s p 500 trading strategies and stock betas this paper shows that s p 500 stock betas are overstated and the non s p 500 stock betas are understated because of liquidity price effects caused by the s p 500 trading strategies the daily and weekly betas of stocks added to the s p 500 index during 1985 1989 increase on average by 0 211 and 0 130 the difference between monthly betas of otherwise similar s p 500 and non s p 500 stocks also equals 0 125 during this period some of these increases can be explained by the reduced nonsynchroneity of s p 500 stock prices but the remaining increases are explained by the price pressure or excess volatility caused by the s p500 trading strategies i estimate that theprice pressures accountfor 8 5 percent of the total variance of daily returns of a value weighted portfolio of nyse amex stocks the negative own autocorrelations in s p 500 index returns and the negative cross autocorrelations between s p 500 stock returns provide further evidence consistent with the price pressure hypothesis

s p 500 cash stock price volatilities s p 500 stock return volatilities are compared to the volatilities of a matched set of stocks after controlling for cross sectional differences in firm attributes known to affect volatility no significant difference in volatility is observed between 1975 and 1983before the start of trade in index futures and index options since then s p 500 stocks have been relatively more volatile the difference is statistically but not economically significant the relative increase occurs primarily in daily returns and only to a lesser extent in longer interval returns other factors besides the start of derivative trade could be responsible for the small increase in volatility stock price volatility has received much attention in the popular press over the last few years especially since the october 19 1987 stock market crash the rise in volatility has alarmed investors regulators and the public in general some suggest that the start of trade in stock index futures and index options increased speculative activity that in turn destabilized cash markets causing higher volatility large trading activity in the derivative contracts makes the suggestion plausible volume in index futures and index options increased dramatically since their introductions in 1982 and 1983 by 1987 the average daily dollar volume in the s p 500 futures contracts alone exceeded the dollar volume of cash s p 500 trade by a factor of about two while the dollar value of the daily net change in total open interest is about 8 of s p 500 stock dollar volume speculative trade in futures and options frequently is accused of destabilizing underlying cash markets the charge has been made for more than a century in the agricultural precious metal and currency markets recent evidence by french and roll 1986 showing stock variance to be strongly related to trading session hours heightens these concerns unfortunately theoretical analyses of whether speculative trade destabilizes cash markets lead to conflicting conclusions depending on what assumptions are made 1 school of business administration university of southern california and office of economic analysis u s securities and exchange commission i wish to thank mary denny mcsweeny and steve hornstein for their valuable research assistance and the referee and editor for their many suggestions and insights the opinions expressed in this paper do not necessarily reflect those of the u s securities and exchange commission or those of the author s colleagues on its staff an increase in well informed speculative trade has two opposite effects on measured volatility it decreases volatility due to order flow imbalances caused by uninformed traders because informed traders provide liquidity in such events and it increases volatility due to new fundamental information since the information which is assumed to be generated at discrete time intervals is impounded into

do bond credit ratings lead to excess comovement abstract we investigate whether non fundamental comovement results from investors using credit ratings to group assets into different styles we find that bonds that join a new rating class start comoving more with the bonds in this class even when fundamental factors suggest otherwise we show that this comovement effect varies according to the nature of the bond considered and the modalities of the rating action downgrades have a larger impact than upgrades and rating reviews matter as much as actual movements finally rating changes between grades bbb and bb which lead bonds to be reclassified as either high yield or investment grade assets seem to be of particular importance

program trading and expiration day effects the arbitrage between index futures and the underlying cash index and the cash settlement feature of index futures contracts which requires arbitrageurs to unwind positions in the stock market are thought to be at the heart of the abnormal stock price movements during the triple witching hour the last hour of trading on days on which index futures index options and options on index futures expire simultaneously during 1984 and 1985 volume was substantially higher than normal in the last hour of trading on those quarterly fridays open interest in the expiring futures contracts on the expiration day amounted to about 40 per cent of the average month end open interest the incremental stock market volume however was approximately one third the volume that would be inmplied if the entire expiration day open interest were traded in the stock market analysis of stock market price changes in the last hour of expiration days and the first halfhour of the following day indicates that the volatility of price changes was significantly higher on expiration days with the stock market tending to fall stocks not in the sp index option expirations themselves did not lead to abnormal market movements when the magnitude of price effects was measured by the degree of reversal in prices on the morning after the expiration day the average magnitude of the price effect in the 10 most recent quarterly futures contract expirations examined was about 0 4 per cent of the closing index value at expiration the average expiration day price effect of 0 4 per cent is not large considering that a price impact of approximately 0 25 per cent of the value of the transaction can be expected on the basis of the bid ask spread once this market impact cost is drawn out the average expiration day price impact falls to about 0 15 per cent of the value of the transaction an amount representing the additional cost of liquidity furthermore price impacts in excess of those found on expiration days are frequently encountered in large block transactions where the cost of providing liquidity also increases on expiration days however transactions in many stocks occur simultaneously so the market as a whole is affected

research advances in environmentally and socially sustainable operations abstract consumers and governments are pressuring firms to strike a balance between profitability and sustainability however this balance can only be maintained in the long run if the firm can take a holistic approach to sustain the financial flow profit resource flow planet and development flow people for the entire ecosystem comprising poor producers in emerging developing markets global supply chain partners consumers in developed countries and the planet by considering the flows associated with different entities within the ecosystem we classify and summarize recent operations research management science or ms research developments also we identify several gaps for future research in this important area

industry window dressing we explore a new mechanism by which investors take correlated shortcuts and present evidence that managers using sales management take advantage of these shortcuts specifically we exploit a regulatory provision wherein a firm s primary industry is determined by the highest sales segment exploiting this regulation we provide evidence that investors classify operationally nearly identical firms as starkly different depending on their placement around this sales cutoff moreover managers appear to exploit this by manipulating sales to be just over the cutoff in favorable industries further evidence suggests that managers engage in activities to realize large tangible benefits from this opportunistic action

time aggregation and the estimation of the market model empirical evidence data for heavily and lightly traded firms are used to evaluate the effects of temporal aggregation on beta estimates t values and r 2 estimates in addition to our analysis of the standard market model dynamic and random coefficient models are estimated this study evaluates differences in the short term and long term dynamic relationships between the market and each type of firm it is found that temporal aggregation has important effects on both the specification of a market model and the stability of beta estimates

another day another collar an evaluation of the effects of nyse rule 80a on trading costs and intermarket arbitrage in 1990 the new york stock exchange amended its rule 80a to restrict stock index arbitrage on days of large price movements the authors find that rule 80a significantly curtails or collars index arbitrage activity in spite of this curtailment in index arbitrage volume they find that rule 80a appears to have had little overall impact on trading costs and intermarket linkage although pricing discrepancies between the markets do appear to be eliminated less quickly the authors results are consistent with the hypothesis that information is conveyed from one market to the other by means other than formal arbitrage copyright 1998 by university of chicago press

optimal acquisition and remanufacturing policies for multi product remanufacturing systems abstract this paper studies an acquisition and remanufacturing problem in a market driven multi product remanufacturing system where the remanufacturer acquires multiple used products cores of highly variable quality under independently uncertain demand and carbon emissions regulation in order to balance between the environmental and economic benefit the problem is formulated as a nonlinear programming model in presence of the quality variability of cores and carbon tax scheme subject to budget and risk constraints since the average cost of the remanufactured products is independent of the remanufacturing quantity the model is then decomposed into two separated sub problems namely the remanufacturing problem and the acquisition problem in the remanufacturing problem the optimal remanufacturing policies including the optimal remanufacturing cost thresholds and the optimal remanufacturing rate are derived in the acquisition problem the optimal policies of core portfolio acquisition quantities and remanufacturing quantities can be derived the acquisition problem viewed as an extended multi product newsvendor problem mpnp is a convex optimization problem furthermore a two tier bisection method with polynomial computational complexity can be developed to obtain the optimal policies based on the karush kuhn tucker kkt conditions finally numerical experiments are provided to show the application of the model and the effect of the quality variability

a general equilibrium model of portfolio insurance this article examines the effects of portfolio insurance on market and asset price dynamics in a general equilibrium continuous time model portfolio insurers are modeled as expected utility maximizing agents martingale methods are employed in solving the individual agents dynamic consumption portfolio problems comparisons are made between the optimal consumption processes optimally invested wealth and portfolio strategies of the portfolio insurers and normal agents at a general equilibrium level comparisons across economies reveal that the market volatility and risk premium are decreased and the asset and market price levels increased by the presence of portfolio insurance article published by oxford university press on behalf of the society for financial studies in its journal the review of financial studies

a transactions data analysis of nonsynchronous trading weekly returns of stock portfolios exhibit substantial autocorrelation analytical studies suggest that nonsynchronous trading is capable of explaining from 5 to 65 of the autocorrelation the varying importance of nonsynchronous trading in these studies arises primarily from differing assumptions regarding nontrading periods of stocks we simulate the effects of nonsynchronous trading by sampling stock returns from a return generating process using transactions data to obtain the precise time of each stock s last trade we find that simulated weekly portfolio returns exhibit autocorrelations that are roughly 25 that of their observed crsp weekly returns article published by oxford university press on behalf of the society for financial studies in its journal the review of financial studies

portfolio serial correlation and nonsynchronous trading common stock portfolios of large heavily traded firms exhibit daily first order serial correlation in excess of what would be expected given the individual security coefficients further this correlation rises as the number of securities in the portfolio increases the direct implication of this finding is that nonsynchronous trading is not the only cause of correlation in daily market indices related implications are also discussed

further international evidence on asset pricing the case of the spanish capital market abstract a multivariate framework is used in order to study the price formation of risky assets in the spanish capital market issues regarding the efficiency of the spanish value weighted stock market index the validity of equilibrium considerations the size effect and the nature of the return generating process during january are analyzed

the value of active investing can active institutional investors remove excess comovement of stock returns this study uses cremers and petajisto s 2009 method to separate active institutional investors from passive ones and shows that active investors can alleviate the anomalous comovement of stock returns focusing on 2 events linked to the excess comovement anomaly standard poor s 500 index additions and stock splits i find that if an event stock has more active institutional investors trading in the post event period the anomalous comovement effect disappears in contrast if an event stock experiences a massive exit of active investors this anomaly persists the exit of active institutional investors also results in a strong price synchronicity effect

order characteristics and stock price evolution an application to program trading abstract this paper is an econometric analysis of the information content of automated orders arriving at the nyse the model captures the joint behavior of automated orders and also the return on the stock index future and the futures spot basis the results indicate that orders contain information useful in predicting stock returns beyond the information contained in the reported trades furthermore program and index arbitrage orders contain information beyond that available from the futures return and basis suggesting that these orders are not merely passive conveyors of common factor information nonprogram program and index arbitrage orders have roughly similar price impacts

corrections for trading frictions in multivariate returns when observed stock returns are obtained from trades subject to friction it is known that an individual stock s beta and covariance are measured with error univariate models of additive error adjustment are available and are often applied simultaneously to more than one stock unfortunately these multivariate adjustments produce nonpositive definite covariance and correlation matrices unless the return sample sizes are very large to prevent this restrictions on the adjustment matrix are developed and a correction is proposed which dominates the uncorrected estimator the estimators are illustrated with asset opportunity set estimates where daily returns have trading frictions a number of univariate nonsynchronous trading adjustments are available for beta but no multivariate adjustment has been specifically designed for a general covariance matrix for example the univariate trading friction adjustment of cohen hawawini maier schwartz and whitcomb chmsw 1983 is a generalization of scholes and williams 1977 the chmsw procedure adjusts beta to account for price adjustment delays exceeding one period where a portion of the true return is reflected in lagged returns the procedure is extended and applied in shanken 1987 to estimation of the daily multivariate covariance matrix of stocks returns observed covariances significantly understated true covariances by a factor of two suggesting that a daily covariance adjustment is necessary because of a large number of studies which employ multivariate daily stock returns it is therefore important that the adjustment results in a good estimator of the covariance matrix while no evidence is available regarding other properties it is shown in chmsw that their univariate adjusted estimator has the desirable statistical properties of consistency and unbiasedness unfortunately when the adjusted covariance estimator is applied in finite samples the resulting adjusted covariance matrix may not be a covariance matrix and the implied adjusted correlation matrix independently may not be a correlation matrix because the adjustment does not restrict the covariance and correlation matrices to be positive definite 1 when these matrices are not positive definite functions of these matrices can produce very unreliable inference results this paper provides empirical examples of the violations of the positive definite

friction in the trading process and the estimation of systematic risk abstract this paper considers how estimates of the market model beta parameter can be biased by friction in the trading process information decision and transaction costs that a leads to a distinction between observed and true returns b causes observed returns to be generated asynchronously for a set of interdependent securities and c thereby introduces serial cross correlation into security returns several propositions are derived from which consistent estimators of beta are obtained and the effect of differencing interval length on beta estimates is specified the formulation is contrasted with the related analyses of scholes williams 1977 and dimson 1979

a cautious price adjustment mechanism chaotic behavior abstract it is well known that adjustment processes like tatonnement can show erratic dynamic behavior the prices can make big jumps and vary over a wide range a discrete tatonnement process in a simple two goods economy is studied with only one price adjusted it is shown that the interval in which the price varies can be restricted to a neighborhood of an equilibrium price with big jumps excluded if the relative price adjustment is restricted by a maximal rate of increase or decrease of the price within the interval any type of erratic dynamics remains possible

arbitrage nontrading and stale prices october 1987 this article explains a puzzle created by the standard and poor s 500 cash and futures prices during the crash of october 1987 the cash index appears to be a moving average of the futures but nontrading in constituent stocks explains only the initial period of delayed openings however execution of stale limit buy orders given the high volume and nyse market mechanisms at the time resulted in extraordinary levels of stock prices that were not caused by nontrading the model is supported in aggregate s p data and transactions data for individual stocks copyright 1992 by university of chicago press

an econometric model of serial correlation and illiquidity in hedge fund returns the returns to hedge funds and other alternative investments are often highly serially correlated in sharp contrast to the returns of more traditional investment vehicles such as long only equity portfolios and mutual funds in this paper we explore several sources of such serial correlation and show that the most likely explanation is illiquidity exposure i e investments in securities that are not actively traded and for which market prices are not always readily available for portfolios of illiquid securities reported returns will tend to be smoother than true economic returns which will understate volatility and increase risk adjusted performance measures such as the sharpe ratio we propose an econometric model of illiquidity exposure and develop estimators for the smoothing prole as well as a smoothing adjusted sharpe ratio for a sample of 908 hedge funds drawn from the tass database we show that our estimated smoothing coecien ts vary considerably across hedge fund style categories and may be a useful proxy for quantifying illiquidity exposure

friction in the trading process and risk measurement abstract when stock returns are non synchronous ols estimates of market model parameters are biased we show that the unbiased estimators for beta which have recently been proposed are for practical purposes the same as the dimson 1979 estimator the choice of estimation method is therefore largely a matter of computational convenience

estimating betas on daily data for a small stock market abstract this paper examines the properties of different market risk beta measures computed on daily data for a thin security market i e the helsinki stock exchange in finland in accordance with the results by dimson and marsh 1983 the paper shows that differences in trading frequency between different stocks produce a serious bias towards what appears to be stability in estimated betas furthermore the paper shows that when betas are computed the exclusive use of stock prices based on actual trades will not solve the problem of a thin trading bias in measured stability of these beta estimates in fact other methods proposed to cope with the thin trading problem seem to be at least as efficient as use of trade to trade returns finally betas corrected for differences in trading frequency are still shown to be statistically related for firm size

program trading and market volatility a report on interday relationships ten months of daily observations on stock market volatility and program trading on the nyse reveal no relation between volatility and program trading intensity the days on which volatility was high were not systematically the days on which program trading intensity was high this is evident both from casual observation of the data and from analyses of the correlation and regression results there does appear to be however a positive relation between the intensity of dot volume relative to nyse volume and volatility there also appears to be a positive relation between the intensity of non program dot volume relative to nyse volume and volatility this suggests that very volatile days are also days when the retail customer generated dot order flow is large relative to institutional block trades which are not dot delivered

program trading and intraday volatility program trading and intraday changes in the s p 500 index are correlated future prices and to a lesser extent cash prices lead program trades index arbitrage trades are followed by an immediate change in the cash index which ultimately reverses slightly no reversal follows nonarbitrage trades the cumulative index changes associated with buy and sell trades and with arbitrage and nonarbitrage trades all are similar price decompositions suggest that the results are not due to microstructure effects program trades in this 1989 1990 sample do not seem to have created major short term liquidity problems the results are stable within the sample many practitioners regulators and public commentators have expressed concerns about potential destabilizing effects of program trading they argue that program trades especially index arbitrage programs increase intraday volatility and decrease

estimating and adjusting for the intervalling effect bias in beta the concept of beta as the measure of systematic risk has been widely accepted in the academic and financial community increasingly betas are being used to estimate the cost of capital for corporations despite this however biases are generally present in ordinary least squares ols estimates of beta in particular empirical estimates of beta are affected by friction in the trading process which delays the adjustment of a security s price to informational change and hence leads to an intervalling effect bias in this paper we present and empirically test two procedures for correcting this bias the first is to estimate the asymptotic value that ols beta approaches as the differencing interval is lengthened without bound the second procedure is to infer the value of beta by adjusting ols beta for cross sectional differences in the intervalling effect as a function of the depth of the market for a security as measured by its value of shares outstanding our results suggest that a substantial correction is needed to get true beta estimates from short differencing interval data

predicting risk some new generalizations existing adjustment techniques for forecasting systematic risk of individual firms have been based on relatively uniformative prior knowledge about the cross sectional distribution of risk estimates this study introduces prior information in the form of size and industry based cross sectional distributions of risk estimates such information is incorporated into forecasts using familiar and generalized adjustment techniques the latter being based on recently developed multiple shrinkage methods improved forecast performance results

the coexistence of stable equilibria under least squares learning abstract in this paper we consider firms that learn about market conditions by estimating the demand function using past market data we show that learning may lead to suboptimal outcomes even when the estimated demand function perfectly fits the observations used in the regression and firms thus perceive to have learned the demand function correctly we consider the salop model with three firms and two types of consumers that differ in their sensitivity to product differences firms do not know the demand structure and they apply least squares learning to learn the demand function in each period firms estimate a linear perceived demand function and they play the perceived best response to the previous period price of the other firms this learning rule can lead to three different outcomes a self sustaining equilibrium the nash equilibrium or an asymmetric learning equilibrium in this last equilibrium one firm underestimates the demand for low prices and it attracts consumers with high sensitivity only this type of equilibrium has not been found in the literature on least squares learning before both the nash equilibrium and the asymmetric learning equilibrium are locally stable therefore the model has coexisting stable equilibria

the stability of uk risk measures and the problem of thin trading this paper examines the problems of estimating risk measures and their stability in thin markets it shows analytically that conventional approaches used in previous studies can lead to serious overestimates of the stability of risk measures when shares are subject to thin trading it then demonstrates using uk data that this is in fact a serious practical problem and that the resultant biases are of precisely the form predicted finally the paper presents reliable evidence on the stability of uk risk measures by using an estimation method designed to avoid thin trading bias using this approach risk measures are found to be as stable in the uk as they are in the usa this paper examines the stability of risk measures in the uk the focus is on providing reliable evidence in a market where many of the shares suffer from thin trading this is important because thin trading can seriously distort stability measures leading to incorrect conclusions indeed this is a problem which has almost certainly afflicted many previous studies of stability the paper makes four main contributions first it shows analytically that thin trading can lead to serious overstatements about stability second it uses uk data to illustrate that this is in fact a serious practical problem and that the biases are of precisely the form predicted this is important for anyone who wishes to interpret previous claims on beta stability in thin markets third the paper presents reliable evidence on the stability of uk betas by using an estimation method designed to avoid thin trading bias besides avoiding bias our

an analysis of the implications for stock and futures price volatility of program trading and dynamic hedging strategies the notion that a real security is redundant when it can be synthesized by a dynamic trading strategy ignores the informati onal role of real securities markets portfolio insurance uses a dyna mic strategy to synthesize a european put the absence of trading in an appropriate real put option prevents the transmittal of informatio n to market participants about the future price volatility associated with current dynamic hedging strategies less information is transmi tted to potential liquidity providers it will therefore be more di fficult for the market to absorb the trades implied by the dynamic he dging strategies and the stocks future price volatility will rise copyright 1988 by the university of chicago

a robust rational route to randomness in a simple asset pricing model abstract we investigate asset pricing dynamics in an adaptive evolutionary asset pricing model with fundamentalists trend followers and a market maker agents can choose between a fundamentalist strategy at positive information cost or choose a trend following strategy for free price adjustment is proportional to the excess demand in the asset market agents asynchronously update their strategy according to realized net profits in the recent past as agents become more sensitive to differences in strategy performance the fundamental steady state becomes unstable and multiple steady states may arise as the traders sensitivity to differences in fitness increases a bifurcation route to chaos sets in due to homoclinic bifurcations of stable and unstable manifolds of the fundamental steady state

the intervalling effect bias in beta a note abstract based on a comprehensive sample of domestic securities traded on the brussels stock exchange this paper points out the intervalling effect in the estimated betas and examines the speed of convergence of these the results reveal that the estimated betas seem to converge to their asymptotic values and that their value depends on what day the differencing interval starts it also appears that the magnitude of the intervalling effect is inversely related to the market value of the firms

the relation between the return interval and betas abstract the size effect is sensitive to the length of the return interval used in estimating betas beta changes with the return interval because an asset s covariance with the market and the market s variance do not change proportionately as the return interval is changed we document beta sensitivity to the return interval evidence from cross sectional regressions of returns on monthly and annual betas is inconsistent with beta changes stemming only from the higher standard errors of the longer interval betas we provide evidence that the size effect becomes statistically insignificant when risk is measured by betas estimated using annual returns

on the disequilibrium dynamics of sequential monetary economies the purpose of this paper is to study the dynamic behavior of a sequential monetary exchange economy transactions take place sequentially against non equilibrium prices there is quantity rationing and credit or cash are the only means of exchange agents have optimistic or pessimistic expectations about quantity constraints that represent their beliefs about future trading opportunities in the credit model the agents incur debts along the transition path towards equilibrium while in the cash in advance model convergence takes place without the occurrence of any debts or claims the credit mechanism is shown to act as a soft correction mechanism on credit fluctuations while the cash in advance constraint acts as a hard negative feedback effect driving the prices back towards a neighborhood of a monetary cash in advance equilibrium

information and index arbitrage a random cash futures basis is derived in a dynamic multimarket learning game with sequential information shocks and strategic arbitrageurs who trade to exploit gaps in the basis statistical properties of the authors theoretical basis are derived both with and without index arbitrage the authors find that basis volatility a measure of intermarket mispricing may initially increase even as individual prices become more precise and that arbitrage reduces basis volatility the model is also used to analyze regulatory issues such as the possible impact of circuit breakers on the quality of the trading process copyright 1994 by university of chicago press

price competition and co operation in a duopoly closed loop supply chain abstract this paper studies co operation and competition issues in a closed loop supply chain the supply chain comprises of two manufacturers who compete for selling their new product as well as for collection of the used products for remanufacturing through a common retailer to analyze the situation mathematical models are developed here for three different cases i non co operative system ii channel co operative system and iii global co operative system for each of the cases we have characterized optimal wholesale price and fraction of collection of used product to draw more managerial insights we also examine the sensitivity of various parameters such as market size acquisition cost and transfer price on total channel profit a numerical study is carried out to illustrate the model and the results reveal that global co operative system is the best among all the three cases considered here weighted shapely value mechanism is used for sharing of surplus generated in the system due to channel co operation

the reaction of bank stock prices to the international debt crisis abstract in this paper we develop a cross sectional regression approach to estimate the impact of foreign loan exposure on the pricing of u s bank stocks a new approach is required because news about foreign loan problems may arrive incremently over time rather than reaching the market on a few specific dates the way earnings and dividend announcements do consistent with this interpretation we find that foreign loan exposure had a significant impact on the pricing of u s bank stocks during the years 1982 and 1983 but that the stock prices adjusted continually over the two year period rather than jumping on a few particular days

statistical dynamics and walras law abstract much interest has been shown on identifying the chaotic behavior generated from t tonnement process recently the aim of this article is to direct the research in exploring its statistical dynamical properties two typical types of ergodic t tonnement processes restricted t tonnement and unrestricted t tonnement have been studied their long run statistical characteristics such as time average of price excess demand and inflation rate are discussed in theory and by computer simulations

intraday relationships among index arbitrage spot and futures price volatility and spot market volume a transactions data test abstract this paper examines intraday temporal relationships among arbitrage spreads cash and futures price volatility and cash trading volume using transactions data for the major market index futures contracts and the component stocks of the index results indicate that changes in the spread have a significant impact on cash and futures price volatility as well as on cash trading volume the impact of the spread however is attenuated by the short sale restriction in the cash market contrary to popular beliefs a more volatile market leads to subsequent decreases in the spread probably because of increases in the supply of arbitrage services or faster price adjustments

combined pricing and inventory control under uncertainty this paper addresses the simultaneous determination of pricing and inventory replenishment strategies in the face of demand uncertainty more specifically we analyze the following single item periodic review model demands in consecutive periods are independent but their distributions depend on the item s price in accordance with general stochastic demand functions the price charged in any given period can be specified dynamically as a function of the state of the system a replenishment order may be placed at the beginning of some or all of the periods stockouts are fully backlogged we address both finite and infinite horizon models with the objective of maximizing total expected discounted profit or its time average value assuming that prices can either be adjusted arbitrarily upward or downward or that they can only be decreased we characterize the structure of an optimal combined pricing and inventory strategy for all of the above types of models we also develop an efficient value iteration method to compute these optimal strategies finally we report on an extensive numerical study that characterizes various qualitative properties of the optimal strategies and corresponding optimal profit values

investing in the presence of massive flows the case of msci country reclassifications almost 10 trillion is benchmarked to msci s developed emerging frontier and standalone market indexes reclassifications from one index to another require thousands of investors to decide how to react we study a comprehensive sample of past reclassifications to inform this decision on average reclassified markets prices substantially overshoot between the announcement date and the effective date prices fall when a market moves from an index with more benchmarked ownership to one with less such as from emerging to frontier and vice versa but largely revert within a year we identify alpha maximizing responses to reclassifications for both benchmarked and more flexible investors

program trading and individual stock returns ingredients of the triple witching brew the price and trading volume behaviors of individual stocks in the standard and poor s 500 stock index s p 500 are analyzed on stock index futures expiration days a time when the market is known to be subject to heavy program trading the price behavior of stocks that are subject to program trading is shown to be very similar to stocks that are not stocks that decline in price in the last half hour friday tend to increase in price at the opening on monday and vice versa the monday reversal as a fraction of the friday price change is only slightly higher for the s p 500 stocks than for non s p 500 stocks indicating that the price reversals reflect for the most part the bid ask spreads of the individual stocks trading volume in the last half hour of expiration days is shown to be substantially higher than normal copyright 1990 by the university of chicago

stability and complex dynamics in a discrete tâtonnement model abstract in this paper we study the dynamics of discrete price adjustment processes we show that gross substitutability leads to a kind of stability of the process it guarantees that all prices converge to some bounded region that contains the unique equilibrium price the dynamics inside this region is by no means trivial we demonstrate that as the speed of adjustment increases the process undergoes several bifurcations and the dynamics may become quite complex our approach differs from other literature on t tonnement processes in that our systems are not necessarily one dimensional

a discrete and symmetric price adjustment process on the simplex abstract we study the t tonnement process in an exchange economy with three commodities and three agents we argue that for the multiplicative t tonnement process the simplex is a natural normalization rule we analyse the influence of symmetry in preferences and endowments on the dynamics of the t tonnement process depending on this symmetry there are different bifurcation routes to chaos in particular coexisting attractors may emerge when the symmetric equilibrium price vector becomes unstable this coexistence of attractors is robust in the sense that it also exists for close by asymmetric t tonnement processes

optimal control of a production inventory system with productreturns abstract we consider a production inventory system that consists of n stages each stage has a finite production capacity modelled by an exponential server the downstream stage faces a poisson demand each stage receives returns of products according to independent poisson processes that can be used to serve demand the problem is to control production to minimize discounted or average holding and backordering costs for the single stage problem n 1 we fully characterize the optimal policy we show that the optimal policy is base stock and we derive an explicit formula for the optimal base stock level for the general n stage problem we show that the optimal policy is characterized by state dependent base stock levels in a numerical study we investigate three heuristic policies the base stock policy the kanban policy and the fixed buffer policy the fixed buffer policy obtains poor results while the relative performances of base stock and kanban policies depend on bottlenecks we also show that returns have a non monotonic effect on average costs and strongly affect the performances of heuristics finally we observe that having returns at the upstream stage is preferable in some situations

on the impact of infrequent trading on the apt systematic risk components evidence from a thin security market abstract the purpose of this note is to analyze the effects of infrequent trading on the apt systematic risk components using finnish data infrequent trading is reported to influence especially the first systematic risk component produced by factor analysis on stock returns

index futures arbitrage and the behavior of stock index futures prices this article examines intraday transaction datafor s p 500 stock indexfutures prices and the intraday quotes for the underlying index the data indicate that thefutures price changes are uncorrelated and that the variability of these price changes exceeds the variability ofprice changes in the s p 500 index this excess variability of the futures over the index remains even after controlling for the nonsynchronous prices in the index quotes which induces autocorrelation in the index changes we advance and examine empirically two hypotheses regarding the difference between the futures price and its theoretical value that this mispricing increases on average with maturity and that it is path dependent evidence supporting these hypotheses is presented

statistical dynamics and economics abstract it is shown in this paper how complex economic dynamics can be characterized using the statistical or distributional theory of dynamical systems the basic concepts of the latter are summarized then applications to supply and demand adjustments in competitive markets aggregate business fluctuations and economic growth in the very long run are briefly reviewed

excess comovement in international equity markets evidence from cross border mergers we examine the changes in betas from international mergers we find that the beta with respect to the acquirer s home market rises and that with respect to the target s home market falls the effect is large and robust with respect to controls for changes in the operations of the companies involved such an effect can occur only if international equity markets are not integrated we also find that the effect has not reduced over time that cross listings do not generally have a significant effect on international betas and that the u s and u k are more integrated internationally than other markets

stock return comovement around the dow jones islamic market world index revisions we examine patterns of comovement in stock returns around the dow jones islamic market world index djimwi quarterly revision events our analysis is based on a sample of 8250 companies from eighteen countries during the period may 1999 june 2012 we find that a stock s comovement with the djimwi increases when it joins and decreases when it leaves the index we also find that the comovement of newly added deleted stocks with the existing djimwi constituents increases declines during periods of high trading activity and during the month of ramadan further tests reveal that changes in the fundamentals have no impact on the comovements of added and deleted stocks overall our results indicate that stock returns respond to the emotional state of investors around information free events

price reaction of ethically screened stocks a study of the dow jones islamic market world index this paper investigates the short term effects on the price of the ethically screened stocks of the dow jones islamic market world index djimwi quarterly revisions using a sample of 8 250 stocks from may 1999 through june 2012 we find a significant price reaction of the ethically screened stocks following additions and deletions the results show that additions deletions from emerging stock markets tend to experience a greater and significantly positive negative price response than additions deletions from the developed markets further tests reveal that the price reactions following djimwi revisions are likely to be driven by shifts in investor sentiment rather than changes in firm fundamentals

coordinating inventory control and pricing strategies with random demand and fixed ordering cost the finite horizon case we analyze a finite horizon single product periodic review model in which pricing and production inventory decisions are made simultaneously demands in different periods are random variables that are independent of each other and their distributions depend on the product price pricing and ordering decisions are made at the beginning of each period and all shortages are backlogged ordering cost includes both a fixed cost and a variable cost proportional to the amount ordered the objective is to find an inventory policy and a pricing strategy maximizing expected profit over the finite horizon we show that when the demand model is additive the profit to go functions arek concave and hence an s s p policy is optimal in such a policy the period inventory is managed based on the classical s s policy and price is determined based on the inventory position at the beginning of each period for more general demand functions i e multiplicative plus additive functions we demonstrate that the profit to go function is not necessarilyk concave and an s s p policy is not necessarily optimal we introduce a new concept the symmetrick concave functions and apply it to provide a characterization of the optimal policy

the analytic relationship between intervaling and nontrading effects in continuous time empirical studies in finance generally use data defined over the shortest re turn period available originally data bases such as crsp tended to have data collected over monthly periods and most analyses tended to use monthly data rather than data compounded over periods greater than a month with the implicit argument that the more data the better since the development of data bases with data collected over shorter differencing intervals there has been a growing tendency in finance to use returns data defined over increasingly shorter differ encing intervals 1 this development is desirable but is not without problems the problem with using data defined over shorter differencing intervals is that although greater estimating efficiency will be achieved 2 nontrading effects could be introduced into the analysis these will lead to biased beta estimators and biases in tests of capital market efficiency the purpose of this paper is to investi gate analytically the interrelation of the intervaling and nontrading effects both in estimating beta factors and in testing capital market efficiency levhari and levy 9 demonstrated theoretically and empirically that beta will be dependent upon the return interval length when returns are measured in discrete time in continuous time this dependency will be removed due to the additivity of the return variables in this domain however several studies carried out on u s 15 french 1 and u k data 7 16 have demonstrated that beta factors estimated in continuous time increase with the differencing interval seemingly contradicting this invariance property this paper will demonstrate analytically how this phenomenon can arise in the presence of nontrading ef fects and how this intervaling effect relates to the estimators developed by scholes and williams 14 and dimson 7 for handling the nontrading problems manchester university england the author is grateful to two anonymous referees for their

on the perils of financial intermediaries setting security prices the mutual fund wild card option economic distortions can arise when financial claims trade at prices set by an intermediary rather than direct negotiation between principals we demonstrate the problem in a specific context the exchange of open end mutual fund shares mutual funds typically set fund share price nav using an algorithm that fails to account for nonsynchronous trading in the fund s underlying securities this results in predictable changes in nav which lead to exploitable trading opportunities a modification to the pricing algorithm that corrects for nonsynchronous trading eliminates much of the predictability however there are many other potential sources of distortion when intermediaries set prices copyright the american finance association 2001

direct tests of index arbitrage models previous tests of stock index arbitrage models have rejected the no arbitrage constraint imposed by these models this paper provides a detailed analysis of actual s p 500 arbitrage trades and directly relates these trades to the predictions of index arbitrage models an analysis of arbitrage trades suggests that i short sale rules are unlikely to affect the cashfutures mispricing ii the opportunity cost of arbitrage funds exceeds the treasury bill rate and iii the average price discrepancy captured by arbitrage trades is small tests of the models provide some support for a version ofthe arbitrage model that incorporates an early liquidation option the ability of these models to explain arbitrage trades however is surprisingly low

data frequency and the number of factors in stock returns abstract determining the number of factors that explain stock returns plays an important role in empirical tests of the arbitrage pricing theory this paper examines the sensitivity of the number of factors to different data frequencies using daily weekly and monthly returns the empirical results are consistent with the null hypothesis that the number of factors is the same for different data frequencies once daily returns are adjusted for nonsynchronous trading the evidence also identifies only one or two factors

efficiency in index options markets and trading in stock baskets abstract researchers have reported mispricing in index options markets this study further examines the efficiency of the s p 500 index options market by testing theoretical pricing relationships implied by no arbitrage conditions the effect of a traded stock basket standard and poor s depository receipts spdrs on the link between index and options markets is also examined we find that pricing efficiency within option markets improves but there is little evidence to support the hypothesis that a stock basket enhances arbitrage across markets when transactions costs and short sales constraints are included very few violations of inter market pricing relationships such as put call parity are reported however violations of within market pricing relationships such as the box spread remain frequent extensive analysis suggests that the results are robust

technical note optimal product acquisition pricing and inventory management for systems with remanufacturing acquisition of used products cores is central to the success of remanufacturing programs for companies at the same time dynamic pricing strategies have been adopted in various industries to better balance supply and customer demand in this paper we study the integration of these two aspects of operations together with inventory management for a production remanufacturing firm we develop a periodic review single product inventory system with price dependent customer demand the product return in each period is random but can be actively controlled by the firm s acquisition effort the firm aims to maximize its total discounted profit over a finite planning horizon by implementing optimal production remanufacturing product acquisition and pricing strategies we first show that with an exogenous selling price the optimal production remanufacturing disposal policy is simple and characterized by three state independent parameters the optimal acquisition effort is decreasing in the aggregate inventory level of serviceable product and cores nevertheless when pricing is an endogenous decision we find that the optimal policy becomes much more complicated and its control parameters are state dependent the optimal selling price is decreasing whereas the optimal acquisition effort is increasing in the serviceable product inventory level and both decisions decrease with the aggregate inventory level

the october 1987 s p 500 stock futures basis five minute changes in the s p 500 index and futures contract are examined over a ten day period surrounding the october 1987 stock market crash since nonsynchronous trading problems are severe in these data new index estimators are derived and used the estimators use the complete transaction history of all 500 stocks nonsynchronous trading explains part of the large absolute futures cash basis observed during the crash the remainder may be due to disintegration of the two markets even after adjustment for nonsynchronous trading the index displays more autocorrelation than does the futures and the futures leads the index

the long run benefits of chaos to oligopolistic firms abstract conventional economic beliefs that equilibrium is better than disequilibrium and stability is better than fluctuation are challenged with a heterogeneous oligopolistic model that consists of a naive firm and a group of sophisticated firms the naive firm is assumed to adopt a simple cobweb strategy while the sophisticate firms who command all market information form a collusion and best respond the naive firm s current action when the market equilibrium is unstable the naive firm is able to turn an explosively diverging market into a bounded but chaotic one by adopting simultaneously a cautious adjustment strategy that is limiting the growth rate of output there exists an upper bound such that as long as the growth rate does not exceed this bound the average profits made by all oligopolistic firms are higher than their respective equilibrium profits moreover the average economic surplus can also be higher than the equilibrium surplus in this sense chaos is beneficial not only to all oligopolistic firms but also to the economy as a whole

beta changes around stock splits revisited recent papers by lamoureux and poon 1987 and brennan and copeland 1988 document a significant permanent increase in average beta subsequent to stock split ex dates this paper demonstrates that the shift in estimated beta following ex dates decays as the measurement interval is lengthened there is no statistically significant difference between pre and post split betas using the scholes williams 1977 estimator and weekly return data or using monthly returns we conclude that lamoureux and poon s and brennan and copeland s results can be attributed to a bias created by using too short a return measurement interval to estimate beta

the impact of the return interval on common factors in stock returns evidence from a thin security market abstract the purpose of this paper is to analyze the effect of the return interval on common factors estimated in finnish stock returns firstly common factors are identified by factor analysis using daily weekly and monthly return intervals the similarity of these factors is then studied applying transformation analysis it is discovered that the factors produced by alternative return intervals significantly differ from each other an exception is the first factor representing the market index of securities

price formation on stock exchanges the evolution of trading within the day prior analyses of prices of the nyse and other exchanges find that transitory price volatility is greater at the open of trading than at the close we extend this line of research by using 40 years of hourly dow jones 65 composite price index data to estimate transitory volatility throughout the trading day our results indicate that transitory volatility steadily declines during the trading day we find a similar intraday decline in transitory volatility for a 2 1 2 year sample of the individual firms in the dow jones 30 industrials index the results are consistent with the hypothesis that trading aids price formation and do not support the argument that particular trading mechanisms are the source of greater volatility at the open of trading article published by oxford university press on behalf of the society for financial studies in its journal the review of financial studies

a closing call s impact on market quality at euronext paris abstract the paris bourse currently euronext paris refined its trading system to include electronic call auctions at market closings in 1996 for its less liquid continuous b stocks and in 1998 for its more actively traded continuous a stocks this paper analyzes the effects of the innovation on market quality our empirical analysis of price behavior for two samples of firms 50 b stocks and 50 a stocks for two different calendar dates 1996 and 1998 indicates that introduction of the closing calls has lowered execution costs for individual participants and sharpened price discovery for the broad market we further observe that market quality is improved at market openings albeit to a lesser extent we suggest that a positive spillover effect explains the closing call s more pervasive impact

impact of bovine spongiform encephalopathy on agribusiness in the united kingdom results of an event study of equity prices this article assesses the impact on agribusinesses of the united kingdom government s announcement of a possible link between bovine spongiform encephalopathy and human health three approaches are employed to derive benchmark models against which abnormal returns are estimated a simple market model scholes williams approach and an autoregressive distributed lag model abnormal returns are estimated for single firms and for subsectors over an eight day event window the autoregressive distributed lag model performs best and indicates significant negative abnormal returns in the beef pet food animal feed and dairy sectors and positive abnormal returns in the other meats sector

multiple equilibria and chaos in a discrete tâtonnement process the purpose of this note is to demonstrate a sufficient condition for a discrete t tonnement process to lead to chaos in a general equilibrium model with multiple commodities the result indicates that as the speed of price adjustment increases the discrete t tonnement process is complex in a general equilibrium economy in which there are multiple equilibria

volume and turn of the year behavior abstract this paper studies the trading characteristics of listed companies by size and year end behavior there were no transactions on nearly 25 of the days for the smallest decile even at the turn of year which is an active trading period for small companies as a result of low levels of trading and the regulations governing exchange specialists transaction prices and quotations of small listed companies may require several days to fully reflect equilibrium price changes the data confirm the existence of a year end seasonal pattern in rates of return for small companies and suggest that there may be a seasonal pattern for large companies as well

the puzzle in post listing common stock returns prior studies indicate that common stocks tend to earn negative returns immediately following listing on the nyse the authors document the phenomenon in detail and investigate a number of possible explanations no full explanation is discovered although several are ruled out a number of studies have examined common stock returns around the time at which the stocks became listed on a major stock exchange these studies cover a variety of time periods and employ a variety of empirical methodologies but they reveal two common patterns in stock returns first stocks appear to rise in price immediately prior to listing second stock prices appear to decline immediately thereafter for example ule 26 examines a sample of twenty nine overthe counter otc stocks that listed on the new york stock exchange nyse or the curb exchange over the period 1934 through 1937 he compares monthly stock price changes with changes in an appropriate industry index over a sixmonth period prior to and following listing ule reports that the prices of the stocks in his sample increased relative to their respective industry indexes prior

conducting event studies with thinly traded stocks abstract procedures for measuring abnormal performance around events when securities do not trade daily are examined a rank test patterned after the statistic proposed by corrado corrado c j 1989 a nonparametne test for abnormal security price performance in event studies journal of financial economics 23 385 395 is derived the empirical frequency distributions of the rank test statistic and a conventional test statistic are assessed under different rules for handling missing stock returns the results suggest that the traditional procedures are reasonably well specified for thickly and moderately traded stocks but misspecified for thinly traded stocks the rank test however performs well for all trading frequencies and trade to trade returns are the best way to handle missing returns