Lotteries, Sunspots, and Incentive Constraints

We study a prototypical class of exchange economies with private information and indivisibilities. We establish an equivalence between lottery equilibria and sunspot equilibria and show that the welfare and existence theorems hold. To establish these results, we introduce the concept of the stand-in consumer economy, which is a standard, convex, finite consumer, finite good, pure exchange economy. With decreasing absolute risk aversion and no indivisibilities, we prove that no lotteries are actually used in equilibrium. We provide a simple numerical example with increasing absolute risk aversion in which lotteries are necessarily used in equilibrium. We also show how the equilibrium allocation in this example can be implemented in a sunspot equilibrium. Journal of Economic Literature Classification Numbers: D11, D50, D82.     

Feasible Bayesian Implementation with State Dependent Feasible Sets

This paper considers feasible Bayesian implementation for an environment with state dependent feasible sets. We assume no externality in individual feasibility constraint sets and no exaggeration on the part of agents, but allow for flexible information structures. Bayesian Incentive Compatibility, Closure, and Bayesian Monotonicity are found to be necessary and sufficient for feasible Bayesian implementation. This result is applied to an exchange economy where agents have fixed preferences but uncertain initial endowments and complete information. A condition called the Endowment Condition, which is weaker than Individual Rationality, is identified as necessary and sufficient for feasible Nash implementation.Journal of Economic LiteratureClassification Numbers: D70; D71; D74; D82.     

Existence and Welfare Properties of Equilibrium in an Exchange Economy with Multiple Divisible and Indivisible Commodities and Linear Production Technologies

In this paper we consider a class of economies with a finite number of divisible commodities, linear production technologies, and indivisible goods and a finite number of agents. This class contains several well-known economies with indivisible goods and money as special cases. It is shown that if the utility functions are continuous on the divisible commodities and are weakly monotonic both on one of the divisible commodities and on all the indivisible commodities, if each agent initially owns a sufficient amount of one of the divisible commodities, and if a “no production without input”-like assumption on the production sector holds, then there exists a competitive equilibrium for any economy in this class. The usual convexity assumption is not needed here. Furthermore, by imposing strong monotonicity on one of the divisible commodities we show that any competitive equilibrium is in the core of the economy and therefore the first theorem of welfare also holds. We further obtain a second welfare theorem stating that under some conditions a Pareto efficient allocation can be sustained by a competitive equilibrium allocation for some well-chosen redistribution of the total initial endowments. Journal of Economic Literature Classification Numbers: D4, D46, D5, D51, D6, D61.     

Information disclosure, banking development and knowledge-driven growth

In this study we develop a knowledge-driven growth model which explicitly models the banking sector as monopolistically competitive. The main mechanism through which financial intermediaries affect the real economy is through the evaluation and provision of liquidity to R&D projects. We distinguish two scenarios. In the regime with information disclosure, banks are able to use the stock of information obtained by the banking industry from evaluating R&D projects. This information externality brings about efficiency improvements, thereby leading to a positive entry of banks, more bank-funded research and in turn positive economic growth. By contrast, in the regime with no information disclosure, it is not profitable for new banks to enter the industry. This implies that no more potential R&D projects can be evaluated and hence financed, thus leading the economy to a zero-growth equilibrium.     

INTELLECTUAL PROPERTY MEETS ECONOMIC GEOGRAPHY: GLOBALIZATION, INEQUALITY, AND INNOVATION STRATEGIES

I perform a Schumpeterian analysis of a world economy in which heterogenous individuals and firms endogenously respond to stronger global competition by undertaking more education and by spending more in research and development (R&D). A more globalized economy is predicted to exacerbate wage inequality, but to spur human capital accumulation within each country. However, despite its positive level effects on consumption and output, globalization can reduce each country's per-capita output growth rate. R&D specialization allows each country to positively invest in manufacturing, variety proliferation R&D, and product quality upgrading R&D. The existence of such an R&D specialization – jointly with domestic size – allows us to explain some different economic performance about inequality and R&D effort of developed regions, such as the US and the EU countries.     

Has New Zealand benefited from its investments in research & development?

We use panel data for nine industries to evaluate research and development (R&D) investments in New Zealand over the past forty years. We estimate the impact of R&D stocks in a particular industry on output per person in that industry and on output per person in the rest of the economy. We examine both public and private R&D investments. Privately provided R&D has a statistically significant positive impact on own-industry output per person, suggesting it increases productivity. However, publicly provided R&D has no impact on own-industry output per person. There is also evidence that private R&D in certain industries positively affects output per person in the rest of the economy, i.e. it generates positive spillovers. There is no evidence of positive spillovers from publicly provided R&D.     

Quantitative growth effects of subsidies in a search theoretic R&D model

Should government subsidize R&D and does it matter how these subsidies are allocated? We examine these questions in a dynamic model where R&D is described as sequential sampling from a distribution of new ideas. Successful discoveries affect future available resources and incentives for further R&D. Consequently, there may be under-investment in R&D. We study the effect of government interventions aimed at fostering growth through R&D. Calibrating the model with aggregate data from the Israeli business sector allows us to quantitatively compare two forms of support resembling those actually used to encourage R&D in the Israeli business sector: (i) an unrestricted subsidy that may be used at the recipients' discretion to finance R&D or other investments, (ii) a subsidy earmarked by the government for R&D activities only. While there is no theoretical way to determine which of the two subsidies will have a greater impact on search for new ideas and growth, we find that in the calibrated economy both subsidies have a significant but similar impact on the economy's output and TFP growth rates. Accordingly, in the case of the Israeli business sector, the incentives to conduct R&D were sufficiently strong, and no R&D-specific encouragement was needed. However, a sensitivity analysis reveals that for economies characterized by other parameter values this result may not be true. Correspondence to: B. Bental     

RE‐EXAMINATION OF THE GROWTH‐ENHANCING BUBBLE

We investigate the growth and welfare effects of the bubble that arise on equities on newly created firms by R&D activities. Considering an economy where the input to the R&D sector is the final goods financed by the savings of the household sector, we show that such a bubble has a growth‐enhancing effect under the condition opposite to the previous literature. We also explore the characteristics of the steady state equilibrium with the bubble and demonstrate that there can be dual bubbly equilibria, one of which is unstable and the other stable, and that the growth and welfare effects of an unexpected permanent change in the initial bubble are very different depending on which equilibrium the economy stays in.     

Growth and optimal policies in an R&D-growth model with imperfect international capital mobility

In this paper, we examine the effects of international capital mobility on innovation, growth, and optimal growth policies in a small open economy with R&D-driven growth. Households can borrow funds from an imperfect international capital market to finance their investment in R&D firms. We show that the economy can reach a higher growth rate if international capital is more mobile. This result is consistent with recent empirical findings. Moreover, we show that the common growth-enhancing policies, such as patent protection and the R&D subsidies, have an additional negative welfare effect when households can access the international capital market. Accordingly, the optimal patent protection and R&D subsidy should be smaller when the degree of international capital mobility is higher.     

Growth in economies with non convexities: sunspots and lottery equilibria

Summary. We investigate the relation between lotteries and sunspot allocations in a dynamic economy where the utility functions are not concave. In an intertemporal competitive economy, the household consumption set is identified with the set of lotteries, while in the intertemporal sunspot economy it is the set of measurable allocations in the given probability space of sunspots. Sunspot intertemporal equilibria whenever they exist are efficient, independently of the sunspot space specification. If feasibility is, at each point in time, a restriction over the average value of the lotteries, competitive equilibrium prices are linear in basic commodities and intertemporal sunspot and competitive equilibria are equivalent. Two models have this feature: Large economies and economies with semi-linear technologies. We provide examples showing that in general, intertemporal competitive equilibrium prices are non-linear in basic commodities and, hence, intertemporal sunspot equilibria do not exist. The competitive static equilibrium allocations are stationary, intertemporal equilibrium allocations, but the static sunspot equilibria need not to be stationary, intertemporal sunspot equilibria. We construct examples of non-convex economies with indeterminate and Pareto ranked static sunspot equilibrium allocations associated to distinct specifications of the sunspot probability space.Received: 25 August 2003, Revised: 16 March 2004, JEL Classification Numbers: D84, D90.Correspondence to: Paolo SiconolfiWe thank Herakles Polemarchakis for helpful conversations on the topic. The research of Aldo Rustichini was supported by the NSF grant NSF/SES-0136556.     

Too much of a good thing: Endogenous business cycles generated by bounded technological progress

Following Jones and Williams [Jones, C.I., Williams, J., 2000. Too much of a good thing? The economics of investment in R&D. Journal of Economic Growth vol. 5 (no. 1), 65–85], we assume that R&D is simultaneously subject to positive and to negative external effects (e.g., the non-rival nature of technology conflicts with congestion externalities). This observation allows to conceive an economy where two R&D sectors evolve without departing significantly from each other in terms of their productive results (society tends to penalize imbalances in technical progress, making negative external effects to appear associated to a sector when this outstands relatively to the other sector; the second sector, in turn, will be subject to positive externalities that reflect a catching up effect). The proposed framework, when associated to a growth setup, is able to replicate the existence of endogenous fluctuations and, therefore, it intends to be a contribution to the literature on endogenous business cycles.     

MISERY LOVES COMPANY: EQUILIBRIUM PORTFOLIOS WITH HETEROGENEOUS CONSUMPTION EXTERNALITIES*

The present article extends the Arrow–Debreu portfolio model to consumption externalities. It is assumed that each investor has a von Neumann–Morgenstern utility that is a function of her own consumption and of the average consumption in the group to which she belongs. Individual degrees of risk aversion and conformism are heterogeneous within each group and between the different groups in the economy. We show that, under some conditions on the degree of conformism in the economy, the optimal portfolio and consumption choices observed at equilibrium in each group with consumption externalities are equivalent to those that are optimal without any externality, but with an adjusted degree of risk aversion. If these conditions are not fulfilled, groups have no representative agent and the demand for pure zero‐mean lotteries may be positive, thereby showing that not all diversifiable risks are washed away at equilibrium. We characterize the relationship between the distribution of conformism in the economy to the competitive allocation of risk and to the equity premium. We provide conditions for the two‐fund separation property to hold.     

Minimum wage, exports and growth

Using an endogenous growth model in an open economy, we study the impact of minimum wages on growth for an innovator country. We state that a minimum wage shifts efforts from production to R&D, but only in an open economy. Thus, it speeds up long-run growth in proportional to exports. Calibrations suggest the growth surplus can be significant. An empirical study on 11 OECD countries illustrates these results. The impact on welfare is ambiguous because the minimum wage induces unemployment. However, we show that in an open economy, a minimum wage associated with unemployment benefits can Pareto dominate laissez-faire.     

International Cooperation on Climate-friendly Technologies

We examine international cooperation on technological development as an alternative to international cooperation on emission reductions. We show that without any R&D cooperation, R&D in each country should be increased beyond the non-cooperative level if (i) the technology level in one country is positively affected by R&D in other countries, (ii) the domestic carbon tax is lower than the Pigovian level, or (iii) the domestic carbon tax is set directly through an international tax agreement. We also show that a second-best technology agreement has higher R&D, higher emissions, or both compared with the first-best-outcome. The second-best subsidy always exceeds the subsidy under no international R&D cooperation. Further, when the price of carbon is the same in the second-best technology agreement and in the case without R&D cooperation, welfare is highest, R&D is highest and emissions are lowest in the second-best R&D agreement.     

Outside versus inside bonds: A Modigliani–Miller type result for liquidity constrained economies

When agents are liquidity constrained, two options exist – sell assets or borrow. We compare the allocations arising in two economies: in one, agents can sell government (outside) bonds and in the other they can borrow by issuing (inside) bonds. All transactions are voluntary, implying no taxation or forced redemption of private debt. We show that any allocation in the economy with inside bonds can be replicated in the economy with outside bonds but that the converse is not true. However, the optimal policy in each economy makes the allocations equivalent.     

ACE versus CBIT: Which is Better for Investment and Welfare?

This article analyses the switch to an Allowance for CorporateEquity (ACE) or to a Comprehensive Business Income Tax (CBIT)type of tax system starting from the present German tax system.We show that in case an ACE type of reform is financed by anincrease in the VAT and not in the profit tax, it might be preferredto a CBIT even in the context of an open economy. Moreover,the required exogenous increase in the profit tax rate cannotensure revenue neutrality on its own due to the negative generalequilibrium effects it triggers on the whole economy. For aCBIT, the exogenous reduction in the tax rates on corporateand non-corporate profits leads to better results than whenwe allow for an endogenous change in the VAT. The best resultsarise when the CBIT is accompanied by a provision for immediatewrite-off and a lower profit tax or when the ACE with no additionalcapital gains taxation on household side is financed by an increasein the VAT. (JEL-Classification: C68, D58, D92, E62, H25.)     

Core is manipulable via segmentation

Any allocation rule that picks only core allocations is manipulable via segmentation. That is, there exists an economy with a coalition of agents such that, once this coalition splits momentarily from the rest of the economy and institutes the allocation rule within itself, no matter which individually rational sub-allocation the complementary coalition picks, when we paste all the agents back together at their new endowments and apply the allocation rule to this “collage” economy, each member of the former coalition will be strictly better off than under direct application of the allocation rule to the original economy.     

Incomplete Markets, Allocative Efficiency, and the Information Revealed by Prices

We compare rational expectations equilibria with different degrees of information revelation through prices. These equilibria arise in a two-period exchange economy with finitely many states and signals, multiple commodities and incomplete financial markets for nominal assets. We show that there are always equilibria where information is redundant in the sense of being of no value to the uninformed traders. We give conditions under which for a generic set of economies, parametrized by endowments and utilities, there exist open sets of equilibria for which allocative and informational efficiency are independent, with implications for monetary policy. Journal of Economic Literature Classification Numbers: D52, D60, D82, E52.     

Existence of competitive equilibrium when incomes may be zero

Summary In a pure exchange economy, there exists a price vector which is a quasi-equilibrium (Debreu 1962), but this may not be a competitive equilibrium if some individuals' demand functions are discontinuous because their incomes may be zero. We show nonetheless, in a pure exchange economy with free disposal, that there is asequence of prices approaching the quasi-equilibrium along which total excess demands tend to a non-positive limit.Comments on earlier drafts from K. J. Arrow, D. Duffie, H. E. Scarf, and D. Schmeidler are gratefully acknowledged.     

Too Much of a Good Thing? The Economics of Investment in R&D

Research and development is a key determinant of long-run productivity and welfare. A central issue is whether a decentralized economy undertakes too little or too much R&D. We develop an endogenous growth model that incorporates parametrically four important distortions to R&D: the surplus appropriability problem, knowledge spillovers, creative destruction, and duplication externalities. Calibrating the model, we find that the decentralized economy typically underinvests in R&D relative to what is socially optimal. The only exceptions to this conclusion occur when the duplication externality is strong and the equilibrium real interest rate is simultaneously high.