the economics of a blend mandate for biofuels a biofuel blend mandate may increase or decrease consumer fuel prices with endogenous oil prices depending on relative supply elasticities biofuel tax credits always reduce fuel prices tax credits result in lower fuel prices than under a mandate for the same level of biofuel production if tax credits are implemented alongside mandates then tax credits subsidize fuel consumption instead of biofuels this contradicts energy policy goals by increasing oil dependency co 2 emissions and traffic congestion while providing little benefit to either corn or ethanol producers these social costs will be substantial with tax credits costing taxpayers 28 7 billion annually by 2022 copyright 2008 oxford university press

sales and collusion in a market with storage sales are a widespread and well known phenomenon documented in several product markets this paper presents a novel rationale for sales that does not rely on consumer heterogeneity or on any form of randomness to explain such periodic price fluctuations the analysis is carried out in the context of a simple repeated price competition model and establishes that firms must periodically reduce prices in order to sustain collusion when goods are storable and the market is large the largest equilibrium profits are characterized at any market size a trade off between the size of the industry and its profits arises sales foster collusion by magnifying the inter temporal links in consumers decisions

durable goods theory for real world markets the early 1970s witnessed three major advances in durable goods theory swan 1970 1971 and sieper and swan 1973 on optimal durability coase 1972 on time inconsistency and akerlof 1970 on adverse selection this paper surveys durable goods theory starting with these three contributions where much of the focus is on recent literature and on models that explain real world phenomena in addition to the ideas found in the contributions of swan coase and akerlof topics covered include why producers sometimes practice planned obsolescence the role of adverse selection in new car leasing and reasons for aftermarket monopolization

evading the use tax on cross border sales abstract a use tax is similar to a sales tax except that it is imposed on purchases made from out of state firms historically the use tax has been widely evaded this paper uses a spatial model to analyze the welfare effects of such evasion the analysis shows that the ability of consumers to evade the use tax alters their behavior in a way that leads firms to charge lower prices this reduces the welfare loss created by the sellers market power and implies that evasion can increase welfare even when tax rates are adjusted to offset the effect of evasion on tax revenue

durable goods monopolists durable goods monopolists face special problems because the sale of their products creates a secondhand market not controlled by the monopolist to the extent the monopolist is able to rent his product rather than sell it or to make binding promises about his future production such problems are ameliorated given the inability to do the above the monopolist is led to producing goods less durable than those produced by either competitive firms or monopolist returns a reverse averch johnson result that monopolist sellers may invest less in fixed costs including plant modernization and research and development than would the renters is shown it is also shown that even though sellers have less monopoly power than renters and nondurable goods monopolists it is possible that the seller will cause a greater deadweight loss than the other types of monopolies

coase versus pacman who eats whom in the durable goods monopoly in standard durable goods monopoly models both the set of buyers and the set of prices are assumed to be continua if the set of buyers is finite the perfectly discriminating monopoly outcome is a unique subgame perfect equilibrium when the seller is sufficiently patient introducing instead a smallest unit of account yields the coasian outcome as a generically unique subgame perfect equilibrium for patient enough buyers a folk theorem is obtained if both sets are finite these results reflect a strategic disadvantage of having to make moves with a large impact on other players payoffs the analysis is extended to durable goods oligopoly

outside options and the failure of the coase conjecture a buyer wishes to purchase a good from a seller who chooses a sequence of prices over time each period the buyer can also exercise an outside option abandoning their search or moving on to another seller we show there is a unique equilibrium in which the seller charges a constant price in every period equal to the monopoly price contravening the coase conjecture we then embed the singleseller model into a search framework and show the result provides a foundation for the usual no haggling assumption jel c78 d42 d43 l12 l13 the coase conjecture is a cornerstone of modern microeconomic theory informing monopoly theory and providing a canonical example of the problem of commitment the idea is that for any given price high value buyers are more likely to purchase than low value buyers leading to negative selection in the demand pool accordingly the seller cuts its price over time causing high value buyers to delay their purchases the seller s inability to commit thus leads its later selves to exert a negative externality on its former selves reducing its overall profit gul sonnenschein and wilson 1986 this idea of negative selection is robust versions of it hold when costs are nonlinear kahn 1986 when goods depreciate over time bond and samuelson 1984 when there is entry of new buyers sobel 1991 and when the buyers face future competition fuchs and skrzypacz 2010 in this article we show that the coase conjecture fails in a natural environment where buyers have an outside option they can choose to exercise we consider a seller who faces a buyer or a continuum of buyers with unknown value for the good and unknown outside option each period the seller chooses price p t the buyer then chooses to buy wait or exercise his option and terminate the game the outside option may come from the possibility of buying another product for example when waiting for the price of the iphone to fall a customer could instead buy a comparable phone from a competitor similarly when bargaining over the price of a car a buyer may abandon negotiations and move on to the next dealer the outside option may also come from pursuing other objectives once the negotiation has terminated for example after he finishes bargaining at a bazaar a tourist could start seeing local attractions

durable goods oligopoly abstract this paper models a durable goods oligopoly as a differential game two cases are treated sales where firms cannot lease but must sell the good in question and leasing where firms do not sell but only rent in the sales case firms face increasing marginal cost of production and the good in question depreciates for this case a rational expectations feedback nash equilibrium is constructed for which monopoly or oligopoly output is less than the efficient level this gap between oligopoly and competitive output diminishes as the number of firms increases when firms can only lease the good the good is assumed not to depreciate and the monopoly level of steady state output is compared with the level of steady state output for a feedback equilibrium duopoly for this case the duopoly equilibrium has steady state output that is less than the corresponding efficient level but greater than the monopoly level the leasing model is shown to be isomorphic to the adjustment cost duopoly model of driskill and mccafferty journal of economic theory 49 1989 324 338

foundations of dynamic monopoly and the coase conjecture subgame perfect equilibria are characterized for a market in which the seller quotes a price each period assume zero costs positive interest rate continuum of buyers and some technical conditions if buyers valuations are positive then equilibrium is unique buyers strategies are stationary and the price sequence is determinant along the equilibrium path but possibly randomized elsewhere otherwise a continuum of stationary equilibria can exist but at most one with analytic strategies coase s conjecture is verified for stationary strategies reducing the period length drives all prices to zero or the least valuation connections to bargaining models are described journal qf economic literature classification

long run price competition we generalize the standard repeated games model of dynamic oligopolistic competition to allow for consumers who are long lived and forward looking each period leaves some residual demand to future periods and pricing in one period affects consumers expectations about future prices we analyze this setting for an indivisible durable good with price setting firms and overlapping cohorts of consumers the model nests the repeated game model and the coasian durable goods model as its two extreme cases the analysis is mostly focused on constant price collusion but conditions for collusive recurrent sales are also identified

electoral competition and politician turnover abstract in this paper we analyze the selection by opportunistic parties of the candidates who run for election we consider a setting with incomplete but symmetric information about the candidates abilities in which electoral campaigns provide voters with additional information about candidates parties care only about selecting an appropriate candidate to win the election while voters elect the best candidate conditional on their information we first argue that in order to defeat an established very good candidate of its rival a party may favor a new candidate with highly uncertain ability rather than an established good candidate next we establish that the discrepancy between the objective of parties and the objective of the electorate leads to inefficient conservatism in the selection of candidates i e each party keeps its incumbents too often from the voters viewpoint

no taxation without information deterrence and self enforcement in the value added tax abstract claims that the vat facilitates tax enforcement by generating paper trails on transactions between firms contributed to widespread vat adoption worldwide but there is surprisingly little evidence this paper analyzes the role of third party information for vat enforcement through two randomized experiments among over 400 000 chilean firms announcing additional monitoring has less impact on transactions that are subject to a paper trail indicating the paper trail s preventive deterrence effect this leads to strong enforcement spillovers up the vat chain these findings confirm that when taking evasion into account significant differences emerge between otherwise equivalent forms of taxation jel d83 h25 h26 k34 o17

anticompetitive financial contracting the design of financial claims this paper presents the first model where entry deterrence takes place through financial rather than product market channels in standard models of the interaction between product and financial markets a firm s use of financial instruments deters entry by affecting product market behavior whereas in our model entry deterrence occurs by affecting the credit market behavior of investors towards entrant firms we find that in order to deter entry the claims held on incumbent firms should be sufficiently risky i e equity in contrast to the standard branderlewis 1986 result that debt deters entry the model sheds light on the policy debate on the separation of banking as to whether banks should be permitted to hold equity in firms it also provides an explanation for why venture capitalists hold automatically convertible securities in start up firms

resale and collusion in a dynamic market for semidurable goods the paper studies the incentives to form collusive agreements when goods can be traded in second hand markets it will be shown that such incentives crucially depend on the rate of depreciation of the durable good and on consumer heterogeneity the main contribution of the paper shows that an active second hand market may strengthen the incentives to collude as do policies that affect the functioning of the second hand market e g leasing policy and buy back it will also be argued that the oligopoly incentives to adopt strategies that strengthen collusion often differ from the monopoly incentives to increase profits

optimal best price policy abstract a best price policy bp is a promise by a seller to give her customer a refund if she reduces her price after the customer has already purchased the product we characterize the optimal bp policy as when the seller can control both the policy length when the promise expires and the refund scale what portion of the price difference is refunded we explain why the policy length is finite and varies across industries in a setting where consumers valuations decline over time we show that a finite length bp allows the seller to commit to not lowering her price too soon while at the same time letting her capture some of the benefits of intertemporal price discrimination however because the decline in consumers valuations is uncertain a bp does not allow the monopolist to achieve the profit she could earn with a full commitment

individual morality and reputation costs as deterrents to tax evasion abstract empirical evidence suggests some taxpayers never evade evasion increases with the tax rate and evasion decisions are interdependent these findings are not easily explained by the existing theory which models evasion as an independently made amoral gamble this paper uses nonpecuniary costs of evasion to reconcile theory with evidence once individuals are assumed to differ by an honesty characteristic taxpayers dichotomise into groups the more honest of which responds to a tax change as the evidence suggests a further extension is to introduce an endogenous reputation cost this suggests a positive relationship between the number of evaders and the tax rate

the danish green certificate system some simple analytical results we formulate a simple static equilibrium model for the electricity market taking account of both green certificates and co2 emission permits the objective is to investigate the relationship between these markets under the existence of upper and lower price bounds on the green certificates both in the short and in the long run we perform various comparative static changes of the parameters of the model and study how these affect the endogenous variables of the model as well as producers and consumers surplus we also investigate the effects of imports and exports of electricity several comparative static results are derived and in particular it is shown that harsher co2 emission constraints and increased import wholesale price both may lead to reduced capacity of green electricity

the rise and fall of bioenergy abstract if bioenergy has a less negative impact on the climate than fossil energy it may be optimal to have a significant increase in the use of bioenergy over time due to the difference in the way the climate is affected by the two types of energy the future time path of the use of bioenergy may be non monotonic it may be optimal to first have an increase in its use and later a reduction optimal taxes subsidies are derived both for the first best case and for the case of a constraint on the size of the fossil tax

reputation in bargaining and durable goods monopoly this paper analyzes durable goods monopoly in an infinite horizon discrete time game we prove that as the time interval between successive offers approaches zero all seller payoffs between zero and static monopoly profits are supported by subgame perfect equilibria this reverses a well known conjecture of coase alternatively one can interpret the model as a sequential bargaining game with one sided incomplete information in which an uninformed seller makes all the offers our folk theorem for seller payoffs equally applies to the set of sequential equilibria of this bargaining game

ordering the extraction of polluting nonrenewable resources energy markets are often characterized by the use of multiple nonrenewable resources such as coal and natural gas with different pollution characteristics the same resource may have different qualities as when high and low sulfur coal is used to generate electricity multiple resources are used in providing transportation services such as cars running on gasoline or plug in hybrids that may be fueled by electricity produced from coal when these nonrenewable resources contribute differentially to pollution what is the opti mal sequence of extraction over time harold hotelling 1931 developed the classical theory of extraction of a nonrenewable resource orris c herfindahl 1967 extended the hotelling model by considering many resources with different unit costs of extraction and proposed the least cost first principle extraction must be ordered by cost with the cheapest resource used first others have examined whether herfindahl s model remains valid in a variety of situations in a general equilibrium setting see murray kemp and ngo v long 1980 tracy r lewis 1982 in the presence of setup costs g rard gaudet moreaux and stephen w salant 2001 under het erogeneous demands chakravorty and darrell l krulce 1994 and when the extraction rate is constrained jean pierre amigues et al 1998 stephen p holland 2003 in these studies following hotelling and herfindahl resources were differentiated by cost alone in this paper we abstract from cost considerations and focus on how the sequence of extraction may be affected when resources are differentiated only by their pollution character istics we consider two resources one more polluting than the other without loss of generality consider coal to be the dirty resource and natural gas the clean one both may be used to generate electricity environmental regulation is imposed through a cap on the stock of pollution this may be a stylized approximation of an international agreement such as the kyoto protocol which aims to stabilize the concentration of greenhouse gases in the atmosphere 1 with heterogeneity in pollution the results are nonintuitive and do not depend on the emis sion rates of the resources when the economy is already at its allowable stock of pollution the clean natural gas is used first and use of the dirty coal is postponed to the future this is what one would expect armed with insights from the herfindahl model however when the economy starts from below the ceiling and accumulates pollution coal may be used first and use of the clean natural gas is postponed the optimal strategy is to benefit from natural dilution by build ing the stock of pollution as quickly as possible this is done by burning coal rather than natural

coase and hotelling a meeting of the minds in this paper we tie together the two literatures of durable goods monopoly and exhaustible resource pricing we show that the intertemporal no arbitrage condition that arises if the durable good monopolist seller can commit to a price path mirrors the intertemporal no arbitrage condition if the monopsonist buyer of an exhaustible resource can commit to a price path the intuition is that the durable good monopolist initially announces high future prices to get high valuation buyers to buy early and subsequently lowers the price to attract additional buyers on the other hand the monopsonist buyer of the exhaustible resource initially announces low future prices to encourage sellers to supply their units early and subsequently as the stock of the resource declines raises the price to call forth additional supply as the period of commitment shrinks to zero the durable good s price drops to its marginal cost and the exhaustible resource s price jumps to its choke level all in a twinkling of the eye a

on the optimal tax base for commodity taxation taxed considerable effort has been devoted to characterizing the manner in which the optimal tax rates differ across the taxable commodities but the literature has rarely addressed the issue of which commodities should be included in the tax base in fact the standard optimal tax model cannot provide a useful answer to this question because it does not contain any of the resource costs normally associated with the collection of taxes an omission that seriously diminishes the policy relevance of the model 2

second best biofuel policies and the welfare effects of quantity mandates and subsidies abstract the quest for biorenewable energy sources is held to justify a number of government interventions including support policies for biofuels such as those responsible for the recent rapid growth of us ethanol production this article provides an analytical assessment of such policies we construct a general equilibrium open economy model that captures the rationale typically invoked to justify government intervention in this setting to alleviate the environmental impact of energy consumption and to decrease us energy dependence on foreign sources the model is used to study both the positive and normative implications of alternative policy instruments including the subsidies and mandates specified by the 2007 energy independence and security act from a positive perspective we find that biofuels mandates are equivalent to a combination of fuel taxes and biofuels subsidies that are revenue neutral from a welfare perspective we show that biofuels mandates dominate biofuels subsidies and that combining fuel taxes with mandates would be welfare enhancing

incentive to reduce crop trait durability to reduce the competition from farmers who self produce seed an inbred line seed producer can switch to nondurable hybrid seed in a two period model we investigate the impact of crop durability on self production pricing and switching decisions and we examine the impact of license fees paid by self producing farmers first in an inbred line seed monopoly model we find that the monopolist may produce technologically dominated hybrid seed in order to extract more surplus from farmers further the introduction of license fees improves efficiency second we study how the monopolist s behavior is affected by the entry of a nondurable hybrid seed producer we show that the inbred line seed producer might benefit from competing with a technologically dominated hybrid seed producer as this allows for consumers discrimination

optimal pricing strategy for durable goods monopoly abstract in this paper we reconsider the profitability of a durable good monopoly when the seller s discount rate may be different from the buyers in an infinite horizon continuous time full commitment model the monopoly can achieve more than the static monopoly profit if and only if the seller is more patient than the buyers under this condition the price function is strictly decreasing over time these results remain valid in models with buyers arriving sequentially where the seller may have only one unit to sell or can produce more at constant marginal cost

the design of a dynamic tradeable quota system under market imperfections abstract market power within a dynamic system of tradeable quotas with banking and borrowing of quotas leads to a nonoptimal distribution of abatement across agents in this paper we introduce a quota system that may reduce the efficiency loss from market power and thereby result in a distribution of abatement across agents that is closer to a cost effective outcome however this system will in general lead to a nonoptimal distribution of abatement across periods hence we may face a trade off between a cost effective distribution of abatement across periods and reduced adverse effects of market power

durable goods monopoly with limited choice of commitment strategy when should the monopolist precommit consider a firm a monopolist offering a unique product to a fixed number of potential customers suppose that no consumer desires more than one unit of the good within a given period or across periods that is there is no value to repeat purchases in addition suppose that customers vary with respect to their initial reservation prices which decline over time a natural interpretation is that the monopolist is selling a good that is durable alternatively the firm is providing an entertainment or fashion good consumers may place a premium on obtaining the product quickly before it becomes less useful less stylish or less novel coase 7 conjectured that this firm s ability to extract surplus is limited because the firm has to compete with itself across time periods high valuation customers would be unwilling to pay a high initial price because they would anticipate that over time the firm will be reducing the price in order to sell to lower valuation customers subsequent literature formalizes this as a time inconsistency problem faced by a monopolist unable to make intertemporal commitments a separate strand of the literature proceeds from the polar assumption that the monopolist can precommit to any multiperiod pricing strategy comparison to coase s monopolist is simple higher profits are obtainable under precommitment because more surplus is extracted from high valuation customers an important proposition due to stokey 22 is that it will be optimal for the monopolist to precommit to a declining intertemporal price schedule if consumers with higher initial valuations have a higher rate of time preference 2 otherwise the optimal strategy is to hold price constant at the static monopoly level and to sell no more than the static monopoly quantity 3

one is almost enough for monopoly it has been argued that two factors product durability and potential entry may force a monopolist to price at marginal cost this article shows that when these two forces coexist the tendency toward competition may be negated first we prove that durable goods oligopolists without commitment powers may attain joint profits arbitrarily close to those of a monopolist with perfect commitment power second we demonstrate that the presence of a potential entrant may enable a durable goods monopolist to act as if he had commitment power thus potential as well as actual entry may restore monopoly power

interstate commodity tax differentials and the distribution of residents abstract this paper considers the manner in which an unequal distribution of consumers affects the commodity tax policies of neighboring jurisdictions the paper uses a spatial model in which the residents of two states are distributed non uniformly and employs a variety of assumptions about the behavior of governments and firms throughout the paper shows that at a nash equilibrium in tax levels the sparsely populated state imposes a lower tax than does its densely populated neighbor the paper also demonstrates how equilibrium state taxes differ depending on whether firms employ marginal cost or profit maximizing pricing

fulfilled expectations of entry i develop a two period model of entry deterrence with endogenous market demands such that the consumer s expectation about the future market structure is fulfilled in equilibrium i find that both expectations duopoly and monopoly are fulfilled in the incumbent s price setting game while there is a unique equilibrium in the quantity setting game i also find that quantity is more entry deterring than price in the sense that the maximum value of the entry cost that allows entry in the price setting game is higher than or equal to that of the quantity setting game

modelling competitive behavior a single seller of an indivisible object wishes to sell the good to one of many buyers the seller has zero value for the good the buyers have a commonly known identical value of one this article attempts to determine strategic environments that ensure the seller s ability to exploit the competitive behavior of the buyers to extract all the surplus in the game i show that in many simple dynamic games there are subgame perfect equilibria that involve the seller s giving up the good for free even if the seller has an informational advantage that allows him to keep bidders from learning the bidding behavior of their opponents there still exist perfect bayesian equilibria that involve a sale at the price of zero however in this case a simple refinement in the spirit of sequential equilibria can be used to rule out such collusive behavior and to show that the unique equilibrium outcome satisfying this refinement yields the seller a price of one

substitution between biofuels and fossil fuels is there a green paradox we show that i subsidies for renewable energy policies with the intention of encouraging substitution away from fossil fuels may accentuate climate change damages by hastening fossil fuel extraction and that ii the opposite result holds under some specified conditions we focus on the case of subsidies for renewable resources produced under increasing marginal costs and assume that both the renewable resources and the fossil fuels are currently in use such subsidies have a direct effect and an indirect effect working in opposite directions the direct effect is the reduction in demand for fossil fuels at any given price the indirect effect is the reduction in the current equilibrium price for fossil fuels which tends to increase the amount of fossil fuels demanded whether the sum of the two effects will actually result in an earlier or later date of exhaustion of the stock of fossil fuels depends on the curvature of the demand curve for energy and of the supply curve for the renewable substitute

when do secondary markets harm firms to investigate whether secondary markets aid or harm durable goods manufacturers we build a dynamic model of durable goods oligopoly with transaction costs in the secondary market calibrating model parameters using data from the us automobile industry we find the net effect of opening the secondary market is to decrease new car manufacturers profits by 35 percent counterfactual scenarios in which the size of the used good stock decreases such as when products become less durable when the number of firms decreases or when firms can commit to future production levels increase the profitability of opening the secondary market

entry deterrence and innovation in durable goods monopoly this paper investigates the efficiency of innovation investments in a durable goods monopoly when a potential entrant threatens to innovate as well we show that the durability of the good endows the monopolist with the power to discourage rival innovation since current sales alter the demand for a new generation of the good the equilibrium is therefore determined not only by competitive pressure due to time inconsistency but also by the incumbent s concern for maintaining the technological leadership we demonstrate that entry deterrence followed by no innovation always implies underinvestment in innovation

will destination based taxes be fully exploited when available an application to the u s commodity tax system abstract we develop a tax competition model that allows for the setting of both an origin based and a destination based commodity tax rate in the presence of avoidance and evasion in the presence of evasion jurisdictions will give cross border shoppers tax preferential treatment thus not fully exploiting the potential of destination based taxation moreover the divergence between origin based and destination based taxes is stronger when the incentives for consumers tax arbitrage opportunities increase the united states is one example of many such systems while sales taxes are due at the point of sale use taxes are due on goods purchased out of state we document that when able to set both rates a majority of jurisdictions levy destination based use taxes at a lower rate than origin based sales taxes in response to changes in state level policies that increase tax avoidance opportunities the results of the empirical model broadly confirm our theory

noncooperative collusion in durable goods oligopoly coase conjectured that a durable goods monopolist who can make offers to sell arbitrarily frequently will lose the ability to extract positive profits this result which has now been proved can be attributed to the inability of the monopolist to commit to maintaining sufficiently high prices in the near future for the case of durable goods oligopoly we show that letting the firms make offers arbitrarily frequently enhances their ability to commit to high prices and in the limit enables the firms to enjoy total market profits equal to the full commitment one shot monopoly profit

jeux sans frontieres tax competition and tax coordination when countries differ in size closer international integration is putting increasing pressure on existing national tax structures this paper uses a simple two country model to address a range of consequent policy concerns focusing particularly on the role of country size differences in size exacerbate the inefficiency from noncooperative behavior harming both countries the smaller country loses from harmonization to any tax rate between those set in the noncooperative equilibrium but both countries gain from the imposition of a minimum tax anywhere in that range the fully optimal response to freer cross border trade however may be to do nothing jel h20 h77

do vertical mergers facilitate upstream collusion we investigate the impact of vertical mergers on upstream firms ability to collude when selling to downstream firms in a repeated game we show that vertical mergers give rise to an outlets effect the deviation profits of cheating unintegrated firms are reduced as these firms can no longer profitably sell to the downstream affiliates of their integrated rivals vertical mergers also result in an opposing punishment effect integrated firms typically make more profit in the punishment phase than unintegrated upstream firms the net result of these effects in an unintegrated industry is to facilitate upstream collusion we provide conditions under which further vertical integration also facilitates collusion

a dynamic equilibrium model of durable goods monopoly abstract in this paper we construct a simple dynamic general equilibrium model of durable goods monopoly in a discrete time framework and show that a revised coase conjecture monopolists are efficient under a proper tax subsidy policy holds even in the case of increasing marginal cost if the length of each period in the discrete model is sufficiently short

economic growth and transitions between renewable and nonrenewable energy resources abstract we study transitions between nonrenewable and renewable energy forms at different development stages of an economy it is shown that in the historical context the emphasis on energy production may evolve from renewables to nonrenewables and back to renewables typically both energy forms are used simultaneously along the equilibrium path nonrenewable resource consumption may increase and their price decrease an inverted u relation between carbon emissions and income level may follow even without environmental policy

durable good monopoly with one hoss shay depreciation abstract this paper analyzes the effects of one hoss shay depreciation on the equilibrium stock path in a monopoly market for a durable good it is shown that the stock path oscillates converging to a stationary level lower than the competitive level