technical change land quality and income distribution a general equilibrium analysis this paper investigates the distributional effects of technical progress in agriculture a small computable general equilibrium model is developed in which agricultural production occurs in two environments with fixed land resources of different quality the analytical structure permits not only the rate but also the factor biases of technical change to differ between environments distributional results are generated for several classes of households distinguished both by their ownership of factors and by their consumption patterns the results demonstrate that technical change produces distributional outcomes which are highly sensitive to its factor biases and to prior differences in land quality

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

day of the week effects and asset returns the number of empirical studies using daily stock returns is rapidly increasing researchers generally assume that the distribution of stock returns is identical for all days of the week a convenient statistical assumption but not a necessary condition of market equilibrium nevertheless there are reasons to suspect that the distribution of returns may vary according to the day of the week the most obvious is the impact of weekends on monday s return since monday s return is calculated over three instead of one calender day the mean and variance may well be higher on monday compared with any other daily return perhaps three times as large previous research has examined the daily distribution of stock returns for a monday effect while fama 1965 does not compare daily mean returns he does report that monday s variance is about 20o greater than other daily returns with a traditional distributional assumption regarding the returns on a financial asset specifies that the expected returns are identical for all days of the week contrary to this plausible assumption this paper discovers that the expected returns on common stocks and treasury bills are not constant across days of the week the most notable evidence is for monday s returns where the mean is unusually low or even negative several explanations of the results are investigated but none proves satisfactory aside from documenting significant day of the week effects the implications of the results for tests of market efficiency are examined while market adjusted returns continue to exhibit day of the week effects these effects are no longer concentrated on monday during the last year we have had many conversations with our colleagues throughout the professions we are particularly thankful to the participants at sessions of the western and american finance associations where preliminary versions of this paper were presented special thanks are due to gene fama gailen hite jon ingersoll robert jarrow merton miller clifford smith and rex thompson the expert research assistance of frank rabinovitch and youngsup yun is gratefully acknowledged 1 the list of papers using daily stock returns is too long to name recent examples include charest 1978 dodd 1980 banz 1981 and reinganum 1981

poverty productivity and production environment a review of the evidence abstract this paper reviews the state of knowledge about the key issues needing to be understood to satisfactorily resolve a long standing debate within the consultative group for international agricultural research cgiar system the debate revolves around the effects on various populations particularly the poor of different allocations of research effort between marginal and favoured production environments this paper specifically focuses on what is known about the geographical distribution of the rural poor across agro ecological zones and over time variations in the income generating activities including non agricultural activities engaged in by the poor are examined and the ways in which specific technology packages affect the economic well being of different types of households both directly and indirectly

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

pricing options on scenario trees abstract we examine valuation procedures that can be applied to incorporate options in scenario based portfolio optimization models stochastic programming models use discrete scenarios to represent the stochastic evolution of asset prices at issue is the adoption of suitable procedures to price options on the basis of the postulated discrete distributions of asset prices so as to ensure internally consistent portfolio optimization models we adapt and implement two methods to price european options in accordance with discrete distributions represented by scenario trees and assess their performance with numerical tests we consider features of option prices that are observed in practice we find that asymmetries and or leptokurtic features in the distribution of the underlying materially affect option prices we quantify the impact of higher moments skewness and excess kurtosis on option prices we demonstrate through empirical tests using market prices of the s p500 stock index and options on the index that the proposed procedures consistently approximate the observed prices of options under different market regimes especially for deep out of the money options

differential technology adoption and income distribution in pakistan implications for research resource allocation a multi market model of technological change in food production is used to simulate the long run income distributional implications of differential diffusion of currently available wheat technologies in pakistan the results indicate that a research agenda emphasizing technologies suited to pakistan s favored production environments would enhance overall production without compromising inter group equity it is found that when commodity prices are market determined net consuming households are the major beneficiaries of technological change however in the more common situation of government intervention in markets for staple foods net producing households are the principal beneficiaries of technological change

a dynamic stochastic programming model for international portfolio management we develop a multi stage stochastic programming model for international portfolio management in a dynamic setting we model uncertainty in asset prices and exchange rates in terms of scenario trees that reflect the empirical distributions implied by market data the model takes a holistic view of the problem it considers portfolio rebalancing decisions over multiple periods in accordance with the contingencies of the scenario tree the solution jointly determines capital allocations to international markets the selection of assets within each market and appropriate currency hedging levels we investigate the performance of alternative hedging strategies through extensive numerical tests with real market data we show that appropriate selection of currency forward contracts materially reduces risk in international portfolios we further find that multi stage models consistently outperform single stage models our results demonstrate that the stochastic programming framework provides a flexible and effective decision support tool for international portfolio management

rural infrastructure transactions costs and market participation in kenya abstract we develop a conceptual framework for quantifying fixed transactions costs facing semisubsistence households using household survey data from a sample of 324 kenyan maize farmers we jointly estimate household supply and demand schedules and transactions costs econometric results indicate that on average the ad valorem tax equivalent of fixed transactions costs for households in our sample is 15 additional analysis indicates that economic isolation is positively associated with the size of transactions costs to the best of our knowledge ours are the first empirical estimates of the magnitude of fixed transactions costs for agricultural households in developing countries

analyzing the impact of futures trading on spot price volatility evidence from the spot electricity market in france and germany abstract this paper examines the impact of the introduction of electricity futures on the spot price volatility of the french powernext and german eex electricity markets as well as the degree of their price correlation over the period 2002 2011 our working hypotheses were tested based on a bivariate vecm garch model the results indicate that the introduction of futures contracts in the french electricity market as well as the launch of the joint futures market in these countries in 2009 has decreased spot price volatility however this effect was not as explicit for the german market due to data specificities other interesting results are the german market dominates and leads the long run price relationship the impact of cooling needs on demand is greater than the impact of heating needs there is a substantial systematic pattern of electricity prices and their respective volatilities during weekdays and holidays overall results are supportive of policy making at the european commission regarding electricity market integration

on the effectiveness of scenario generation techniques in single period portfolio optimization in single period portfolio selection problems the expected value of both the risk measure and the portfolio return have to be estimated historical data realizations used as equally probable scenarios are frequently used to this aim several other parametric and non parametric methods can be applied when dealing with scenario generation techniques practitioners are mainly concerned on how reliable and effective such methods are when embedded into portfolio selection models in this paper we survey different techniques to generate scenarios for the rates of return we also compare the techniques by providing in sample and out of sample analysis of the portfolios obtained by using these techniques to generate the rates of return evidence on the computational burden required by the different techniques is also provided as reference model we use the worst conditional expectation model with transaction costs extensive computational results based on different historical data sets from london stock exchange market ftse are presented and some interesting financial conclusions are drawn

an empirical examination of information differences of opinion and trading activity abstract we investigate the relations between trading volumes and our proxies for information flows and divergences in opinions we view s p 500 index futures open interest as a useful proxy for divergences of traders opinions and find that volumes are higher on days when open interest increases than on days with declines volume in individual equities is more closely related to firm specific information flows while equity basket volume is more closely associated with market information this differential impact is greatest for small capitalization stocks where market wide news has no explanatory power

new markets and technological change for the traditional cereals in semiarid sub saharan africa the malian case during the last three decades in sub saharan africa development and research resources have concentrated on the higher rainfall and irrigated regions especially on export crops and the principal food crops grown there there has been much less concern and investment in semiarid regions without irrigation another negative factor has been the lack of public policy concern with the profitability of the basic food crops with good weather prices collapse with bad weather governments and ngos dispense food crops as food aid or at subsidized prices this article documents the importance of the demand side to facilitate diffusion of new technologies for the basic food commodities of semiarid regions the traditional cereals with farm programming models aggregated into a sector model the combination of technological change and demand shifts for sorghum are evaluated in one semiarid region where the traditional cereals are concentrated it focuses on combining policies to increase the prices farmers receive after introduction of technologies that use higher input levels it also compares benefits of a strategy that focuses on yield and demand increases for a traditional cereal of the semiarid region sorghum with two alternative strategies for the higher rainfall zone

newsvendor solutions via conditional value at risk minimization abstract in this paper we consider the minimization of the conditional value at risk cvar a most preferable risk measure in financial risk management in the context of the well known single period newsvendor problem which is originally formulated as the maximization of the expected profit or the minimization of the expected cost we show that downside risk measures including the cvar are tractable in the problem due to their convexity and consequently under mild assumptions on the probability distribution of products demand we provide analytical solutions or linear programming lp formulation of the minimization of the cvar measures defined with two different loss functions numerical examples are also exhibited clarifying the difference among the models analyzed in this paper and demonstrating the efficiency of the lp solutions

value at risk and inventory control the purposes of this paper are two fold on the one hand we shall provide a decision analysis justification for the value at risk var approach based on ex post disappointment decision making arguments we shall show that the var approach is justified by a disappointment criterion in other words the asymmetric valuation between ex ante expected returns above an appropriate target return and the expected returns below that same target level provide an explanation for the var criterion when it is used as a tool for var efficiency design second this paper provides applications to inventory management based on var risk exposure although the mathematical problems arising from an application of the var approach tuned to current practice in financial risk management are difficult to solve analytically solutions can be found by application of standard computational and simulation techniques a number of cases are solved and formulated to demonstrate the paper s applicability

order consolidation price efficiency and extreme liquidity shocks we show that the consolidation of orders is important for producing efficient prices especially during times of high liquidity demand the nyse s centralized opening call market performs better than nasdaq s decentralized opening process on typical trading days the nyse is much better than nasdaq on witching days when index arbitrage activity subjects s p 500 stocks to large predictable and mostly informationless order flow around quarterly futures contract expirations nasdaq opening price efficiency improves to nyse levels once nasdaq initiates a consolidated opening call in november 2004 but prices on the decentralized nasdaq remain less efficient at other times of day

modern varieties productivity and sustainability recent experience and emerging challenges abstract the contribution of modern varieties of cereal crops to increased productivity in the postgreen revolution period is reviewed and the future role of hybrids and biotechnology discussed particular emphasis is given to the ways in which modern varieties may contribute to input efficiency and sustainability finally economic and institutional issues in restructuring plant breeding programs for the most efficient use of resources in both the public and private sectors and at the national and international levels are analyzed

the dynamics of stock index and stock index futures returns in rational efficiently functioning markets the returns on stock index and stock index futures contracts should be perfectly contemporaneously correlated this study investigates the time series properties of 5 minute intraday returns of stock index and stock index futures contracts and finds that sp however the effect is not completely unidirectional with lagged stock index returns having a mild positive predictive impact on futures returns

estimating the benefits of plant breeding research methodological issues and practical challenges impact assessment studies consistently show that the benefits generated by plant breeding are large positive and widely distributed numerous case studies have concluded that investment in plant breeding research generates attractive rates of return compared to alternative investment opportunities that welfare gains resulting from the adoption of modern varieties mvs reach both favoured and marginal environments and that benefits are broadly shared by producers and consumers but just how reliable are the results of studies that estimate the benefits of plant breeding research this article reviews methods used to estimate the benefits of plant breeding research and discusses theoretical and empirical issues that often receive inadequate attention in applied impact assessment work our objective is not to question the validity of the theoretical frameworks commonly used to estimate the benefits of plant breeding research but rather to examine problems that can arise when the widely accepted theoretical frameworks are used for empirical analysis most of these problems can be grouped into three basic categories 1 problems associated with measuring adoption and diffusion of mvs 2 problems associated with estimating benefits attributable to adoption of mvs and 3 problems associated with assigning credit among the various plant breeding programmes that participated in developing the mvs

technical note a risk averse newsvendor model under the cvar criterion the classical risk neutral newsvendor problem is to decide the order quantity that maximizes the one period expected profit in this note we consider a risk averse newsvendor with stochastic price dependent demand we adopt conditional value at risk cvar a risk measure commonly used in finance as the decision criterion the aim of our study is to investigate the optimal pricing and ordering decisions in such a setting for both additive and multiplicative demand models we provide sufficient conditions for the uniqueness and existence of the optimal policy comparative statics show the monotonicity properties and other characteristics of the optimal pricing and ordering decisions we also compare our results with those of the newsvendor with a risk neutral attitude and a general utility function

peanut research and poverty reduction impacts of variety improvement to control peanut viruses in uganda a procedure is developed and applied for predicting ex ante impacts of agricultural research on aggregate poverty using as an example the poverty reducing impact of peanut research in uganda market level information on economic surplus changes is combined with a procedure for allocating income changes to individual households characteristics of farmers that affect their likelihood of technology adoption are used to create a technology adoption profile associated changes in poverty resulting from adoption are computed using poverty indices predicted income changes at the household level are aggregated to the market level and reconciled with calculations of economic surplus changes

the multi product price setting newsvendor with resource capacity constraints abstract in this paper we consider a newsvendor problem commonly encountered in retail stores that cater to budget sensitive shoppers the newsvendor sells multiple products and in addition to determining order quantities must also determine the selling price of each product sold the demand for each product is of a stochastic nature and depends on the demands of other products i e is cross elastic we transform the objective function into a form that is amenable to developing integer programming solutions and then develop a numeric optimization procedure rooted in the nelder mead search technique we obtain encouraging numerical results on some small scale and large scale problems to the best of our knowledge this is the first work that produces implementable solutions for a scenario that is particularly relevant to retailers catering to budget sensitive customers who are abundant in the current economy

a further investigation of the weekend effect in stock returns this study uses a longer time period and additional stocks to further investigate the weekend effect we find consistently negative monday returns 1 for the s p composite as early as 1928 2 for exchange traded stocks of firms of all sizes and 3 for actively traded over the counter otc stocks the otc results are based on bid prices and therefore appear to reject specialist related explanations for the 30 individual stocks of the dow jones industrial index the average correlation between friday and monday returns is positive and the highest of all pairs of successive days the latter finding is inconsistent with fairly general measurement error explanations some of the most puzzling empirical findings reported in recent years indicate that the distribution of common stock returns varies by day of the week most notably the average return for monday close friday to close monday is significantly negative cross 3 and french 6 find negative monday returns using the standard and poor s composite index and gibbons and hess 7 find negative monday returns for the 30 individual stocks of the dow jones industrial index 1 this negative monday return or weekend effect has yet to be explained this study undertakes a further investigation of the weekend effect in stock returns we examine additional time periods extending the total period covered to 55 years we examine additional stocks such as those of small low capitalization firms and those traded over the counter in all cases the data exhibit a weekend effect that is at least as strong as that reported in previous studies the study also readdresses potential explanations for the effect such as measurement error but concludes that none of these explanations is satisfactory the first section presents a history of the weekend effect from 1928 through 1982 based on the standard and poor s composite index we essentially double the length of the period beginning in 1953 examined by french 6 the results indicate consistently negative monday returns throughout the 55 year period during much of the 25 year period from 1928 through 1952 the new york stock exchange was open on saturdays so monday s return is then computed from saturday s close to monday s close 2 these returns for one day weekends are consistently negative and not significantly different from the two day weekend

cvar models with selective hedging for international asset allocation abstract we develop an integrated simulation and optimization framework for multicurrency asset allocation problems the simulation applies principal component analysis to generate scenarios depicting the discrete joint distributions of uncertain asset returns and exchange rates we then develop and implement models that optimize the conditional value at risk cvar metric the scenario based optimization models encompass alternative hedging strategies including selective hedging that incorporates currency hedging decisions within the portfolio selection problem thus the selective hedging model determines jointly the portfolio composition and the level of currency hedging for each market via forward exchanges we examine empirically the benefits of international diversification and the impact of hedging policies on risk return profiles of portfolios we assess the effectiveness of the scenario generation procedure and the stability of the model s results by means of out of sample simulations we also compare the performance of the cvar model against that of a model that employs the mean absolute deviation mad risk measure we investigate empirically the ex post performance of the models on international portfolios of stock and bond indices using historical market data selective hedging proves to be the superior hedging strategy that improves the risk return profile of portfolios regardless of the risk measurement metric although in static tests the mad and cvar models often select portfolios that trace practically indistinguishable ex ante risk return efficient frontiers in successive applications over several consecutive time periods the cvar model attains superior ex post results in terms of both higher returns and lower volatility

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

the impact of public information on the stock market we study the relation between the number of news announcements reported daily by dow jones company and aggregate measures of securities market activity including trading volume and market returns we find that the number of dow jones announcements and market activity are directly related and that the results are robust to the addition of factors previously found to influence financial markets such as day of the week dummy variables news importance as proxied by large new york times headlines and major macroeconomic announcements and non information sources of market activity as measured by dividend capture and triple witching trading however the observed relation between news and market activity is not particularly strong and the patterns in news announcements do not explain the day of the week seasonalities in market activity our analysis of the dow jones database confirms the difficulty of linking volume and volatility to observed measures of information

modeling the impact of agricultural growth and government policy on income distribution in india this article uses a limited general equilibrium model to investigate the growth and equity effects of a variety of economic and technical changes and selected agricultural policies in india it explores how changes in food prices rural wages and farm profits associated with the green revolution period affected income distribution between net buyers and sellers of food the model shows that income gains from the green revolution initially accrued to the wealthier rural groups but that after 1972 73 they were transferred to urban consumers and that by 1980 81 the per capita incomes of poor and wealthier rural groups alike were barely above their respective 1960 61 levels the model is also used in counterfactual analysis of the impact of changes in technological demographic investment taxation and income redistribution variables its findings indicate the importance of trade policies for the nature of the equity outcomes from agricultural growth and suggest that a reduction in population growth and an increase in nonagricultural employment and income are required to convert agricultural growth into reduced rural poverty

misspecification of capital asset pricing this study documents empirical anomalies which suggest that either the simple one period capital asset pricing model capm is misspecified or that capital markets are inefficient in particular portfolios based on firm size or earnings price e p ratios experience average returns systematically different from those predicted by the capm furthermore the abnormal returns persist for at least two years this persistence reduces the likelihood that these results are being generated by a market inefficiency rather the evidence seems to indicate that the equilibrium pricing model is misspecified however the data also reveals that an e p effect does not emerge after returns are controlled for the firm size effect the firm size effect largely subsumes the e p effect thus while the e p anomaly and value anomaly exist when each variable is considered separately the two anomalies seem to be related to the same set of missing factors and these factors appear to be more closely associated with firm size than e p ratios

stock and option markets the swiss evidence abstract the interactions between the markets for options and underlying shares are examined for switzerland three topics are investigated first the introduction of traded options in the spring of 1988 lead to a permanent and significant increase in the prices of the underlying shares and a reduction in the volatility of returns second price changes on the stock and options markets are positively related during trading on the exchanges the evidence suggests that the stock leads the options market by about ten minutes some feedback is also present third the stochastic characteristics of stock returns are not affected by the expiration of options

risk preferences of a newsvendor with service and loss constraints abstract using the newsvendor framework we present an approach to determine an order quantity which is relevant for the observed ordering behavior of an inventory manager whereas in literature just one constraint has been used we suggest two conflicting constraints the service constraint specified by a target value for the cycle service level is fulfilled by high order quantities the loss constraint is characterized by a target resulting in losses is met by low order quantities choosing as objective function a mean deviation rule where risk attitudes are measured by the conditional value at risk the optimal order quantity is determined depending on the risk parameters if the newsvendor is not able to specify the risk preferences we use the constraints to describe the risk attitudes of the decision maker in dependence of the profitability of the product and its demand distribution including those products where no admissible order quantity exists if there are admissible solutions we identify conditions such that the service constraint is dominating i e the prescribed service level is high and necessarily risk taking behavior is implied contrary if the loss constraint dominates i e the probability of loss is low the decision maker in any case is a risk averter but if both the service target and the loss target are not too challenging then for products with high profitability all risk preferences are possible

optimal ordering quantities for multi products with stochastic demand return cvar model abstract multi product ordering problem with stochastic demand is often optimized by the expected cost reduction or the expected profit improvement in most of previous works moreover risk preference of decision maker is often ignored evidently this approach is impracticable when the corresponding volatility is larger based on the outstanding characteristics of conditional value at risk cvar as a risk measure the paper proposes an optimal order model for multi product with cvar constraints also the model is finally formulated as a linear programming problem the model is simulated for the case of a newsvendor to analyze to what degree it succeeds the solution in fact is bound consistent fully with the decision maker s intuition on return risk decision making finally results of return cvar model and the classical model are compared and shows that return cvar model is more flexible than the classical model

the behavior of the volatility implicit in the prices of stock index options abstract we examine stock market volatility around the quarterly expirations of stock index futures contracts and nonquarterly expirations of stock index options using estimates of the volatility implicit in the option prices the option prices reflect increases in the volatility of the underlying stock indexes around both quarterly and nonquarterly expiration dates analysis of the residual returns on index options provides evidence consistent with an unexpected increase in market volatility around expiration dates

stock market structure and volatility the procedure for opening stocks on the nyse appears to affect price volatility an analytical framework for assessing the magnitude of the structurally induced volatility is presented the ratio of variance of open to open returns to closeto close returns is shown to be consistently greater than one for nyse common stocks during the period 1982 through 1986 tbe greater volatility at the open is not attributable to the way in which public information is released since both the opento open return and the close to close return span the same period of time instead the greater volatility appears to be attributable to private information revealed in trading and to temporaryprice deviations induced by specialist and other traders the implied cost of immediacy at the open is significantly higher than at the close other empirical evidence in this article documents the volume of trading at the open the time delays between the exchange opening and the first transaction in a stock the difference in daytime volatility versus overnight volatility and the extent to which volatility is related to trading volume

stock index futures mispricing profit opportunities or risk premia this paper reports empirical evidence on stock index futures pricing based on about four years of synchronous hourly data from the uk reported index values are based on firm quotes identified arbitrage opportunities are therefore actually exploitable and economically significant the analysis controls for cash market settlement procedures the results show that ex ante trading rules would have generated attractive profits after transaction costs and after the risks of dividend uncertainties marking to market and possible delays in execution are considered the far contract and the near contract tend to be mispriced in the same direction the mild tendency of futures to be overpriced in rising markets and underpriced in falling markets appears to be unimportant finally significant positive relationships are observed between the absolute magnitude of mispricing and time to maturity and between mispricing and index option implied volatility

arbitrage in stock index futures the textbook description of arbitrage suggests that it is a straightforward matter of taking offsetting positions in different securities and realizing the arbitrage profit such descriptions however typically ignore the transaction costs that give rise to the arbitrage opportunity in the first place taking proper account of these transactions costs may considerably complicate the problem particularly when as is usually the case the arbitrage potential is restricted this article is concerned withoptimal arbitrage strategies with transaction costs when the arbitrage potential is restricted by position limits the particular case we shall analyze is the standard and poor s sp the corresponding figure for the s p 500 portfolio for the same period was

mean downside risk and mean variance newsvendor models implications for sustainable fashion retailing abstract newsvendor models have been well established for studying supply chain management problems with fashionable products in this paper we explore the mean downside risk mdr and mean variance mv newsvendor models under both the exogenous and endogenous retail price decision cases we first construct analytical models with the mdr and mv objectives we then show that the analytical solution schemes for both the mdr and mv problems are the same with the measures for sustainability such as the expected quantity of goods leftover the expected sales to expected goods leftover ratio the rate of return on investment and the probability of achieving a pre determined profit target we proceed to compare the levels of sustainability by the fashion retailers which employ the mean risk and the risk neutral models insights are generated

welfare effects of maize technologies in marginal and high potential regions of kenya this paper describes the findings of a study that used a multi market model to assess the potential impact of improved maize technologies on the welfare of various types of rural and urban households in kenya the modelling results indicate that technologies developed for high potential regions are likely to have more profound aggregate impacts on maize production and lead to greater reductions in import demand if prices are controlled or maize prices if maize prices are flexible technology adoption in high potential regions is likely to have substantially greater positive impacts on aggregate real incomes but inferior income distributional outcomes compared to technology adoption in marginal regions

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

optimal decisions for the loss averse newsvendor problem under cvar abstract most of the existing literature about the newsvendor problem mainly focused on choosing an optimal order quantity to maximize the expected profit of a risk neutral newsvendor however some studies pointed out that in practice managers decisions as to order quantities always deviate from the profit maximization order quantity which is referred to as decision bias in the newsvendor problem then many studies introduced other preferences rather than risk neutrality of the newsvendor to explain such a decision bias this paper thus introduces loss aversion to the research of the newsvendor decision bias we propose a new definition to the loss averse newsvendor problem legacy loss which is defined either as the loss for excess order or the shortage penalty for lost sales when sales time is due the optimal decisions of a loss averse newsvendor are obtained through the following three ways i minimizing the expected legacy loss ii minimizing cvar of legacy loss by combining the cvar measure in risk management iii minimizing the combination of expected legacy loss and cvar of legacy loss and are compared with other existing results besides we present some properties of the optimal decisions as well as relations among them some numerical examples are given to illustrate the obtained results

futures trading activity and stock price volatility we examine whether greater futures trading activity volume and open interest is associated with greater equity volatility we partition each trading activity series into expected and unexpected components and document that while equity volatility covaries positively with unexpected futures trading volume it is negatively related to forecastable futures trading activity further though futures trading activity is systematically related to the futures contract life cycle we find no evidence of a relation between the futures life cycle and spot equity volatility these findings are consistent with theories predicting that active futures markets enhance the liquidity and depth of the equity markets

the impact of stock index futures trading on daily returns seasonality a multicountry study in this article we investigate the impact of the introduction of stock index futures trading on the daily returns seasonality of the underlying index for seven national markets it has been previously argued that the introduction of futures trading should lead to reduced seasonality of mean returns and generally our results support this conclusion the impact of index futures introduction on return autocorrelations and volatility is also tested and the evidence presented suggests that futures trading has no impact on the former although a change in the seasonal for the latter was detected

role of agricultural research in poverty reduction lessons from the asian experience abstract the poor spend much of their income on food depend primarily on labour earnings and tend to reside in marginal agricultural areas to reduce poverty agricultural research should aim to ensure adequate food supplies by developing yield increasing technologies to increase labour demand by developing labour using technologies and to develop technologies suitable for marginal areas this article seeks to identify appropriate technologies that agricultural research should generate for poverty reduction the identification is based on a review of the experience of the green revolution in rice production in asia and an assessment of the changing structure of income sources among rural households in the philippines

volatility risk and the value premium evidence from the french stock market this paper documents that systematic volatility risk is an important factor that drives the value premium observed in the french stock market using returns on at the money straddles written on the cac 40 index as a proxy for systematic volatility risk i document significant differences between volatility factor loadings of value and growth stocks furthermore when markets are classified into expected booms and recessions volatility factor loadings are also time varying when expected market risk premium is above its average i e during expected recessions value stocks are seen riskier than their growth counterparts this implies in bad times investors shift their preferences away from value firms instead they use growth stocks as hedges against deteriorations in their wealth during those times the findings are in line with the predictions of rational asset pricing theory and support a flight to quality explanation

asymmetry and ambiguity in newsvendor models a basic assumption of the classical newsvendor model is that the probability distribution of the random demand is known but in most realistic settings only partial distribution information is available or reliably estimated the distributionally robust newsvendor model is often used in this case where the worst case expected profit is maximized over the set of distributions satisfying the known information which is usually the mean and covariance of demands however covariance does not capture information on asymmetry of the demand distribution in this paper we introduce a measure of distribution asymmetry using second order partitioned statistics semivariance is a special case with a single partition of the univariate demand with mean variance and semivariance information we show that a three point distribution achieves the worst case expected profit and derive a closed form expression for the distributionally robust order quantity for multivariate demand the distributionally robust problem

stock price clustering on option expiration dates abstract this paper presents striking evidence that option trading changes the prices of underlying stocks in particular we show that on expiration dates the closing prices of stocks with listed options cluster at option strike prices on each expiration date the returns of optionable stocks are altered by an average of at least 16 5 basis points which translates into aggregate market capitalization shifts on the order of 9 billion we provide evidence that hedge rebalancing by option market makers and stock price manipulation by firm proprietary traders contribute to the clustering

technology production environment and household income assessing the regional impacts of technological change abstract this paper clarifies the factors determining the welfare effects of improved agricultural technologies when technology diffusion is unevenly distributed across production environments household level income effects are shown to depend primarily on a whether the economy is open or closed with respect to world markets b whether households are net consumers or net producers of the commodity for which technological change occurs c whether households are adopters or non adopters of the new technology d the degree to which labor is mobile across agricultural regions and e government intervention in commodity and or factor markets a review of recent empirical work indicates considerable variation in the relative strength of these various factors across countries and that assumptions regarding the mechanism by which commodity prices are determined endogenously as in a closed economy or exogenously as in an open economy is especially critical

a risk tolerance analysis for a joint price differentiation and inventory decisions problem with demand leakage effect abstract price differentiation is a commonly used practice in revenue management rm to improve a firm s profitability however most studies in the literature have considered a risk neutral firm to demonstrate the benefits of price differentiation the main contribution of this paper is in considering several important objectives while determining the optimal product prices and order production quantities for a risk adjusted firm with demand leakage effects in the presence of a price dependent stochastic demand the objectives considered include the maximization of a firm s expected profit and maximizing the probability of exceeding the risk adjusted expected revenue closed form expressions for optimal product prices and production quantities are derived for several of these objectives a numerical study is also presented to calibrate the impact of a firm s risk tolerance and other factors such as demand leakage market demand variability on the firm s profitability and its optimal decision

expiration and maturity effect empirical evidence from the spanish spot and futures stock index the paper studies how the time remaining to the expiration date of derivative markets affects the volatility of the ibex 35 index expiration effect and its futures market maturity effect the innovation of the study lies in both effects being studied together for the spanish stock market using bivariate ecm garch including dummy variables that express the time left to expiration day the results obtained show that during the week of the expiration day the conditional variance of both markets increases without presenting any significant behaviour in the correlation level during the second week however the conditional variance diminishes and the degree of correlation between both markets increases

a transaction data study of weekly and intradaily patterns in stock returns abstract weekly and intradaily patterns in common stock prices are examined using transaction data for large firms negative monday close to close returns accrue between the friday close and the monday open for smaller firms they accrue primarily during the monday trading day for all firms significant weekday differences in intraday returns accrue during the first 45 minutes after the market opens on monday mornings prices drop while on the other weekday mornings they rise otherwise the pattern of intraday returns is similar on all weekdays most notable is an increase in prices on the last trade of the day

the saga of the first stock index futures contract benchmarks models and learning in the presence of imperfect or perturbed benchmarks pricing based on relative valuation or arbitrage can be affected adversely this study highlights persistent pricing irregularities in the kansas city value line kcvl stock index futures market this contract is especially interesting because the underlying benchmark underwent a midstream change in definition from a complex equally weighted geometric index to an equally weighted arithmetic index empirical analysis reveals that during a four year period the market displayed herd like behavior and priced the kcvl geometric contract using the simple but wrong cost of carry benchmark model a dramatic change occurs around the publication of the eytan harpaz 1986 model when the market turns efficient from the perspective of this new model the market appears to have succumbed initially to a bad information cascade primarily because arbitrage was difficult to understand and carry out under complex benchmarking the evidence provides empirical extension to the observational social learning paradigms of simon 1955 banerjee 1992 and bikhchandani hirshleifer and welch 1992 that lead to behavioral herding and information cascades

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

reasonable expectations on the prospects for documenting the impact of agricultural research on poverty in ex post case studies abstract the increasing emphasis on poverty alleviation as a motivation for investing in public sector international agricultural research is discussed from the perspective of practitioners engaged in ex post impact evaluation context is largely provided from the experience of the international potato center cip in impact assessment of improved potato and sweet potato technologies the poverty content of 10 cip related success stories of technological change was qualitatively assessed with a checklist of key questions with this admittedly crude method the size of project net present value npv appears to be an informative guide to the magnitude of poverty effects hence projects that generate widespread benefits to many people particularly to net consumers of food crops remain likely to be the most effective vehicles to contribute to poverty alleviation from public sector investments in the improvement of food crops in developing countries

effects of higher order moments on the newsvendor problem abstract in this paper we propose a stochastic programming model for the well known single period newsvendor problem by adopting the conditional value at risk cvar as the risk metric in the objective function the demand uncertainty is modeled in terms of discrete scenarios that reflect the empirical distributions implied by market demand data our numerical results demonstrate that the higher order moments skewness and kurtosis of demand have obvious effects on the newsvendor problem and the stochastic programming framework provides a flexible and effective decision support tool for the newsvendor problem

multi product newsvendor problem with value at risk considerations abstract we consider the single period stochastic inventory newsvendor problem with downside risk constraints the aim in the classical newsvendor problem is maximizing the expected profit this formulation does not take into account the risk of earning less than a desired target profit or losing more than an acceptable level due to the randomness of demand we utilize value at risk var as the risk measure in a newsvendor framework and investigate the multi product newsvendor problem under a var constraint to this end we first derive the exact distribution function for the two product newsvendor problem and develop an approximation method for the profit distribution of the n product case n 2 a mathematical programming approach is used to determine the solution of the newsvendor problem with a var constraint this approach allows us to handle a wide range of cases including the correlated demand case that yields new results and insights the accuracy of the approximation method and the effects of the system parameters on the solution are investigated numerically

weekend effects on stock returns a note some researchers have apparently been surprised to discover that the distribution of stock returns depends on the day of the week kenneth french 3 for example in testing whether daily stock returns are generated by a trading time or calendar time hypothesis provided convincing evidence of a negative market return on mondays as french carefully notes this finding runs counter to both hypotheses since a trading time view would have expected stock returns equal on different days and a calendar time view would have higher expected returns on monday to compensate for the longer holding period in this paper we offer a partial explanation for the apparently puzzling discovery of different daily returns we argue that the expected stock returns as measured for example from closing to closing prices should depend on the day of the week in general we argue that the expected returns on mondays should be lower than would be implied simply by a trading time or calendar time model and the returns on fridays should be higher in addition we anticipate that holidays will have complex effects on stock returns on other days of the week our argument is based on the delay between trading and settlements in stocks and in clearing checks the explanation that we offer for different measured daily returns does not contradict the efficient market hypothesis as correctly adjusted expected returns should not differ according to the day of the week