the informational role of stock and bond volume in a kyle 1985 model the sign of the correlation between a firm s debt and equity returns is the same as the sign of the cross market kyle s lambda the sign is positive negative if private information concerns the mean risk of the firm s assets we show empirically that information conveyed by order flows is primarily about asset means the cross market lambdas are quite large consequently the portions of bond and stock returns explained by order flows are highly correlated even though the order flows themselves are virtually uncorrelated

betting on hitler the value of political connections in nazi germany this paper examines the value of connections between german industry and the nazi movement in early 1933 drawing on previously unused contemporary sources about management and supervisory board composition and stock returns we find that one out of seven firms and a large proportion of the biggest companies had substantive links with the national socialist german workers party firms supporting the nazi movement experienced unusually high returns outperforming unconnected ones by 5 to 8 between january and march 1933 these results are not driven by sectoral composition and are robust to alternative estimators and definitions of affiliation

insider trading revisited a recent article in this journal argued that insider trading is an unethical practice leading to an inefficiently functioning market the debate on this topic has primarily pitted ethical defenses of prohibition against economic arguments extolling its allowance in addition to being incomplete this approach ignores other unwanted economic effects of prohibition itself and unethical implications of its existence this article shows that adam smith s free market concept when properly interpreted provides all the incentive structure necessary for an efficient and ethical marketplace even when insider trading is permitted

a day end transaction price anomaly a large mean price change is observed on the last daily nyse transaction this suggests that closing prices may not consistently represent stock values transaction prices are studied to further characterize the day end price rise and to determine whether it is due to any limited subsample of stocks or dates the results indicate that the phenomenon is pervasive over most firms and days some evidence suggests that it is caused by a change in the frequency of ask prices at day end

one security many markets determining the contributions to price discovery when homogeneous or closely linked securities trade in multiple markets it is often of interest to determine where price discovery the incorporation of new information occurs this article suggests an econometric approach based on an implicit unobservable efficient price common to all markets the information share associated with a particular market is defined as the proportional contribution of that market s innovations to the innovation in the common efficient price applied to quotes for the thirty dow stocks the technique suggests that the preponderance of the price discovery takes place at the new york stock exchange nyse a median 92 7 percent information share although most of the classic paradigms in market microstructure concern a security that trades in a single centralized market such situations are becoming increasingly rare in practice fragmentation the dispersal of trading in a security to multiple sites has emerged as a dominant institutional trend this process is of concern to financial economists and regulators because price information and price discovery the impounding of new information into the security price arguably the most important products of a security market have many attributes of public goods as the process of fragmentation accelerates it may be important to determine where the price information and price discovery are being produced 1 this paper suggests a practical econometric approach to this problem the technique is illustrated with an application to u s equity markets many stocks listed on the new york stock exchange nyse trade concurrently on the regional exchanges and the national association of securities dealers national market system nasd nms since a share of ibm stock is the same security whether purchased on the midwest or pacific exchange this is a particularly clear instance of multiple markets nevertheless the expres

imperfect information and cross autocorrelation among stock prices i develop a model to explain why stock returns are positively cross autocorrelated when market makers observe noisy signals about the value of their stocks but cannot instantaneously condition prices on the signals of other stocks which contain marketwide information the pricing error of one stock is correlated with the other signals as market makers adjust prices after observing true values or previous price changes of other stocks stock returns become positively crossautocorrelated if the signal quality differs among stocks the cross autocorrelation pattern is asymmetric i show that both own and cross autocorrelations are higher when market movements are larger

the interrelation of stock and options market trading volume data this research empirically investigates the relation between common stock and call option trading volumes the paper hyothesizes and tests a sequential flow of information between the stock and option markets if information trading for cboe listed firms is predominantly accomplished through option trading then existing research methodologies may be biased against finding any significant economic consequences in those instances where option listing is an important variable results indicate that trading in call options leads trading in the underlying shares with a one day lag black 2 suggests that information traders may prefer trading in options rather than shares due to economic incentives provided by reduced transaction costs capital requirements and trading restrictions and due to the greater action afforded by option trading manaster and rendleman 12 empirically support black s 2 option information trading preference finding incremental information content in option prices up to twenty four hours prior to its reflection in stock prices jennings and starks 10 report that the stock price adjustment process upon arrival of new information differs for those firms listed on the chicago board option exchange cboe and they demonstrate that stock price adjustment to new information occurs more rapidly for firms with listed call options the results in both papers appear to warrant consideration of an optiontrading variable in the design of empirical tests both manaster and rendleman 12 and jennings and starks 10 investigate the price relation between shares and call options this paper investigates trading volume copeland 4 posits the use of trading volume as a proxy for the rate of information arrival he concludes that the relation between absolute value of price changes and volume is positive and linear if one accepts a sequentialinformation arrival hypothesis as valid the present research hypothesizes and tests a sequential flow of information between the stock and option markets analyses presented are based on econometric tests for causality1 derived from the works of granger 6 and sims 22 if information trading takes place

insider trading investment and liquidity a welfare analysis we compare equilibrium trading outcomes with and without participation by an informed insider assuming inflexible ex ante aggregate investment choices by agents noise trading arises from aggregate uncertainty regarding other agents intertemporal consumption preferences the welfare levels of outsiders can thus be ascertained the allocations without insider trading are not ex ante pareto efficient because our model differs from standard ones with negative exponential utility functions and normal returns we characterize the circumstances under which the revelation of payoff relevant information via prices arising from insider tradingbenefits outsiders with stochastic liquidity needs by improving risk sharing among them in models of informed trading allen 1984 dennert 1992 grossman and stiglitz 1980 kyle 1985 leland 1992 repullo 1994 it has been customary in order not to have an unrealistic fully revealing rational expectation equilibrium ree and no profits for informed traders to postulate some portion of the market demand for securities as arising from unmodeled noise traders whose endowments and preferences for consumption are left unspecified this makes it difficult to reach a welfare judgment regarding the impact of insider trading even when the implications for the informativeness of asset prices and investment can be ascertained thus an important issue in financial regulatory policy regarding the desirability of allowing trading by asymmetrically informed corporate insiders remains largely unresolved at the conceptual level our major goal in this paper is to rectify this shortcoming by modeling both noise traders and rational a priori uninformed traders together as agents with well specified preferences these agents allocate their endowments across a risky long term and a riskless short term investment ex ante london school of economics and political science and cepr and universita degli studi di torino respectively we are grateful for financial support from the ente einaudi the italian murst and the international centre for economic research icer torino it is a pleasure to acknowledge the excellent research assistance of giacomo elena work on this paper was begun while bhattacharya was a visiting fellow at icer during the summer of 1995 we wish to thank without implicating in errors gabriella chiesa and jose marin for advice and encouragement and participants at seminars at the universities of brescia roma tor vergata tilburg torino the cepr conference on information financial intermediation and the macroeconomy alghero 1997 as well as an anonymous referee and the editor rene stulz for their very helpful comments and suggestions

asymmetric information and options in an extension of the kyle 1985 model of continuous insider trading it is shown that asymmetric information can make it impossible to price options by arbitrage even when an option would appear to be redundant its introduction into the market can cause the volatility of the underlying asset to become stochastic this eliminates the potential for dynamically replicating the option the change in the price process of the asset reflects a change in the information transmitted by volume and prices when the option is traded article published by oxford university press on behalf of the society for financial studies in its journal the review of financial studies

option prices as predictors of equilibrium stock prices the black scholes option pricing model modified for dividend payments is used to calculate jointly implied stock prices and implied standard deviations a comparison of the implied stock prices with observed stock prices reveals that the implied prices contain information regarding equilibrium stock prices that is not fully reflected in observed stock prices the implications of this finding are discussed this study investigates the role of call option prices as predictors of the equilibrium prices of their underlying stocks using the black scholes 3 bs model previous tests of the bs model have shown that the formula is highly successful in explaining the observed market prices of options see black and scholes 2 galai 8 chiras and manaster 6 and macbeth and merville 12 according to the model the option price is a function of the current value of the underlying stock the instantaneous variance of the stock s rate of return the time to maturity of the option the risk free rate of interest and the exercise price of the option 1 given an observed option price and known values of all input parameters to the bs model except the stock price one can determine the price of the underlying stock that equates the observed option price to its calculated value it follows from the underlying logic of the model that the implied price is the value of the underlying stock for which a continuously revised option bond portfolio would be a perfect substitute for the stock hence if options are actually priced according to the model implied stock prices will be the option market s assessment of equilibrium stock values previous empirical studies have assumed that observed stock prices are the relevant stock prices for option valuation however just as stock prices may differ in the short run from one exchange to another i e nyse midwest

where should the line be drawn on insider trading ethics finance ethics have drawn increasing attention from both government regulators and academic researchers this paper addresses the issue of insider trading ethics previous studies on insider trading ethics have failed to provide convincing arguments and consistent results in particular the arguments against insider trading are based primarily on moral and philosophical grounds and lack empirical rigor this study intends to establish and examine the relationship between the ethical issue and economic issue of insider trading we argue that the ethics of insider trading is in essence an economic rather than a moral issue it is so far not clear to what extent insider trading may increase or decrease shareholders wealth until then we must take care to avoid over regulating insider trading

option volume and stock prices evidence on where informed traders trade this paper investigates the informational role of transactions volume in options markets we develop an asymmetric information model in which informed traders may trade in option or equity markets we show conditions under which informed traders trade options and we investigate the implications of this for the linkage between markets our model predicts an important informational role for the volume of particular types of option trades we empirically test our model s hypotheses with intraday option data our main empirical result is that negative and positive option volumes contain information about future stock prices the information content of trading activity is a subject of widespread interest if trades are correlated with private information then the outcome of the transaction process may portend future movements in price the extension of trading to different venues or to derivative instruments however means that this link between transactions and information need not be easily discernible if there are alternative markets in which informed traders can profit from their information then where informed traders choose to trade may have important implications not only for security p rice movements but for the behavior of related prices as well this suggests that transactions in derivative markets may be an important predictor of future security price movements in this paper we investigate the informational role of transactions volume in options markets for some readers this focus may seem puzzling an option is a derivative security so its price should be dictated unilaterally by the behavior of the stock price this unidirectional linkage is only true however in complete markets if information is impounded into prices by trading then the ability of informed traders to transact in options markets mearns

large option trades market makers and limit orders this article focuses on the difference between market makers and limit orders in their role as suppliers of liquidity for both sources of liquidity i analyze the price behavior of stocks and options around large option trades and i estimate the premium paid by the initiator of the large trade my findings suggest that limit orders for options are picked off after adverse changes in the underlying stock price furthermore i find that for these transactions there is a permanent change in quotations in the direction of the transaction after transactions where market makers supply liquidity quotes tend to return to their pretrade level article published by oxford university press on behalf of the society for financial studies in its journal the review of financial studies

ethical reasoning and the use of insider information in stock trading the cognitive developmental theory of ethics suggests that there is a positive relationship between ethical reasoning and ethical behavior in this study we trained a sample of accounting and finance students in performing competitive stock trading in our state of the art trading room the subjects then performed trading of stocks under two experimental conditions insider information and no insider information where significant performance based financial awards were at stake we also administered the defining issues test dit ethical behavior as the dependent variable was measured in a binary scale whether the subjects used insider information for trading of stocks or not ethical reasoning as measured by the dit p score indicated statistically significant effect on ethical behavior the results have important implications for recruitment and training of professionals engaged in the use of financial markets for securities trading

ma and sun on insider trading ethics ma and sun have recently argued that some forms of insider trading are ethically acceptable we argue that the authors fail to prove three key premises of their argument which is therefore unsound

stealth trading in options markets we investigate how price discovery occurs in the options markets through traders trade size choice by employing transactions data on all options traded on a sample of 100 firms we show that informed traders fragment their orders into small medium trades for low high volume contracts we also find that almost 60 of the price discovery occurs in the exchange with the largest market share for a given option where informed traders favor medium size trades upon examining distinct option series for a given stock we find that at the money calls display the highest information share

market making in the options markets and the costs of discrete hedge rebalancing in this paper we provide empirical evidence consistent with the hypothesis that options market makers face risks in managing inventory that are unique to the options markets in particular we show that risks associated with the inability to rebalance an option position continuously and uncertainty about the return volatility of the underlying stock each account for a statistically and economically significant proportion of the bid ask spreads quoted for a sample of chicago board options exchange options it is widely recognized that securities dealers face risk associated with inventory positions taken in the course of their trading activities for the equity dealer this has been shown both theoretically e g stoll 1978a ho and stoll 1983 and empirically e g stoll 1978b to depend on the stock s return volatility and the expected duration of the risk exposure in this paper we recognize that option dealers face an additional dimension of risk as a result of the option s stochastic return volatility and demonstrate that this option characteristic contributes to the cost of liquidity in the options market ho and stoll 1983 show that if the stock return volatility is constant the specialist s risk exposure per dollar of investment is nonstochastic over the interval during which the inventory is held in contrast unless the option dealer is able to trade continuously an option transaction s contribution to the dealer s risk exposure will be stochastic since the volatility of an option is a function of both its stochastic hedge ratio as well as the underlying stock s return volatility the problem that arises is particularly clear in the context of a dealer attempting to maintain a delta neutral exposure a strategy common among market makers in the options markets imagine a market maker who simultaneously buys 10 option contracts with a hedge ratio of 1 4 and sells 5

the ethics of insider trading despite the fact that a number of economists and philosophers of late defend insider trading both as a viable and useful practice in a free market and as not immoral i shall question the value of insider trading both from a moral and an economic point of view i shall argue that insider trading both in its present illegal form and as a legalized market mechanism undermines the efficient and proper functioning of a free market thereby bringing into question its own raison d etre it does so and is economically inefficient for the very reason that it is immoral thus this practice cannot be justified either from an economic or a moral point of view

value of corruption in china evidence from anti corruption investigation abstract using recent anti corruption investigation in china we show that chinese listed firms suffered an aggregate loss of usd 30 billion in firm value due to corruption furthermore we show that anti corruption investigation is more effective when top officials are targeted

why option prices lag stock prices a trading based explanation while many studies find that option prices lead stock prices stephan and wvhaley 1990 find that stocks lead options we find no evidence that options even deep out of the money options lead stocks after confirming stephan and whaley s results we show their results can be explained as spurious leads induced by infrequent trading of options we show that the stock lead disappears when the average of the bid and ask prices is used instead of transaction prices hence we find no evidence of arbitrage opportunities associated with the stock lead in a perfect market price discrepancies should be instantly arbitraged away in particular option prices should neither lead nor lag stock prices in real markets only very short leads should occur traders with private information who are confident that their information is valid and that they will not be detected generally want highly leveraged positions to exploit their advantage thus we might expect options with their greater leverage to lead stocks if information trading is important manaster and rendleman 1982 bhattacharya 1987 and anthony 1988 find evidence that options

the informational role of stock and option volume this article analyzes the intraday interdependence of order flows and price movements for actively traded nyse stocks and their chicago board options exchange cboe traded options stock net trade volume buyer initiated volume minus seller initiated volume has strong predictive ability for stock and option quote revisions but option net trade volume has no incremental predictive ability this suggests that informed investors initiate trades in the stock market but not in the option market on the other hand both stock and option quote revisions have predictive ability for each other thus while information in the stock market is contained in both quote revisions and trades information in the option market is contained only in quote revisions copyright 2002 oxford university press

is there price discovery in equity options abstract we use tick by tick quote data for 39 liquid us stocks and options on them and we focus on events when the two markets disagree about the stock price in the sense that the option implied stock price obtained from the put call parity relation is inconsistent with the actual stock price option market quotes adjust to eliminate the disagreement while the stock market quotes behave normally as if there were no disagreement the disagreement events are typically precipitated by stock price movements and display signed option volume in the direction that tends to eliminate the disagreements these results show that option price quotes do not contain economically significant information about future stock prices beyond what is already reflected in current stock prices i e no economically significant price discovery occurs in the option market we also find no option market price discovery using a much larger sample of disagreement events based on a weaker definition of a disagreement which verifies that the findings for the primary sample are not due to unusual or unrepresentative market behavior during the put call parity violations

analyzing insider trading from the perspectives of utilitarian ethics and rights theory the common view is that insider trading is always unethical and illegal but such is not the case some forms of insider trading are legal furthermore applying ethical principles to insider trading causes one to conclude that it is also sometimes ethical this paper attempts to get past the hype the press reports and the political grandstanding to get to the truth of the matter the author applies two sets of ethical principles utilitarianism and rights theory in an attempt to determine when and in what circumstances insider trading is ethical the views of henry manne an early proponent of insider trading are critically examined as are the major arguments against insider trading is insider trading good for the company if it is used as a form of executive compensation which makes it possible to pay lower salaries than would otherwise be the case does insider trading cause the stock market to work more efficiently if insider trading does increase efficiency is that sufficient to call for its total legalization or are there other things to be considered several arguments against insider trading have been put forth over the last few decades but there are problems with all of them one of the main arguments is the fairness argument the problem with this argument is that different people have different definitions of unfairness a closely related argument is the level playing field argument which advocates wider dissemination of information so that it is less asymmetric one problem with the level playing field argument is that it is better applied to sporting competitions than to trading in information some economists argue that forcing the disclosure of nonpublic information can actually result in more harm than good and must necessarily involve the violation of property rights other arguments examined in this chapter include the fiduciary duty argument the problem of outside traders the misappropriation doctrine and the restrictions that insider trading laws place on freedom of speech and press the article concludes by setting forth some principles or guidelines to determine when insider trading should be punished and when it should not

stock and option market divergence in the presence of noisy information we examine market behavior of the stock and option markets upon the arrival of noisy information in the form of cnbc s mad money recommendations if stock and option markets are not equally efficient they should respond differently to noisy information with the less efficient market more susceptible to noise we find that the stock market is less efficient than the option market the abnormal difference between option implied and actual stock returns is negative and significant upon exposure to noisy information this difference may yield an economically significant monthly trading profit of up to 5 we conclude that the stock market is more susceptible to noisy information than the option market and is therefore less efficient published by elsevier b v

information content of options trading volume for future volatility evidence from the taiwan options market abstract this study follows the approach of ni et al ni s x pan j poteshman a m 2008 volatility information trading in the option market journal of finance 63 1059 1091 based upon the vega weighted net demand for volatility to determine whether volatility information exists within the taiwan options market our empirical results show that foreign institutional investors possess the strongest and most direct volatility information which is realized by the delta neutral options futures trades in addition a few individual investors less than 1 of individuals trades might be informed and realize their volatility information using the strangle strategy surprisingly we find no evidence to support the predictive ability of the volatility demand from straddle trades despite the widespread acknowledgement that such trades are sensitive to volatility

some remarks on leland s model of insider trading this paper shows that leland s 1992 results on the positive effects of insider trading on investment are not robust to the introduction of noise in the insider s information the paper then considers two variations of his model in which the insider is risk neutral to ensure robustness and the investment decision is prior to the placing of the stock in the market it is shown that if insider trading takes place in the primary market it has no effect on the level of investment whereas if it takes place in the secondary market it has a negative effect on investment ing debate insider trading moves the resolution of uncertainty forward and this may bring benefits better information for investment decisions as well as costs increased volatility of prices and hence higher risk premia to analyse these effects leland 1992 constructs a model with an endogen ous level of investment and he shows that when insider trading is permitted stock prices will be higher on average expected real investment will rise and markets will be less liquid and more volatile leland s model is however very special first of all he assumes that the risk averse insider learns exactly the future return of the risky asset in this paper i analyse the robustness of leland s results to the introduction of some noise in the insider s information i show that given the assumptions of his model an arbitrarily small amount of noise is sufficient to make negligible all the effects of insider trading the source of this lack of robustness lies in the assumption that because of risk aversion the insider s trade is always negligible except in the limit case where holding the asset entails no risk to ensure robustness to the intro duction of noise in the insider s information i then consider a model with a risk neutral insider however for this model insider trading does not have any effect on the average price of the risky asset and hence no effect on the average level of investment another feature of leland s model is the fact that the only supplier of the risky asset is assumed to be a price taker this seems a fairly implausible assumption so i propose an alternative model with a risk neutral insider in which the investment decision is prior to the placing of the asset in the market and which allows the supplier to have market power the equilibrium of this model can be easily derived from leland s analysis and although we get the same results for the volatility of the price and the liquidity of the market now insider trading has no effect on the level of investment the result however depends crucially on the assumption that the supplier of the asset is risk neu tral under risk aversion the increase in price volatility would imply a negative

an experiment testing the determinants of non compliance with insider trading laws recent stories of corporate insiders avoiding losses and in some cases generating enormous personal profits as their companies crumbled have led investors to question the integrity of american business and the fairness of the united states stock markets the sec tries to ensure the fairness of the stock markets by making and enforcing laws against unfair practices such as insider trading in the united states when insiders trade stock based on non public information they have broken the law and betrayed the trust that has been placed in them

transactions volume and volatility we show that the positive volatility volume relation documented by numerous researchers actually reflects the positive relation between volatility and the number of transactions thus it is the occurrence of transactions per se and not their size that generates volatility trade size has no information beyond that contained in the frequency of transactions our results suggest that theoretical research needs to entertain scenarios in which 1 both the frequency and size of trades are endogenously determined yet 2 the size of trades has no information content beyond that contained in the number of transactions article published by oxford university press on behalf of the society for financial studies in its journal the review of financial studies

do lenders favor politically connected firms rent provision in an emerging financial market corruption by the politically connected is often blamed for economic ills particularly in less developed economies using a loan level data set of more than 90 000 rms that represents the universe of corporate lending in pakistan between 1996 and 2002 we investigate rents to politically connected rms in banking classifying a rm as political if its director participates in an election we examine the extent nature and economic costs of political rent provision we nd that political rms borrow 45 percent more and have 50 percent higher default rates such preferential treatment occurs exclusively in government banks private banks provide no

the cultures of insider trading paul bond is a lawyer who overheard two other lawyers at his office discussing the proposed purchase of a company by one of their clients he proceeds to buy shares of this company would you rate bond s behavior completely fair acceptable unfair or very unfair i posed this vignette to samples of university students in china taiwan and the u s most students in the u s and taiwan samples rated bond s behavior unfair or very unfair while most students in the china rated bond s behavior completely fair or acceptable perceptions of fairness are part of the culture of a country and culture affects business practices i discuss culture perceptions of fairness and business practices in china taiwan and the u s

partial privatization and firm performance most privatization programs begin with a period of partial privatization in which only non controlling shares of firms are sold on the stock market since management control is not transferred to private owners it is widely contended that partial privatization has little impact this perspective ignores the role that the stock market can play in monitoring and rewarding managerial performance even when the government remains the controlling owner using data on indian state owned enterprises we find that partial privatization has a positive impact on profitability productivity and investment widespread privatization in recent decades has generated a large empirical literature concerning the effect of ownership on firm performance most studies find that privatization has a positive impact on the profitability and efficiency of firms see megginson and netter 2001 for a recent survey 1 the firms in these studies have had a majority of their assets privatized and control rights have been transferred from the government to private owners surprisingly little is known about the effect of partial privatization where the government remains the controlling owner this paper seeks to address this gap in the literature by investigating whether the performance of state owned enterprises in india is affected by the sale of non controlling equity stakes on the stock market

insider trading in a rational expectations economy it is often argued that efficiency considerations require society to freely permit insider trading in this article an opposing efficiency argument is formalized the model incorporates an investment stage followed by a trading stage if outsiders expect insiders to take advantage of them in trading outsiders will reduce their investment the insiders loss from this diminished investor confidence may more than offset their trading gains consequently a prohibition on insider trading may effect a pareto improvement insiders are made better off if they can precommit not to trade on their privileged information govemment regulation accomplishes exactly this jel 022 026 313 the traditional rationale articulated for insider trading regulation and other securities law is that such rules promote confidence in markets indeed president franklin d roosevelt justified the first major u s securities legislation by saying it should give impetus to honest dealing in securities and thereby bring back public confidence similar language is still invoked half a century later in connection with enforcement efforts against insider trading and in proposals for tightened stock

the ethics of insider trading revisited following manne 1966 insider trading and the stock market new york free press we introduce a distinction between insider trading and market manipulation on the one hand and corporate insiders versus misappropriators on the other hand this gives rise to four types of alleged inside transactions we argue that the literature on insider trading has often targeted inside transactions type ii iii and iv but that these arguments do not necessarily hold for type i transactions we look for consequentionalist as well as non consequentionalist arguments against type i transactions and demonstrate that these are hard to find throughout the article we refer extensively to the economic literature on insider trading in order to overcome a relative divide between the economic legal and philosophical discussion on insider trading

options short sale constraints and market efficiency a new perspective this paper undertakes a new investigation of the potential for options to mitigate short sale constraints i find that option introduction alleviates 79 of the price adjustment efficiency disparity between short sale constrained and unconstrained stocks in relation to negative news no significant improvement in adjustment efficiency is found in response to positive information these results are robust to controls for endogeneity biases associated with the option introduction selection process further i find evidence that post option improvement in efficiency is similar in relation to private and public information this suggests that short sale constraint effects stem at least in part from an irrational optimism bias or another behavioral source as suggested theoretically by miller 1977 collectively these results suggest that options act as an effective substitute to short sales significantly contributing to the informational efficiency of the market

intraday price change and trading volume relations in the stock and stock option markets this study investigates intraday relations between price changes and trading volume of options and stocks for a sample of firms whose options traded on the cboe during the first quarter of 1986 after purging the price change series of the effects of bid ask spreads multivariate time series analysis is used to estimate the lead lag relation between the price changes in the option and stock markets the results indicate that price changes in the stock market lead the option market by as much as fifteen minutes the analysis of trading volume indicates that the stock market lead may be even longer the intense trading activity in and in fact the very existence of organized stock option markets attest to the economic benefits that these financial contracts provide reduced transaction costs and increased financial leverage are two reasons why trading in the stock option market may be more attractive than trading in the market for the underlying stock in addition these cheaper and more flexible trading opportunities attract new and differently informed investors to the marketplace the resulting increase in trading activity together with the inextricable arbitrage linkage between stock and option prices imply an increase in market efficiency this study investigates empirically the intraday price change and trading volume relations between stocks and options for a sample of firms whose options were actively traded on the chicago board options exchange during the first quarter of 1986 in particular intraday call option price changes are translated into implied stock price changes using the american call option pricing model these intraday implied stock price changes are then compared with the actual stock price changes to identify which if either market leads the other in perfectly functioning capital markets there should be complete simultaneity between the series that is new information disseminating into the marketplace should be reflected in the prices and the trading activity of both securities simultaneously institutional factors however may make the stock option market more attractive to information traders this may cause price changes and trading activity due to new information to be observed in the option market first followed by price

price changes of related securities the case of call options and stocks this paper tests the hypothesis that option prices contain information not reflected in con temporaneous stock prices an options transactions data base is used for the purpose the evidence suggests that the magnitude of anticipation of stock prices by option prices is insufficient to overcome the bid ask spread for intra day holding periods implications of the profits in the overnight holding periods are discussed

revolving door lobbyists we study how ex government ocials benet from the personal connections acquired during public service lobbyists with experience in the oce of a us senator suer a 24 drop in generated revenue when that senator leaves oce the eect is immediate discontinuous around the exit period and long lasting consistent with the notion that lobbyists sell access to powerful politicians the drop in revenue is increasing in the committee assignments power held by the exiting politician

the indefensibility of insider trading the article inside trading revisited has taken the stance that insider trading is neither unethical nor economically inefficient attacking my arguments to the contrary developed in an earlier article the ethics of inside trading journal of business ethics 1989 this article constructs careful arguments and even appeals to adam smith to justify its conclusions in my response to this article i shall clarify my position as well as that of smith to support my counter contention that insider trading is both unethical and inefficient