJoningiftherewasnotagenerallyacceptedmediumofexchangeandpayments,becausetransacJoncostswouldbecomeprohibiJve.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 5

MoneyasaStoreofValue• Moneyisastoreofvalue,i.e.ameansofholdingwealth,andis

indeedtheassetthatischaracterizedbygreaterliquidity,asitcanbeuseddirectlyforpaymentsfortheacquisiJonofgoodsandservices.

• Thisisakeyfeatureofmoney,becauseifmoneywerenotastoreofvalue,andlostitsvaluequickly,itwouldnotbegenerallyacceptedasameansofpaymentseither.Thenagain,sincemoneyistheonlystoreofvaluewhichisalsoameansofpayments,bydefiniJonitisthemostliquidstoreofvalue.

• However,asameansofholdingwealth,moneyhastheweaknessthatitdoesnotpayinterest,unlikeotherlessliquidassets.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 6

DefiningtheMoneySupply• Wedefineasmoneythesumofbanknotes,coinsanddepositsin

currentaccountsincommercialbanksheldbyhouseholdsandfirms.

• ThisdefiniJonofmoneysupplyisusuallyknownasM1.Itemphasizesthemoreliquidassetsofhouseholdsandfirms,whichusuallydonotyieldinterest.However,therearebroaderdefiniJonsofthemoneysupply,thatincludelessliquidassetssuchasJmedepositsandotherlessliquiddepositsandsecuriJes(M2,M3etc).

• DepositsofcreditinsJtuJonsandotherinsJtuJonsparJcipaJngintheinterbankmarketandtheforeignexchangemarketarenotconsideredaspartofthemoneysupply.ThesedepositsarenotusedforthetransacJonsofthegeneralpublic.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 7

TheSupplyofMoney• MonetarycondiJonsinmoderneconomiesaredeterminedbycentral

banks.

• Thecentralbankmayaffect,throughavarietyofpolicyinstrumentsatitsdisposal,boththequanJtyofbanknotes(andcoins)incirculaJon,and,indirectly,theamountofdepositsincommercialbanks,whicharealsopartofthemoneysupply.

• AlternaJvely,acentralbankmayfollowaninterestraterule,interveninginthemoneymarketandpeggingnominalinterestrates.Inthisla[ercase,thestockofmoneyintheeconomyisdeterminedbythedemandformoney,andthemoneysupplyadaptstodemandinordertoachievethegoalofthecentralbankregardingthenominalinterestrate.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 8

TheRolesofCentralBanks• CentralbanksarepublicinsJtuJonsthatmanageastate’smoney

supply,interestratesandregulatethecommercialbankingsystem.Inmostcountriesthecentralbankpossessesamonopolyonprin9ngnotes,andmin9ngcoins,whichserveasthestate’slegaltender.InaddiJon,centralbanksusuallyactaslendersoflastresorttothebankingsystemand,inmanycases,thegovernment.CentralbankscanthusdirectlydeterminethecirculaJonofnotes(andcoins)andindirectlytheamountofdepositsincommercialbanks.

• ThedeterminaJonofthemoneysupplybycentralbanksisnotasimpleprocess.ItdependsontherulesunderwhichthecentralbankparJcipatesinmoneyandassetmarketsandregulatesthefinancialsystem,onitsrelaJonswiththegovernment,andonthegoalsenvisagedinitscharter.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 9

TheGoalsandPolicyInstrumentsofCentralBanks

• Themaingoalsofacentralbankarethecontrolofinfla9on,thestabilityofthefinancialsystem,andinsomecases,thesupportofthegeneraleconomicpoliciesofthegovernment.

• InwhatfollowsweshallignoremanyoftheinsJtuJonaldetailsthatrelatetohowacentralbankoperates,andwillmaketwoalternaJvesimpleassumpJons.

• First,weshallassumethatthecentralbankhasfullcontrolofthemoneysupply.ThisisanassumpJonwithalonghistoryinmacroeconomicanalysis,althoughnotparJcularlyrealisJc,ascentralbankshaveimperfectcontroloverthemoneysupply.

• AlternaJvelyweshallassumethatthecentralbankfollowsapolicyofpeggingthenominalinterestrateandcommi^ngtoprovidingunlimitedcredittohouseholds,businessesandcommercialbanksatthisrate.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 10

TheDemandforMoney• Thedemandformoneydependsonthreemainfactors.

• Thefirstfactoristhepricelevel.Thehigherthelevelofprices,thehigherwillbetheamountofmoneythathouseholdsandfirmswouldwanttoholdfortheircurrentandfuturetransacJons.ThedemandformoneyisusuallyassumedtobeproporJonaltothepricelevel.

• ThesecondfactoristhevolumeoftransacJons.WhenthevolumeoftransacJons,usuallymeasuredbyaggregaterealoutput,increases,householdsandfirmswillneedmoremoneytocarryouttheirincreasedtransacJons.

• Thethirdfactoristhelevelofinterestrates.Banknotespaynointerest.Ontheotherhand,demanddepositsandcurrentaccounts,evenwhentheypayinterest,payaverylowratecomparedtotheyieldsoflessliquidassetssuchasJmedeposits,treasurybillsorbonds.Consequently,thedemandformoneywilldependnegaJvelyonthenominalinterestrate,asthenominalinterestratemeasurestheopportunitycostofholdingmoney.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 11

TheMoneyDemandFuncJon

M d = P ×m(Y ,i)

whereMdisthequanJtyofmoneydemanded,Pisthepricelevel,Yreal

aggregateoutputandincome(GDP)andithenominalinterestrate.misafuncJonincreasinginrealaggregateincomeanddecreasinginthenominalinterestrate.

ThedemandformoneyisproporJonaltothepricelevel,inthesensethatanincreaseinthepricelevelrequiresanincreaseinthequanJtyofmoneybythesameproporJon,inordertocompletethesamenumberoftransacJons.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 12

TheDemandforRealMoneyBalances

M d

P= m(Y ,i)

SincethedemandformoneyisproporJonaltothepricelevel,itcanbeexpressedasademandforrealmoneybalances.Holdingmoneyisusefulforitspurchasingpower.

TherelaJonshipbetweenrealmoneydemandandthenominalinterestrateisnegaJve,becauseholdingmoneybecomesmoreexpensiveasinterestratesrise,sincemoneydoesnotpayinterest.Therefore,householdsandfirmsreducetheamountofmoneyholdingsandincreaseholdingsofsecuriJesandotherinterestyieldingassets.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 13

TheDemandforRealMoneyBalances,theNominalInterestRateandRealIncome

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 14

ShortRunEquilibriumintheMoneyMarket

M s

P= M d

P= m(Y ,i)

TheequilibriumcondiJoninthemoneymarketisforthemoneysupplytobeequaltomoneydemandbyhouseholdsandfirms.

Intheshortrun,withpricesandincomegiven,howthemoneymarketequilibratesdependsonthemodusoperandiofthecentralbank.

Ifthecentralbankfixesthemoneysupply,theequilibraJngmechanismisthenominalinterestrate.Ifthecentralbankfixesthenominalinterestrate,theequilibraJngmechanismisthemoneysupply.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 15

ShortRunEquilibriumintheMoneyMarketwhentheCentralBankFixestheMoneySupply

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 16

AnIncreaseintheMoneySupplyandNominalInterestRates:TheLiquidityEffect

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 17

AnIncreaseinMoneyDemandandNominalInterestRates:TheLiquidityEffect

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 18

ShortRunEquilibriumintheMoneyMarketwhentheCentralBankFixestheNominalInterest

Rate

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 19

LongRunEffectsoftheMoneySupply

P = M s

m(Y ,i)

• Inthelongerterm,thepricelevelalsoadjusts.WecanseethedirecJonofthisadjustmentbyrearrangingtheequilibriumcondiJoninthemoneymarket,andsolvingforthepricelevel.Wethenget,

• Inlongrunequilibrium,aggregaterealincomeandtherealinterestrateareontheirbalancedgrowthpaths.WithconstantinflaJon,nominalinterestratesarealsoconstant.Thus,thefactorsaffecJngthedemandformoneyaregiven,andthemoneysupplydeterminesthepricelevel,withoutaffecJngtheevoluJonofrealvariables.Thispropertyiscalledlong-runneutralityofmoney.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 20

TheNeutralityofMoneyinStaJcGeneralEquilibriumModels

• TheneutralityofmoneyappliestoallstaJcgeneraleconomicequilibriummodelswithflexibleprices.

• Whatdeterminesthelevelofequilibriumrealincome,andotherrealvariablesaretheavailableresources,technology,preferences,thefuncJoningofmarkets,aswellaseconomicinsJtuJonsthatdeterminetotalfactorproducJvityandtheproducJvityofspecificfactors.

• InstaJcgeneralequilibriummodelsrealoutputandincomeandotherrealvariablesdonotdependonthemoneysupply.Moneyismerelya“veil”whichcoverstheeconomy,simplydeterminingnominalvariablessuchasthepricelevel.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 21

TheNeutralityandSuper-neutralityofMoneyinDynamicGeneralEquilibriumModels

• IndynamicgeneralequilibriummodelsweusuallydisJnguishbetweenthe“neutrality”andthe“super-neutrality”ofmoney.

• The“neutrality”ofmoneyreferstotheeffectsofaoneoffchangeinthemoneysupply,andthe“super-neutrality”ofmoneytotheeffectsoftherateofchangeofthemoneysupply.

• Theneutralityofmoneyappliestoalldynamicgeneraleconomicequilibriummodelswithflexibleprices.

• However,asthegrowthrateofmoneysupplyaffectsinflaJonandlong-termnominalinterestrates,itthusaffectsrealmoneydemand.

• The“super-neutrality”ofmoneyholdsinrepresentaJvehouseholdmodels,asmoneydoesnotaffectotherrealvariables,butdoesnotholdinoverlappinggeneraJonsmodels.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 22

LongRunNeutralityofMoneyandMonetaryReforms

• AnalternaJvewaytothinkabouttheneutralityofmoney,istoconsiderwhatwouldbetheimpactofaveryradicalchangeinthemoneysupply.SuchradicalchangestakeplaceinJmesofmonetaryreforms.Anumberofsuchhistoricalexamplesexist,whichsuggestthat,aderamonetaryreform,thepriceleveladjustsimmediatelytothenewmonetarystandard.

• Forexample,inMay1954,therewasaradicalmonetaryreforminGreece.Anewdrachmawascreated,whichamountedto1,000olddrachmas.EssenJallythisamountedtoadirectreducJoninthemoneysupplytoonethousandthoftheoldmoneysupply.AsonewouldexpectonthebasisofourmoneydemandfuncJon,thepricelevelinGreecefellimmediatelytoonethousandthofthepricelevelbeforethereform.Nothingelsechanged,otherthanthelevelofprices.

• Gradualincreasesinthemoneysupplyinthelongrunhaveeffectssimilartosuchmonetaryreforms.Thetriplingofthemoneysupplyinadecade,inthelongrunhasthesameeffectasamonetaryreforminwhichacurrencyunitisreplacedwiththreeunitsofa“new”currency.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 23

DynamicGeneralEquilibriumModelswithMoney

• TheSamuelson(1958)overlappinggeneraJonsmodel.

• RepresentaJveHouseholdModelswithMoneyintheUJlityFuncJon(PaJnkin1956,Sidrauski1967)

• OverlappingGeneraJonsModelswithMoneyintheUJlityFuncJon(Weil1987).

• Cash-in-AdvanceRepresentaJveHouseholdModels(Clower1967,GrandmontandYounes1972,Lucas1980,1982,Svensson1985).

• Cash-in-AdvanceModelsofOverlappingGeneraJons(Samuelson-Lucas).

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 24

TheSamuelsonOverlappingGeneraJonsModel:MoneyasaStoreofValue

• WeassumethattheeconomyconsistsofsuccessivegeneraJonsofhouseholds,eachofwhichlivesfortwoperiods.

• Everyhouseholdhasexogenousincomey1inthefirstperiodoflifeandy2inthesecondperiodoflife.

• Thisincomeisintheformofanonstorablegood,whichcannotbetransferredfromperiodtoperiod.

• Theonlynon-perishablecommodityismoney,whichcanbeusedasameansofholdingwealth.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 25

TheInter-temporalOpJmizaJonProblemofHouseholds

ΤhehouseholdborninperiodtmaximizestheuJlityfuncJon,

Ut = u(C1t )+ βu(C2t+1) = lnC1t + β lnC2t+1

PtC1t +Mt = PtY1

Pt+1C2t+1 = Mt + Pt+1Y2

undertheconstraints,

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 26

DefiniJonsofVariablesandParameters

C1ishouseholdconsumpJoninthefirstperiodoflifeandC2consumpJoninthesecondperiodoflife.

uisaconcaveuJlityfuncJonandβ=1/(1+ρ)thediscountfactor,whereρisthepurerateofJmepreference.

Mtisthemoneysupply,carriedoverbythehouseholdfromthefirsttoitssecondperiodoflife.Themoneysupplyisequaltothesavingsofhouseholdsintheirfirstperiodoflife.

PtisthemoneypriceoftheconsumpJongoodinperiodtandPt+1themoneypriceoftheconsumpJongoodinperiodt+1.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 27

ConsumpJonofYoungandOldHouseholdsinPeriodt

PtC1t =1

1+ βPtY1 + Pt+1Y2( )

PtC2t = M + PtY2

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 28

GoodsMarketEquilibriumandMoneyDemand

C1t +C2t = Y1 +Y2

MPt

= 11+ β

βY1 −Pt+1PtY2

⎛⎝⎜

⎞⎠⎟

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 29

EquilibriumPriceLevel

MP*

= 11+ β

βY1 −Y2( )

P*> 0⇔ βY1Y2

>1

Thedemandformoney,andhencethepricelevel,willbeposiJveonlyifthediscountedfirstperiodincomeofhouseholdsexceedssecondperiodincome.Itisonlythenthatsavings,andhencemoneydemand,willbeposiJve.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 30

PriceAdjustmentEquaJon

Pt+1 − P*=βY1Y2(Pt − P*)

• Sincethepricelevelisanonpredeterminedvariable,thecondiJonforthestabilityofthedynamicadjustmenttotheequilibriumpricelevelP*isthattherootofthedifferenceequaJonaboveisgreaterthanone.Consequently,thecondiJonfortheexistenceofaposiJveequilibriumpricelevelcoincideswiththecondiJonforthestabilityoftheequilibrium.IfβY1/Y2>1,thenaposiJveequilibriumpricelevelexists,andinaddiJontheequilibriumisasaddlepoint,i.e.dynamicallystable.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 31

ImplicaJonsoftheSamuelsonModel

• TheSamuelsonmodelhasastrikingimplicaJon:Moneyimproveswelfare,becauseitallowshouseholdstoengageininter-temporaltradeandsmoothconsumpJonoverJme.

• Intheabsenceofmoney,consumpJonineachperiodwouldhavetobeequaltocurrentincomeforallgeneraJons.ThisequilibriumisclearlysubopJmalcomparedwiththeequilibriumofamonetaryeconomywhichallowsforconsumpJonsmoothing.

• TheSamuelsonmodelofoverlappinggeneraJonsisoneofthefirstdynamicgeneralequilibriummodelsthatgenerateaposiJvedemandformoneyasastoreofvalue.TheneutralityofmoneyfollowsimmediatelyfromthemoneydemandfuncJon.Moreover,inthismodel,sincethepricelevelisanonpredeterminedvariable,theincreaseinthepricelevelwouldhappenimmediately.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 32

WeaknessesoftheSamuelsonModel

• Thefirstweaknessisthattheequilibriumwehavejustdescribed,whichentailsaposiJvedemandformoney,isnotunique.Thereisasecond,subopJmal,equilibrium,withzeromoneydemand.Thusthedemandformoneyinthismodelisextremelyfragile.

• AsecondweaknessofthismodelisthatthereisnoalternaJvestoreofvalue.Theonlywaytosaveinthismodelisbyholdingmoney.However,ifthereisanalternaJveassetwhichpaysinterest,forexamplebondsorcapital,thenmoneywouldbeostracizedfromthiseconomy,becauseitsonlyroleisasastoreofvalue,andmoneydoesnotpayinterest.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 33

MulJplicityofEquilibriumintheSamuelsonModel

Twolong-runequilibria:

MPt+1

= MPt

Y2βY1 − (1+ β ) M / Pt( )

MP*

= 11+ β

βY1 −Y2( ) andMP**

= 0

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 34

MulJplicityofEquilibriumintheSamuelsonModel

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 35

UniqueEquilibriumiftheOldHavenoIncome

IfY2=0thenthereisauniqueequilibrium,

MP*

= β1+ β

Y1

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 36

MoneyintheUJlityFuncJonofaRepresentaJveHousehold

ThereisarepresentaJvehouseholdmaximizinganinter-temporaluJlityfuncJonoftheform,

Ut = β s−tu(Cs ,Ms

Ps)

s=t

∞∑

undertheconstraint,

Cs +Ms

Ps+ BsPs

= Ys −Ts +Ms−1

Ps+ (1+ is−1)Bs−1

Ps

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 37

LagrangeFuncJonandFirstOrderCondiJon

Et β s−t u(Cs ,Ms

Ps)+ λs

Ms−1

Ps+ (1+ is−1)Bs−1

Ps+Ys −Ts −Cs −

Ms

Ps− BsPs

⎛⎝⎜

⎞⎠⎟

⎝⎜⎞

⎠⎟s=t

∞∑

λt =∂u∂Ct

λtPt

= β(1+ it )Etλt+1Pt+1

⎛⎝⎜

⎞⎠⎟

λtPt

= 1Pt

∂u∂Mt

+ βEtλt+1Pt+1

⎛⎝⎜

⎞⎠⎟

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 38

InterpretaJonofFirstOrderCondiJons

• First,isthestaJcfirstordercondiJon,accordingtowhich,themarginaluJlityofconsumpJonshouldinanyperiodisequaltothe“shadowvalue”ofmarginalsavings.EssenJally,thehouseholdshouldbeindifferentatthemarginbetweenconsumpJonandsavings.

• SecondisthedynamicfirstordercondiJon,accordingtowhichthetotalexpectedrealreturnonsavingsshouldbeequaltothepurerateofJmepreferenceofthehousehold.

• ThirdisthedynamicfirstordercondiJonaccordingtowhichthemarginaluJlityofrealmoneybalancesisequaltothedifferenceofthepurerateofJmepreferencefromtheexpectedrealreturnofmoney,takingintoaccountexpectedinflaJonandexpectedcapitalgainsfromachangeinλ.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 39

TheUJlityFuncJonandtheMoneyDemandFuncJon

u = ln γ Ct( )ε + (1− γ ) Mt

Pt

⎛⎝⎜

⎞⎠⎟

ε⎛

⎝⎜

⎠⎟

Mt

Pt= γ1− γ

it1+ it

⎛⎝⎜

⎞⎠⎟

− 11−εCt =

γ1− γ

it1+ it

⎛⎝⎜

⎞⎠⎟

− 11−εYt

AssumingthattheperiodicuJlityfuncJonutakestheform,

ImposingthegoodsmarketequilibriumcondiJonCt=Yt,thefirstordercondiJonsimplythat,

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 40

TheCash-in-AdvanceConstraintandMoneyDemand

• Thebasicideaofmodelsinwhichmoneyistheonlymeansofpayment,isthatinordertocompleteanyeconomictransacJon,paymentmustbeinmoney,andinparJcularcash,whichthebuyerholdsinadvanceofthecompleJonofthetransacJon.

• ThisideaisduetoClower(1967),anditsintegraJonintogeneralequilibriummodelsleadstoaclassofmodelsknownascash-in-advancemodels.

• TherestricJonthatthetransacJonmustbepaidwithmoneyheldinadvance,imposesacostofholdingmoney,because,alternaJvely,economicagentscouldholdanotherasset,suchasbonds,whichpaysinterest.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 41

AlternaJveCash-in-AdvanceModels

• ThecashinadvancerestricJoncantakeseveralforms,dependingontheassumpJonsmadeaboutthesequencingoftransacJons.AsimpletradiJonalwayofexpressingthisconstraintistoassumethatspendingcannotexceedthemoneybalancescarriedoverfromtheendofthepreviousperiod(Svensson1985).

• AnalternaJvehypothesisisthateachperiodconsistsoftwodifferentsub-periods.Inthefirstsub-periodagentsvisitafinancialmarket,sayabank,wheretheycanswapinterestbearingassetswithmoney,orborrowcash,andinthesecondsub-periodtheydealinmarketsforgoodsandservices,whichareliabletothecash-in-advanceconstraint(seeHelpman1981,Lucas1980,1982).

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 42

TheCash-in-AdvanceConstraintwhenHouseholdsCanVisitFinancialMarketspriorto

MakingPurchases

At = Mt + Bt

PtCt ≤ Mt

At+1 = Mt + (1+ it )Bt + Pt (Yt −Tt −Ct ) = (1+ it )At − itMt + Pt (Yt −Tt −Ct )

Inthefirstsub-periodagentsvisitafinancialmarket,sayabank,wheretheycanswapinterestbearingassetswithmoney,orborrowcash.Inthesecondsub-periodtheydealinmarketsforgoodsandservices,whichareliabletothecash-in-advanceconstraint.Inthesecondsub-period,householdsalsoreceivetheirexogenousrealincomeYandpaytheirtaxes(netoftransfers)Τ.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 43

TheLagrangianoftheRepresentaJveHouseholdandtheFirstOrderCondiJons

Et β s−t u(Cs )+ν tMt

Pt−Ct

⎛⎝⎜

⎞⎠⎟+ λt (1+ it )

AtPt

+Yt −Tt −Ct − itMt

Pt− At+1Pt

⎛⎝⎜

⎞⎠⎟

⎝⎜⎞

⎠⎟s=t

∞∑

λt +ν t =∂u∂Ct

= ′u (Ct ) ν t = λtitλtPt

= βEt (1+ it+1)λt+1Pt+1

⎛⎝⎜

⎞⎠⎟

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 44

InterpreJngtheFirstOrderCondiJonsoftheRepresentaJveHouseholdwithaCash-in-

AdvanceConstraint• FirstisthestaJcfirstordercondiJonaccordingtowhichtheopJmal

consumpJonequatesthemarginaluJlityofconsumpJonwiththe“shadowvalue”ofsavingsλ,plustheshadowvalueofmoneyν.TheshadowvalueofmoneyresultsfromtherestricJonforcashinadvanceinordertobuyconsumergoods.

• Secondisthedynamicfirst-ordercondiJon,accordingtowhichthetotalexpectedrealreturnonsavings,includingexpectedinflaJonandexpectedcapitalgains,shouldbeequaltothepurerateofJmepreferenceofthehousehold.

• ThirdisthestaJcfirstordercondiJonaccordingtowhich,theshadowvalueofmoneyshouldbeequaltotheshadowvalueofsavingsJmestheopportunitycostofholdingmoney,whichisnoneotherthanthenominalrate,sincemoneypaysnointerest.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 45

TheEulerEquaJonandtheMoneyDemandFuncJonintheCash-in-AdvanceRepresentaJve

HouseholdModel

′u (Ct )Pt

= β(1+ it )Et′u (Ct+1)Pt+1

⎛⎝⎜

⎞⎠⎟

FromthefirstordercondiJonwecanderivetheEulerequaJonforconsumpJoninamonetaryeconomy.

Mt

Pt= Ct

ThemoneydemandfuncJonisderivedfromthecash-in-advanceconstraint.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 46

TheEulerEquaJonforConsumpJonandtheNominalInterestRatewithLogarithmic

Preferences

1PtCt

= β(1+ it )Et1

Pt+1Ct+1

⎛⎝⎜

⎞⎠⎟

Assuminglogarithmicpreferences,theEulerequaJonforconsumpJoncanbewri[enas,

11+ it

= βEtMt

Mt+1

⎛⎝⎜

⎞⎠⎟

FromtheEulerequaJonaboveandthemoneydemandfuncJonitfollowsthatthenominalinterestrateisdeterminedby

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 47

Cash-in-AdvanceinanOverlappingGeneraJonsModel

WefinallyexaminetheimplicaJonsformoneydemandofacashinadvanceconstraintinavariantoftheSamuelsonoverlappinggeneraJonsmodels.Inthismodel,moneyfuncJonsbothasameansofpaymentsandastoreofvalue.

Thehouseholdborninthebeginningofperiodtlivesfortwoperiods,periodtandperiodt+1.ItreceivesincomeYtandpaystaxesTt,inthefirstperiodoflife,andconsumesinbothperiods.

Itmaximizesaninter-temporaluJlityfuncJonundertheconstraintsthatthepresentvalueofconsumpJonmustbeequaltothepresentvalueofincomenetoftaxes,andthecash-in-advanceconstraintsforeachperiod.

Ut = lnC1t + β lnC2t+1

PtC1t ≤ M1t Pt+1C2t+1 ≤ M 2t+1PtCt +11+ it

Pt+1C2t+1 = Pt (Yt −Tt )

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 48

Cash-in-AdvanceinanOverlappingGeneraJonsModel

AggregateconsumpJonandaggregatemoneybalancesineachperiodaregivenby,

Ct = C1t +C2t Mt = M1t +M 2t

TotalassetsofhouseholdsareequaltoA,andweassumethatyounghouseholdsarebornwithoutassets.Asaresult,allassetsbelongtotheoldhouseholds.ForsimplicityweassumethattaxesTareonlypaidbyyounghouseholds.

Giventhatoldhouseholdsreceivenocurrentincome,theirconsumpJonisequaltotheirassets,which,however,theyneedtoconvertintomoney,inordertopurchaseconsumergoods.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 49

Cash-in-AdvanceinanOverlappingGeneraJonsModel

ConsumpJonofoldhouseholdsisthusgivenby,

C2t =AtPt

Giventhatyounghouseholdsholdnoassets,theyneedtoborrowandconverttheirloanintomoney,inordertofinancetheirconsumpJon.Asaresult,foryounghouseholdsthefollowingconstraintsmusthold,

M1t = PtC1t = −B1t

At+1 = M1t + (1+ it )B1t + Pt Yt −Tt −C1t( ) = Pt Yt −Tt − (1+ it )C1t( )

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 50

Cash-in-AdvanceinanOverlappingGeneraJonsModel

IntroducingassetsinplaceofsecondperiodconsumpJonintheuJlityfuncJon,wefindthatyounghouseholdswillchooseconsumpJonintheirfirstperiodoflifeinordertomaximize,

Ut = lnC1t + β lnPt Yt −Tt − (1+ it )C1t( )

Pt+1

⎛⎝⎜

⎞⎠⎟

C1t =1

1+ βYt −Tt1+ it

FromthefirstordercondiJonsitfollowsthat,

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 51

Cash-in-AdvanceinanOverlappingGeneraJonsModel

AggregateconsumpJoninperiodtisgivenby,

Ct = C1t +C2t =1

1+ βYt −Tt1+ it

+ AtPt

Yt = Ct =1

1+ βYt −Tt1+ it

+ AtPt

Fromequilibriuminthemarketforgoodsandservicesandmoneyitfollowsthat,

Thesecanbesolvedforthepricelevelandthenominalinterestrate.Theneutralityofmoneyholdssincerealincomeisexogenous.

Mt = PtYt

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 52

NominalandRealInterestRates:MoneyintheUJlityFuncJon

Withlogarithmicpreferences,thefirstordercondiJonsforthemaximizaJonoftheuJlityfuncJonoftherepresentaJvehouseholdaregivenby,

λt =γCt

FromthesecondiJons,itfollowsthat,

λtPt

= β(1+ it )Etλt+1Pt+1

⎛⎝⎜

⎞⎠⎟

λtPt

= 1− γMt

+ βEtλt+1Pt+1

⎛⎝⎜

⎞⎠⎟

1PtCt

= β(1+ it )Et1

Pt+1Ct+1

⎛⎝⎜

⎞⎠⎟

1PtCt

= 1− γγ

1Mt

+ βEt1

Pt+1Ct+1

⎛⎝⎜

⎞⎠⎟

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 53

NominalandRealInterestRates:MoneyintheUJlityFuncJon

ThelastfirstordercondiJoncanbesolvedas.

1PtCt

= 1− γγ

β s−tEt1Ms

⎛⎝⎜

⎞⎠⎟s=t

∞∑

GiventhatCt=Ytwhichisexogenous,thisequaJondeterminestheequilibriumpricelevel,asafuncJonofexpectaJonsaboutthefutureevoluJonofthemoneysupply.SubsJtuJnginthemoneydemandequaJonforε=0,andsolvingforthenominalinterestrate,

1+ itit

= γ1− γ

Mt

PtCt

= β s−tEtMt

Ms

⎛⎝⎜

⎞⎠⎟s=t

∞∑

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 54

NominalandRealInterestRates:MoneyintheUJlityFuncJon

ThenominalinterestratesisdeterminedbythecurrentmoneysupplyandexpectaJonsaboutthefuturedevelopmentofthemoneysupply,atarateofdiscountthatdependsonthepurerateofJmepreferenceofthehousehold.Supposetheexpectedgrowthrateofthemoneysupplyisconstantandequaltoμ.

1+ itit

= β s−t 11+ µ

⎛⎝⎜

⎞⎠⎟s=t

∞∑s−t

= 11+ ρ( ) 1+ µ( )

⎛⎝⎜

⎞⎠⎟s=t

∞∑s−t

= (1+ ρ)(1+ µ)(1+ ρ)(1+ µ)−1

Itfollowsthat,

it = (1+ ρ)(1+ µ)−1! ρ + µ

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 55

NominalandRealInterestRates:MoneyintheUJlityFuncJon

Thehigherthegrowthrateofmoneysupplyμ,thehigherwillbethenominalinterestratei,astheexpectedfutureinflaJonratewillbehigher.

ItisworthnoJngthattherealequilibriuminterestrateinthemodelisequaltoρ.Forμ=0,i=ρ.Inthiscase,becausetheexpectedfutureinflaJonrateisequaltozero,thenominalinterestrateequalstheequilibriumrealinterestrate,i.e.thepurerateofJmepreferenceoftherepresentaJvehousehold.

ItisworthnoJngthatifμ=-ρ/(1+ρ),i.e.ifthemoneysupplyisreducedatthisrate,thenominalinterestrateisdriventozero.Azeronominalinterestratehasa[racJveproperJesandleadstotheop9malmoneydemandbyhouseholds.

it = (1+ ρ)(1+ µ)−1! ρ + µ

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 56

NominalandRealInterestRates:Cash-in-Advance

IntherepresentaJvehouseholdmodelinwhichmoneydemandresultsfromthecash-in-advanceconstraint,undertheassumpJonoflogarithmicpreferences,thenominalinterestrateisdeterminedby,

it = (1+ ρ)(1+ µ)−1! ρ + µ

11+ it

= βEtMt

Mt+1

⎛⎝⎜

⎞⎠⎟= β 1

1+ µ⎛⎝⎜

⎞⎠⎟= 1(1+ ρ)(1+ µ)

FromthiscondiJon,itfollowsthat,

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 57

TheIndeterminacyofthePriceLevelwhentheCentralBankpegstheNominalInterestRate:

MoneyintheUJlityFuncJon

FromtheequilibriumcondiJonsinthegoodsandmoneymarkets,ifthecentralbankpegsthenominalinterestrateattheleveli0,thentherepresentaJvehouseholdmodelwithmoneyintheuJlityfuncJon,impliesthat,

Mt

Pt= 1− γ

γ1+ i0i0

Yt

Giventhatrealincomeisexogenous,thiscondiJonissaJsfiedforaninfinitenumberofcombinaJonsofΜandP.IfitissaJsfiedforM0andP0,itisalsosaJsfiedforλM0andλP0,foranyλ.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 58

TheIndeterminacyofthePriceLevelwhentheCentralBankpegstheNominalInterestRate:

Cash-in-Advance

FromtheEulerequaJonforconsumpJonandtheequilibriumcondiJoninthegoodsmarket,itfollowsthat,

Pt+1Yt+1 = β(1+ i0 )PtYt

Giventhatrealincomeisexogenous,thiscondiJonissaJsfiedforaninfinitenumberofcombinaJonsofPtκαιPt+1.IfitsaJsfiedforP0andP1,thenitisalsosaJsfiedforλP0andλP1,foranyλ.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 59

InterestRatePeggingandPriceLevelIndeterminacy

ThisindeterminacywasfirstdemonstratedbySargentandWallace(1975)inthecontextofanadhocmacromodelwithraJonalexpectaJons.ThisindeterminacydoesnotonlyariseinrepresentaJvehouseholdmonetarymodels,butinmoneymodelswithraJonalexpectaJons.

Thereasonfortheindeterminacyisthat,underinterestratepegging,thereisnomonetaryanchorwhichcandeterminethepricelevel,asinthecasewherethecentralbankdeterminesthemoneysupply.

Sincethecentralbankiscommi[edtoprovidingunlimitedcreditatanominalinterestratei0,thenthemoneysupplyisdeterminedbythedemandformoney.Neitherthepricelevel,northemoneysupplycanbeidenJfieduniquely.

TheequilibriumcondiJonsforprivateconsumpJonandmoneydemandcanbesaJsfiedwithbothhighpricesandaconsequenthighstockofmoney,andwithlowpricesandaconsequentlowstockofmoney,i.e.virtuallyforanylevelofprices.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 60

DealingwithPriceLevelIndeterminacyunderInterestRateRules:TheWicksellandTaylorRules

Oneofthefirstanswerstothisproblemwasprovidedbythemonetaryeconomistwhofirstrealizeditsexistence,namelyWicksell(1898).Wicksellproposedthat,“Solongaspricesremainunaltered,thebanks’rateofinterestistoremainunaltered.Ifpricesrise,therateofinterestistoberaised;andifpricesfall,therateofinterestistobelowered;andtherateofinterestishenceforthtobemaintainedatitsnewlevelunJlafurthermovementofpricescallsforafurtherchangeinonedirecJonortheother.”(p.189).Thus,Wicksellproposedthatcentralbanksshouldhaveapriceleveltarget,andchangeinterestrateswhenthepriceleveldeviatesfromthistarget.

AlternaJvewaystosolvetheproblemofpricelevelindeterminacywhenthepolicyinstrumentofthecentralbankisthenominalinterestrate,havebeenproposed:InflaJontargeJngrules,nominalincomerules,andmorerecentlytheTaylor(1993),whichisageneralizaJonofWicksell’srule.WeshallexaminetheproperJesofsuchrulesinthelecturesonaggregatefluctuaJonsandmonetarypolicy.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 61

TheFiscalTheoryofthePriceLevel

OnetheoreJcaldevelopmentworthmenJoningistheso-calledfiscaltheoryofthepricelevel(see.Leeper1991,Sims1994andWoodford1994,1995).

Thistheoryarguesthatevenifmonetarypolicyisnotsufficienttodeterminethepricelevel,asunderinterestratepegging,thepricelevelcanbedeterminedatthelevelwhichensuresthatpublicdebt,whichisdefinedinnominalterms,doesnotfollowanexplosivepath.

ApathforthepricelevelthatensuresapathofnominalpublicdebtthatsaJsfiestheinter-temporalbudgetconstraintofthegovernmentissufficientinthosemodelstodeterminethepricelevel.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 62

PriceLevelDeterminacyinOverlappingGeneraJonsModelsandthePigouEffect

ItisalsoworthstressingthattheproblemofpricelevelindeterminacydoesnotariseinoverlappinggeneraJonsmodels.UnliketherepresentaJvehouseholdmodel,whereboththecurrentandthefuturepricelevelarenonpredeterminedvariables,intheoverlappinggeneraJonsmodel,thepricelevelisdeterminedthroughthepredeterminednominalfinancialassetsof“old”households.ThesefuncJonasamonetaryanchorandhelpindeterminingthepricelevel.

IntradiJonalmonetarymodels,thedependenceofconsumpJononthefinancialwealthofhouseholdswascalledthePigoueffect(seePigou1943),ortherealbalanceeffect(seePaJnkin1956).AsSargentandWallace(1975)hadindicatedintheiroriginalanalysisofpricelevelindeterminacy,inthepresenceofaPigouorrealbalanceeffect,theproblemdoesnotariseevenifthecentralbankpegsthenominalinterestrate.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 63

SeigniorageandInflaJon• If the growth of the money supply translates into higher inflation in the longer

term, why don’t governments and central banks keep the rate of growth of the money supply low and stable in order to control and eliminate inflation?

• The answer is that governments often have other policy motives besides the motive of tackling inflation. Perhaps the most important incentive for the issuance of new money by governments is to finance expenditure that they cannot, or do not want to, finance through other methods, such as higher taxes or higher government debt.

• The main cause of all the episodes of high inflation or hyperinflation appears to have been the need of governments to use revenue from money creation (seigniorage) to finance wars and war reparations, revolutions, extraordinary costs related to natural disasters or sudden reductions in their borrowing capacity from financial markets and their capacity to raise revenue from taxes and customs revenues.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 64

HighInflaJonandHyperinflaJon

• WeexploretherelaJonshipbetweenthegrowthrateofmoneysupply,inflaJonandtheneedsofgovernmentstoraiserevenuethroughseigniorage.

• Weexamineboththecaseinwhichtherequiredincomefromseignioragecanberaisedonthebalancedgrowthpath,asituaJoninwhichequilibriumturnsouttobecharacterizedbyhighinfla9on,andthesituaJoninwhichtherequiredrevenuefromseigniorageissohigh,thatitcannotberaisedinsteadystateequilibrium,whichcanleadtohyperinfla9on.

• ThegenerallyaccepteddefiniJonofhyperinflaJonisduetoCagan(1956).CagandefinedaaperiodofhyperinflaJonasone“beginninginthemonthinwhichtheriseinpricesexceeds50%andasendinginthemonthbeforethemonthlyriseinpricesdropsbelowthatamountandstaysbelowforatleastayear.”

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 65

EpisodesofHighInflaJonandHyperinflaJon

• ThefirstmodernepisodesofhyperinflaJonoccurredinEuropeintheadermathofWorldWarI,aswellasduringandintheadermathofWorldWarII.

• InthelastfortyyearsveryhighinflaJonandhyperinflaJonreappearedinsomeLaJnAmericancountries,insometransiJoneconomiesaderthecollapseoftheSovietUnionandinsomebelligerentcountriesofAsiaandAfrica.

• Moreover,manycountries,withoutreachingthelevelsofhyperinflaJon,haveexperienceswithhighinflaJonfrom100%to1000%peryearforquitelongperiods.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 66

MonetaryGrowth,InflaJonandSeigniorage:TheDemandforMoneyFuncJon

InordertostudytherelaJonbetweentherateofgrowthofthemoneysupply,inflaJonandrevenuefromseigniorage,weshallstartfromalinearlogarithmicformofthemoneydemandfuncJon.Inequilibrium,thedemandformoneyequalsthesupplyofmoney,soitfollowsthat,

κisaconstant,ethebasisofnaturallogarithms,καιη>0thesemi-elasJcityofmoneydemandwithrespecttothenominalinterestratei.

MP

=κYe−ηi

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 67

MonetaryGrowth,InflaJonandSeigniorage:NominalandRealInterestRates

ThenominalinterestrateisdefinedbytheFisherequaJon,

whereristherealinterestrate,andπeexpectedinflaJon.

RealOutputYisconsideredexogenous,withagrowthrateg+n>0,whiletherateofgrowthofthenominalmoneysupplyMisdenotedbyμ>0.

UndertheseassumpJon,inflaJononthebalancedgrowthpath,saJsfies,

i = r +π e

π = µ − (g + n)

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 68

TheDemandforMoneyandtheRateofGrowthoftheMoneySupply

AssumingraJonalexpectaJons,themoneydemandfuncJoncanthusbewri[enas,

Tofurthersimplifyma[ers,weshallassumethatthegoldenruleappliesonthebalancedgrowthpath,whichimpliesthatr=g+n.UnderthisaddiJonalassumpJon,

MP

=κYe−η(r+µ−(g+n))

MP

=κYe−ηµ

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 69

SeigniorageRevenueandRateofGrowthoftheMoneySupply

Seignioragerevenueisequalto,

AsaproporJonoftotaloutput,seignioragerevenueisdefinedby,

S = M•

P= M

MMP

= µ MP

= µκYe−ηµ

s = SY= µ M

PY= µκ e−ηµ

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 70

MaximizingSeigniorageRevenueSeignioragerevenuesasaproporJonoftotaloutput,dependonμ,accordingto,

ThisdependenceisposiJveinμ,uptothepointwhereμ=1/η.Whenμ>1/ηthedependencebecomesnegaJve.Seignioragerevenue,asaproporJonoftotaloutputisthusmaximizedwhenμ=1/η.Maximumseignioragerevenueinsteadystateisthusgivenby,

∂s∂µ

= (1−ηµ)κ e−ηµ

smax =κλe

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 71

TheSeigniorageLafferCurve

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 72

TheRateofGrowthoftheMoneyandMaximumSeigniorageRevenue

• Cagan,usingannualdata,esJmatedthatηliesbetween1/2and1/3.Consequently,heesJmatedthegrowthrateofthemoneysupplythatmaximizesrevenuesfromseigniorage,asapercentageoftotaloutput,andthecorrespondinginflaJon,atbetween200%and300%peryear.

• Assumingthatκ=0.10,themaximumrevenuefromseigniorageasapercentageoftotaloutputisbetween7-11%.ThisisroughlytheesJmateofCagan(1956).

• Fortheperiod1975-1985,SachsandLarrain(1993)esJmatedactualrevenuefromseigniorageatabout5to6.5%forhighinflaJoncountriessuchasItaly,Bolivia,TurkeyandPeru,andmuchlowerforaseriesofothercountries.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 73

HighInflaJonBalancedGrowthPath

• LetusnowconsideragovernmentwhichneedstofundaproporJonofitspublicspendingthroughseigniorage.Wewillassumethatthisfinancingrequirement,asaproporJonoftotaloutputisequaltosE,whichislessthanthemaximumseignioragesmaxthatthegovernmentcanachievebyse^ngthegrowthrateofthemoneysupplyatμ=1/η.

• TherearetwoopJonstoachieverevenueequaltosE.OneiswithagrowthrateofthemoneysupplyμE<1/η,andtheotheriswithagrowthrateofthemoneysupplyμE΄>1/η.

• AssumingthatthegovernmentdislikesinflaJon,itwillchoosethelowestgrowthrateofthemoneysupplythatiscompaJblewiththeobjecJveofraisingrevenuesEfromseigniorage.

• ForaslongasthegovernmentneedstofinanceaproporJonsEofitsoutputthroughseigniorage,theeconomyistrappedinanequilibriumwitharateofgrowthofthemoneysupplyequaltoμEandthecorrespondinghighinflaJon.Forexample,ifthegovernmentwantstoraiseseignioragecorrespondingto6%oftotaloutput,assumingη=1/2,thisimpliesanannualgrowthrateofthemoneysupply(andcorrespondingsteadystateinflaJon)equaltoabout100%.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 74

AHighInflaJonBalancedGrowthPath

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 75

SeigniorageRevenueOutsidetheBalancedGrowthPath:GradualAdjustmentofMoney

DemandorGradualAdjustmentinExpectaJons• Supposenowthatthegovernmentneedstoraiseseigniorage

which,asaproporJonoftotaloutput,ishigherthanthemaximumthatcanberaisedinthesteadystate.WeassumesE>smax.

• Obviouslytherecanbenobalancedgrowthpathinwhichthegovernmentcanraiserevenuesfromseignioragetoexceedssmax.

• However,foraJme,andastheeconomyadjuststowardsthebalancedgrowthpath,thegovernmentmaybeabletoraiseseignioragerevenuesgreaterthansmax.Thiscouldhappenifforexamplethereisgradualadjustmentinthedemandformoney,orgradualadjustmentininflaJonaryexpectaJons.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 76

SeigniorageRevenueOutsidetheBalancedGrowthPath:GradualAdjustmentofMoney

Demand• Supposethatthedemandformoneydoesnotadjustimmediatelytoitssteady

stateleveladerachangeinthenominalinterestrate,butonlyadjustsgradually.Thus,whenthenominalinterestrateincreases,moneydemandistemporarilyhigherthaninthesteadystate.

• Inthiscase,duringtheadjustment,themonetarybaseuponwhichtheinflaJonarytaxisimposedishigherthanthesteadystatemonetarybase.Consequently,duringtheadjustment,asμincreases,seignioragerevenueswillexceedsmaxbecauserealmoneybalancesarehigherthanonthebalancedgrowthpath.

• Asthedemandformoneydecreasesgradually,thegovernmentshouldconstantlyincreasetherateofmonetaryexpansionandtheconsequentinflaJon,tobeabletohavetherequiredhighrevenuesfromseigniorage.Thiscanleadtoanexplosivepathfortherateofgrowthofthemoneysupply,andaconsequenthyperinflaJon.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 77

GradualAdjustmentinMoneyDemand

Assumethat,intheshortrun,realmoneydemandadjustsgraduallytowardsitssteadystatevalueaccordingto,

d lnm(t)dt

= m•(t)

m(t)=ψ lnm*− lnm(t)( )

where,ψisthespeedofadjustment,and,

m(t) = M (t)P(t)Y (t)

m*= MPY

=κ e−ηµ

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 78

MonetaryGrowthandtheGradualAdjustmentinMoneyDemand

SubsJtuJngforthedeterminantsofsteadystatemoneydemandm*,theadjustmentofmoneydemandtakestheform,

m•(t)

m(t)=ψ lnκ −ηµ(t)− lnm(t)( )

InordedtoachieveaconstanttargetsEforseignioragerevenue,therateofgrowthofthemoneysupplymustbeequaltotherateofreducJonofthedemandforrealmoneybalances

sE = µ(t)m(t) µ•(t)

µ(t)= − m

•(t)

m(t)and

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 79

DynamicAdjustmentoftheRateofGrowthoftheMoneySupply

inordertomaintainrevenuesfromseigniorageconstantasapercentageoftotalincomeatthelevelsE,thegrowthrateofthemoneysupplymustkeepincreasingconJnuously,atthesamerateasthedeclineofrealmoneydemandrelaJvetooutput.FromthepreviousequaJonsthisimpliesthat,

µ•(t)

µ(t)= −ψ lnκ − ln sE + lnµ(t)−ηµ(t)( )

sE = µκ e−ηµ ≤ smax

AnecessaryandsufficientcondiJonforstabilizingtherateofgrowthofthemoneysupplyisthat,

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 80

TransiJontoHyperinflaJon

IfsE>smaxthentherateofgrowthofthemoneysupplyincreasesconJnuously.Aderapointitstartsincreasingatanincreasingrate,withtheresultanexplosivepathfortherateofgrowthofthemoneysupplyandinflaJon.TheresultishyperinflaJon.

µ•(t)

µ(t)= −ψ lnκ − ln sE + lnµ(t)− λµ(t)( )

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 81

HighInflaJonandHyperinflaJonwithParJalAdjustmentinMoneyDemand

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 82

RequiredSeigniorageRevenue,MoneySupplyGrowthandInflaJon• Inthecasewherethefinancingneedsofthegovernmentfromseigniorage

arelessthanorequaltothemaximumpossibleonthebalancedgrowthpath,thentherateofgrowthofthemoneysupplystabilizesataratethatmayindeedentailsignificantinflaJon,butinflaJonisstableanddoesnotevolveintohyperinflaJon.

• However,ifthefinancingneedsofgovernmentexceedthemaximumthatissustainableonthebalancedgrowthpath,then,asthegovernmenttriestoraisethenecessaryrevenuefromseigniorage,therateofgrowthofthemoneysupplygraduallyaccelerates,inordertokeepupwiththedecliningmonetarybase,andtheeconomyfallsintoastateofhyperinflaJon.ThereasonisthatinflaJongraduallyreducesthedemandformoneyrelaJvetototaloutput,andthegovernmentneedsaneverincreasinggrowthrateofthemoneysupplyinordertobeabletocollecttheneededseignioragerevenue.

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 83

ConclusionsontheDeterminantsofHighInflaJon

• Ourbasicanalysisexplainswhy,inmanycases,inflaJonmaybedriventoveryhighlevels.Thisisduetotheinabilityofagovernmenttofinanceitsspendingfromotherrevenuesources,suchastaxaJonorborrowingfromthemarkets,anditsneedtouseseigniorage,i.erevenuefrommoneycreaJon.

• TheanalysisalsoexplainswhyeventhoughinflaJonmayreachveryhighlevels,itisnotnecessarythatitwillevolveintoanexplosivehyperinflaJon.Forthistohappen,thefinancingneedsofthegovernmentmustbesohighthattheyexceedthemaximumlevelthatcanbefinancedthroughseigniorageonthebalancedgrowthpath.

• Finally,theanalysisemphasizesthecentralroleoffiscalproblemsasthemainrootcausesofbothhighinflaJonandhyperinflaJon.AsignificantprecondiJonfortacklinghighinflaJonorhyperinflaJonistopursuereformsthataddresstheunderlyingfiscalproblems(Sargent1982).

ProfGeorgeAlogoskoufis,DynamicMacroeconomicTheory,2015 84

FinalConclusions• InthislecturewehaveanalyzedtheroleandfuncJonsofmoney.Moneyperformsthree

funcJons.First,itisaunitofaccount,second,itisagenerallyacceptedmeansofpayment,and,thirdly,itisastoreofwealth.

• WefirstreviewedthebasicfuncJonsofmoneyandthefactorsthatdeterminethedemandforandsupplyofmoney.Weanalyzedtheconceptofshortrunequilibriuminthemoneymarket,assumingthatthecentralbankfollowsapolicyofeithertargeJngthemoneysupplyorpeggingnominalinterestrates,andalsodefinedthenoJonofthelong-termneutralityofmoney.

• Wethenfocusedonanumberofdynamicgeneraleconomicequilibriummodelswithmoney,inordertoanalyzethedeterminaJonofthepricelevelandnominalinterestratesandalsoanalyzedthelongrelaJonshipbetweenthemoneysupply,thepricelevelandinflaJon.

• FinallyweexaminedthefiscalincenJveforincreasingthemoneysupplyanditseffectsoninflaJon.ThemostimportantmoJveforsustainedlargeincreasesinthemoneysupplybygovernmentshasbeentheincenJvetouseseigniorageinordertofinancegovernmentexpenditurethatcouldnotbefinancedbyothermethods,suchasaddiJonaltaxesorgovernmentbonds.