martingales and arbitrage in securities markets with transaction costs abstract we derive the implications from the absence of arbitrage in dynamic securities markets with bid ask spreads the absence of arbitrage is equivalent to the existence of at least an equivalent probability measure that transforms some process between the bid and the ask price processes of traded securities into a martingale the martingale measures can be interpreted as possible linear pricing rules and can be used to determine the investment opportunities available in such an economy the minimum cost at which a contingent claim can be obtained through securities trading is its largest expected value with respect to the martingale measures journal of economic literature classification numbers g11 g12 g13 d52 and d90

approximate option valuation for arbitrary stochastic processes abstract we show how a given probability distribution can be approximated by an arbitrary distribution in terms of a series expansion involving second and higher moments this theoretical development is specialized to the problem of option valuation where the underlying security distribution if not lognormal can be approximated by a lognormally distributed random variable the resulting option price is expressed as the sum of a black scholes price plus adjustment terms which depend on the second and higher moments of the underlying security stochastic process this approach permits the impact on the option price of skewness and kurtosis of the underlying stock s distribution to be evaluated

political and institutional checks on corruption explaining the performance of brazilian audit institutions this article investigates the performance determinants of accountability institutions in new democracies current scholarship on accountability has identified a distinct mechanism through which the introduction of political competition may affect such institutions the electoral connection or vertical accountability mechanism this connection is not expected to be effective in new democracies because political competition is found to be volatile and nonprogrammatic another strand of the literature focuses on the effect of power alternation government turnover is expected to generate incentives for the creation and strengthening of autonomous institutions by exploring a unique data set on 33 state audit institutions the authors bring together these distinct claims and provide systematic empirical tests for them they find a negative effect of volatility on their institutional activism and a positive direct and indirect influence of power alternation on their levels of autonomy and sanctioning patterns

the subjective and objective evaluation of incentive stock options owners of incentive options invariably hold undiversified portfolios this paper derives a model for the subjective and objective values of such options the subjective value the value to the holder is less than the market value because the option is held in an undiversified portfolio and because it is exercised suboptimally from the market perspective the objective value is the cost to the firm of issuing the option and lies between the market and subjective values this value recognizes the suboptimal exercise but not the undiversified discount the model which is the black scholes model with modified parameters is simple to use

option replication in discrete time with transaction costs option replication is discussed in a discrete time framework with transaction costs the model represents an extension of the cox ross rubinstein binomial option pricing model to cover the case of proportional transaction costs the method proceeds by constructing the appropriate replicating portfolio at each trading interval numerical values of these prices are presented for a range of parameter values the paper derives a simple black scholes type approximation for the option prices with transaction costs and demonstrates numerically that it is quite accurate for plausible parameter values

information aggregation rationality and the condorcet jury theorem the condorcet jury theorem states that majorities are more likely than any single individual to select the better of two alternatives when there exists uncertainty about which of the two alternatives is in fact preferred most extant proofs of this theorem implicitly make the behavioral assumption that individuals vote sincerely in the collective decision making a seemingly innocuous assumption given that individuals are taken to possess a common preference for selecting the better alternative however in the model analyzed here we find that sincere behavior by all individuals is not rational even when individuals have such a common preference in particular sincere voting does not constitute a nash equilibrium a satisfactory rational choice foundation for the claim that majorities invariably do better than individuals therefore has yet to be derived

the effects of transaction costs and different borrowing and lending rates on the option pricing model a note this paper modifies the black scholes option pricing model to include the effects of transaction costs and different borrowing and lending rates the paper demonstrates that these market imperfections tend to offset each other yielding a bounded range of prices for each option the paper also shows that under some conditions the option pricing hedge may be society s lowest cost financial intermediary

using tucker s theorem of the alternative to simplify review and expand discrete arbitrage theory abstract for valuing derivatives and other assets in securities and commodities markets arbitrage pricing theory has been a major approach for decades this paper derives fundamental arbitrage pricing results in finite dimensions in a simple unified framework using tucker s theorem of the alternative frictionless results that is perfect market results plus imperfect market results such as those with dividends periodic interest payments transaction costs different interest rates for lending and borrowing shorting costs and constrained short selling are presented while the results are mostly known and appear in various places our contribution is to present them in a coherent and comprehensive fashion with very simple proofs the analysis yields a simple procedure to prove new results and some are presented for cases with imperfect market frictions

an intertemporal general equilibrium model of asset prices this paper develops a continuous time general equilibrium model of a simple but complete economy and uses it to examine the behavior of asset prices in this model asset prices and their stochastic properties are determined endogenously one principal result is a partial differential equation which asset prices must satisfy the solution of this equation gives the equilibrium price of any asset in terms of the underlying real variables in the economy in this paper we develop a general equilibrium asset pricing model for use in applied research an important feature of the model is its integration of real and financial markets among other things the model endogenously determines the stochastic process followed by the equilibrium price of any financial asset and shows how this process depends on the underlying real variables the model is fully consistent with rational expectations and maximizing behavior on the part of all agents our framework is general enough to include many of the fundamental forces affecting asset markets yet it is tractable enough to be specialized easily to produce specific testable results furthermore the model can be extended in a number of straightforward ways consequently it is well suited to a wide variety of applications for example in a companion paper cox ingersoll and ross 7 we use the model to develop a theory of the term structure of interest rates many studies have been concerned with various aspects of asset pricing under uncertainty the most relevant to our work are the important papers on intertemporal asset pricing by merton 19 and lucas 16 working in a continuous time framework merton derives a relationship among the equilibrium expected rates of return on assets he shows that when investment opportunities are changing randomly over time this relationship will include effects which have no analogue in a static one period model lucas considers an economy with homogeneous individuals and a single consumption good which is produced by a number of processes the random output of these processes is exogenously determined and perishable assets are defined as claims to all or a part of the output of a process and the equilibrium determines the asset prices our theory draws on some elements of both of these papers like merton we formulate our model in continuous time and make full use of the analytical tractability that this affords the economic structure of our model is somewhat similar to that of lucas however we include both endogenous production and

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 new economics of organization over the last ten years or so an important new approach to the study of organizations has emerged within economics it is perhaps best characterized by three elements a contractual perspective on organizational relationships a theoretical focus on hierarchical control and formal analysis via principal agent models this paper provides political scientists with an overview of the new economics of organization and explores its implications for the study of public bureaucracy so far positive political theory has not contributed much to our understanding of public bureaucracy in part this is due to the unsympathetic treatment that rational modeling and most other modes of quantitative analysis have long received from students of public administration the other side of the coin however is that positive theorists have not made much of an effort to develop theories of bureaucracy their concerns have centered around two basic mechanisms of social choice voting and markets and they have devoted little systematic attention to a third mechanism that is clearly important for understanding how societies and other aggregates make collective decisions this third and relatively unexplored mechanism is hierarchy movement toward a positive theory of hierarchies would fill a serious gap in the social choice literature while at the same time making a theoretical contribution that strikes to the essence of public bureaucracy indeed of all organizations in fact significant steps toward a positive theory of hierarchies have very recently been taken but by economists not political scientists in small numbers of course economists made contributions to the study of public bureaucracy some time ago with the pioneering works of downs 1967 tullock 1965 and niskanen 1971 but this new wave of theoretical work is different it is already a large complex body of literature that is the focus of innovation and excitement among a growing number of economists and it reflects an unusual degree of theoretical coherence and cumulative effort work in this tradition tends to receive orientation from a distinctive economic approach to the analysis of organizations an approach perhaps best characterized by three elements a contractual perspective on organizational relationships a focus on hierarchical control and formal analysis via principal agent models this approach has emerged from recent attempts to move beyond the neoclassical theory of the firm which assumes away all organizational considerations to a theory of economic organizations that can explain why firms corporations and other enterprises behave as they do propo

exposing corrupt politicians the effects of brazil s publicly released audits on electoral outcomes author s finan frederico ferraz claudio abstract this paper examines the extent to which access to information enhances political accountability based upon the results of brazil s recent anti corruption program that randomly audits municipal expenditures of federally transferred funds it estimates the effect of the disclosure of local government corruption practices upon the re election success of incumbent mayors in municipal elections comparing municipalities which were randomly audited before the elections with those audited after the analysis shows that the disclosure of audit results had a significant impact on the re election rates of mayors found to be corrupt for a one standard deviation increase in reported corruption the audit policy reduced the incumbent s likelihood of re election by 25 percent this effect is more pronounced in municipalities where radio stations are present and higher levels of corruption are identified these findings highlight the value of information and the role of the media in reducing informational asymmetries in the political process thus enabling voters to not only hold corrupt politicians accountable but also to reward non corrupt politicians

selection on observed and unobserved variables assessing the effectiveness of catholic schools in this paper we measure the effect of catholic high school attendance on educational attainment and test scores because we do not have a good instrumental variable for catholic school attendance we develop new estimation methods based on the idea that the amount of selection on the observed explanatory variables in a model provides a guide to the amount of selection on the unobservables we also propose an informal way to assess selectivity bias based on measuring the ratio of selection on unobservables to selection on observables that would be required if one is to attribute the entire effect of catholic school attendance to selection bias we use our methods to estimate the effect of attending a catholic high school on a variety of outcomes our main conclusion is that catholic high schools substantially increase the probability of graduating from high school and more tentatively attending college we find little evidence of an effect on test scores

the value of information in the court get it right keep it tight one should always subordinate his own personal views whether they be economic social political or whatever they may be because when you are talking about your own views you are only one of millions of individuals in the country when you are interpreting the law perhaps you have a special skill and special training that does give you the right to pass on these questions i have to confess that in this open area sometimes inevitably a man is the product of his own background and he may be somewhat influenced but i will do my very best to subordinate those considerations because i think that is the duty of any judge justice john stevens in his senate confirmation hearing

option pricing with differential interest rates the classic option pricing model is generalized to a more realistic imperfect dynamically incomplete capital market with different interest rates for borrowing and for lending and a return differential between long and short positions in stock it is found that in the absence of arbitrage opportunities the equilibrium price of any contingent claim must lie within an arbitrage band the boundaries of an arbitrage band are computed as solutions to a quasi linear partial differential equation and in generals each end point of such a band depends on both interest rates for borrowing and for lending this in turn implies that the vector of concurrent equilibrium prices of different contingent claims even claims that are written on different underlying assets must lie within a computable arbitrage oval in the price space article published by oxford university press on behalf of the society for financial studies in its journal the review of financial studies

asset pricing puzzles and incomplete markets the representative agent theory of asset pricing is modified to incorporate heterogeneous agents and incomplete markets the model features two types of agents who differ up to a nontradable idiosyncratic component in their endowment processes numerical solutions indicate that individuals are able to diversify a substantial portion of their idiosyncratic income risk through riskless borrowing and lending alone restrictions on the variability of intertemporal marginal rates of substitution hansen and jagannathan 1991 are used to argue that incomplete markets as modeled here cannot account for the properties of asset returns that are anomalous from the perspective of representative agent theory a large literature in financial economics has investigated the extent to which variants of the lucas 1978 general equilibrium theory of asset pricing can account for the joint behavior of aggregate u s consumption and asset returns by and large this literature has concluded that a theory based upon frictionless arrow debreu markets and or a representative agent makes strongly counterfactual predictions regarding even the simple unconditional properties of this relationship mehra and prescott 1985 for instance show that the theory drastically underpredicts the average excess rate of return on u s stocks the so called equity premium puzzle weil 1989 points out as did mehra and prescott that the magnitude of the average risk free rate is far below that predicted by the theory this has been dubbed the risk free rate puzzle numerous authors including grossman melino and shiller 1987 and backus gregory and zin 1989 show that the theory cannot account for term premia inherent in the yield curve hodrick 1987 surveys a large literature which documents the theory s shortcomings in accounting for excess expected returns in foreign exchange markets the notion that the representative agent model cannot account for excess returns across a wide array of asset markets can be made more precise by using tools developed by hansen and jagannathan 1991 and shiller 1982

short sales and speed of price adjustment evidence from the hong kong stock market abstract we present empirical evidence that short sales contribute to market efficiency by increasing the speed of price adjustment to not only private public firm specific information but also market wide information shortable stocks are characterized by weaker trade continuity and stronger quote reversals they adjust faster to new information than non shortable counterparts these findings remain robust even in an up market condition in which short sales are not binding the amount of information incorporated in each trade is also significantly higher for shortable than non shortable stocks in both up and down market conditions after controlling for firm size trading volume liquidity price and option trading short sales stand out as one of the significant factors that speed up the price adjustment

option pricing and replication with transactions costs transactions costs invalidate the black scholes arbitrage argument for option pricing since continuous revision implies infinite trading discrete revision using black scholes deltas generates errors which are correlated with the market and do not approach zero with more frequent revision when transactions costs are included this paper develops a modified option replicating strategy which depends on the size of transactions costs and the frequency of revision hedging errors are uncorrelated with the market and approach zero with more frequent revision the technique permits calculation of the transactions costs of option replication and provides bounds on option prices

pesticides productivity and farmer health a philippine case study health is recognized as one of the most important components of the human capital of rural people in developing countries there is a growing body of literature showing the productivity effects of health associated with nutrition e g bliss and stern 1978 strauss 1986 deolalikar 1988 pitt rosenzweig and hassan 1990 in this literature the productivity effects of health are inferred either by correlating health indicators with wages or by including health indicators in an agricultural production function the human capital literature also has demonstrated that farmer education plays an important role in the allocative and technical efficiency of farmers welch 1970 schultz 1975

economic impacts of integrated pest management ipm farmer field schools ffs evidence from onion farmers in the philippines this article comprehensively examines the impact of integrated pest management farmer field school ipm ffs on yield insecticide expenditures labor expenditures herbicide expenditures fertilizer expenditures and profit based on data from onion producers in the philippines propensity score matching psm and regression based approaches that account for potential bias due to selection problems from observable variables are used to achieve the objective of the study sensitivity of our ipm ffs impact results to potential bias due to selection on unobservables was also assessed we find that farmers who participate in the ipm ffs training program have statistically lower insecticide expenditures than the non ipm ffs farmers but we do not find any evidence that the ipm ffs training program significantly affects yield and the other inputs there is some evidence indicating that ipm ffs farmers may have statistically higher profit levels than non ipm ffs producers but these results are sensitive to and may still be invalidated by bias due to unobservable variables since ipm ffs seem to only significantly reduce insecticide use policymakers and extension educators may need to adjust the ipm ffs curriculum to further emphasize or include other agronomic practices that also optimize the use of other inputs like labor fertilizer and herbicides the more efficient use of all inputs would likely reduce total expenditures and eventually translate to higher incomes jel classifications q10 q12 q16

a test of racial bias in capital sentencing this paper proposes a test of racial bias in capital sentencing based upon patterns of judicial errors in lower courts we model the behavior of the trial court as minimizing a weighted sum of the probability of sentencing an innocent and that of letting a guilty defendant free we de ne racial bias as a situation where the relative weight on the two types of errors is a function of defendant and or victim race the key prediction of the model is that if the court is unbiased ex post the error rate should be independent of the combination of defendant and victim race we test this prediction using an original dataset that contains the the race of the defendant and of the victim s for all capital appeals that became nal between 1973 and 1995 we nd robust evidence of bias against minority defendants who killed white victims in direct appeal and habeas corpus the probability of error in these cases is 3 and 9 percentage points higher respectively than for minority defendants who killed minority victims

option values under stochastic volatility theory and empirical estimates abstract this paper numerically solves the call option valuation problem given a fairly general continuous stochastic process for return volatility statistical estimators for volatility process parameters are derived and parameter estimates are calculated for several individual stocks and indices the resulting estimated option values do not differ dramatically from black scholes values in most cases although there is some evidence that for longer maturity index options black scholes overvalues out of the money calls in relation to in the money calls

optimal replication of options with transactions costs and trading restrictions this paper analyzes the strategy that minimizes the initial cost of replicating a contingent claim in a market with transactions costs and trading constraints the linear programming and two stage backward recursive models developed are applicable to the replication of convex as well as nonconvex payoffs and to a portfolio of options with different maturities the paper s formulation conveniently accounts for fixed and variable transactions costs lot size constraints and position limits on trading the article shows that in the presence of trading frictions it is no longer optimal to revise one s portfolio in each period at the optimum cash flows in excess of the desired ones may be generated the optimal policy trades off the curvature of the payoff that is generated against the terminal slack

can politicians police themselves natural experimental evidence from brazil s audit courts to enhance government accountability reformers have advocated strengthening institutions of horizontal accountability particularly auditing institutions that can punish lawbreaking elected offi

consumption and portfolio policies with incomplete markets and short sale constraints the infinite dimensional case abstract we employ a martingale approach to study a dynamic consumption portfolio problem in continuous time with incomplete markets and short sale constraints we introduce a notion of minimax local martingale and transform the dynamic problem into a static problem of maximizing expected utility over the consumption bundles that satisfy a single budget constraint formed using that measure we establish the existence of and characterize the minimax local measure provide sufficient conditions for the dynamic consumption portfolio problem to have a solution and relate the optimal policies to the solution of quasi linear partial differential equation

valuation of risky assets in arbitrage free economies with transactions costs abstract this paper analyzes the equilibrium valuation of risky assets in the case where transactions costs are present the methodology involves applying theorems of the alternative farkas lemma as a consequence of arbitrage free markets under relevant assumptions it is found that the price of an asset having transactions costs is the corresponding price that would obtain in a perfect market plus a fudge factor this latter factor is provided explicit bounds

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

hedging derivative securities and incomplete markets an e arbitrage approach given a european derivative security with an arbitrary payoff function and a corresponding set of underlying securities on which the derivative security is based we solve the optimal replication problem find a self financing dynamic portfolio strategy involving only the underlying securities that most closely approximates the payoff function at maturity by applying stochastic dynamic programming to the minimization of a mean squared error loss function under markov state dynamics we derive recursive expressions for the optimal replication strategy that are readily implemented in practice the approximation error or e of the optimal replication strategy is also given recursively and may be used to quantify the degree of market incompleteness to investigate the practical significance of these e arbitrage strategies we consider several numerical examples including path dependent options and options on assets with stochastic volatility and jumps