bulls bears and market sheep abstract a deterministic excess demand model of stock market behavior is presented that generates stochastically fluctuating prices and randomly switching bear and bull markets

performance evaluation of optimized portfolio insurance strategies abstract we use s p 500 index return data for the time period 1985 2013 to evaluate the performance of portfolio insurance strategies we shed light on the question if the performance of a constant proportion portfolio insurance cppi strategy can be improved by means of a time varying multiplier which depends on the estimated future volatility neglecting any inter temporal hedging demand the theoretical foundation of the strategies is given by maximizing the expected utility of a hara investor in a diffusion model setup if the risk premium is assumed to be proportional to the variance the optimal strategy is a cppi strategy otherwise the multiple is time varying ppi it turns out that even time varying multiple strategies based on a rolling window of historical volatility estimates give a significant improvement of cppi strategies the out performance is robust w r t alternative performance measures and is also true for proportional transaction costs and adequate trigger trading

omega performance measure and portfolio insurance abstract we analyze the performance of the two main portfolio insurance methods the obpi and cppi strategies using downside risk measures for this purpose we introduce kappa performance measures and especially the omega measure these measures take account of the entire return distribution we show that the cppi method performs better than the obpi as a by product we determine the set of threshold values for these risk reward performance measures

commodities momentum a behavioral perspective the growth in commodity related investments has sparked interest in the performance of momentum strategies in these markets this paper introduces a behavioral proxy of the 52 week high and low momentum that explains a significant proportion of the variation of conventional momentum returns after controlling for commodity specific risk factors our findings show that the 52 week high strategy generates significant profits after accounting for transaction costs we report that the 52 week high strategy is a better predictor of returns than conventional momentum our findings suggest that term structure and hedging pressure risk factors provide only a partial explanation of the results

financial integration credit market imperfections and consumption smoothing abstract contrary to standard theoretical reasoning recent empirical research shows that financial integration is associated with higher consumption volatility in developing countries this paper illustrates how domestic credit market imperfections can alter the standard predictions about the consumption smoothing possibilities under financial autarky and international financial integration i use a two country international real business cycle model where the non traded sector in the small country faces borrowing constraints due to contract enforceability problems if the international risk sharing opportunities are non existent households can secure themselves against the shocks in the non traded sector only by adjusting their labor effort which leads to changes in sectorial output and terms of trade the deterioration of the terms of trade acts as a dampening effect on consumption causing it to be less volatile under financial autarky relative to financial integration under financial integration international financial assets provide the insurance against domestic productivity shocks without affecting the relative prices hence allowing the consumption to react more

benchmarking portfolio insurance and technical analysis a monte carlo comparison of dynamic strategies of asset allocation abstract this paper makes an extensive simulation comparison of popular dynamic strategies of asset allocation for each strategy alternative measures have been calculated for risk return and risk adjusted performance sharpe ratio sortino ratio return at risk moreover the strategies are compared in different market situations bull bear no trend markets and with different market volatility taking into account transaction costs and discrete rebalancing of portfolios the simulations show a dominant role of constant proportion strategies in bear and no trend markets and a preference for benchmarking strategies in bull markets these results are independent of the volatility level and the risk adjusted measure adopted

adaptive markets and the new world order corrected may 2012 in the adaptive markets hypothesis amh intelligent but fallible investors learn from and adapt to changing economic environments this implies that markets are not always efficient but are usually competitive and adaptive varying in their degree of efficiency as the environment and investor population change over time the amh has several implications including the possibility of negative risk premiums alpha converging to beta and the importance of macro factors and risk budgeting in asset allocation policies

consumer demand for vehicle safety an empirical study although numerous studies on the effects of vehicle safety regulation exist few are devoted to consumer demands for vehicle safety this study uses an extensive data set combining vehicle specific information with responses from a national household survey of new car buyers to estimate individual demand for safety it finds ceteris paribus purchase probability rises with an increase in safety features in particular an index of vehicle crashworthiness is a strong determinant of purchase decisions the results favor a policy of posting crash test results and suggest that passive restraint systems enhance the likelihood of purchasing a given model

the wisdom of the minority we consider a simple variant of the canonical model of social learning and show that in many situations it is optimal for an agent to abandon her own information and follow the minority rather than the majority this possibility depends on two economically meaningful requirements agents are differentially informed and observe only the number of agents having chosen each option such as consumers observing only market shares we show that minority wisdom arises when information is sufficiently heterogeneous and the well informed are not overly abundant yet the conditions necessary are not overly restrictive in fact it is possible for the minority to be wise even when the minority consists of a lone dissenter and a majority of citizens are well informed

traders expectations in asset markets experimental evidence we elicit traders predictions of future price trajectories in repeated experimental markets for a 15 period lived asset we find that individuals beliefs about prices are adaptive and primarily based on past trends in the current and previous markets in which they have participated most traders do not anticipate market downturns the first time they participate in a market and when experienced they typically overestimate the time remaining before market peaks and downturns occur when prices deviate from fundamental values belief data are informative to an observer in predicting the direction of future price movements and the timing of market peaks

why do stocks and consumption imply such different gains from international risk sharing abstract estimates of the gains to international risk sharing based upon stock returns tend to find dramatically higher gains than do estimates from consumption based models in this paper i examine the reasons for these differences using a common theoretical framework for both approaches i find that the differences are largely due to the much higher variability of stock returns and its implied intertemporal substitution in marginal utility also contrary to conventional wisdom the differences in gains from the two approaches do not arise from treating stock returns as exogenous rather than endogenous

commodity trade and international risk sharing how much do financial markets matter abstract this paper evaluates the social gains from international risk sharing in some simple general equilibrium models with output uncertainty a simulation model calibrated to selected moments of u s and japanese data estimates the incremental loss from a ban on international portfolio diversification to be on the order of 0 20 percent of output per year even the theoretical gains from asset trade may disappear under alternative sets of assumptions on preferences and technology the paper argues that the small magnitude of potential trade gains may help explain the apparently inconsistent findings of empirical studies on the degree of international capital mobility

commodity markets price limiters and speculative price dynamics abstract we develop a behavioral commodity market model with consumers producers and heterogeneous speculators to characterize the nature of commodity price fluctuations and to explore the effectiveness of price stabilization schemes within our model we analyze how nonlinear interactions between market participants can create either bull or bear markets or irregular price fluctuations between bull and bear markets through a global homoclinic bifurcation both the imposition of a bottoming price level to support producers or a topping price level to protect consumers can eliminate such homoclinic bifurcations and hence reduce market price volatility however simple policy rules such as price limiters may have unexpected consequences in a complex environment a minimum price level decreases the average price while a maximum price limit increases the average price in addition price limiters influence the price dynamics in an intricate way and may cause volatility clustering

market share dynamics in a duopoly model with word of mouth communication abstract we analyze dynamic price competition in a homogeneous goods duopoly where consumers exchange information via word of mouth communication a fraction of consumers who do not learn any new information remain locked in at their previous supplier in each period we analyze markov perfect equilibria in which firms use mixed pricing strategies market share dynamics are driven by the endogenous price dispersion depending on the parameters we obtain different classes of dynamics when firms are impatient there is a tendency towards equal market shares when firms are patient there are extended intervals of market dominance interrupted by sudden changes in the leadership position

dynamic asset allocation when bequests are luxury goods abstract luxury bequests impart systematic effects of age to an investor s optimal allocation the expected percentage allocation to equities rises throughout retirement when bequests are luxuries the marginal utility of bequests declines more slowly than the marginal utility of consumption this is essentially lower risk aversion as a retiree approaches death her expected remaining lifetime utility is increasingly composed of bequest utility and thus generates progressively lower risk aversion a retiree responds by increasingly favoring the higher return risky asset compared to standard preferences luxury bequests elevate a retiree s average exposure to the risky asset but the difference is small in early retirement

automobile safety regulation and offsetting behavior some new empirical estimates suppose that engineers can demonstrate that air bags will reduce the risk of death in an automobile by 25 percent for any given frequency and severity of accidents would the installation of these devices necessarily reduce the fatality rate by 25 percent the answer depends upon the response of drivers to the increased protection from dangerous accidents if they increase their driving intensity speed recklessness driving while intoxicated driving in unsafe conditions etc they may realize substantially less than a 25 percent reduction in expected fatalities such offsetting behavior is not irrational it merely represents a substitution of the marginal benefits of driving intensity for the reduced marginal cost of risk if offsetting behavior actually occurs it may be realized in increased risks for bicyclists motorcyclists and pedestrians these externalities could be substantial unless there is a reduction in risk taking among these groups as a result the net effect of mandating air bags or any other safety device is far from obvious there may be no net reduction in fatalities or serious injuries these theoretical considerations are at the core of sam peltzman s classic study 1975 of automobile safety regulation for policymakers however the key question is how much offsetting behavior actually occurs as peltzman 1977 acknowledges offsetting behavior could be trivial or substantial in this paper we explore this issue providing new empirical estimates of the effects of crashworthiness standards established for automobiles over the past fifteen years these standards have required the installation of lapshoulder belts energy absorbing steering columns head restraints padded dashboards crush resistant passenger compartments safer windshield mounting more secure locks and a variety of other features

risk perceptions endogenous demand and regulation of agricultural biotechnology abstract this paper presents a dynamic model of optimal product regulation in which consumer acceptance and the rate of product innovation are included as endogenous variables insights derived from the model are used to critically evaluate recent policy controversies regarding regulation of agricultural biotechnology the results of the analysis indicate that if regulatory policy significantly affects consumer risk perceptions more stringent regulatory requirements than those based solely on scientific risk assessment may be economically efficient when demand is endogenously affected by regulatory policies industry may also benefit from stronger regulations even if this results in a significant increase in product development costs

imperfect information and dynamic conjectural variations this article analyzes oligopoly interaction in an environment where firms are imperfectly informed about the evolution of the market demand curve the analysis develops a two period cournot framework under the assumptions that demand shifts are positively serially correlated that firms never directly observe the demand curve and that firms never observe the previous quantity decisions of rivals firms do draw inferences about the position of the demand curve from past observations on prices consequently the current output of a firm will influence the current market price which will then influence rivals inferences about future demand the future output decisions of rivals will respond accordingly the theory predicts negative dynamic conjectural variations essentially a firm perceives that an increase in its output will lower the current market clearing price which will cause rival firms to think that the demand curve has shifted down and hence induce them to lower their outputs in the future

financial crises and regime dependent dynamics abstract generalized with the regime dependent beliefs and regime switching dynamics the simple market maker framework established by day and huang 1990 is capable to model all types of crises that is sudden crisis disturbing crisis and smooth crisis and to offer economic and dynamic justifications on how and why these crises appear moreover the model simulations verify the salient qualitative and statistical properties commonly observed in the real financial data such as fat tails volatility clustering long range dependence leverage effect and other stylized facts additionally the model replicates the various chart patterns widely applied in the technical analysis

high and declining prices signal product quality high and declining prices signal a high quality product high prices are the efficient means of signaling because the consequent loss of sales volume is most damaging for lower cost lower quality products as time passes and the number of informed consumers increases the signaling distortion lessens resulting in a declining price profile the prediction of high and declining prices is robust across a variety of dynamic models and is consistent with recent empirical findings copyright 1991 by american economic association

using asset allocation to protect spending the management of an educational endowment or other income producing portfolio involves two strategic decisions at the fund level asset allocation and choice of a spending rule traditionally these two decisions are linked for example to preserve capital on average but the optimal link would be more dynamic this article describes a new protective strategy that links spending and asset allocation in a way that preserves spending power in down markets but participates significantly in up markets the strategy is similar to constant proportions portfolio insurance in that part of the fund is maintained in safe assets to preserve the value needed for continued expenditures like portfolio insurance the strategy outperforms traditional strategies when markets are persistently up or persistently down but underperforms when portfolios are whipsawed by alternating ups and downs

who matters in coordination problems we consider a common investment project that is vulnerable to a self fullling coordination failure and hence is strategically risky based on their private information agents who have heterogeneous investment incentives form expectations or sentiments about the project s outcome we nd that the sum of these sentiments is constant across dierent strategy proles and it is independent of the distribution of incentives as a result we can think of sentiment as a scarce resource divided up among the dierent payo types applying this nding we show that agents who benet little from the project s success have a large impact on the coordination process the agents with small benets invest only if their sentiment towards the project is large per unit investment cost as the average sentiment is constant a subsidy decreasing the investment costs of these agents will free up a large amount of sentiment provoking a large impact on the whole economy intuitively these agents insensitive to the project s outcome and hence to the actions of others are inuential because they modify their

conquering misperceptions about commodity futures investing long only commodity futures returns have been very disappointing over the last decade leading some to wonder whether investing in commodities was a mistake the poor performance is largely the result of poor income returns a return building block similar to a stock s dividend yield or a bond s yield three misperceptions have contributed to this disappointment 1 commodities are a play on commodity prices 2 commodity prices provide an inflation hedge and 3 commodity markets which are smaller than facebook s market capitalization can absorb abundant capital learning from mistakes and conquering misperceptions are key to becoming a better investor

price competition for an informed buyer abstract this paper investigates price competition with private information on the demand side two sellers each offer a different variety of a good to a buyer endowed with a private binary signal on their relative quality the model provides an informational foundation to differentiation in hotelling s price competition game equilibrium comparative statics is performed with respect to the prior belief and the precision of the private information competition is fierce when the prior strongly favors one seller and private signals are relatively uninformative sellers equilibrium profits may fall with the revelation of public information and are nonmonotonic in the prior belief journal of economic literature classification numbers c72 d43 d82 l15

consumer search with observational learning this article studies observational learning in a consumer search environment consumers observe the purchasing decision of a predecessor with similar preferences consumers rationally emulate by initiating their search at the firm from which their predecessor purchased free riding on search effort and reacting less to price changes prices are nonmonotone in search costs and may be as low as marginal costs we discuss several extensions and show that the effect of emulation on prices is stronger when i the number of firms increases ii consumers first visits are more elastic with respect to market shares and iii prices are adjusted more frequently

stochastic lifestyling optimal dynamic asset allocation for defined contribution pension plans this paper considers the asset allocation strategies open to members of deflnedcontribution pension plans we investigate a model that incorporates three sources of risk asset risk and salary or labour income risk in the accumulation phase and interest rate risk at the point of retirement we propose a new form of terminal utility function incorporating habit formation that uses the plan member s flnal salary as a numeraire the paper discusses various properties and characteristics of the optimal stochastic asset allocation strategy which we call stochastic lifestyling both with and without the presence of non hedgeable salary risk we compare the performance of stochastic lifestlying with some popular strategies used by pension providers including deterministic lifestyling which involves a gradual switch from equities to bonds according to preset rules and static strategies that invest in benchmark mixed funds we flnd that the use of stochastic lifestyling signiflcantly enhances the welfare of a wide range of potential plan members relative to these other strategies jel classiflcation e21 g11 g23

learning and complementarities in speculative attacks we study a model where the aggregate trading of currency speculators reveals new information to the central bank and affects its policy decision we show that the learning process gives rise to coordination motives among speculators leading to large currency attacks and introducing non fundamental volatility into exchange rates and policy decisions we show that the central bank can improve the ex ante effectiveness of its policy by committing to put a lower weight ex post on the information from the market and that transparency may either increase or decrease the effectiveness of learning from the market depending on how it is implemented

investment horizon and the attractiveness of investment strategies a behavioral approach we analyze the attractiveness of investment strategies over a variety of investment horizons from the viewpoint of an investor with preferences described by cumulative prospect theory cpt currently the most prominent descriptive theory for decision making under uncertainty a bootstrap technique is applied using historical return data of 1926 2008 to allow for variety in investors preferences we conduct several sensitivity analyses and further provide robustness checks for the results in addition we analyze the attractiveness of the investment strategies based on a set of experimentally elicited preference parameters our study reveals that strategy attractiveness substantially depends on the investment horizon while for almost every preference parameter combination a bond strategy is preferred for the short run stocks show an outperformance for longer horizons portfolio insurance turns out to be attractive for almost every investment horizon interestingly we find probability weighting to be a driving factor for insurance strategies attractiveness

public information and uninformed trading implications for market liquidity and price efficiency abstract we develop a rational expectations equilibrium model in which noise trading comes from discretionary liquidity traders the equilibrium quantity of aggregate noise trading is endogenously determined by the population size of liquidity traders active in the financial market by improving market liquidity public information reduces the expected trading loss of liquidity traders and thus attracts more such traders to the market which negatively affects information aggregation analyzing an alternative setting that models noise trading as coming from hedgers yields similar insights in a setting with endogenous information public information can harm information aggregation both through crowding out private information and through attracting noise trading

global implications of self oriented national monetary rules author s obstfeld maurice rogoff kenneth abstract it is well known that if international linkages are relatively small the potential gains to international monetary policy coordination are typically quite limited but what if goods and financial markets are tightly linked is it then problematic if countries unilaterally design their institutions for monetary stabilization are the stabilization gains from having separate currencies largely squandered in the absence of effective international monetary coordination we argue that under plausible assumptions the answer is no unless risk aversion is very high lack of coordination in rule setting is a second order problem compared to the overall gains from monetary policy stabilization

international financial integration and national price levels the role of the exchange rate regime abstract this paper proposes a new perspective on systematic deviations from purchasing power parity panel evidence for oecd countries shows that international financial integration increases the national price level under managed exchange rate regimes and lowers the price level under floating exchange rates an open economy sticky price model reproduces these findings by relating them to the possibility of insurance against consumption losses in internationally integrated financial markets the utilization of insurance is reflected by relative price adjustments which manifest themselves in changes of the national price level the direction of relative price adjustments however depends on the extent to which insurance is used under different exchange rate regimes under a peg financial integration raises the national price level under a float however financial integration lowers the national price level

bertrand supertraps we study oligopoly price competition between multiproduct firms firms whose products interact in the profit function specifically we focus on the impact of intrafirm product interactions on the level of equilibrium profits this impact may be decomposed in two different ways a a direct effect keeping the competitors actions fixed plus a strategic effect i e through the competitors actions or alternatively b a competitive advantage effect change in firmi only plus an imitation effect change in all other firms we derive conditions such that a the strategic effect more than outweighs the direct effect and conditions such that b the imitation effect more than outweighs the competitive advantage effect bertrand supertraps for example an increase in the degree of economies of scope would increase profits if prices were fixed or if the change were limited to firmi s cost function however if all firms increase the degree of economies of scope then all firms receive lower profits a variety of other applications is considered including learning curves core competencies demand synergies systems competition compatibility bundling network effects switching costs durable goods long term contracts

effectiveness of cppi strategies under discrete time trading abstract the paper analyzes the effectiveness of the constant proportion portfolio insurance cppi method under trading restrictions if the cppi method is applied in continuous time the cppi strategies provide a value above a floor level unless the price dynamics of the risky asset permit jumps the risk of violating the floor protection is called gap risk in practice it is caused by liquidity constraints and price jumps both can be modelled in a setup where the price dynamics of the risky asset are described by a continuous time stochastic process but trading is restricted to discrete time we propose a discrete time version of the continuous time cppi strategies which satisfies three conditions the resulting strategies are self financing the asset exposure is non negative and the value process converges we determine risk measures such as the shortfall probability and the expected shortfall and discuss criteria which ensure that the gap risk does not increase to a level which contradicts the original intention of portfolio insurance in addition we introduce proportional transaction costs and analyze their effects on the risk profile

welfare effects of financial innovation in incomplete markets economies with several consumption goods abstract we show that in almost every incomplete markets economy with more than one consumption good and with sufficiently many uninsured states of nature at any general equilibrium of this economy it is possible to arbitrarily perturb the equilibrium utilities merely by introducing the appropriate asset making for example all agents worse off this result demonstrates that the examples given by hart on the optimality of equilibrium when the market structure is incomplete j econ theory11 1975 418 443 and others are actually general phenomena and is in sharp contrast to the intuition that innovation since it expands financial opportunities should benefit all agents journal of economic literature classification numbers d52 d60 g10

how big are potential welfare gains from international risksharing abstract there is extensive evidence that risksharing across countries is far from perfect some have attributed this to small benefits from risksharing gains from riskpooling that have been reported range from negligible to enormous this paper documents to what extent the results are sensitive to the parameterization of preferences the stochastic process of the endowment and its measurement we find that gains from risksharing are quite sizable for realistic assumptions about the underlying factors for oecd countries they are equivalent to a permanent increase in tradables consumption in the range of 1 1 to 3 5 for a 50 year horizon and 2 5 to 7 4 for a 100 year horizon

a dynamic autoregressive expectile for time invariant portfolio protection strategies constant proportion portfolio insurance cppi is nowadays one of the most popular techniques for portfolio insurance strategies it simply consists of reallocating the risky part of a portfolio with respect to market conditions via a leverage parameter called the multiple guaranteeing a predetermined floor we propose to introduce a conditional time varying multiple as an alternative to the standard unconditional cppi method directly linked to actual risk management problematics this ex ante approach for the conditional multiple aims to diversify the risk model associated for example with the expected shortfall es or extreme risk measure estimations first we recall the portfolio insurance principles and main properties of the cppi strategy including the time invariant portfolio protection tipp strategy as introduced by estep and kritzman 1988 we emphasize the existence of an upper bound on the multiple for example to hedge against sudden drops in the market then we provide the main properties of the conditional multiples for well known financial models including the discrete time portfolio rebalancing case and levy processes to describe the risky asset dynamics for this purpose we precisely define and evaluate different gap risks in both conditional and unconditional frameworks as a by product the introduction of discrete or random time portfolio rebalancing allows us to determine and or estimate the density of durations between rebalancements finally from a more practical and statistical point of view due to trading restrictions we present the class of dynamic autoregressive expectile dare models for estimating the conditional multiple this latter approach provides useful complementary information about the risk and performance associated with probabilistic approaches to the conditional multiple

advertising as signal jamming abstract this paper considers a model of informative advertising that allows firms to jam the consumers signals on product quality before choosing prices at a second stage we find that the price competition at the second stage may overrule the basic insights from the signal jamming approach in other areas of application as a consequence a firm may advertise more intensely the higher is the difference of the expected product qualities moreover a firm s optimal advertising intensity can decrease with quality uncertainty

the efficacy of government safety policies on traffic related fatalities empirical estimates from japan a time series analysis of japanese data for the period 1966 85 estimates the effectiveness of seat belt and government safety policies on various types of traffic related fatalities the results indicate that these policies reduce the risk of death for both motor vehicle occupants and non occupants

why market shares matter an information based theory consider a duopoly market in which consumers have heterogeneous information about the quality differential q of the two goods when firms are ignorant about q consumers rationally believe that a firm with high market shares is likely to produce a high quality good as a result firms try to signal jam the inferences of consumers and compete for market shares beyond the level explained by short run profit maximization when firms know q multiple equilibria may exist but there is always one equilibrium in which market shares signal quality and then the market tends to be more competitive

a comparative study of portfolio insurance abstract this paper undertakes a comparative study of portfolio insurance under a variety of modeling strategies specifically we focus on portfolio insurers who derive utility from horizon wealth with marginal utility tending smoothly to infinity at some pre specified floor we solve for the optimal consumption portfolio wealth of these portfolio insurers and compare with constrained portfolio insurers and normal agents general equilibrium conditions are contrasted under pure exchange and production type models while the market price level is unambiguously increased under pure exchange under production the effect on market level is state dependent in both models the market volatility and risk premium are decreased by portfolio insurance the paper also investigates the possible relationship between portfolio insurance type trading strategies and market volatility

coordinated bubbles and crashes abstract in a market with information friction investors strategically consider the actions of others and evolutionarily switch between fundamental and technical strategies to maximize their payoffs the collective actions of all investors exert feedback on asset price which affects investors subsequent actions we find that investors have the incentive to adopt fundamental strategy to restore market efficiency only if the mispricing is sufficiently large when investors fail to coordinate on the fundamental strategy market inefficiency increases which blows the bubble as market inefficiency grows the coordination on fundamental strategy strengthens which eventually bursts the bubble

heterogeneous speculators endogenous fluctuations and interacting markets a model of stock prices and exchange rates abstract we develop a discrete time model in which the stock markets of two countries are linked via and with the foreign exchange market the foreign exchange market is characterized by nonlinear interactions between technical and fundamental traders such interactions may generate complex dynamics and recurrent switching between bull and bear market phases via a well known pitchfork and period doubling bifurcation path when technical traders become more aggressive the two stock markets are populated by fundamentalists and prices tend to evolve towards stable steady states driven by linear laws of motion a connection between such markets is established by allowing investors to trade abroad and the resulting three dimensional dynamical system is analyzed one goal of our paper is to explore potential spill over effects between foreign exchange and stock markets a second related goal is to study how the bifurcation sequence which characterizes the market with heterogeneous speculators is modified in the presence of interactions with other markets

price and quality in a new product monopoly in a signal extraction model of consumer behaviour higher prices signal higher quality products for a new product monopoly even without cost asymmetries across different qualities moreover higher quality products earn greater expected profits and the monopolist has an incentive to provide even transient improvements in quality finally the monopolist has a positive incentive to conduct market research about quality and produces more information than is socially optimal

stochastic network programming for financial planning problems several financial planning problems are posed as dynamic generalized network models with stochastic parameters examples include asset allocation for portfolio selection international cash management and programmed trading arbitrage despite the large size of the resulting stochastic programs the network structure can be exploited within the solution strategy giving rise to efficient implementations empirical results are presented indicating the benefits of the stochastic network approach for the asset allocation case

valuation optimal asset allocation and retirement incentives of pension plans we provide a framework in which we link the valuation and asset allocation policies of defined benefits plans with the lifetime marginal productivity schedule of the worker and the pension plan formula in turn we examine the retirement policies that are implied by the primitives of the model and the value of pension obligations our model provides an explicit valuation formula for a stylized defined benefits plan the optimal asset allocation policies consist of the replicating portfolio of the pension liabilities and the growth optimum portfolio independent of the pension liabilities we show that the worker will retire when the ratio of pension benefits to current wages reaches a critical value which depends on the parameters of the pension plan and the discount rate using numerical techniques we analyze the feedback effect of retirement policies on the valuation of plans and on the asset allocation decisions article published by oxford university press on behalf of the society for financial studies in its journal the review of financial studies

technology adoption in the presence of network externalities we analyze technology adoption in industries where network externalities are significant the pattern of adoption depends on whether technologies are sponsored a sponsor is an entity that has property rights to the technology and hence is willing to make investments to promote it key findings include the following 1 compatibility tends to be undersupplied by the market but excessive standardization can occur 2 in the absence of sponsors the technology superior today has a strategic advantage and is likely to dominate the market 3 when one of two rival technologies is sponsored that technology has a strategic advantage and may be adopted even if it is inferior 4 when two competing technologies both are sponsored the technology that will be superior tomorrow has a strategic advantage

rational contagion and the globalization of securities markets this paper argues that globalization may promote contagion by weakening incentives for gathering costly information and by strengthening incentives for imitating arbitrary market portfolios in the presence of short selling constraints the gain of gathering information at a fixed cost may diminish as markets grow moreover if a portfolio manager s marginal cost for yielding below market returns exceeds the marginal gain for above market returns there is a range of optimal portfolios in which all investors imitate arbitrary market portfolios and this range widens as the market grows numerical simulations suggest that these frictions can have significant implications for capital flows in emerging markets

duopoly information equilibrium cournot and bertrand abstract in a duopoly model where firms have private information about an uncertain linear demand it is shown that if the goods are substitutes not to share information is a dominant strategy for each firm in bertrand cournot competition if the goods are complements the result is reversed furthermore the following welfare results are obtained 1 i with substitutes in cournot competition the market outcome is never optimal with respect to information sharing but it may be optimal in bertrand competition if the products are good substitutes with complements the market outcome is always optimal 2 ii bertrand competition is more efficient than cournot competition 3 iii the private value of information to the firms is always positive but the social value of information is positive in cournot and negative in bertrand competition

portfolio insurance gap risk under conditional multiples abstract the research on financial portfolio optimization has been originally developed by markowitz 1952 it has been further extended in many directions among them the portfolio insurance theory introduced by leland and rubinstein 1976 for the option based portfolio insurance obpi and perold 1986 for the constant proportion portfolio insurance method cppi the recent financial crisis has dramatically emphasized the interest of such portfolio strategies this paper examines the cppi method when the multiple is allowed to vary over time to control the risk of such portfolio management a quantile approach is introduced together with expected shortfall criteria in this framework we provide explicit upper bounds on the multiple as function of past asset returns and volatilities these values can be statistically estimated from financial data using for example arch type models we show how the multiple can be chosen in order to satisfy the guarantee condition at a given level of probability and for various financial market conditions

information in cournot signaling with incomplete control abstract we embed signaling in the classical cournot model in which several firms sell a homogeneous good the quality is known to all the firms but only to some buyers the quantity setting firms can manipulate the price to signal quality because there is only one price in a market for a homogeneous good each firm incompletely controls the price signal through the quantity decision we characterize the unique signaling cournot equilibrium in which the price signals quality to the uninformed buyers we then compare the signaling cournot equilibrium with the full information cournot equilibrium signaling is shown to increase the equilibrium price moreover under certain conditions regarding the composition of buyers the number of firms and the distribution of costs across firms the effects of signaling and market externality cancel each other in other words the profits under signaling cournot equal the profits of a cartel in a full information environment

patience persistence and welfare costs of incomplete markets in open economies abstract we investigate the welfare implications of alternative financial market structures in a two country endowment economy model we obtain an analytic expression for the expected lifetime utility of the representative household when sovereign bonds are the only internationally traded asset and we compare this welfare level with that obtained under complete asset markets the welfare cost of incomplete markets is negligible if agents are very patient and shocks are not very persistent but this cost is dramatically larger if agents are relatively impatient and shocks are highly persistent for realistic cases in which agents are very patient and shocks are highly persistent the welfare cost of incomplete markets is highly sensitive to the specific values of these parameters

international risk sharing and economic growth international risk sharing which diversifies away income risk will reduce saving with constant relative risk aversion if growth arises from the external effects of human capital accumulation then reducing saving will reduce growth welfare also may fall with risk sharing because endogenous growth with external effects of capital accumulation typically implies a competitive equilibrium growth rate already less than the optimal growth rate we demonstrate these results in a standard representative agent economy diversifying away rate of return risk also will reduce saving and growth rates if relative risk aversion exceeds one but this diversification always increases welfare this paper studies the effects of international risk sharing portfolio diversification in a world economy in which growth rates of income are endogenous growth is based upon the spillover effects of human capital accumulation as in lucas 1988 and romer 1986 there are positive economy wide spillovers of human capital intensity on individual labour productivity in section 2 we construct a multi country growth model with an infinitely lived representative agent in each country each country faces income risk but there is no aggregate uncertainty at the world level we focus on two market structures in the first structure there are no markets which allow for international diversification of country specific income risk in the second structure there are complete international markets for risksharing with no aggregate world uncertainty this completeness allows full diversification of country specific risk the paper has two central results first growth rates in all countries are lower in the equilibrium with full diversification second in this same structure welfare of each country may be lower than in an equilibrium without risk sharing the reasoning is as follows with external effects of capital accumulation the compet

an empirical test of the offset hypothesis abstract i exploit cross province and time series variation in canadian mandatory seat belt legislation to empirically test the offset hypothesis the results of this study offer modest evidence of the existence of offsetting behavior by drivers specifically increased use of seat belts by drivers after the enactment of seat belt legislation should have led to a 29 percent decrease in driver fatalities however econometric estimates indicate that the introduction of seat belt legislation is significantly correlated with only a 21 percent decline in driver fatalities furthermore the use of legislative and nonlegislative factors to control for the effects of independent determinants of traffic fatalities is critical as the omission of these effects implies that seat belt laws are associated with roughly a 32 percent decrease in driver deaths thus implying an absence of significant offsetting behavior

the speed of information revelation in a financial market mechanism abstract the paper studies the rate at which dispersed private information about the value v of a risky financial asset is incorporated into prices in an information adjustment mechanism the mechanism in the presence of competitive market makers aggregates the information of risk averse agents at a rate of n 1 2 where n is the number of rounds of the adjustment process without market makers convergence of prices to v is much slower in any case the asymptotic precision of prices is negatively related to the degree of risk aversion and the amount of noise in the system journal of economic literature classification numbers d83 g14

how effective is automobile safety regulation loeb 1989 questions the results of recent work on automobile safety inspection garbacz and kelly 1987 in which the results of a paper by leob and gilad 1984 were questioned specifically their time series model using new jersey data is missing a key economic variable accident price as well as some well known variables associated with traffic accidents yothful drivers and a proxy for drunk driving an estimate of their model with us data results in no statistical effect for automobile inspection variables garbacz and kelly 1987

equilibrium analysis of portfolio insurance a martingale approach is used to characterize general equilibrium in the presence of portfolio insurance insurers sell to noninsurers in bad states and general equilibrium requires that the risk premium rises to induce noninsurers to increase their holdings we show that portfolio insurance increases price volatility causes mean reversion in asset returns raises the sharpe ratio and volatility in bad states and causes volatility to be correlated with volume we also explain why out of the money sp that is the demand for an absolute level of price protection is equivalent to a demand for put options 1 we show that a similar argument can be used in a

social learning and delay in a dynamic model of price competition abstract this paper studies dynamic price competition between two firms selling differentiated durable goods to two buyers whose valuations of the two goods depend on their own private type as well as that of the other buyer we derive a key intertemporal property of the equilibrium prices and construct an equilibrium based on this property we show that social learning reduces the equilibrium prices in the sense that when the buyers are more interdependent and hence have a stronger incentive to wait and see the firms respond by lowering their period 1 prices interestingly we find that this response by the firms along with the intertemporal property of the equilibrium prices implies that buyers delay their decisions less often when they become more interdependent

a new choice of dynamic asset management the variable proportion portfolio insurance the constant proportion portfolio insurance cppi achieves the advantage of simplicity due to its constant multiple however a dynamic multiple could improve the effectiveness of portfolio management in this article we provide a complete and detailed examination of the mechanism of variable proportion portfolio insurance vppi strategy the multiple of the vppi states that when the stock price goes up the multiple gets larger accordingly and when the stock price goes down the multiple gets smaller a portfolio insurance strategy with this discipline could yield better performance based on this principle we recommend an exponential proportion portfolio insurance eppi in addition we also propose a new performance measure for portfolio insurance compared with the cppi simulation and empirical evidence support that the eppi works better in both upside capture and downside protection implying that the eppi could be an effective tool for asset management

waterfall versus sprinkler product launch strategy influencing the herd a seller decides the price and sequence in which a product of unknown value is introduced to consumers consumers inspect the product before consumption and observe past prices and sales consumption at a high price is informative for later consumers as it indicates that the product is likely to be of high value i show that on an average prices decrease over time however expected revenue on an average rises over time for a high enough discount factor i find that for extreme beliefs the firm introduces the product to all consumers but for intermediate values the product is introduced only to one consumer

price and advertising signals of product quality we present a signaling model based on ideas of phillip nelson in which both the introductory price and the level of directly uninformative advertising or other dissipative marketing expenditures are choice variables and may be used as signals for the initially unobservable quality of a newly introduced experience good repeat purchases play a crucial role in our model a second focus of the paper is on illustrating an approach to refining the set of equilibria in signalling games with multiple potential signals

theory of constant proportion portfolio insurance abstract we study constant proportion portfolio insurance cppi a dynamic strategy that maintains the portfolio s risk exposure a constant multiple of the excess of wealth over a floor up to a borrowing limit we use this simple rule to investigate how transaction costs and borrowing constraints affect portfolio insurance type strategies absent transaction costs cppi is equivalent to investing in perpetual american call options and is optimal for a piecewise hara utility function with a minimum consumption constraint as the multiple increases the payoffs under cppi approach those of a stop loss strategy the expected holding period return is not monotonic in the multiple and a higher expected return can be obtained under cppi than with a stop loss strategy

the new open economy macroeconomics a survey since the 1995 publication of obsteld and rogoff s redux model there has been an outpouring of research on open economy dynamic general equilibrium models that incorporate imperfect competition and nominal rigidities this paper offers an interim survey of this recent literature 2001 elsevier science b v all rights reserved

portfolio insurance and prospect theory investors popularity and optimal design of capital protected financial products abstract portfolio insurance strategies are used on both the institutional and the retail side of the asset management industry while standard utility theory struggles to provide an explanation this study justifies the popularity of portfolio insurance strategies in a behavioral finance context we run monte carlo simulations as well as historical simulations for popular portfolio insurance strategies and benchmark strategies in order to evaluate the outcomes using cumulative prospect theory our simulation results indicate that most portfolio insurance strategies are the preferred investment strategy for a prospect theory investor moreover the analysis provides insights into how portfolio insurance products should be designed and structured to meet the preferences of prospect theory investors as accurately as possible

a signal jamming theory of predation we propose a new theory ofpredation based on signal jamming in our model the predator s characteristics are common knowledge while the entrant is uncertain of his own future profitability the entrant uses his current profit to decide whether to remain in the market and the predator preys to jam or interfere with this inference problem thus our model differs from those based on reputation effects in which the predator preys to signal information about himself

international dimensions of optimal monetary policy abstract this paper provides a baseline general equilibrium model of optimal monetary policy among interdependent economies with monopolistic firms and nominal rigidities an inward looking policy of domestic price stabilization is not optimal when firms markups are exposed to currency fluctuations such a policy raises exchange rate volatility leading foreign exporters to charge higher prices vis a vis increased uncertainty in the export market as higher import prices reduce the purchasing power of domestic consumers optimal monetary rules trade off a larger domestic output gap against lower consumer prices optimal rules in a world nash equilibrium lead to less exchange rate volatility relative to both inward looking rules and discretionary policies even when the latter do not suffer from any inflationary or deflationary bias gains from international monetary cooperation are related in a non monotonic way to the degree of exchange rate pass through

strategic complementarities and the twin crises the economic literature has emphasized the role of strategic complementarities in generating banking crises and currency crises motivated by evidence from recent financial crises we study a model where strategic complementarities exist not only within a group of creditors or within a group of currency speculators but also between the two groups the additional type of strategic complementarities generates a vicious cycle between banking crises and currency crises this vicious cycle magnifies the correlation between the two crises and destabilizes the economy we discuss some empirical implications and policy implications and in particular show that due to the interaction between the banking sector and the currency market a lender of last resort might not be able to prevent bank runs

model free cppi abstract we consider constant proportion portfolio insurance cppi and its dynamic extension which may be called dynamic proportion portfolio insurance dppi it is shown that these investment strategies work within the setting of follmer s pathwise ito calculus which makes no probabilistic assumptions whatsoever this shows on one hand that cppi and dppi are completely independent of any choice of a particular model for the dynamics of asset prices they even make sense beyond the class of semimartingale sample paths and can be successfully defined for models admitting arbitrage including some models based on fractional brownian motion on the other hand the result can be seen as a case study for the general issue of robustness in the face of model uncertainty in finance

performance evaluation of portfolio insurance strategies using stochastic dominance criteria abstract this paper evaluates the performance of the stop loss synthetic put and constant proportion portfolio insurance techniques based on a block bootstrap simulation we consider not only traditional performance measures but also some recently developed measures that capture the non normality of the return distribution value at risk expected shortfall and the omega measure we compare them to the more comprehensive stochastic dominance criteria the impact of changing the rebalancing frequency and level of capital protection is examined we find that even though a buy and hold strategy generates higher average excess returns it does not stochastically dominate the portfolio insurance strategies nor vice versa our results indicate that a 100 floor value should be preferred to lower floor values and that daily rebalanced synthetic put and cppi strategies dominate their counterparts with less frequent rebalancing

accounting for u s real exchange rate changes this study measures the proportion of u s real exchange rate movements that can be accounted for by movements in the relative prices of nontraded goods the decomposition is done at all possible h

optimal investment with minimum performance constraints abstract we consider the portfolio problem of an investor whose wealth is constrained to be at least as large as that generated by investment in a stochastic benchmark portfolio using standard option pricing results the optimal portfolio policy of a hara utility investor is derived explicitly this policy is shown to be equivalent at any point in time to the investor s optimal unconstrained policy when he has contracted to paying out a proportion of the value of the benchmark portfolio at the terminal date this proportion which lies between zero and one is smaller the more likely it is that the investor will strictly outperform the benchmark over the investment horizon

feedback effects and asset prices feedback effects from asset prices to firm cash flows have been empirically documented this finding raises a question for asset pricing how are asset prices determined if price affects fundamental value which in turn affects price in this environment by buying assets that others are buying investors ensure high future cash flows for the firm and subsequent high returns for themselves hence investors have an incentive to coordinate which may generate self fulfilling beliefs and multiple equilibria using insights from global games we pin down investors beliefs analyze equilibrium prices and show that strong feedback leads to higher excess volatility

when more is less using multiple constraints to reduce tail risk abstract financial institutions suffered large trading losses during the 2007 2009 global financial crisis these losses cast doubt on the effectiveness of regulations and risk management systems based on a single value at risk var constraint while some researchers have recommended using conditional value at risk cvar to control tail risk var remains popular among practitioners and regulators accordingly our paper examines the effectiveness of multiple var constraints in controlling cvar under certain conditions we theoretically show that they are more effective than a single var constraint furthermore we numerically find that the maximum cvar permitted by the constraints is notably smaller than with a single constraint these results suggest that regulations and risk management systems based on multiple var constraints are more effective in reducing tail risk than those based on a single var constraint

the welfare effect of international asset market integration under nominal rigidities abstract this paper assesses the impact of integrating international asset markets when segmented markets are not the only distortion using a two country general equilibrium model with nominal rigidities and monetary shocks we show that integration is not universally beneficial instead the welfare impact depends on the degree to which exchange rate fluctuations are passed through to consumer prices while the integration is welfare neutral in the polar cases of complete or zero pass through this is not the case when pass through is partial when shocks are equally volatile in both countries integration can be detrimental or beneficial depending on the degree of pass through when shocks are more volatile in one country it benefits from integration compared with the more stable country

optimal dynamic trading with leverage constraints we solve for the optimal dynamic trading strategy of an investor who faces a leverage constraint i e a limitation on his ability to borrow for the purpose of investing in a risky asset we assume that the investor has constant relative risk aversion and that the value of the risky asset follows a geometric brownian motion in the absence of the leverage constraint the optimal strategy involves investing a fixed proportion of wealth in the risky asset we prove that in the presence of the leverage constraint the optimal investment also involves investing a fixed proportion of wealth in the risky asset when the leverage constraint is not binding however the two proportions are different reflecting the extent to which the investor alters his strategy even when the leverage constraint is not binding because of the possibility that the leverage constraint will become binding in the future

on the informational role of quantities durable goods and consumers word of mouth communication a dynamic incomplete information game is set up to study the introduction of a durable good when consumers can learn its quality from previous buyers high sales today imply fewer potential buyers tomorrow but each buyer will have better information about the good consumers are fully rational and can update their beliefs even when they do not directly receive information in equilibrium no news is bad news a low quality firm follows a fly by night strategy randomizing over the timing of sales a high quality firm spreads out its sales more smoothly solving a stochastic dynamic programming problem copyright 1997 by economics department of the university of pennsylvania and the osaka university institute of social and economic research association