global strategies multinational subsidiary roles and economic impact in scotland young s hood n and dunlop s 1988 global strategies multinational subsidiary roles and economic impact in scotland reg studies 22 487 497 this paper considers in a preliminary way the influence of mne global strategies on foreign subsidiary roles in scotland and from this some of the economic effects on the scottish economy are highlighted the study is based on a postal survey of mne subsidiaries in scotland the responses being analysed using the statistical techniques of cluster analysis and discriminant analysis despite the weaknesses of the former technique in particular the preliminary findings suggest substantial benefits to the economy from the one third of affiliates in the strategic independent product specialist categories as compared with the conventional branch plants rationalized manufacturers and miniature replica subsidiaries young s hood n et dunlop s 1988 strategies globales role des filiales des societes multi nationales et impact economique en ecosse

factorization of european and american option prices under complete and incomplete markets abstract in a standard option pricing model with continuous trading and diffusion processes this paper shows that the price of one european style option can be factorized into two intuitive components one robust x 0 which is priced by arbitrage and a second 0 which depends on a risk orthogonal to the traded securities this result implies the following 1 in an incomplete market these parts represent the price of a hedging portfolio which is unique and a premium which depends only on the risk premiums associated with the residual risk respectively 2 in a complete market it allows factoring the contribution of the different sources of risk to the final option price for example in a stochastic volatility model we can quantify the impact on the option price of volatility risk relative to market risk 0 and x 0 respectively hence certain misspricings in option markets can be directly related to the premium 0 3 moreover these results extend to american securities which have a third component an additional early exercise premium

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

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

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

option valuation with systematic stochastic volatility we use an extension of the equilibrium framework of rubinstein 1976 and brennan 1979 to derive an option valuation formula when the stock return volatility is both stochastic and systematic our formula incorporates a stochastic volatility process as well as a stochastic interest rate process in the valuation of options if the mean volatility and covariance processes for the stock return and the consumption growth are predictable our option valuation formula can be written in preference free form further many popular option valuation formulae in the literature can be written as special cases of our general formula in this paper we investigate the valuation of individual stock options when the volatility of the underlying stock return is stochastic and has a systematic component which is related to the stochastic volatility of the consumption growth or the market return such an investigation is timely and of significant interest because there is now a considerable amount of evidence that the volatility of stock prices is not only stochastic but that it is also highly correlated with the volatility of the market as a whole for example see black 1975 conrad kaul and gultekin 1991 jarrow and rosenfeld 1984 jorion 1988 and ng engle and rothschild 1992 furthermore empirical work by black and scholes 1972 gultekin rogalski and tinic 1982 and whaley 1982 has shown that the empirical biases inherent in the black scholes option prices are different for options on high and low risk stocks because low risk stocks are mainly large firm stocks with stochastic return volatilities that are highly correlated with the return volatility of the market and high risk stocks are mainly small firm stocks with a lessimportant systematic volatility component incorporating systematic volatility effects in option valuation models has the potential to reduce the empirical biases exhibited by prices computed from the black scholes formula we use equilibrium arguments that extend the consumption based representative agent framework of rubinstein 1976 brennan 1979 and stapleton and subrahmanyam 1984 to allow individual asset returns and the consumption growth to exhibit stochastic volatility in particular we permit the volatility of individual asset returns to consist of a systematic component that is related to the consumption or market volatility in addi

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

on the stock control performance of intermittent demand estimators the purpose of this paper is to assess the empirical stock control performance of intermittent demand estimation procedures the forecasting methods considered are the simple moving average single exponential smoothing croston s method and a new method recently developed by the authors of this paper we first discuss the nature of the empirical demand data set 3000 stock keeping units and we specify the stock control model to be used for experimentation purposes performance measures are then selected to report customer service level and stock volume differences the out of sample empirical comparison results demonstrate the superior stock control performance of the new intermittent demand forecasting method and enable insights to be gained into the empirical utility of the other estimators

on the mean variance tradeoff in option replication with transactions costs this paper analyzes the tradeoff between cost and risk of discretely rebalanced option hedges in the presence of transactions costs i present closed form solutions for expected hedging error transactions costs and variance of the cash flow from a time based hedging strategy similar to that analyzed by leland 1985 furthermore i characterize the cost and risk of a move based hedging strategy without resorting to monte carlo simulations all results are sufficiently general to accommodate the use of a transactions costs adjusted hedging volatility and an asset rate of return that differs from the risk free rate of return

optimal hedging and equilibrium in a dynamic futures market abstract this paper considers an agent maximizing the expected utility of the sum of the terminal value of a fixed portfolio of spot market assets and the terminal value of a margin account on a futures trading position closed form solutions for the optimal hedging strategy are provided in several special cases

displaced diffusion option pricing this paper develops a new option pricing formula that pushes the underlying source of risk back to the risk of individual assets of the firm the formula simultaneously encompasses differential riskiness of the assets of the firm their relative weights in determining the value of the firm the effects of firm debt and the effects of a dividend policy with both constant and random components although this setting considerably generalizes the black scholes 1 analysis it nonetheless produces a formula via riskless arbitrage arguments that given estimated inputs is as easy to use as the black scholes formula

implied volatility functions empirical tests derman and kani 1994 dupire 1994 and rubinstein 1994 hypothesize that asset return volatility is a deterministic function of asset price and time and develop a deterministic volatility function dvf option valuation model that has the potential of fitting the observed cross section of option prices exactly using s p 500 options from june 1988 through december 1993 we examine the predictive and hedging performance of the dvf option valuation model and find it is no better than an ad hoc procedure that merely smooths black scholes 1973 implied volatilities across exercise prices and times to expiration

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

market frictions and consumption based asset pricing a fundamental equilibrium condition underlying most utility based asset pricing models is the equilibration of intertemporal marginal rates of substitution imrs previous empirical research however has found that the comovements of consumption and asset return data fail to satisfy the restrictions imposed by this equilibrium condition in this paper we examine whether market frictions can explain previous findings our results suggest that a combination of short sale borrowing solvency and trading cost frictions can drive a large enough wedge between imrs so that the apparent violations may not be inconsistent with market equilibrium

on jumps in common stock prices and their impact on call option pricing the black scholes call option pricing model exhibits systematic empirical biases the merton call option pricing model which explicitly admits jumps in the underlying security return process may potentially eliminate these biases we provide statistical evidence consistent with the existence of lognormally distributed jumps in a majority of the daily returns of a sample of nyse listed common stocks however we find no operationally significant differences between the black scholes and merton model prices of the call options written on the sampled common stocks

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

jump diffusion option valuation in discrete time we develop a simple discrete time model to value options when the underlying process follows a jump diffusion process multivariate jumps are superimposed on the binomial model of cox ross and rubinstein 1979 to obtain a model with a limiting jump diffusion process this model incorporates the early exercise feature of american options as well as arbitrary jump distributions it yields an efficient computational procedure that can be implemented in practice as an application of the model we illustrate some characteristics of the early exercise boundary of american options with certain types of jump distributions jump diffusion processes are popular in option valuation models these processes were incorporated by merton 1976 into the theory of option valuation and constitute an important alternative to the lognormal diffusion process assumed in the black and scholes 1973 model in this paper we develop a tractable discrete time model for valuing options with these processes many authors have suggested that incorporating jumps in option valuation models may explain some of the large empirical biases exhibited by the black scholes model 1 however in many cases closed form solutions for valuing options are not available for example this is true when there is a positive probability of early exercise when the jump distribution is neither lognormal nor discrete or when the option is based on the term structure of interest rates see ahn and thompson 1988 and jarrow and madan 1991 in these important cases the model developed in this paper can be used to value options another aim of this paper is to provide a model which relies on only simple mathematics to price options with jump diffusion processes it is hoped that the key economic relationships underlying jump diffusion models are transparent in this model we provide enough details to make the procedure readily accessible

assessing the impacts of foreign manufacturing on regional economies the cases of wales scotland and the west midlands brand s hill s and munday m 2000 assessing the impacts of foreign manufacturing on regional economies the cases of wales scotland and the west midlands reg studies 34 343 355 this paper examines the direct and indirect contributions made by foreign manufacturing companies to the regional economies of wales scotland and the west midlands survey data derived from foreign manufacturers in each region were used in conjunction with regional input output tables to assess the comparative contributions of defined foreign and domestically owned sectors to regional value added the analyses are a starting point for the more accurate targeting of regional resources to industry sectors in the respective regional economies brand s hills s et munday m 2000 evaluer les retombees de l industrie etrangere sur les economies regionales etude de cas du pays de galles de l ecosse et des west midlands reg studies 34 343 355 cet article cherche a examiner les roles direct et indirect joue par les en

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

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

utilization of r d results in the home and foreign plants of multinationals this paper analyzes the utilization of r d results in the home and foreign plants of swedish multinational enterprises mnes the findings indicate that firms r d undertaken in the home country is used as an input in both the home and foreign plants of the mnes this suggests that technology is transferred to the foreign plants around four fifths of the gain in value added attributed to home r d was realized in the mnes home plants while the remaining fifth benefitted the foreign plants r d in foreign affiliates does not appear to be used as an input in home plants

arbitrage and martingales with taxation this paper extends the martingale analysis of no arbitrage pricing to worlds with taxation the absence of arbitrage is shown to imply the existence of different shadow prices for income streams that are subject to differing tax treatments for example no arbitrage implies the existence of different martingale measures for capita l gains and for ordinary income when they are differentially taxed andfor item s such as depreciation expenses that influence only after tax cash flows the analysis is applied to several topics in finance including the debt equity decision tax options and the taxation of dividends and pensions copyright 1987 by university of chicago press

systematic equity based credit risk a cev model with jump to default we use equity as the traded primitive for a detailed analysis of systematic default risk default is parsimoniously represented by equity value hitting the zero barrier so that unlike in reduced form models the explicit linkage to the firm s capital structure is preserved but unlike in structural models restrictive assumptions on the structure are avoided default risk is either jump like or diffusive the equity price can jump to default in line with recent empirical evidence on the jump to default risk price we highlight how reasonable choices of the pricing kernel can imply remarkable differences in the equity price dependent status between the objective default intensity and the risk neutral intensity as equity returns experience negative diffusive shocks their cev type local variance increases and boosts the objective and risk neutral probabilities of diffusive default a parsimonious version of our general model simultaneously enables analytical credit risk management and analytical pricing of credit sensitive instruments easy cross asset hedging ensues

stochastic equilibria with incomplete financial markets abstract we demonstrate the existence of equilibria with incomplete financial markets for stochastic economies whose information structure is given by an event tree restricting attention to purely financial securities those paying in units of account e g dollars financial markets may be incomplete some consumption streams may be impossible to obtain by any trading strategy securities may be individually precluded from trade at arbitrary states and dates sufficient conditions for the existence of stochastic equilibria are continuous convex strictly monotonic preferences and strictly positive aggregate endowments these conditions are weakened a corollary states that any regime of security prices precluding arbitrage can be embedded in an equilibrium

asset returns with transactions costs and uninsured individual risk abstract we explore whether incorporating an explicit motive for holding liquid assets within an equilibrium asset pricing model helps explain the following features of asset returns and turnover in the post war u s economy i the low risk free real interest rate ii the large spread between returns on liquid assets and stocks and iii the greater transaction velocity of liquid assets relative to stocks we introduce a demand for liquid assets by adding uninsured individual risk together with differential costs of trading securities numerical simulations attempting to match the return data generate a ratio of liquid assets to income considerably below observed levels

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

intermittent demand linking forecasting to inventory obsolescence the standard method to forecast intermittent demand is that by croston this method is available in erp type solutions such as sap and specialised forecasting software packages e g forecast pro and often applied in practice it uses exponential smoothing to separately update the estimated demand size and demand interval whenever a positive demand occurs and their ratio provides the forecast of demand per period the croston method has two important disadvantages first and foremost not updating after many periods with zero demand renders the method unsuitable for dealing with obsolescence issues second the method is positively biased and this is true for all points in time i e considering the forecasts made at an arbitrary time period and issue points only i e considering the forecasts following a positive demand occurrence only the second issue has been addressed in the literature by the proposal of an estimator syntetos boylan approximation sba that is approximately unbiased in this paper we propose a new method that overcomes both these shortcomings while not adding complexity different from the croston method the new method is unbiased for all points in time and it updates the demand probability instead of the demand interval doing so in every period the comparative merits of the new estimator are assessed by means of an extensive simulation experiment the results indicate its superior performance and enable insights to be gained into the linkage between demand forecasting and obsolescence

option pricing when the variance is changing the monte carlo method is used to solve for the price of a call when the variance is changing stochastically

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

on the bias of intermittent demand estimates forecasting and inventory control for intermittent demand items has been a major problem in the manufacturing and supply environment croston operational research quarterly 23 1972 289 proposed a method according to which intermittent demand estimates can be built from constituent events croston s method has been reported to be a robust method but has shown more modest benefits in forecasting accuracy than expected in this research one of the causes of this unexpected performance has been identified as a first step towards improving croston s method certain limitations are identified in croston s approach and a correction in his derivation of the expected estimate of demand per time period is presented in addition a modification to his method that gives approximately unbiased demand per period estimates is introduced all the conclusions are confirmed by means of an extended simulation experiment where croston s and revised croston s methods are compared the forecasting accuracy comparison corresponds to a situation of an inventory control system employing a re order interval or product group review

an intertemporal general equilibrium asset pricing model the case of diffusion information this paper provides sufficient conditions for the equilibrium price system and a vector of exogenously specified state variable processes to form a diffusion process in a pure exchange economy the conditions involve smoothness of agents utility functions and certain nice properties of the aggregate endowment process and the dividend processes of traded assets in place of the dynamic programming a martingale representation technique is utilized to characterize equilibrium portfolio policies this technique is useful even when there does not exist a finite dimensional markov structure in the economy and thus the markovian stochastic dynamic programming is not applicable a gents are shown to hold certain hedging mutual funds and the riskless asset in contrast to earlier results the market portfolio does not have a special role in hedging since the markets are dynamically complete when there exists a finite dimensional markov system in the economy the dimension of the hedging demand identified through the markovian dynamic programming may be much larger than that identified by the martingale method copyright 1987 by the econometric society

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

technology transfer within multinational firms and its impact on the productivity of scottish subsidiaries siler p wang c and liu x 2003 technology transfer within multinational firms and its impact on the productivity of scottish subsidiaries reg studies 37 15 25 this paper aims to examine the extent to which the technology generated in us parent firms is transferred to their scottish affiliates in the form of productivity gains using a firm level panel data set the empirical results show that the labour productivity growth of scottish subsidiaries is positively linked to the rd those that already have achieved a relatively high level of productivity and those that compete in industries based on product technology the results have implications

equilibrium asset prices with undiversifiable labor income risk abstract in a two period lucas tree economy in which ex ante identical but ex post dissimilar agents face undiversifiable labor income risk calibrating a wrong representative agent model results in overstating the equilibrium riskfree rate and in understating the equilibrium equity premium if the utility function exhibits decreasing absolute risk aversion and decreasing absolute prudence these behavioral assumptions provide as a consequence a theoretical rationale for the often advanced conjecture that nontraded risk contributes to the solution of the riskfree rate and equity premium puzzles

the accuracy of a modified croston procedure a modified croston procedure to forecast intermittent demand is reviewed the modified procedure published in this journal in 2004 consists of a new method for estimating the mean demand and a smoothing method for estimating the variance of the forecasted demand rate it is found that the smoothed variance estimate is based on an invalid measure of forecast accuracy moreover it is shown that the method of forecasting mean demand produces biased forecasts the accuracy of this method is assessed using simulated data and the mean square error measure and compared with croston s method and single exponential smoothing it is found that croston s method is generally more accurate than its modification particularly for strongly intermittent series

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

a simple nonparametric approach to derivative security valuation canonical valuation uses historical time series to predict the probability distribution of the discounted value of primary assets discounted prices plus accumulated dividends at any future date then the axiomatically rationalized maximum entropy principle is used to estimate risk neutral equivalent martingale probabilities that correctly price the primary assets as well as any predesignated subset of derivative securities whose payoffs occur at this date valuation of other derivative securities proceeds by calculation of its discounted risk neutral expected value both simulation and empirical evidence suggest that canonical valuation has merit since the advent of the justly celebrated black scholes option pricing formula intense interest has focused on testing its implications there is consensus

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

quadratic variation based dynamic strategies the paper analyzes a family of dynamic trading strategies which do not rely on any stochastic process assumptions aside from continuity and positivity and in particular do not require predicting future volatilities derivative payoffs can still be replicated except that this occurs at the stopping time at which the realized cumulative squared volatility hits a predetermined level the application of these results to portfolio insurance is emphasized and hedging strategies studied by black and jones and by brennan and schwartz are generalized classical results on european style options arise as special cases for example the initial cost of replicating a call or a put under the new method is given by a generalized black scholes formula which yields the ordinary black scholes formula when the volatility is derterministic

exploiting elapsed time for managing intermittent demand for spare parts we present an intermittent demand forecasting method that conditions on the elapsed time since the last demand occurrence to anticipate incoming demand and show using empirical data that this can substantially reduce both stock investment and lost revenue for spare parts management we extensively benchmark our method against existing forecasting and bootstrapping methods on forecast accuracy and inventory performance and demonstrate that its performance is robust under general conditions our method is the first to incorporate that activities at the demand side such as aggregation of demand preventive and corrective maintenance can lead to a positive relation between demand size and inter arrival time of demand occurrences by anticipating incoming demand our method offers substantial financial gains

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

forecasting sales of slow and fast moving inventories abstract traditional computerised inventory control systems usually rely on exponential smoothing to forecast the demand for fast moving inventories practices in relation to slow moving inventories are more varied but the croston method is often used it is an adaptation of exponential smoothing that 1 incorporates a bernoulli process to capture the sporadic nature of demand and 2 allows the average variability to change over time the croston approach is critically appraised in this paper corrections are made to underlying theory and modifications are proposed to overcome certain implementation difficulties a parametric bootstrap approach is outlined that integrates demand forecasting with inventory control the approach is illustrated on real demand data for car parts

the effects of integrating management judgement into intermittent demand forecasts empirical research suggests that quantitatively derived forecasts are very frequently judgementally adjusted nevertheless little work has been conducted to evaluate the performance of these judgemental adjustments in a practical demand sales context in addition the relevant analysis does not distinguish between slow and fast moving items currently there are neither conceptual developments nor empirical evidence on the issue of integrating judgements and statistical forecasts for slow intermittent demand items moreover no results have ever been reported on the stock control implications of these human judgements our work analyses monthly intermittent demand forecasts for the uk branch of a major international pharmaceutical company the company relies upon a commercially available statistical forecasting system to produce forecasts that are subsequently judgementally adjusted based on marketing intelligence gathered by the company forecasters the benefits of the intervention are evaluated by comparing the actual sales to system and final forecasts using both forecast accuracy and inventory control accuracy implication metrics our study allows insights to be gained on potential improvements to intermittent demand forecasting processes and subsequently the design effectiveness of forecasting support systems

effects of correlation on intermittent demand forecasting and stock control abstract this study investigates the effects of three different types of correlation on forecasting and stock control of intermittent demand items applying appropriate forecasting and stock control methods to theoretically generated compound poisson demand data we show that correlation in intermittent demand does play a role in forecast quality and stock control performance negative autocorrelation levels lead to higher service levels than positive values while cost does not significantly change our results also show that high intermittency levels intensify these changes in service level we also show that cross correlation produces results in the opposite direction of autocorrelation in size or intervals that is positive negative cross correlation leads to higher lower service levels

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

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

valuation of risky assets in arbitrage free economies with frictions this paper derives a framework for arbitrage models in markets with frictions it generalizes the existence of a valuation operator to such markets as in perfect markets the valuation operator is a linear operator and its existence is implied by the no arbitrage condition in imperfect markets the valuation operator is individual specific and depends on the agent s position in the market the methodology employed in the paper is duality in convex programming

intermittent demand forecasting an empirical study on accuracy and the risk of obsolescence intermittent demand items account collectively for considerable proportions of the total stock value of any organization forecasting the relevant inventory requirements constitutes a very difficult task and most work in this area is based on croston s estimator that relies upon exponentially smoothed demand sizes and inter demand intervals this method has been shown to be biased and a number of variants have been introduced in the literature including the recently proposed tsb method that updates the demand probability instead of the demand interval and in doing so reacts faster to decreasing demand the tsb has been shown theoretically to be unbiased for all points in time but its empirical performance has not been investigated yet and this constitutes one of the objectives of our work more generally we explore the empirical performance of forecasting methods used in an intermittent demand context paying particular attention to the effects and implications of the smoothing constant values employed for updating purposes we do so by means of experimentation on large empirical datasets from the military sector and automotive industry the results enable insights to be gained into the sensitivity of the various methods forecasting and stock control performance to the smoothing constant values used the paper concludes with an agenda for further research

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