Stochastic growth with short-run prediction of shocks

We study a variation of the one-sector stochastic optimal growth model with independent and identically distributed shocks where agents acquire information that enables them to accurately predict the next period??s productivity shock (but not shocks in later periods). Optimal policy depends on the forthcoming shock. A ??better?? predicted realization of the shock that increases both marginal and total product always increases next period??s optimal output. We derive conditions on the degree of relative risk aversion and the elasticity of marginal product under which optimal investment increases or decreases with a better shock. Under fairly regular restrictions, optimal outputs converge in distribution to a unique invariant distribution whose support is bounded away from zero. We derive explicit solutions to the optimal policy for three well-known families of production and utility functions and use these to show that volatility of output, sensitivity of output to shocks, and expected total investment may be higher or lower than in the standard model where no new information is acquired over time; the limiting steady state may also differ significantly from that in the standard model.     

Using Market Structure to Regulate a Vertically Integrated Monopolist

A natural monopolist whose cost is private information produces a good which is combined with another good that can be produced by the monopolist or by other firms. The agency that regulates the monopolist can impose any of several different market structures in the industry: integrated monopoly, vertical separation with free entry downstream, or liberalization downstream (both integrated and independent production). When several firms produce downstream, a Cournot quantity-setting game with free entry determines the market price. We derive the optimal contracts to offer the monopolist under all three market structures and examine the influence of downstream cost differences on access prices.We then study the optimal regulatory policy where the regulator can condition the downstream market structure on the monopolist's cost report to the regulator. The optimal regulatory policy awards a monopoly to a low-cost upstream firm, but requires free entry downstream if the monopolist reports high upstream costs. Thus, the choice of market structure is an additional tool to limit rent extraction by the monopolist. Simulation analysis reveals the possibility of significant welfare gains from this additional regulatory tool.     

Optimizing replenishment policy in an EPQ-based inventory model with nonconforming items and breakdown

The optimal replenishment policy for an economic production quantity (EPQ)-based inventory model with nonconforming items and breakdown is presented. A real-life production system inevitably generates nonconforming items and has equipment breakdowns owing to process deterioration or other uncontrollable factors. This study addressed these issues in an EPQ-based system to optimize a replenishment policy that minimizes the long-run average cost for the proposed system. Whenever a breakdown occurs, the machine is assumed to immediately be under repair, and an abort/resume inventory control policy is adopted. Under this control policy production of the interrupted lot resumes immediately after the machine is fixed and restored. A mathematical model and a recursive algorithm were used to derive the optimal replenishment policy. A numerical example was used to demonstrate the practical application and better cost efficiency of the proposed policy compared to a breakdown that occurs under a no-resumption policy.     

Optimal tax policy and foreign direct investment under ambiguity

We analyze the optimal timing of an irreversible foreign direct investment by a foreign firm and the optimal tax policy by a host country under ambiguity. We derive the optimal GDP level at which the foreign firm switches from exporting to a foreign direct investment. Furthermore, we derive the optimal tax policy by the host country, and analyze the effect of an increase in ambiguity on the optimal tax policy. We show that the host country should reduce the optimal corporate tax rate from the host government’s perspective in response to an increase in ambiguity. Our result is different from the one obtained by Pennings (2005) that shows that an increase in risk induces an increase in the optimal corporate tax rate.     

Optimal emission-extraction policy in a world of scarcity and irreversibility

This paper extends the classical exhaustible-resource/stock-pollution model with irreversibility of pollution decay, meaning that after reaching some threshold there is no decay of the pollution stock. Within this framework, we answer the question how the potential irreversibility of pollution affects the extraction path. We investigate the conditions under which the economy will optimally adopt a reversible policy, and when it is optimal to enter the irreversible region. In the case of irreversibility it may be optimal to leave a positive amount of resource in the ground forever. As far as the optimal extraction/emission policy is concerned, several types of solutions may arise, including solutions where the economy stays at the threshold for a while. Given that different programs may satisfy the first order conditions for optimality, we further investigate when each of these is optimal. We show that it is never optimal for the economy to stay at the threshold for a while before entering the irreversible region. The optimality analysis is then illustrated by means of a calibrated example. To sum up, for any pollution level, we can identify a critical resource stock such that there exist multiple optima i.e. a reversible and an irreversible policy that yield exactly the same present value. For any resource stock below this critical value, the optimal policy is reversible whereas with large enough resources, irreversible policies outperform reversible programs.     

Optimal emission-extraction policy in a world of scarcity and irreversibility

This paper extends the classical exhaustible-resource/stock-pollution model with irreversibility of pollution decay, meaning that after reaching some threshold there is no decay of the pollution stock. Within this framework, we answer the question how the potential irreversibility of pollution affects the extraction path. We investigate the conditions under which the economy will optimally adopt a reversible policy, and when it is optimal to enter the irreversible region. In the case of irreversibility it may be optimal to leave a positive amount of resource in the ground forever. As far as the optimal extraction/emission policy is concerned, several types of solutions may arise, including solutions where the economy stays at the threshold for a while. Given that different programs may satisfy the first order conditions for optimality, we further investigate when each of these is optimal. We show that it is never optimal for the economy to stay at the threshold for a while before entering the irreversible region. The optimality analysis is then illustrated by means of a calibrated example. To sum up, for any pollution level, we can identify a critical resource stock such that there exist multiple optima i.e. a reversible and an irreversible policy that yield exactly the same present value. For any resource stock below this critical value, the optimal policy is reversible whereas with large enough resources, irreversible policies outperform reversible programs.     

On Functionally Distributed Quotas

We consider “functionally distributed” quotas, where trade is restricted to a function of another economic activity, paying special attention to the ratio constraint and its relation to “proportionally distributed” quotas. We propose a simple principle defining the optimal policy under a functionally defined restriction, extend the analysis of ratio import/production constraints to general equilibrium, introduce export constraints, and constraints defined in proportion to factor use. We develop the general‐equilibrium geometry of functional trade constraints and the concomitant optimal policies, deriving a “quota locus” that depicts the consumption possibilities under various regimes.     

Tariffs versus quotas in the presence of imperfect competition and cross‐border externalities

Abstract.  We consider trade policies intended to affect the production of a foreign monopolist that generates negative externalities. We derive the optimal tariff and optimal import quota and examine which policy measure should be used to maximize domestic welfare. We find that if the domestic government does not have full information on the foreign firm's production method and if cross‐border externalities exist, import quotas are in some cases preferable to tariffs. Otherwise, however, tariffs are preferable to quotas. JEL Classification: F13, F18     

Credit Constraint and the Asymmetric Monetary Policy Effect on House Prices

We study the possible asymmetric effect of monetary policy on house prices under different credit regimes. We first derive the implications of a theoretical model in which agents may be collateral‐constrained. We then empirically examine the implications of the model using the threshold vector autoregression model. Two different measures reflecting the tightness of the credit market are computed to serve as the threshold variable. We find that house prices react to a monetary shock initially more strongly but the effect is less persistent in a credit boom regime than in a normal credit regime. This result is consistent with the findings of our theoretical model.     

Regulating a Polluting Firm Under Asymmetric Information

This paper reinterprets the Laffont-Tirole model of regulation under asymmetric information to cover the case of pollution control. The asymmetry of information concerns the firm's cost of lowering its pollution. The regulator has three objectives: Ensuring an efficient abatement level, generating 'green taxes' and securing the survival of the firm. We show that when optimal abatement is important relative to tax generation, the regulator cannot use the policy of offering the firm a set of linear tax schemes from which to choose. By contrast, this policy is optimal in the Laffont-Tirole model under certain not very restrictive assumptions. We proceed to establish a simple rule for when to shut-down inefficient types. In an example with specific functional forms, we derive the optimal tax function both analytically and graphically. We show the effect on the optimal tax system of a change in a technological parameter.     

Strategic Environmental Policy, Clean Technologies and the Learning Curve

In the political discussion, it is often emphasized that the environmental service industry (which produces a clean factor of production) benefits from an early and strong environmental policy. This is especially likely if the costs of production are decreasing over time due to learning curve effects. Surprisingly, the environmental service industry has not been integrated into the theory of strategic environmental policy yet. Our main question is whether a national leadership in environmental policy can pay off if profits of the environmental service industry are taken into account. We consider a two-period model with one firm in each country competing on a third market. Emissions can be substituted by the clean factor when deciding upon the production technology. The unit costs of producing the clean factor in the second period are decreasing in the quantity produced in the initial period. We derive the optimal environmental policy for both periods from a national point of view and show that the presence of the environmental service industry can indeed lead to a national leadership in pollution control.     

On policymakers’ loss functions and the evaluation of early warning systems: Comment

Sarlin (2013) suggests that if a loss function approach is chosen to derive the optimal threshold for financial crisis early warning indicators, the loss function specification should explicitly take into account the unconditional sample crisis probability. In this comment we argue that this approach is not robust to small perturbations of the preference parameter and is not easy to use for policy purposes. We suggest therefore to continue using a simpler loss function specification.     

State‐Dependent Forward Guidance and the Problem of Inconsistent Announcements

Forward guidance can be provided as an unconditional promise, i.e. commitment to a specific low policy rate. Alternatively, the promise may include an escape clause, i.e. a condition defining the state of the economy under which the central bank would not keep such a low rate and, instead, it would revert to setting policy under discretion. The escape clause can be expressed as a threshold in terms of a specific variable. The present paper shows that, when such a threshold is expressed in terms of an endogenous variable (e.g. output, inflation), there are cases where it becomes impossible for the central bank to act in a way that is consistent with its promise. Consistency imposes limits on the policy rate that can be set since reverting immediately to the optimal discretionary rate can be incompatible with exceeding the threshold.     

国际多市场寡头条件下的贸易政策和产业政策

国际多市场寡头是Bulow( 1 985)提出的多市场寡头概念在国际贸易领域的自然延伸。在本文中 ,市场之间联系的纽带是本国企业具有规模收益递减的生产技术。本文的主要结论是 ,第一 ,如果本国企业与外国企业在外国市场进行价格竞争 ,那么 ,最优干预组合包括国内生产补贴与出口税 ,它们对本国福利的作用是一致的。第二 ,如果本国企业与外国企业在外国市场进行数量竞争 ,那么 ,最优干预政策组合包括国内生产补贴与出口补贴 ,它们作用于本国福利的方向是不一致的 ,这时 ,本国政府用国内生产补贴执行反托拉斯职能 ,用出口补贴执行利润转移职能。第三 ,作为模型的一个应用 ,本文论证了出口退税政策会加剧国内市场的扭曲 ;而且它不一定能够提高本国福利。     

The Optimal Timing of Adoption of a Green Technology

We study the optimal timing of adoption of a cleaner technology and its effects on the rate of growth of an economy in the context of an AK endogenous growth model. We show that the results depend upon the behavior of the marginal utility of environmental quality with respect to consumption. When it is increasing, we derive the capital level at the optimal timing of adoption. We show that this capital threshold is independent of the initial conditions on the stock of capital, implying that capital-poor countries tend to take longer to adopt. Also, country-specific characteristics, as the existence of high barriers to adoption, may lead to different capital thresholds for different countries. If the marginal utility of environmental quality decreases with consumption, a country should never delay adoption; the optimal policy is either to adopt immediately or, if adoption costs are “too high”, to never adopt. The policy implications of these results are discussed in the context of the international debate surrounding the environmental political agenda.      

On optimal growth under uncertainty

In a recent paper Brock and Mirman showed that in a one-sector model of economic growth under uncertainty the long-run behavior of the optimal capital stock is governed by the basic properties of an acyclic ergodic Markov process. This paper considers a similar model and has two purposes. First, necessary and sufficient conditions for optimal policy functions are derived in a regime in which future utilities are discounted. These conditions lead, in an example, to an explicit optimal policy function, which is used to display the steady-state solution for the capital stock under an optimal policy. Secondly, in the Brock and Mirman paper it was assumed that the production functions are ordered. We show that all the properties proved by Brock and Mirman are satisfied even when the production functions are not ordered.     

Environmental Ramsey Policy and Sustainable Balanced Growth

We study the link among economic growth, renewable natural resources and environmental policy. The context is a general equilibrium model of endogenous growth and environmental policy. We examine the conditions under which sustainable growth is both feasible and optimal, where the latter takes the form of second‐best optimal environmental Ramsey policies. We also investigate the conditions for an inverted U‐shaped relation between environmental policies and sustainable growth. We show that the combination of environmental production externalities and second‐best optimal Ramsey policies can lead to both local and global indeterminacy. The introduction of environmental policy, although well‐intentioned and designed to correct for market inefficiencies, triggers an expectations coordination problem; thereby differences in environmental quality and economic growth can be explained among countries with the same fundamentals.     

Steepest ascent tariff reform

The policy reform literature is primarily concerned with the construction of reforms that yield welfare gains. By contrast, this paper’s contribution is to develop a theoretical concept for which the focus is upon the sizes of welfare gains accruing from policy reforms rather than upon their signs. In undertaking this task, and by focusing on tariff reforms, we introduce the concept of a steepest ascent policy reform, which is a locally optimal reform in the sense that it achieves the highest marginal gain in utility of any feasible local reform. We argue that this reform presents itself as a natural benchmark for the evaluation of the welfare effectiveness of other popular tariff reforms such as the proportional tariff reduction and the concertina rules, since it provides the maximal welfare gain of all possible local reforms. We derive properties of the steepest ascent tariff reform, construct an index to measure the relative welfare effectiveness of any given tariff reform, determine conditions under which proportional and concertina reforms are locally optimal and provide illustrative examples.     

The effect of output specification on the optimal policy design for electric utilities

We show that the manner in which the production process is seen when analyzing data on electricity production has an impact on the policy conclusions. In particular, we show that the different specifications of output found in the literature can generate quite diverse views regarding regulation and optimal industry structure, even when using the same data to estimate a cost function. To illustrate this we use information gathered from the Spanish Electric Industry and analyze electricity activities following three approaches: the traditional aggregate activity view, the multistage model and the multioutput-multistage approach. We estimate the degree of economies of scale S and derive marginal costs for all models, plus economies of vertical integration (EVI) for the last two ones. Then we compare these results and verify that the aggregate analysis can mislead policymaking.