efficient and durable decision rules with incomplete information we compare six concepts of efficiency for economies with incomplete information depending on the stage at which individuals welfare is evaluated and on whether incentive constraints are recognized an example is shown in which an incentive efficient decision rule may be unanimously rejected by the individuals in the economy we define durable decision rules which can resist such unanimous rejection and show that efficient durable decision rules exist

introduction to the symposium on growth fluctuations and sunspots confronting the data the papers in this symposium demonstrate the theoretical as well as the empirical plausibility of indeterminacy and of sunspots in equilibrium models with infinitely lived agents they depart from the standard competitive framework because of the presence of externalities or of monopolistic competition some focus on business fluctuations while others address long run growth the second part of the introduction presents a general unifying framework to identify the structure that is common to the papers of the symposium journal of economic literature classification numbers e00 e3 o40 c 1994 academic press inc

a characterization of erratic dynamics in the overlapping generations model abstract in this paper we characterize and give examples o wide classes of utility functions which generate erratic dynamics in the standard deterministic overlapping generations model erratic dynamics refers to feasible trajectories which are bounded but which do not converge to stationary points or periodic orbits we show that such trajectories are pareto efficient we introduce credit into the model and show how a constant credit expansion rate can result in erratic trajectories in prices and the real value of credit finally we briefly discuss certain technical aspects of the mathematics used and the statistical nature of the dynamics that can arise from deterministic dynamical systems

capital labor substitution and competitive nonlinear endogenous business cycles abstract we develop simple geometrical methods to study local indeterminacy bifurcations and stochastic sunspot equilibria near a steady state in nonlinear two dimensional economic models we present in particular a simple constructive geometrical characterization of the support of stochastic sunspot equilibria not only arbitrarily near a steady state but also along local bifurcations these methods are applied to a simple aggregative model to study in particular the influence of capital labor substitution and of the aggregate labor supply wage elasticity on the occurrence of competitive endogenous deterministic or stochastic fluctuations journal of economic literature classification numbers e32 c62

facilitating consumer learning in insurance markets what are the welfare effects we model a monopoly insurance market where consumers can learn their accident risks at a cost c we then ask what are the welfare effects of a policy that reduces c if c is sufficiently small c c marginally reducing c hurts the insurer and weakly benefits the consumer finally a reduction in c that is successful meaning that the consumer gathers information after the reduction but not before it can hurt both parties this article is protected by copyright all rights reserved

stationary sunspot equilibria in a finance constrained economy abstract stationary sunspot equilibria are shown to exist in a production economy with infinite lived agents when it is not possible to borrow against future wage income equilibrium fluctuations exhibit persistence over time scales of the same order of magnitude as observed business cycles an active fiscal policy that stabilizes aggregate money expenditures can prevent such fluctuations

introduction to market psychology and nonlinear endogenous business cycles abstract the purpose of this symposium is to present geometric methods that are useful to study multiple equilibria and endogenous fluctuations in simple two dimensional macroeconomic models with a single predetermined variable characterizing the support of a sunspot equilibrium by its invariance properties in the underlying deterministic dynamics generates a complete description of stochastic endogenous fluctuations near a stationary state and along local bifurcations graphical methods to perform sensitivity analysis of local indeterminacy and bifurcations with respect to variations of uncertain economic parameters are also presented these methods are applied to specific macroeconomic models with constant returns to scale with external increasing returns and with imperfect competition journal of economic literatureclassification numbers e32 c62

the existence of equilibrium in discontinuous economic games ii applications in part i of this study we established two existence theorems for mixed strategy equilibrium in games with discontinuous payoff functions see theorems 4 4 and 5 5 in dasgupta and maskin 1986 hereafter d m 1986 in this second part we use the second of these two theorems to prove the existence of mixed strategy equilibrium in some wellknown discontinuous economic games that fail to have pure strategy equilibria the models we analyse are the bertrand edgeworth example of price setting duopolists with capacity constraints see section 2 2 price competition among firms producing differentiated products hotelling 1929 and d aspremont gabszewicz and thisse 1979 see section 2 3 spatial competition eaton and lipsey 1975 and shaked 1975 see section 3 and models of market dependent information rothschild and stiglitz 1976 and wilson 1977 section 4 the paper concludes section 5 with a classification of these models

equilibrium models displaying endogenous fluctuations and chaos abstract this paper surveys current developments in dynamic general equilibrium theory concerned with conditions under which endogenous fluctuations are possible existing contributions are divided into two classes the larger one consists of models with a unique perfect foresight equilibrium while the second includes models where equilibrium is indeterminate and the set of equilibria involving endogenous fluctuations includes sunspots equilibria while the two classes of models involve oscillations of different natures and with different policy implications we show that both are consistent with optimizing behavior and competitive equilibrium

stabilizing competitive business cycles abstract we study how stylized monetary proportional money transfers fiscal lump sum money transfers and public expenditure policies may eliminate endogenous deterministic cycles and stationary markov sunspot equilibria in a simple version of the overlapping generations model we also present new constructive methods for analyzing stationary markov sunspot equilibria in such a framework

endogenous information adverse selection and prevention implications for genetic testing policy we examine public policy toward the use of genetic information by insurers individuals engage in unobservable primary prevention and have access to different prevention technologies thus insurance markets are affected by moral hazard and adverse selection individuals can choose to take a genetic test to acquire information about their prevention technology information has positive decision making value that is individuals may adjust their behavior based on the result of the test however testing also exposes individuals to uncertainty over the available insurance contract so called classification risk which lowers the value of information in our analysis we distinguish between four different policy regimes determine the value of information under each regime and associated equilibrium outcomes on the insurance market we show that the policy regimes can be pareto ranked with a duty to disclose being the preferred regime and an information ban the least preferred one

on endogenous competitive business cycles the belief that the long run equilibrium of a competitive monetary economy that does not experience any exogeneous shocks whether originating from the external environment or from policy should be modelled as a state that is stationary or perhaps growing at a constant rate seems to be deeply rooted in the mind of some economists

the supply of information by a concerned expert how much information should a policy maker pass on to a currently ill informed citizen in this paper we address this classic question of crawford and sobel 1983 in a setting in which beliefs impact utility as in kreps and porteus 1978 we show that this simple amendment has far reaching implications in particular our question cannot be answered using a utility function with standard revealed preference foundations revealed preference cannot tell us whether in a particular state s a decision maker prefers to believe incorrectly that the state is t or to know the truth to solve the model we go beyond the classical model in two respects relying on the psychological expected utility model of caplin and leahy 2001 to capture preferences and the psychological game model of geanakoplos pearce and stacchetti 1989 to capture strategic interactions

competitive equilibrium cycles recently there has been a surge of interest in endogenous business cycles that arise in competitive laissez faire economies in the context of standard overlapping generations economies conditions for the existence of equilibrium cycles have been given by grandmont 1983 and by benhabib and day 1982 models of the economy with extrinsic uncertainty or sunspots that have been developed by shell 1977 and by cass and shell 1983 see also balasko 1983 can also lead to equilibrium cycles

precautionary and speculative aspects of the behaviour of banks in the united kingdom under competition and credit control 1972 1980 when deciding upon the balance of its portfolio an economic agent must take into account many different types of risk the most obvious are those about future asset prices and transaction flows which respectively lend the problem its speculative and precautionary aspects this paper develops a model of uk bank behaviour under the competition and credit control ccc conventions which allows for both types of risk and yet is sufficiently tractable to be fitted empirically following previous uk studies we suppose that banks are risk averse maximising expected utility over a discrete decision period and assume that the distribution of asset returns is independent of that of cash and reserve losses in addition we assume that if the precautionary balances chosen by the bank initially are insufficient to cope with outflows of funds during the decision period without infringing the ccc conventions then the bank will face transactions or penalty costs this assumption distinguishes our model from those used in previous uk studies and gives it its precautionary aspects the basic model is set out in section i of the paper it is noted that reserve assets cash and short term money market items have similar speculative risk characteristics so that the banks problem can be separated into precautionary and speculative sub problems the first involving holdings of cash and reserve assets the second involving the remaining portfolio items the resulting relationships are discussed in section ii these may be estimated using simultaneous non linear equation methods the results are discussed in section iii

the existence of equilibrium in discontinuous economic games i theory the article presents information about the existence of equilibrium in discontinuous economic games in this paper and its sequel presents study the existence of nash equilibrium in games where agents payoff functions are discontinuous the enquiry is motivated by a number of recent studies that have uncovered serious existence problems in seemingly innocuous economic games in the sequel to this paper authors have explained the utility function in the economic games referred to earlier are neither continuous nor quasi concave however they demonstrate that the payoff functions in mildly modified versions of these constructs exhibit two weaker forms of continuity which together with the requirement of quasi concavity suffice for the existence of an equilibrium from this one may conclude that at least in the modified versions of these models discontinuities in the payoff functions are not the real source of the problem rather it is the failure of the payoff functions to the quasi concave which is responsible for the non existence of equilibrium these observations bear on the existence of nash equilibrium in pure strategies

psychological expected utility theory and anticipatory feelings we extend expected utility theory to situations in which agents experience feelings of anticipation prior to the resolution of uncertainty we show how these anticipatory feelings may result in time inconsistency we provide an example from portfolio theory to illustrate the potential impact of anticipation on asset prices

equilibrium cycles in an overlapping generations economy with production abstract perfect foresight equilibrium trajectories of an overlapping generations model with production may include stable or unstable invariant closed curves these orbits are detected using the hopf bifurcation theorem where the parameter of bifurcation is purely technological the paper also proves that there is a stabilization policy that completely eliminates the cycle finally using a c e s production function it is shown that the range of values of the elasticity of substitution between capital and labor for which cycles may exist is bounded above

the simple economics of bank regulation this paper discusses the effects of central bank regulation of the banking system carried out to control the level of bank lending prudential regulation designed to reduce the frequency of bank failure a problem in the economics of uncertainty and information is not considered the main point of this paper is that bank regulation in so far as it is effective and goes beyond the general effects of government intervention in credit markets can be seen as a tax on transactions intermediated through banks the variations in the incidence and beneficiaries of the tax provide a convenient framework for the different regulatory schemes the paper focuses on the effect of regulation on an individual bank the theory presented here is an elementary comparative static one based on the equality of marginal cost and marginal revenue it does not consider the more complicated issues of dynamic control however it is unlikely that any policy that has unsatisfactory comparative static properties will be successful the main ideas of this approach are due to tobin 1963 and johnson 1967 197 1 they have been further developed in work by spencer and mowl 1978 and artis and miller 1978 however the application of the analysis to the effects of different types of regulation is i believe new a general equilibrium model in the same spirit as the partial equilibrium model used here is given by fama 1980 the following section presents a simple model of the banking system section ii discusses the effect of government intervention and regulation and section iii looks at the way in which government regulation induces disintermediation section iv applies the previous results to consider various actual or proposed schemes in practice the final section draws conclusions

adverse selection with endogenous information in insurance markets abstract models of adverse selection assume that risk type is known to the consumer but not to the insurer many analyses suggest that information has zero social value and negative prior value why then would consumers become informed what is the incentive to gather information and why does adverse selection arise we show that the private value of information is non negative only if insurers cannot observe consumers information status or if consumers can conceal their informational status we examine the existence and characterization of equilibria under different configurations of information costs and benefits finally we examine some welfare implications of the endogenous information model for public policy regarding genetic testing and for state regulations concerning hiv testing

the value of genetic information in the life insurance market abstract this paper analyzes the effects of additional information in a life insurance market under adverse selection individuals have an incentive to acquire information about their risk type if their informational status cannot be observed by insurers in aggregate however the existence of a testing opportunity has an effect on the equilibrium premium we describe the conditions under which from an ex ante standpoint all individuals gain all lose or in which some gain and some lose from the existence of the test

financial deepening and economic growth the core of shapley shubik games and general equilibrium models with a venn diagram is applied for a theory on the role of real finance in economic growth among advanced economies then the dynamic computable general equilibrium dcge models for germany france the uk japan and the usa are constructed to assess the validity of the over financing hypothesis that has reappeared after the financial crisis of 2008 actual financial deepening ratios observed in the nonconsolidated balance sheet of the oecd exceeded by factors of 3 5 2 4 5 1 11 6 and 4 8 than the optimal financial deepening ratios implied by dcge models respectively in these countries because of excessive leveraging and bubbles up to 19 times of gdp which were responsible for this great recession containing such massive fluctuations for macroeconomic stability and growth in these economies are not possible in conventional fiscal and monetary policy models and require a dcge analysis like this along with adoption of separating equilibri

genetic testing in competitive insurance markets with repulsion from chance a welfare analysis a central theme in the international debate on genetic testing concerns the extent to which insurance companies should be allowed to use genetic information when offering insurance contracts we provide a welfare analysis of this issue within a model of an insurance market with asymmetric information having the following crucial feature in addition to a state contingent consumption profile a person s well being depends on her attitude towards resolution of future health uncertainty and this attitude varies across the population we present stylized facts that motivate this approach in the formal analysis we find that both tested high risks and untested individuals are equally well off whether or not test results can be used by insurers individuals who test for being low risks on the other hand are made worse off by not being able to verify this to insurers this implies that in terms of welfare a regulatory regime in which the use of genetic information by insurers is allowed is better than one in which it is not allowed

intrinsic preference for information abstract suppose agents value information not only to make contingent plans but also intrinsically how are such attitudes toward information related to attitudes toward risk we generalize the kreps porteus recursive expected utility model dropping both recursivity and expected utility there is a geometric analogy between risk and information we characterize intrinsic information loving in general by a substitution property analogous to multivariate risk loving and for smooth preferences by the convexity of gateaux derivatives even with recursivity preference for information does not imply expected utility we provide an example we examine connections between information loving and risk aversion for early and late resolving risks journal of economic literatureclassification numbers d80 d81