intrinsic bubbles the case of stock prices several puzzling aspects of the behavior of united states stock prices may be explained by the presence of a specific type of rational bubble that depends exclusively on aggregate dividends the authors call bubbles of this type intrinsic bubbles because they derive all of their variability from exogenous economic fundamentals and none from extraneous factors intrinsic bubbles provide a more plausible empirical account of deviations from present value pricing than do the traditional examples of rational bubbles their explanatory potential comes partly from their ability to generate persistent deviations that appear to be relatively stable over long periods copyright 1991 by american economic association

speculative investor behavior and learning as traders learn about the true distribution of some asset s dividends a speculative premium occurs as each trader anticipates the possibility of reselling the asset to another trader before complete learning has occurred small differences in prior beliefs lead to large speculative premiums during the learning process this phenomenon helps explain a paradox concerning the pricing of initial public offerings the result casts light on the significance of the common prior assumption in economic models

reference dependent ambiguity abstract motivated by experimental and empirical evidence i study a framework where reference points such as a status quo endowment or default option can distort the way an individual responds to ambiguity i characterize a model of reference dependent maxmin expected utility and provide behavioral foundations for comparing reference dependent ambiguity attitudes i also illustrate some implications of reference dependent ambiguity for trade in an asset market including underdiversification no trade and the potential for a market collapse

divergent reactions to convergent strategies investor beliefs and analyst reactions during technological change an important outcome of technological change is industry convergence as a new technology spurs competition between established firms from different industries we study the reactions of securities analysts as important sources of institutional pressures for firms to the similar product market strategies undertaken by firms from different prior industries responding to industry convergence our empirical setting is the convergence between the wireline telecommunications and cable television industries in the period following the advent of voice over internet protocol technology controlling for firm financial performance and capabilities we find that analysts were consistently more positive toward the cable firms than toward the wireline telecom firms our findings further show that this divergence in reactions arises from differences in existing investor expectations and preferences concerning how firms create value stocks owned by investors with a greater preference for growth receive more positive reactions than those owned by investors with a greater preference for margins however this divergence in reactions shrinks over time as convergence unfolds and as investors shift their shareholdings in response to misalignment between their preferences and firms strategic changes reactions from analysts reflecting inertial expectations of investors may persist for a time despite changes to firms strategies thus creating challenges for some firms in responding to technological change and industry convergence while legitimating and enabling similar responses from their competitors

a status based model of market competition this article explores the significance of status processes for generating and reproducing hierarchy among producers in a market it develops a conception of a market as a status order in which each

uncertainty and risk in financial markets this paper considers a general equilibrium model in which the distinction between uncertainty and risk is formalized by assuming agents have incomplete preferences over statecontingent consumption bundles as in bewley 1986 without completeness individual decision making depends on a set of probability distributions over the state space a bundle is preferred to another if and only if it has larger expected utility for all probabilities in this set when preferences are complete this set is a singleton and the model reduces to standard expected utility in this setting we characterize pareto optima and equilibria and show that the presence of uncertainty generates robust indeterminacies in equilibrium prices and allocations for any specification of initial endowments we derive comparative statics results linking the degree of uncertainty with changes in equilibria despite the presence of robust indeterminacies we show that equilibrium prices and allocations vary continuously with underlying fundamentals equilibria in a standard risk economy are thus robust to adding small degrees of uncertainty finally we give conditions under which some assets are not traded due to uncertainty aversion

why the microbrewery movement organizational dynamics of resource partitioning in the u s brewing industry1 the number of small specialty brewers in the u s beer brewing industry has increased dramatically in recent decades even as the market for beer became increasingly dominated by mass production brewing companies using the resource partitioning model of organizational ecology this article shows that these two apparently contradictory trends are fundamentally interrelated hypotheses developed here refine the way scale competition among generalist organizations is modeled and improve the theoretical development of the sociological bases for the appeal of specialist organizations products especially those related to organizational identity evidence drawn from qualitative and quantitative research provides strong support for the theory the article offers a brief discussion of the theoretical and substantive issues involved in application of the model to other industries and to other cultures

open access and academic journal quality ing from complicated signaling behavior by informed authors lerner and tirole show that adding upstream private information does not alter their basic analysis their proposition 4 454 aea papers and proceedings may 2005

evolving standards for academic publishing a q r theory this paper develops models of quality standards to examine two trends academic journals increasingly require extensive revisions of submissions and articles are becoming longer and changing in other ways papers are modeled as varying along two quality dimensions q reflects the importance of the main ideas and r other aspects of quality observed trends are regarded as increases in r quality a static equilibrium model illustrates comparative statics explanations a dynamic model in which referees with a biased view of their own work learn social norms for weighting q and r is shown to produce a long gradual evolution of social norms

status quo maintenance reconsidered changing or incomplete preferences after reviewing the evidence for status quo maintenance sqm i consider how to reconcile sqm with traditional consumer theory behavioural economists usually let agents preferences change as a function of their endowments treating the same person with different endowments as a set of distinct agents many properties of preferences then become immune to empirical test and it becomes impossible to judge whether an agent s decisions make the agent better or worse off this impedes prediction of when decision rules are likely to change sqm can alternatively be explained with unchanging preferences if preferences are incomplete sqm is then consistent with self interest and there is no reason why it should not persist

knightian uncertainty and moral hazard abstract this paper presents a principal agent model in which the agent has imprecise beliefs we model this situation formally by assuming the agent s preferences are incomplete as in bewley 1986 2 in this setting incentives must be robust to knightian uncertainty we study the implications of robustness for the form of the resulting optimal contracts we give conditions under which there is a unique optimal contract and show that it must have a simple flat payment plus bonus structure that is output levels are divided into two sets and the optimal contract pays the same wage for all output levels in each set we derive this result for the case in which the agent s utility function is linear and then show it also holds if this utility function has some limited curvature

is peer review in decline i introduction for the past half century or more peer reviewed journals have played a central role in the evaluation and dissemination of scientific research the internet has enhanced scientific communication in many ways and there is considerable excitement around new institutions for disseminating research 1 a more sobering thought however is that new technologies can also be disruptive this paper begins with some documentation of recent trends in economics publishing roughly the trends involve economists from top ranked departments publishing fewer papers in many top journals this could be a welcome change but is also potentially troublesome one way in which the internet could be disruptive is that it could allow high profile researchers to disseminate their work without subjecting it to peer review which in turn could lead to a broader unraveling of the peer review system the majority of the paper is then devoted to analyses of several additional data sources with the goal of understanding better what may be causing the observed trends the facts part of this paper documents two main facts 1 economists in top ranked departments now publish very few papers in top field journals there is a marked decline in such publications between the early 1990s and early 2000s 2 comparing the early 2000s with the early 1990s there is a decline in both the absolute number of papers and the share of papers in the top general interest journals written by harvard economics department faculty although the second fact just concerns one department i see it as potentially important to understanding what is happening because it comes at a time when harvard is widely regarded i believe correctly as having ascended to the top position in the profession the decline of peer review theory i allude to in the title is that the necessity of going through the peer review process has lessened for high status authors in the old days peer reviewed journals were by far the most effective means of reaching readers whereas with the growth of the internet high status authors can now post papers online and exploit their reputation to attract readers many alternate explanations are possible i focus on four theories the decline in peer review theory and three alternatives 1 the trends could be a consequence of top school authors being crowded out of the top journals by other researchers several such stories have an optimistic message for example there is more talent entering the profession old pro elite biases are being broken down more schools are encouraging faculty to do cutting edge research and the internet is enabling more cutting edge research by breaking down informational barriers that had hampered researchers outside the top schools 2 2 the trends could be a consequence of the growth of revisions at economics journals discussed in ellison 2002a 2002b in this more pessimistic theory highly productive researchers must abandon some projects and or seek out faster outlets to conserve the time now required to publish their most important works 3 the trends could simply reflect that field journals have declined in quality in some relative sense and become a less attractive place to publish this theory is meant to encompass also the rise of new journals which is not obviously desirable or undesirable the majority of this paper is devoted to examining various data sources that provide additional details about how economics publishing has changed over the past decade these are intended both to sharpen understanding of the facts to be explained and to provide tests of auxiliary predictions of the theories two main sources of information are used data on publications and data on citations the publication data include department level counts of publications in various additional journals an individual level dataset containing records of publications in a subset of journals for thousands of economists and a very small dataset containing complete data on a few authors publication records

rational asset price movements without news this paper argues that an important part of movements in asset prices may be caused by neither external news nor irrationality but by the revelation of information by the trading process itself two models are developed that illustrate this general idea one model is based on investor uncertainty about the quality of other investors information the other is based on dispersion of information and small costs to trading the analysis is used to suggest a possible rational explanation of the october 1987 crash copyright 1993 by american economic association

shrewd crude or simply deluded comovement and the internet stock phenomenon we show that i return comovement among internet stocks during the late 1990s and early 2000 was not exceedingly high ii there was substantial consistency in the manner by which investors distinguished among internet stocks and iii high comovement is most common during periods of price erosion these results cast doubt on the view that the extraordinary appreciation of internet stocks was due to the crude classification of all such stocks as members of a hot category

financial complexity and trade what are the implications on trading activity if investors are not sophisticated enough to understand and evaluate trades that have a complex payoff structure can frictions generated by this type of financial complexity be so severe that they lead to a complete market freeze like that of the recent financial crisis starting from an allocation that is not pareto optimal we find that whether complexity impedes trade depends on how investors perceive risk and uncertainty for smooth convex preferences such as subjective expected utility complexity cannot halt trade even in the extreme case where each investor is so unsophisticated that he can only trade up to one arrow debreu security without being able to combine two or more in order to construct a complex trade however for non smooth preferences which allow for kinked indifference curves such as maxmin expected utility complexity can completely shut down trade

the review process in economics is it too fast rewards for publications in good economics journals are very high and submission fees and other monetary costs associated with submitting an existing manuscript are low consequently the editorial delay especially the first response time the time until the first editorial decision by postponing monetary rewards to publication constitutes the major submission cost from the author s perspective reducing the delay will induce many additional submissions of low quality papers to good journals increasing significantly the workload of editors and referees moreover the rejection rate will increase and cause papers to be rejected more times before publication offsetting at least some of the shorter first response times as a result the efforts of many editors to reduce the editorial delay although attracting more submissions to their journals may have adverse effects from a social perspective and the optimal delay might be longer than the current average of four months

information markets and the comovement of asset prices traditional asset pricing models predict that covariance between prices of difierent assets should be lower than what we observe in the data this model generates high covariance within a rational expectations framework by introducing markets for information about asset payofis when information is costly rational investors will not buy information about all assets they will learn about a subset because information production has high flxed costs competitive producers charge more for low demand information than for high demand information a price that declines in quantity makes investors want to purchase a common subset of information if investors price many assets using a common subset of information then a shock to one signal is passed on as a common shock to many asset prices these common shocks to asset prices generate excess covariance the cross sectional and time series properties of asset price covariance are consistent with this explanation

pareto optima and equilibria when preferences are incompletely known an exchange economy in which agents have convex incomplete preferences defined by families of concave utility functions is considered sufficient conditions for the set of efficient allocations and equilibria to coincide with the set of efficient allocations and equilibria that result when each agent has a utility in her family are provided welfare theorems in an incomplete preferences framework therefore hold under these conditions and efficient allocations and equilibria are characterized by first order conditions

dual pareto efficiency abstract consider an economy with d commodities and n individuals a pair p m where p is a price vector and m m1 m2 mn is a set of n individual income levels defines a set of individual budget constraints it is known that such pairs provide a framework for duality based investigations of pareto efficient allocations and of equilibria this paper employs this framework in a general setting not requiring smoothness or boundedness of budget sets to develop duals of the first and second theorems of welfare economics namely under suitable assumptions 1 the price income pair associated with any equilibrium is dual pareto efficient and 2 corresponding to any dual pareto efficient pair there is an allocation which together with the given prices forms an equilibrium journal of economic literature classification number s d00 d50 d51 d6l

intertemporal equilibria with knightian uncertainty we study a dynamic and infinite dimensional model with incomplete multiple prior preferences in interior efficient allocations agents share a common risk adjusted prior and subjective interest rate interior efficient allocations and equilibria coincide with those of economies with subjective expected utility and priors from the agents multiple prior sets a specific model with neither risk nor uncertainty at the aggregate level is considered risk is always fully insured for small levels of ambiguity there exists an equilibrium with inertia where agents also insure fully against knightian uncertainty when the level of ambiguity exceeds a critical threshold full insurance no longer prevails and there exist equilibria with inertia where agents do not insure against uncertainty at all we also show that equilibria with inertia are indeterminate

open access journals and academics behavior the rising star of scholarly publishing is open access oa even some traditional journals now offer this option on author payment and many full freely accessible journals are now available to scholars providing relief to research institutions increasingly unable to afford the escalating subscription rates of serials however proper recognition of full oa journals by the community remains a major obstacle to overcome if they are to become a viable alternative for scholarly communication through a survey this work investigates economics scholars attitudes to oa and attempts to outline the state of practices and norms governing individuals publication choices jel l17 l86 o33

interim efficient allocations under uncertainty abstract this paper considers an exchange economy under uncertainty with asymmetric information uncertainty is represented by multiple priors and posteriors of agents who have either bewley s incomplete preferences or gilboa schmeidler s maximin expected utility preferences the main results characterize interim efficient allocations under uncertainty that is they provide conditions on the sets of posteriors thus implicitly on the way how agents update the sets of priors for non existence of a trade which makes all agents better off at any realization of private information for agents with the incomplete preferences the condition is necessary and sufficient but for agents with the maximin expected utility preferences the condition is sufficient only a couple of necessary conditions for the latter case are provided

arbitrage and martingales with taxation this paper extends the martingale analysis of no arbitrage pricing to worlds with taxation the absence of arbitrage is shown to imply the existence of different shadow prices for income streams that are subject to differing tax treatments for example no arbitrage implies the existence of different martingale measures for capita l gains and for ordinary income when they are differentially taxed andfor item s such as depreciation expenses that influence only after tax cash flows the analysis is applied to several topics in finance including the debt equity decision tax options and the taxation of dividends and pensions copyright 1987 by university of chicago press

the slowdown in first response times of economics journals can it be beneficial the first response time henceforth frt of economics journals has increased over the last four decades from 1 2 months to 3 6 months the optimal frt however is not zero because the frt deters submission of mediocre papers to good journals and consequently saves valuable time of referees and editors the change in the actual frt is in the same direction as the change in the optimal frt which has increased because of the availability of research on the internet prior to publication and because the costs of refereeing a paper have increased

initial labor market conditions and long term outcomes for economists each year graduate students entering the academic job market worry that they will suffer due to uncontrollable macroeconomic risk given the importance of general human capital and the relative ease of publicly observing productivity in academia one might expect that long term labor market outcomes for students graduating in unfavorable climates will resemble long term outcomes for those graduating in favorable climates in this paper i analyze the relationship between macroeconomic conditions at graduation initial job placement and long term outcomes for ph d economists from seven programs using macroeconomic conditions as an instrument for initial placement i show that a quality and type of initial job have a causal effect on long term job characteristics i also show that better initial placement increases research productivity which helps to limit the set of economic models that can explain the effect of initial placement on long term jobs

getting closer or drifting apart advances in communication and transportation technologies have the potential to bring people closer together and create a global village however they also allow heterogenous agents to segregate along special interests which gives rise to communities fragmented by type rather than geography we show that lower communication costs should always decrease separation between individual agents even as group based separation increases each measure of separation is pertinent for distinct types of social interaction a group based measure captures the diversity of group preferences that can have an impact on the provision of public goods an individual measure correlates with the speed of information transmission through the social network that afiects for example learning about job opportunities and new technologies we test the model by looking at coauthoring between academic economists before and during the rise of the internet in the 1990s

rational pricing of internet companies we apply real options theory and capital budgeting techniques to the problem of valuing an internet company we formulate the model in continuous time form a discrete time approximation estimate the model parameters solve the model by simulation and then perform sensitivity analysis we report that depending on the parameters chosen the value of an internet stock may be rational if growth rates in revenues are high enough even with a real chance that a company may go bankrupt if the initial growth rates are sufficiently high and if this growth rate contains enough volatility over time then valuations can reach a level that would otherwise appear dramatically high in addition the valuation is highly sensitive to initial conditions and exact specification of the parameters which is consistent with observations that the returns of internet stocks have been strikingly volatile

sharing risk and ambiguity we study the market implications of ambiguity in common models we show that generic determinacy is a robust feature in general equilibrium models that allow a distinction between ambiguity and risk

the critical trade off identity assignment and box office success in the feature film industry researchers have begun to study markets that are structured in terms of an opposition between market identities in a manner akin to the role pairs analyzed in structural role theory in this paper we analyze the feature film market which came to have such a role structure by the mid 1990s by exploiting the contingency that pertains to the identity of newly released films and the intermediary function played by critics we assess the tendency for offerings to be assigned one or the other of the available market identitiesc independent or major an analysis of the box office success of 396 feature films released in 1997 shows that a film attracted a larger audience when critics who specialized in major releases reviewed the film and implicitly certified it as fit for the mass market such classification was particularly crucial for breaking out of the initial constraints set by theatrical exhibitors however while attaining a major identity was necessary for success in the mass market it was a handicap in penetrating the art house this trade off illustrates how market structures restrict identity in a manner akin that by which role structures place constraints on the identities available to individuals copyright 2003 oxford university press

overlapping risk adjusted sets of priors and the existence of efficient allocations and equilibria with short selling the theory of existence of equilibrium with short selling is reconsidered under risk and ambiguity modelled by risk averse variational preferences no arbitrage conditions are given in terms of risk adjusted priors a sufficient condition for existence of efficient allocations is the overlapping of the interiors of the risk adjusted sets of priors or the inexistence of mutually compatible trades with non negative expectation with respect to any risk adjusted prior these conditions are necessary when agents are not risk neutral at extreme levels of wealths it is shown that the more uncertainty averse or risk averse the agents the more likely are efficient allocations and equilibria to exist

managers investors and crises mutual fund strategies in emerging markets the authors address the trading strategies of mutual funds in emerging markets the data set they develop permits analyses of these strategies at the level of individual portfolios a methodologically novel feature of their analysis they disentangle the behavior of fund managers from that of investors for both managers and investors they strongly reject the null hypothesis of no momentum trading funds momentum trading is positive they systematically buy winners and sell losers contemporaneous momentum trading buying current winners and selling current losers is stronger during crises and stronger for fund investors than for fund managers lagged momentum trading buying past winners and selling past losers is stronger during noncrises and stronger for fund managers investors also engage in contagion trading selling assets from one country when asset prices fall in another these findings are based on data about mutual funds that represent only 10 percent of the market capitalization in the countries considered were it a larger share of the market finding counterparties for their trades the investors who buy when they sell and sell when they buy would be difficult and the premise that funds respond to contemporaneous returns rather than causing them would become tenuous

submission fees and response times in academic publishing both submission fees and response times enable editors to maintain an acceptable refereeing burden by discouraging the submission of articles with low probability of acceptance when authors differ in their ability or willingness to pay submission fees and deal with delays journal quality is maximized under a combination of moderate fees and moderate delays

subjective expected utility with incomplete preferences this paper extends the subjective expected utility model of decision making under uncertainty to include incomplete beliefs and tastes the main results are two axiomatizations of the multiprior expected multiutility representations of preference relations under uncertainty the paper also introduces new axiomatizations of knightian uncertainty and the expected multiutility model with complete beliefs

a theory of anticipated utility abstract a new theory of cardinal utility with an associated set of axioms is presented it is a generalization of the von neumann morgenstern expected utility theory which permits the analysis of phenomena associated with the distortion of subjective probability

the competitive dynamics of status and niche width us investment banking 1920 1949 by integrating the status based model of market competition and the resource partitioning model this paper develops the resource status space imagery of markets and two propositions first the paper argues that the benefit that an organization derives from an increment in status is not independent of the organization s niche width second the paper considers the implications of status based stratification for the resource partitioning model s specification of the effects of increasing market concentration using the resource status space imagery this paper posits that if expanding generalists are reluctant to lower their status or are unable to increase their status they will expand within their current status level the expanding generalists will thus encroach on the niches of similar status generalists and specialists rather than expand into the niches of generalists across the whole status spectrum we discuss implications for the sociology of markets copyright 2000 by oxford university press

financial market reactions following technological discontinuities a non event study in two industries a large body of literature has explored the challenges of technological change for established firms much of this work has focused on factors internal to firms such as inertial routines or managers cognitive limitations that constrain incumbents development of new capabilities and response to new technologies but institutional pressures arising from financial markets and the securities analysts who mediate such markets likely also play a role in whether and how incumbent firms respond to technological change we know little about how financial markets and securities analysts react as an incumbent firm is faced with a radical technological discontinuity that threatens to substitute for the existing technology understanding such reactions is critical as they further influence whether and how incumbents respond to technological discontinuities in this article i explore securities analysts reactions to incumbent firms faced with technological discontinuities in two industries digital technology in photography and voice over internet protocol voip technology in wireline telecommunications i find that these discontinuities go largely unmentioned in analysts reports and appear to have little influence on analysts recommendations or stock prices even for several years the findings suggest further that analysts and investors continue to reward incumbents for cash flows arising from focusing on the existing business and technology despite the increasing certainty of technological obsolescence copyright 2008 oxford university press

the valuation and market rationality of internet stock prices this paper provides an analysis of some existing as well as new evidence of the relation between market prices and fundamentals in the internet sector over the period january 1998 to february 2000 appealing to results across a broad class of outcomes we demonstrate a strong circumstantial case against market rationality in particular we investigate i the level of internet stock prices given their underlying fundamentals ii responses of stock prices to information based events and iii the volatility of internet prices we review several potential explanations of these phenomena including one based on heterogeneous beliefs across investors who are subject to short sales constraints we provide a discussion of the empirical evidence supporting this latter explanation copyright 2002 oxford university press

free labor for costly journals there is a remarkable difference between the prices that commercial publishers charge to libraries for economics journals and the prices charged by professional societies and university presses this price difference does not reflect a difference in quality the six most cited economics journals listed in the social science citation index are all nonprofit journals and their library subscription prices average about 180 per year only five of the 20 most cited journals are owned by commercial publishers and the average price of these five journals is about 1660 per year tables 1 and 2 compare library costs and measures of cost effectiveness for the ten most cited nonprofit journals and the ten most cited journals owned by commercial presses the average price per page of the commercial journals is about six times as high and the average price per citation is about 16 times as high as for the nonprofit journals in tables 1 and 2 the first column shows the year 2001 library subscription price and the second column shows the price per page calculated by dividing year 2001 price by the number of pages published in the year 2000 the third column reports the price per citation this is the library subscription price divided by the number of times that articles in this journal were cited in 1998 as recorded by the social science citation index the fourth column price per recent citation is the library subscription price divided by the number of times that the 1996 and 1997 volumes of the journal were cited in 1998 the citation rank is found by ranking journals according to the number of times that this journal was cited in 1998 the differences in prices and cost effectiveness between nonprofit and commercial journals are similar for less prestigious journals i have assembled a data

incomplete preferences and equilibrium in contingent markets this paper shows that betting or speculative trading between agents with incomplete preferences is likely to occur if agents have access to convex choice sets this contrasts sharply with endowment economy models where preference incompleteness often hinders betting speculative trading or mutually beneficial insurance arrangements our results imply that decision makers with identical tastes and identical feasible sets will potentially gain from speculative trade for generic status quo allocations we also develop a framework for endogenizing the status quo allocations of decision makers that are treated exogenously in the existing literature finally we provide a tractable differential representation of status quo allocations equilibria and conditions where speculative trade may or may not emerge

rational choice with status quo bias abstract motivated by the empirical findings concerning the importance of one s current situation on her choice behavior the main objective of this paper is to propose a rational choice theory that allows for the presence of a status quo bias and that incorporates the standard choice theory as a special case we follow a revealed preference approach and obtain two nested models of rational choice that allow phenomena like the status quo bias and the endowment effect and that are applicable in any choice situation to which the standard static choice model applies

the slowdown of the economics publishing process over the last three decades there has been a dramatic slowdown of the publication process at top economics journals a substantial part is due to journals requiring more extensive revisions various explanations are considered democratization of the review process increases in the complexity of papers growth of the profession and cost and benefit arguments changes in the profession are examined using time series data connections between these changes and the slowdown are examined using paper level data there is evidence for some explanations but most of the slowdown remains unexplained changes may reflect evolving social norms

asset demands without the independence axiom an important application of the theory of choice under uncertainty is to asset markets and an important property in these markets is a preference for portfolio diversification if an investor is an expected utility maximizer then s he is risk averse if and only if s he exhibits a preference for diversification this paper examines the relationship between risk aversion and portfolio diversification when preferences over probability distributions of wealth do not have an expected utility representation

status quo bias multiple priors and uncertainty aversion motivated by the extensive evidence about the relevance of status quo bias both in experiments and in real markets we study this phenomenon from a decision theoretic prospective focusing on the case of preferences under uncertainty we develop an axiomatic framework that takes as a primitive the preferences of an agent for each possible status quo option and provide a characterization according to which the agent considers a full dimensional set of possible priors and abandons her status quo option only if she finds an alternative that returns a higher expected utility for each of these priors we then show that in this framework the very presence of a status quo induces the agent to be more uncertainty averse than she would be without a status quo option

a more robust definition of subjective probability the goal of choice theoretic derivations of subjective probability is to separate a decisionmaker s underlying beliefs subjective probabilities of events from their preferences attitudes toward risk classical derivations have all relied upon some form of the marschak samuelson independence axiom or the savage sure thing principle which imply that preferences over lotteries conform to the expected utility hypothesis this paper presents a choice theoretic derivation of subjective probability in a savage type setting of purely subjective uncertainty which neither assumes nor implies that the decisionmaker s preferences over lotteries necessarily conform to the expected utility hypothesis copyright 1992 by the econometric society

market volatility and investor behavior it appears that speculative asset prices tend to show excess volatility relative to simple present value efficient markets models and that prices are partly forecastable as tending to returning to mean appropriately defined but what does this tell us about how speculative prices are determined are there fads in prices and if so how do they behave the question has arisen recently whether there is really room for fads in speculative prices whether or not speculative prices are too volatile if stock prices are highly correlated with dividends we might conclude that the movements in stock prices are driven by fundamentals not fads a question of longer standing is whether fads models that entail feedback from price change to price change are consistent with the observed approximate random walk price behavior that is rather low serial correlation of short run price changes we can also ask whether the feedback models are consistent with the observed relation of stock prices to dividends and earnings

optimality and the theory of value abstract this paper presents two mutually dual optimization principles termed the zero maximum principle and the zero minimum principle respectively that characterize economic equilibria the first of these principles states an equivalence between equilibrium allocations and allocations that maximize total societal benefit and make that benefit zero the second principle states an equivalence between equilibrium price vectors and price vectors that minimize the total economic surplus and make that surplus zero the two principles provide new characterizations of equilibrium in private ownership economies and a new avenue for a proof of the fundamental existence theorem for such equilibria journal of economic literature classification number d50

valuation of risky assets in arbitrage free economies with frictions this paper derives a framework for arbitrage models in markets with frictions it generalizes the existence of a valuation operator to such markets as in perfect markets the valuation operator is a linear operator and its existence is implied by the no arbitrage condition in imperfect markets the valuation operator is individual specific and depends on the agent s position in the market the methodology employed in the paper is duality in convex programming

liquidity and valuation in an uncertain world abstract during the 2007 2009 financial crisis there was little or no trading in a variety of financial assets even though bid and ask prices existed for many of these assets we develop a model in which this illiquidity arises from uncertainty and we argue that this new form of illiquidity makes bid and ask prices unsuitable as metrics for establishing fair value for these assets we show how the extreme uncertainty that traders face can be characterized by incomplete preferences over portfolios and we use bewley s 2002 model of decision making under uncertainty to derive equilibrium quotes and the nonexistence of trading at these quotes we then suggest alternatives for valuing assets in illiquid markets

academic journal pricing and the demand of libraries the prices of for profit academic journals have increased rapidly over the past decade barbara albee and brenda dingley 2001 there remains substantial debate as to the explanation for these increases among those put forward are the increased concentration of the journal industry see e g mccabe 2002 and the relatively recent effort by major publishers to bundle print and electronic journals aaron s edlin and rubinfeld 2004 while both explanations are undoubtedly important what is missing is the significant role of the primary customers of journal publishers the academic libraries as agents of college and university faculties libraries serve the interests of their principals while having only limited information about faculty journal demands facing little or no hard budget constraint faculty are unlikely or unwilling to make difficult allocative choices as a result libraries have been making hard choices for years between journals and books and among journals in a world of increasing budgetary pressure given that electronic transmission of knowledge is becoming increasingly important an understanding of the reasons for the increases in journal prices is a vital element in the ongoing discussion of best mechanisms by which scholarly communications can be disseminated in this paper we formulate a model of library journal demand and suggest how it can be used to analyze the optimal pricing of journals by publishers this represents part of a larger project whose long range goal is to explain the pattern of journal pricing over time and to evaluate two broad policy questions i to what extent have mergers and or bundling practices been responsible for the increase in journal prices ii to what extent are journal prices likely to change in response to changing library acquisition strategies reallocation of budgets between serials and books journal sharing among libraries setting hard budgets etc

on publication refereeing and working hard we present a model for academia with heterogeneous author types and endogenous effort to evaluate recent changes in the publication process in economics we analyze the implications of these developments on research output lowering the precision of refereeing signals lowers the effort choices of intermediate ability authors but invites more submissions from less able authors increasing the number of journals stimulates less able authors to submit their papers the editor can improve the journal s quality pool of submitted manuscripts by improving the precision of refereeing but not by lowering acceptance standards the submission strategy of an author is informative of his ability

efficient trading strategies in the presence of market frictions we provide a price characterization of efficient contingent claims that is chosen by at least a rational agent in multiperiod economies with market frictions frictions include market incompleteness transaction costs short selling and borrowing costs we characterize the inefficiency cost of a trading strategy its required investment minus the largest amount necessary to obtain the same utility level and we propose a measure of portfolio performance we show that arbitrage bounds cannot be tightened based on efficiency without restricting preferences or endowments we observe common investment strategies becoming inefficient with market frictions and others rationalized by them in this article we characterize efficient contingent claims to future consumption consumption bundles in multiperiod economies with uncertainty taking a wide range of market frictions into account 1 such as dynamic market

risk sharing in the small and in the large abstract this paper analyzes risk sharing in economies with no aggregate uncertainty when agents have non convex preferences in particular agents need not be globally risk averse or uncertainty averse in the sense of schmeidler 1989 we identify a behavioral condition under which betting is inefficient i e every pareto efficient allocation provides full insurance and conversely if and only if agents supporting probabilities defined as in rigotti et al 2008 have a non empty intersection our condition is consistent with empirical and experimental evidence documenting violations of convexity in either outcomes or utilities our results show that the connection between speculative betting and inconsistent beliefs does not depend upon global notions of risk or ambiguity aversion

subjective beliefs and ex ante trade we study a definition of subjective beliefs applicable to preferences that allow for the perception of ambiguity and provide a characterization of such beliefs in terms of market behavior using this definition we derive necessary and sufficient conditions for the efficiency of ex ante trade and show that these conditions follow from the fundamental welfare theorems when aggregate uncertainty is absent our results show that full insurance is efficient if and only if agents share some common subjective beliefs our results hold for a general class of convex preferences which contains many functional forms used in applications involving ambiguity and ambiguity aversion we show how our results can be articulated in the language of these functional forms confirming results existing in the literature generating new results and providing a useful tool for applications

decision theory under ambiguity we review recent advances in the field of decision making under uncertainty or ambiguity we start with a presentation of the general approach to a decision problem under uncertainty as well as the standard bayesian treatment and issues with this treatment we present more general approaches choquet expected utility maximin expected utility smooth ambiguity and so forth that have been developed in the literature under the name of models of ambiguity sensitive preferences we draw a distinction between fully subjective models and models incorporating explicitly some information we review definitions and characterizations of ambiguity aversion in these models we mention the challenges posed by some of the models presented we end with a review of part of the experimental literature and applications of these models to economic settings

ambiguity aversion in the long run to disagree we must also agree abstract we consider an economy populated by smooth ambiguity averse agents with complete markets of securities contingent to economic scenarios where bankruptcy is permitted but there is a penalty for it we show that if agents posterior belief reductions given by their average probabilistic beliefs do not become homogeneous then an equilibrium does not exist it is worth noting that our main result does not imply any convergence of ambiguity perception or even the attitudes towards it in this way complete markets with default and punishment allow for ambiguity aversion in the long run and the agents can disagree on their ambiguity perception but they must agree on their expected beliefs

a definition of uncertainty aversion a definition of uncertainty or ambiguity aversion is proposed it is argued that the definition is well suited to modelling within the savage as opposed to anscombe and aumann domain of acts the defined property of uncertainty aversion has intuitive empirical content behaves well in specific models of preference multiple priors and choquet expected utility and is tractable tractability is established through use of a novel notion of differentiability for utility functions called eventwise differentiability

securities analysts and incumbent response to radical technological change evidence from digital photography and internet telephony a large body of research has explored the factors that impede established firms responses to radical technological changes while it is widely acknowledged that managers face pressures from financial markets to choose strategies that maximize shareholder value little work in the technological change literature has considered the possible influences of public equity markets and the securities analysts who mediate them on incumbent firms challenged with technological change in this paper i begin to address the topic by empirically exploring how securities analysts react to the different strategies undertaken by incumbent firms faced with radical technological change i study the question in two settings the shift to digital technology in photography and the advent of voice over internet protocol voip technology in wireline telecommunications i find evidence that analysts are more attentive and positive toward incumbents strategies that extend and preserve the existing technology than toward strategies that respond directly to the new technology in these settings analysts largely ignore incumbents strategies that directly incorporate the new technology for several years following the discontinuity this study provides insights into the nature and direction of analysts reactions to firms strategies in the context of technological change and is a first step toward better understanding of the potential role of analysts and financial markets in incumbent adaptation

ambiguity and nonparticipation the role of regulation we investigate the implications of ambiguity aversion for performance and regulation of markets in our model agents decision making may incorporate both risk and ambiguity and we demonstrate that nonparticipation arises from the rational decision by some traders to avoid ambiguity in equilibrium these participation decisions affect the equilibrium risk premium and distort market performance when viewed from the perspective of traditional asset pricing models we demonstrate how regulation particularly regulation of unlikely events can moderate the effects of ambiguity thereby increasing participation and generating welfare gains our analysis demonstrates how legal systems affect participation in financial markets through their influence on ambiguity the author 2009 published by oxford university press on behalf of the society for financial studies all rights reserved for permissions please e mail journals permissions oxfordjournals org oxford university press

networks as the pipes and prisms of the market1 this article draws an analytical distinction between two types of market uncertainty egocentric which refers to a focal actor s uncertainty regarding the best way to convert a set of inputs to an output desired by a potential exchange partner and altercentric which denotes the uncertainty confronted by a focal actor s exchange partners regarding the quality of the output that the focal actor brings to the market given this distinction the article considers how the value of structural holes and market status vary with these two types of uncertainty the article proposes that the value of structural holes increases with egocentric uncertainty but not with altercentric uncertainty in contrast the value of status increases with altercentric uncertainty but declines with egocentric uncertainty thus actors with networks rich in structural holes should sort into markets or market segments that are high in egocentric uncertainty high status actors should sort into markets that are low in egocentric