it only takes a few moments to hedge options abstract we propose a novel non structural method for hedging european options relying on two model independent results first under suitable regularity conditions an option price can be disentangled into a linear combination of risk neutral moments second there exists an explicit approximate functional form linking the risk neutral moments to the futures price of the underlying asset and the related variance swap contracts we show that s p 500 call prices are mainly explained by two factors that are related to level and volatility of the underlying index we empirically compare the performance of two strategies where the vega exposure is adjusted either by a direct position in a variance swap contract or indirectly through an at the money call while both strategies ensure effective immunization in periods of market turmoil taking direct exposure on variance swaps is not optimal during extended periods of subdued volatility

the pricing of options on assets with stochastic volatilities one option pricing problem that has hitherto been unsolved is the pricing of a european call on an asset that has a stochastic volatility this paper examines this problem the option price is determined in series form for the case in which the stochastic volatility is independent of the stock price numerical solutions are also produced for the case in which the volatility is correlated with the stock price it is found that the black scholes price frequently overprices options and that the degree of overpricing increases with the time to maturity one option pricing problem that has hitherto remained unsolved is the pricing of a european call on a stock that has a stochastic volatility from the work of merton 12 garman 6 and cox ingersoll and ross 3 the differential equation that the option must satisfy is known the solution of this differential equation is independent of risk preferences if a the volatility is a traded asset or b the volatility is uncorrelated with aggregate consumption if either of these conditions holds the risk neutral valuation arguments of cox and ross 4 can be used in a straightfoward way this paper produces a solution in series form for the situation in which the stock price is instantaneously uncorrelated with the volatility we do not assume that the volatility is a traded asset also a constant correlation between the instantaneous rate of change of the volatility and the rate of change of aggregate consumption can be accommodated the option price is lower than the blackscholes b s 1 price when the option is close to being at the money and higher when it is deep in or deep out of the money the exercise prices for which overpricing by b s takes place are within about ten percent of the security price this is the range of exercise prices over which most option trading takes place so we may in general expect the b s price to overprice options this effect is exaggerated as the time to maturity increases one of the most surprising implications of this is that if the b s equation is used to determine the implied volatility of a near the money option the longer the time to maturity the lower the implied volatility numerical solutions for the case in which the volatility is correlated with the stock price are also examined the stochastic volatility problem has been examined by merton 13 geske 7 johnson 10 johnson and shanno 11 eisenberg 5 wiggins 16 and

discussion of voluntary disclosure choice and earnings information transfer pownall and waymire s paper prompted a general discussion of information transfer research particularly its motivation and methodology this summary begins with a brief introduction to information transfer research it then considers motivation and methodology since the discussion related both to pownall and waymire s research specifically and to information transfer research generally these discussion comments extend to both as well

from maize to haze agricultural shocks and the growth of the mexican drug sector understanding how economic incentives affect illegal drug production is essential for crafting policies in response to the international drug trade policymakers typically face a choice between two strategies targetingcriminalgroupsvialawenforcement andofferingproducersincentivestoengage in alternate activities yet little is known about how the returns to alternate legal activities affect drug supply we contribute to this literature by examining how shocks to legal commodity prices affect the drug trade in mexico our analysis exploits exogenous movements in the mexican maize price stemming from weather conditions in u s maize growing regions as well as exports of other major maize producers using data on over 2200 municipios spanning 1990 2010 we show that lower prices differentially increased the cultivation of both marijuana and opium poppies in municipios

unsystematic security price movements management earnings forecasts and revisions in consensus analyst earnings forecasts empirical evidence suggests that information about a firm s future earnings prospects is important to investors griffin 1976 givoly and lakonishok 1979 1980 and imhoff and lobo 1984 reported statistically significant abnormal stock returns before at and after announcements of analyst earnings forecast revisions in addition imhoff and lobo documented positive correlation between the magnitudes of the forecast revisions and the abnormal returns these findings are consistent with the hypothesis that investors find analyst forecast revisions informative another source of information about future earnings is projections from corporate officials several studies have found unsystematic stock price changes prior to and or immediately surrounding the public release of management earnings forecasts e g foster 1973 nichols and tsay 1979 patell 1976 jaggi 1978 penman 1980 and waymire 1984 the conclusion from this research is that management forecasts also convey information to investors

optimal delta hedging for options abstract as has been pointed out by a number of researchers the normally calculated delta does not minimize the variance of changes in the value of a trader s position this is because there is a non zero correlation between movements in the price of the underlying asset and movements in the asset s volatility the minimum variance delta takes account of both price changes and the expected change in volatility conditional on a price change this paper determines empirically a model for the minimum variance delta we test the model using data on options on the s p 500 and show that it is an improvement over stochastic volatility models even when the latter are calibrated afresh each day for each option maturity we also present results for options on the s p 100 the dow jones individual stocks and commodity and interest rate etfs

the role of supplementary statements with management earnings forecasts we investigate managers decisions to supplement their firms management earnings forecasts we classify these supplementary disclosures as qualitative soft talk disclosures or verifiable forward looking statements we find that managers provide soft talk disclosures with similar frequency for good and bad news forecasts but are more likely to supplement good news forecasts with verifiable forward looking statements we examine the market response to these forecasts and find that bad news earnings forecasts are always informative but that good news forecasts are informative only when supplemented by verifiable forward looking statements supporting our argument that these statements bolster the credibility of good news forecasts

positive and negative information transfers from management forecasts we examine positive and negative information transfers associated with management earnings and revenue forecasts positive information transfers are due to industry commonalities whereas negative information transfers are caused by competitive shifts we argue that positive and negative intra industry information transfers offset each other and lead to an overall finding of no information transfers even though they exist we also conjecture that the type of information transfers from the same management forecast can be positive or negative based on the characteristics of the information receiver we hypothesize positive information transfers to nonrival firms and negative information transfers to rivals consistent with our prediction we find negative positive information transfers between forecasting firms and nonforecasting rival nonrival firms in the same industry through analyses using competitors identified by hoover s and 10 k reports we show more general evidence of negative information transfers to rival firms

managers earnings forecasts and intra industry information transfers abstract the effect that voluntarily disclosed managers earnings forecasts have on the security prices of the announcing firms and other firms in the same industry is examined the results are consistent with information content in managers forecasts and with information transfer between forecast firms and other firms in the industry these inferences are drawn from firms abnormal returns computed from single and two index pricing models where the latter includes market and industry indexes interestingly while a positive information transfer is evident with market model residuals once industry cross sectional covariation in firms returns is removed no directional relation is apparent

violent crime and punishment an application of the lisrel model public anxiety over violent crime has forged a broad consensus to purchase more crime control recently the president brought into law a federal anti crime bill that will put an additional 100 000 police on the nation s streets this paper presents empirical evidence on the deterrence effect of police presence the principal finding is that police presence deters commission of violent crimes by increasing the risk of being punished for committing those crimes this risk is modelled as a latent variable because the probability and severity of punishment for committing a violent crime are generally communicated in an onconsistant fashion the violent crime commission rate is also treated as a latent variable because it is almost certainly afflicted with measurement error

winning isn t everything corruption in sumo wrestling although the theoretical literature on corruption is well developed empirical work in this area has lagged because it has proven difficult to isolate corrupt behavior in the data in this paper we look for evidence of corruption in an unlikely place the highest echelons of japanese sumo wrestling this paper provides strong statistical evidence documenting match rigging in sumo wrestling a non linearity in the incentive structure of promotion leads to gains from trade between wrestlers on the margin for achieving a winning record and their opponents we show that wrestlers win a disproportionate share of the matches when they are on the margin increased effort can not explain the findings winning on the bubble is more frequent when the two competitors have met often in the past success on the bubble tends to rise over the course of a wrestler s career but declines in his last year consistent with the game theoretic predictions wrestlers who are victorious when on the bubble lose more frequently than would be expected the next time they meet that opponent suggesting that part of the payment for throwing a match is future payment in kind systematic differences across wrestling stables suggest that the stables play a role in facilitating the corruption in times of increased media scrutiny the match rigging disappears this abstract was borrowed from another version of this item

do hedge fund managers misreport returns evidence from the pooled distribution we find a significant discontinuity in the pooled distribution of monthly hedge fund returns the number of small gains far exceeds the number of small losses the dis continuity is present in live and defunct funds and funds of all ages suggesting that it is not caused by database biases the discontinuity is absent in the 3 months culminating in an audit suggesting it is not attributable to skillful loss avoidance the discontinuity disappears when using bimonthly returns indicating a reversal in fund performance following small gains this result suggests that the discontinuity is caused at least in part by temporarily overstated returns

point shaving corruption in ncaa basketball a new field of forensic economics has begun to emerge applying price theoretic models to uncover evidence of corruption in domains previously outside the purview of economists by emphasizing the incentives that yield corruption these approaches also provide insight into how to reduce such behavior this paper contributes to this agenda highlighting how the structure of gambling on college basketball yields pay offs to gamblers and players that are both asymmetric and nonlinear thereby encouraging mutually beneficial effort manipulation through point shaving initial evidence suggests that point shaving may be quite widespread the incentives for gambling related corruption derive from the structure of basketball betting to highlight a simple example the university of pennsylvania played harvard on march 5 2005 and was widely expected to win rather than offering short odds on penn winning the game bookmakers offered an almost even bet bet 11 to win 10 on whether penn would win relative to a spread in this example the spread was 14 5 meaning that a bet on penn would win only if penn won the game by 15 or more points while a bet on harvard would be successful if harvard either won or lost by 14 or fewer points the incentive for corruption derives directly from the asymmetric incentives of players who care about winning the game and gamblers who care about whether a team beats or covers the spread indeed the example above is ripe for corruption the outcome that maximizes the joint surplus of the penn players and the gambler occurs when penn wins the game but fails to cover the spread and the gambler has bet on harvard the contract required to induce this outcome simply involves the gambler offering a contingent payment to the player with the contingency being that he pays only if penn fails to cover the spread given the player s approximate indifference over the size of the winning margin even small bribes may dominate his desire to increase the winning margin above 14 points and this in turn yields large profits for the gambler who has bet accordingly the betting market offers a simple technology for the gambler to commit to paying this outcomecontingent bribe he can simply give the player the ticket from a 1 000 bet on his opponent not covering the spread such attempts to shave the winning margin below the point spread are colloquially referred to as point shaving and form the focus of my inquiry i start by outlining the type of corruption that theory suggests will be most prevalent

trafficking networks and the mexican drug war abstract drug trade related violence has escalated dramatically in mexico since 2007 and recent years have also witnessed large scale efforts to combat trafficking spearheaded by mexico s conservative pan party this study examines the direct and spillover effects of mexican policy toward the drug trade regression discontinuity estimates show that drug related violence increases substantially after close elections of pan mayors empirical evidence suggests that the violence reflects rival traffickers attempts to usurp territories after crackdowns have weakened incumbent criminals moreover the study uses a network model of trafficking routes to show that pan victories divert drug traffic increasing violence along alternative drug routes jel d72 d85 k42 o17 z13

cross firm real earnings management cross firm real earnings management our analysis is rooted in the notion that stockholders can learn about the fundamental value of any firm from observing the earnings reports of its rivals we argue that such intra industry information transfers which have been broadly documented in the empirical literature may motivate managers to alter stockholders beliefs about the value of their firm not only by manipulating their own earnings report but also by influencing the earnings reports of rival firms managers obviously do not have access to the accounting system of peer firms but they can nevertheless influence the earnings reports of rival firms by distorting real transactions that relate to the product market competition we demonstrate such managerial behavior which we refer to as cross firm real earnings management and explore its potential consequences and interrelation with the practice of accounting based earnings management within an industry setting with imperfect non proprietary accounting information this article is protected by copyright all rights reserved

model free hedge ratios and scale invariant models a price process is scale invariant if and only if the returns distribution is independent of the price measurement scale we show that most stochastic processes used for pricing options on financial assets have this property and that many models not previously recognised as scale invariant are indeed so we also prove that price hedge ratios for a wide class of contingent claims under a wide class of pricing models are model free in particular previous results on model free price hedge ratios of vanilla options based on scale invariant models are extended to any contingent claim with homogeneous pay off including complex path dependent options however model free hedge ratios only have the minimum variance property in scale invariant stochastic volatility models when price volatility correlation is zero in other stochastic volatility models and in scale invariant local volatility models model free hedge ratios are not minimum variance ratios and our empirical results demonstrate that they are less efficient than minimum variance hedge ratios

intraindustry information transfers associated with management forecasts of earnings this study documents information transfers associated with the sign and magnitude of the changes in earnings expectations conveyed by management forecasts that is the management forecast of one firm discloser generates unexpected price reactions for firms nondisclosers similar to the forecaster the results are consistent with information transfers documented for releases of actual earnings foster 1981 and sales announcements olsen and dietrich 1985 1 these results build on prior management forecast research that has documented a link between the sign and magnitude of the changes in earnings expectations conveyed by management forecasts and the unexpected share returns price reactions of forecasting firms ajinkya and

vix derivatives hedging and vol of vol risk we study the empirical hedging performance of alternative vix option pricing models recent advances in the literature find evidence of asymmetric volatility of volatility similar to the leverage effect in equity markets stochastic mean reversion and jumps using such findings in our model framework we show that while sophisticated models have superior pricing performance and can explain a range of stylized facts in the vix derivatives market their hedging performance is inferior to a simple black model hedge we also study the empirical performance of regime dependent hedge ratio adjustments commonly applied in equity markets

identification of endogenous social effects the reflection problem this paper examines the reflection problem that arises when a researcher observing the distribution of behaviour in a population tries to infer whether the average behaviour in some group influences the behaviour of the individuals that comprise the group it is found that inference is not possible unless the researcher has prior information specifying the compisition of reference groups if this information is available the prospects for inference depend critically on the population relationship between the variables defining reference groups and those directly affecting outcomes inference is difficult to implossible if these variables are functionally dependent or are statistically independent the prospects are better if the variables defining reference groups and those directly affecting outcomes are moderately related in the population

poor institutions rich mines resource curse in the origins of the sicilian mafia with weak law enforcement institutions a positive shock to the value of natural resources may increase demand for private protection and opportunities for rent appropriation through extortion favouring the emergence of mafia type organisations we test this hypothesis by investigating the emergence of the mafia in twentieth century sicily where a severe lack of state property rights enforcement coincided with a steep rise in international demand for sulphur sicily s most valuable export commodity using historical data on the early incidence of mafia activity and on the distribution of sulphur reserves we document that the mafia was more present in municipalities with greater sulphur availability

how to organize crime in criminal organizations diffusing information widely throughout the organization might lead to greater internal efficiency in particular since these organizations are self sustaining through enhancing trust however this may come at the cost of leaving the organization more vulnerable to external threats such as law enforcement we consider the implications of this trade off and characterize the optimal information structure rationalizing both hierarchical structures and organization in cells then we focus on the role of the external authority characterize optimal detection strategies and discuss the implications of different forms of enforcement on the internal structure of the organization and policy finally we discuss a number of applications and extensions in this paper we study the interplay between trust within an illegal organization and its vulnerability to the authorities illegal organizations function more effectively when the people who constitute them trust each other we argue that information sharing is an important factor in building internal trust and cohesion but that can leave the organization vulnerable understanding how this trade off affects an organization s information structure and productivity can allow us to assess detection policies designed to destabilize such organizations since 9 11 the u s congress has passed a 400 billion annual budget for the war on terror new domestic institutions have been created or enhanced among many others the counterterrorism section at the u s department of justice s criminal division international intelligence cooperation has been strengthened and new protocols and controversial legal tools such as the patriot act have been developed however these new agencies and institutions face the same basic questions that have challenged the prosecutors fighting organized crime in italy south america and eastern asia as well as authorities fighting terrorism all over the world now and in the past how can we learn about the internal structure of criminal organizations how should we go about investigating a criminal organization in order to break its internal cohesion how does a criminal organization react to investigation policies we highlight the fact that simply understanding the information links within an organization gives us insight into addressing these questions the anecdotal evidence suggests that there is a wide heterogeneity across the information structures of different criminal organizations the most credited theory about the mafia developed in the early 1990 s has identified the so called cupola as the highest level of the organization supposedly consisting of agents who hold large amounts of information about the organization itself and carry out the enforcement needed for the organization to function 2 these crucial agents are shielded from the authorities since they are typically not directly involved in criminal activities this theory suggests a centralized information and enforcement structure 1 previous drafts have circulated under the titles power and organizational structure under an external threat

a jump diffusion model for pricing and hedging with margined options an application to brent crude oil contracts abstract we develop a jump diffusion model for pricing and hedging with margined options on futures unlike a standard equity option margined options require no up front payment an attractive feature of margined options is that there is no early exercise premiums under general assumptions model parameter estimates and out of sample pricing errors are calculated using data on brent crude contracts using the same pricing technology we also hedge equity style options with margined options hedging coefficients are derived by matching an extended set of greeks we find that a target equity option can be effectively hedged using a portfolio of two margined options and the underlying as has been reported elsewhere a delta hedge is inappropriate when the underlying is a jump diffusion

intra industry information transfers associated with earnings releases abstract the impact that a firm s earnings releases have on the stock prices of other firms in its industry is examined for an identifiable sub set of firms the results are consistent with a significant information transfer occurring between the earnings release firm and the other firms in its industry this subset is identified by examining the impact of the release on the stock price of the announcing firm the magnitude of this impact is more significant for a sample of firms which have a larger percentage of their revenues in the same line of business as the earnings release firm vis a vis a sample with a lower percentage of their revenues from the same line of business alternative interpretations of the empirical results are also discussed the research findings have implications for information content and market efficiency research and for research on policy issues associated with disclosure regulation

do voters affect or elect policies evidence from the u s house there are two fundamentally different views of the role of elections in policy formation in one view voters can affect candidates policy choices competition for votes induces politicians to move toward the center in this view elections have the effect of bringing about some degree of policy compromise in the alternative view voters merely elect policies politicians cannot make credible promises to moderate their policies and elections are merely a means to decide which one of two opposing policy views will be implemented we assess which of these contrasting perspectives is more empirically relevant for the u s house focusing on elections decided by a narrow margin allows us to generate quasi experimental estimates of the impact of a randomized change in electoral strength on subsequent representatives roll call voting records we find that voters merely elect policies the degree of electoral strength has no effect on a legislator s voting behavior for example a large exogenous increase in electoral strength for the democratic party in a district does not result in shifting both parties nominees to the left politicians inability to credibly commit to a compromise appears to dominate any competition induced convergence in policy

differential intra industry information transfer associated with management earnings forecasts abstract this study proposes that the amount of information about one firm conveyed by management forecasts of another firm in the same industry depends on the earnings covariance between the two firms and the forecast firm s earnings variance the covariance reflects the competitive relation between the firms and the variance represents noise contained in forecasts when both variance and covariance are included in regressions nonforecast firms abnormal returns are associated with forecast firms abnormal returns when they are excluded no such association is observed the results are similar but much weaker when the independent variable is unexpected management forecasts