(1.15)-Chap16微觀經(jīng)濟學(xué)課件

OligopolyChapter16ImperfectCompetitionImperfectcompetitionreferstothosemarketstructuresthatfallbetweenperfectcompetitionandpuremonopoly.ImperfectCompetitionImperfectcompetitionincludesindustriesinwhichfirmshavecompetitorsbutdonotfacesomuchcompetitionthattheyarepricetakers.TypesofImperfectlyCompetitiveMarketsOligopolyOnlyafewsellers,eachofferingasimilaroridenticalproducttotheothers.MonopolisticCompetition

Manyfirmssellingproductsthataresimilarbutnotidentical.TheFourTypesofMarketStructureMonopolyOligopolyMonopolisticCompetitionPerfectCompetitionTapwaterCableTVTennisballsCrudeoilNovelsMoviesWheatMilkNumberofFirms?TypeofProducts?ManyfirmsOnefirmFewfirmsDifferentiatedproductsIdenticalproductsMarketsWithOnlya

FewSellersBecauseofthefewsellers,thekeyfeatureofoligopolyisthetensionbetweencooperationandself-interest.CharacteristicsofanOligopolyMarketFewsellersofferingsimilaroridenticalproductsInterdependentfirmsBestoffcooperatingandactinglikeamonopolistbyproducingasmallquantityofoutputandchargingapriceabovemarginalcostADuopolyExampleA

duopolyisanoligopolywithonlytwomembers.Itisthesimplesttypeofoligopoly.

ADuopolyExample:Demand

ScheduleforWaterADuopolyExample:Priceand

QuantitySuppliedThepriceofwaterinaperfectlycompetitivemarketwouldbedriventowherethemarginalcostiszero:P=MC=$0Q=120gallonsThepriceandquantityinamonopolymarketwouldbewheretotalprofitismaximized:P=$60Q=60gallonsADuopolyExample:Priceand

QuantitySuppliedThesociallyefficientquantityofwateris120gallons,butamonopolistwouldproduceonly60gallonsofwater.Sowhatoutcomethencouldbeexpectedfromduopolists?

Competition,Monopolies,andCartelsThe

duopolistsmayagreeonamonopolyoutcome.CollusionThetwofirmsmayagreeonthe quantitytoproduceandthepricetocharge.CartelThetwofirmsmayjointogetherandactinunison.Competition,Monopolies,andCartelsAlthougholigopolistswouldliketoformcartelsandearnmonopolyprofits,oftenthatisnotpossible.Antitrustlawsprohibitexplicitagreementsamongoligopolistsasamatterofpublicpolicy.TheEquilibriumforanOligopolyANashequilibriumisasituationinwhicheconomicactorsinteractingwithoneanothereachchoosetheirbeststrategygiventhestrategiesthatalltheothershavechosen.TheEquilibriumforanOligopolyWhenfirmsinanoligopolyindividuallychooseproductiontomaximizeprofit,theyproducequantityofoutputgreaterthanthelevelproducedbymonopolyandlessthanthelevelproducedbycompetition.TheEquilibriumforanOligopolyTheoligopolypriceislessthanthemonopolypricebutgreaterthanthecompetitiveprice(whichequalsmarginalcost).SummaryofEquilibriumforanOligopolyPossibleoutcomeifoligopolyfirmspursuetheirownself-interests:Jointoutputisgreaterthanthemonopolyquantitybutlessthanthecompetitiveindustryquantity.Marketpricesarelowerthanmonopolypricebutgreaterthancompetitiveprice.Totalprofitsarelessthanthemonopolyprofit.ADuopolyExample:Demand

ScheduleforWaterHowtheSizeofanOligopolyAffectstheMarketOutcomeHowincreasingthenumberofsellersaffectsthepriceandquantity:Theoutputeffect:Becausepriceisabovemarginalcost,sellingmoreatthegoingpriceraisesprofits.Thepriceeffect:Raisingproductionlowersthepriceandtheprofitperunitonallunitssold.HowtheSizeofanOligopolyAffectstheMarketOutcomeAsthenumberofsellersinanoligopolygrowslarger,anoligopolisticmarketlooksmoreandmorelikeacompetitivemarket.Thepriceapproachesmarginalcost,andthequantityproducedapproachesthesociallyefficientlevel.GameTheoryandtheEconomicsofCooperationGametheoryisthestudyofhowpeoplebehaveinstrategicsituations.Strategicdecisionsarethoseinwhicheachperson,indecidingwhatactionstotake,mustconsiderhowothersmightrespondtothataction.GameTheoryandtheEconomicsofCooperationBecausethenumberoffirmsinanoligopolisticmarketissmall,eachfirmmustactstrategically.Eachfirmknowsthatitsprofitdependsnotonlyonhowmuchitproducedbutalsoonhowmuchtheotherfirmsproduce.ThePrisoners’DilemmaTheprisoners’dilemmaprovidesinsightintothedifficultyinmaintainingcooperation.

Oftenpeople(firms)failtocooperatewithoneanotherevenwhencooperationwouldmakethembetteroff.ThePrisoners’DilemmaBonnie’sDecisionConfessRemainSilentConfessRemainSilentClyde’sDecisionClydegets8yearsBonniegets8yearsBonniegets20yearsBonniegets1yearBonniegoesfreeClydegets20yearsClydegets1yearClydegoesfreeThePrisoners’DilemmaThedominantstrategyisthebeststrategyforaplayertofollowregardlessofthestrategiespursuedbyotherplayers.ThePrisoners’DilemmaCooperationisdifficulttomaintain,becausecooperationisnotinthebestinterestoftheindividualplayer.Oligopoliesasa

Prisoners’DilemmaIraq’sDecisionHighProductionLowProductionHighProductionLowProductionIran’sDecisionIrangets$40billionIraqgets$40billionIraqgets$30billionIraqgets$50billionIraqgets$60billionIrangets$30billionIrangets$50billionIrangets$60billionOligopoliesasa

Prisoners’DilemmaSelf-interestmakesitdifficultfortheoligopolytomaintainacooperativeoutcomewithlowproduction,highprices,andmonopolyprofits.AnArms-RaceGameDecisionoftheUnitedStates(U.S.)ArmDisarmArmDisarmDecisionoftheSovietUnion(USSR)USSRatriskU.S.atriskU.S.atriskandweakU.S.safeU.S.safeandpowerfulUSSRatriskandweakUSSRsafeUSSRsafeandpowerfulAnAdvertisingGame

Marlboro’sDecisionAdvertiseDon’tAdvertiseAdvertiseDon’tAdvertiseCamel’sDecisionCamelgets$3billionprofitMarlborogets$3billionprofitMarlborogets$2billionprofitMarlborogets$4billionprofitMarlborogets$5billionprofitCamelgets$2billionprofitCamelgets$4billionprofitCamelgets$5billionprofitACommon-ResourcesGameExxon’sDecisionDrillTwoWellsDrillOneWellDrillTwoWellsDrillOneWellArco’sDecisionArcogets$4millionprofitExxongets$4millionprofitExxongets$3millionprofitExxongets$5millionprofitExxongets$6millionprofitArcogets$3millionprofitArcogets$5millionprofitArcogets$6millionprofitWhyPeopleSometimesCooperateFirmsthatcareaboutfutureprofitswillcooperateinrepeatedgamesratherthancheatinginasinglegametoachieveaone-timegain.

JackandJill’sOligopolyGameJack’sDecisionSell40gallonsSell30gallonsSell40gallonsSell30gallonsJill’sDecisionJillgets$1,600profitJackgets$1,600profitJackgets$1,500profitJackgets$1,800profitJackgets$2,000profitJillgets$1,500profitJillgets$1,800profitJillgets$2,000profitPublicPolicyTowardOligopoliesCooperationamongoligopolistsisundesirablefromthestandpointofsocietyasawholebecauseitleadstoproductionthatistoolowandpricesthataretoohigh.RestraintofTradeandtheAntitrustLawsAntitrustlawsmakeitillegaltorestraintradeorattempttomonopolizeamarket.ShermanAntitrustActof1890ClaytonActof1914ControversiesoverAntitrustPolicyAntitrustpoliciessometimesmaynotallowbusinesspracticesthathavepotentiallypositiveeffects:ResalepricemaintenancePredatorypricingTying

ResalePriceMaintenanceResalepricemaintenance(orfairtrade)occurswhensuppliers(likewholesalers)requiretheretailersthattheysellto,tochargecustomersaspecificamount.PredatoryPricingPredatorypricingoccurswhenalargefirmbeginstocutthepriceofitsproduct(s)withtheintentofdrivingitscompetitor(s)outofthemarket.TyingTyingreferstowhenafirmofferstwo(ormore)ofitsproductstogetheratasingleprice,ratherthanseparately.SummaryOligopolistsmaximizetheirtotalprofitsbyformingacartelandactinglikeamonopolist.Ifoligopolistsmakedecisionsaboutproductionlevelsindividually,theresultisagreaterquantityandalowerpricethanunderthemonopolyoutcome.SummaryTheprisoners’dilemmashowsthatself-interestcanpreventpeoplefrommaintainingcooperation,evenwhencooperationisintheirmutualself-interest.Thelogicoftheprisoners’dilemmaappliesinmanysituations,includingoligopolies.SummaryPolicymakersusetheantitrustlawstopreventoligopoliesfromengaginginbehaviorthatreducescompetition.GraphicalReviewTheFourTypesofMarketStructureMonopolyOligopolyMonopolisticCompetitionPerfectCompetitionTapwaterCableTVTennisballsCrudeoilNovelsMoviesWheatMilkNumberofFirms?TypeofProducts?ManyfirmsOnefirmFewfirmsDifferentiatedproductsIdenticalproductsThePrisoners’DilemmaBonnie’sDecisionConfessRemainSilentConfessRemainSilentClyde’sDecisionClydegets8yearsBonniegets8yearsBonniegets20yearsBonniegets1yearBonniegoesfreeClydegets20yearsClydegets1yearClydegoesfreeOligopoliesasa

Prisoners’DilemmaIraq’sDecisionHighProductionLowProductionHighProductionLowProductionIran’sDecisionIrangets$40billionIraqgets$40billionIraqgets$30billionIraqgets$50billionIraqgets$60billionIrangets$30billionIrangets$50billionIrangets$60billionAnArms-RaceGameDecisionoftheUnitedStates(U.S.)ArmDisarmArmDisarmDecisionoftheSovietUnion(USSR)USSRatriskU.S.atriskU.S.atriskandweakU.S.safe