mean reversion in real exchange rates evidence and implications for forecasting abstract the stationarity of real exchange rates over the recent flexible exchange rate period is an issue that has long bedeviled researchers in international finance using a constrained multivariate framework this paper provides the strongest evidence yet that real exchange rates were mean reverting over the 1973 93 period we also investigate shifts in long run real exchange rates which may be important for the purpose of forecasting out of sample forecasting shows that the random walk model is outperformed by a mean stationary model especially at long horizons in addition there are substantial forecasting benefits from using a multivariate approach

the european union currencies and the us dollar from post bretton woods to the euro abstract in this paper we study the evolution of the us dollar real exchange rate vis a vis the european union currencies in the floating post bretton woods era both before and after the birth of the euro in the first period we find that most of the persistence shown by this rate is due to the movements of the us dollar during the mid 1980s once these effects are isolated we can conclude that the us dollar real exchange rate exhibits stationarity with those currencies that are closely linked to the german mark however when we include the observations covering the period during which the euro was created we cannot reject the unit root null hypothesis for any currency

real exchange rates and time varying trade costs this paper re examines the empirical modeling of purchasing power parity ppp deviations in the presence of commodity market frictions first we show that a specific type of smooth transition models can closely approximate the functional form of the theoretical adjustment mechanism derived by dumas 1992 dynamic equilibrium and the real exchange rate in a spatially separated world review of financial studies 5 2153 180 for the case of constant as well as changing trade costs second we develop for the first time an empirical model of the real exchange rate which allows for changes in the degree of market integration by employing a long span of data on the dollar sterling real exchange rate and a micro founded proxy for trade frictions we provide novel evidence of a significant relationship between the persistence of the real exchange rate and the level of trade costs this finding suggests that both the difficulty of detecting ppp and the extend of rogoff s puzzle vary over time with the degree of trade restrictiveness finally we highlight policy repercussions of our results

customer and retailer rebates under risk aversion abstract in a supply chain setting we analyze a manufacturer s customer and retailer rebates which are sales incentives offered to the end buyers and retailers respectively the performance of both rebates is influenced by the retailer s objective and response to the promotion due to his intermediary position in the channel earlier studies investigating rebates in distribution channels have traditionally assumed that the retailer is risk neutral with the objective of maximizing expected profits in our paper we consider a risk averse retailer we formally model risk aversion by adopting the conditional value at risk cvar decision criterion using a stochastic and effective price dependent demand we analyze the manufacturer s rebate amount decisions and the retailer s joint inventory and pricing decisions in a game theoretical framework we provide several structural properties of the objective functions and show monotonicity of the retailer s decisions in the degree of risk aversion for the case of retailer rebates we characterize the unique equilibrium and for the case of customer rebates we prove the existence of an equilibrium using numerical examples we provide further insights on the impact of risk aversion for example given an exogenous wholesale price we observe a threshold value on the retailer s risk aversion parameter below above which the manufacturer is better off with retailer rebates customer rebates implying that the manufacturer s preferred rebate type can be different depending on whether the retailer is risk neutral or sufficiently risk averse

parity reversion in real exchange rates during the post bretton woods period abstract a common view among recent studies on purchasing power parity is that the post bretton woods period is far too short to reveal any significant parity reversion in individual series of real exchange rates is this really so the answer this study shows depends very much on the statistical test being used two efficient univariate unit root tests are applied to uncover parity reversion these tests require much shorter sample sizes than conventional tests to attain the same statistical power empirical results show that parity reversion can be unveiled over the modern float if an efficient unit root test is applied

deviations from purchasing power parity in the long run this paper demonstrates that deviations from purchasing power parity reveal a remarkable and possibly startling consistency with martingale behavior during both fixed and flexible rate periods for a wide variety of countries and in both monthly and annual data since this pattern appears to be much more general than one would expect on the basis of models founded on international commodity arbitrage the paper proposes an alternative explanation which instead relies on financial arbitrage in bonds as the underlying mechanism this paper will demonstrate that deviations from purchasing power parity ppp reveal a remarkable and possibly startling consistency with martingale behavior during both fixed and flexible exchange rate periods for a wide variety of countries and in both monthly and annual data this pattern appears to be much more general than one would expect on the basis of models founded on international commodity arbitrage the paper therefore proposes an alternative explanation which does not presuppose free trade in goods but which instead relies on financial arbitrage in bonds as the underlying mechanism the major implication of the theory and the results is that ppp is as likely to be violated in the long as in the short run as an empirical matter deviations from ppp can be observed for most currencies at any instant see kravis et al 21 stockman 37 and genberg 15 among others these deviations are typically both cumulative and persistent the real exchange rate can remain on either side of parity for lengthy but variable time intervals of a year or more as a consequence the current consensus shared

the great appreciation the great depreciation and the purchasing power parity hypothesis abstract although there has been much recent work on purchasing power parity ppp neither univariate nor panel methods have produced strong rejections of unit roots in us dollar real exchange rates for industrialized countries during the post 1973 period we investigate the hypothesis that these non rejections can be explained by one episode the large appreciation and depreciation of the dollar in the 1980s by developing unit root tests which account for this event and maintain long run ppp using panel methods we can strongly reject the unit root null for those countries that adhere to the typical pattern of the dollar s rise and fall

testing long run purchasing power parity under exchange rate targeting abstract the present paper exploits the idea that empirical estimates of the long run ppp relationship may compound two distinct influences coming from the behavior of market participants and policy makers when the latter are targeting the exchange rate this tends to bias tests of long run ppp against its acceptance the validity of the theoretical arguments is assessed by drawing on the experience of two european union countries greece and france for the post bretton woods period estimation biases due to the omission of policy effects are found to be significant only in the case of greece for france our test results provide evidence bearing on the effectiveness of the competitive disinflation strategy pursued by the french authorities

modeling a multi attribute utility newsvendor with partial backlogging abstract traditional newsvendor models usually focus on single profit maximization or cost minimization approaches however making a monetary estimate of the consequences of lost sales as a result of shortages is often a difficult task for many practitioners besides there is still a lack of an explicit account of decision making judgments on the multiple consequences of making decisions with regard to order quantities in order to deal with this problem this paper presents a multi attribute utility model for the newsvendor problem with regard to profit the impacts of service level on corporate image and on customers goodwill and the impact on the environment arising from the disposal of unsold products demand is partially backlogged according to a decreasing exponential function of the waiting time the fundamental principles and limitations related to the application of the model built are also discussed

forecasting real exchange rates abstract considerable evidence supports the view that real exchange rates do not have unit roots but rather show mean reversion this is the first paper to present systematic results on if and how this mean reversion is useful for forecasting real rates longer time horizons improve the performance of the estimated forecast models relative to the benchmark driftless random walks longer estimation periods particularly improve performance relative to the benchmark the forecasting ability in simple statistical models seems genuine but the models resolve only a small part of the uncertainty regarding the revolution of real exchange rates

speculative trading in mean reverting markets mean reversion is a feature largely recognized for the price processes of many financial securities and especially commodities in the literature there are examples where some simple speculative strategies before transaction costs were devised to earn excess returns from such price processes actually the gain opportunities of mean reversion must be corrected to account for transaction costs which may represent a major issue in this work we try to determine sufficient conditions for the parameters of a mean reverting price process as a function of transaction costs to allow a speculative trader to have positive expectations when deciding to take a position we estimate the mean reverting parameters for some commodities and correct them for transaction costs to assess whether the potential inefficiency is actually relevant for speculative purposes

genetically modified crops corporate pricing strategies and farmers adoption the case of bt cotton in argentina this article analyzes adoption and impacts of bt cotton in argentina against the background of monopoly pricing based on survey data it is shown that the technology significantly reduces insecticide applications and increases yields however these advantages are curbed by the high price charged for genetically modified seeds using the contingent valuation method it is shown that farmers average willingness to pay is less than half the actual technology price a lower price would not only increase benefits for growers but could also multiply company profits thus resulting in a pareto improvement implications of the sub optimal pricing strategy are discussed recently genetically modified gm crops have brought about important changes in the global market for agricultural technologies especially seeds prospects of high economic returns and tightened intellectual property rights iprs have provided new incentives for the private sector to invest in crop improvement and extend its business to nontraditional markets the increasingly proprietary nature of seed technologies has implications for farmers adoption and benefit distribution private innovators endowed with a patent on a technology will attempt to capture the gains from their innovation through monopoly pricing moschini and lapan recent studies have looked into the partitioning of welfare created by gm crops among agricultural producers consumers and innovating input firms e g moschini lapan and sobolevsky falckzepeda traxler and nelson in these studies however the market price of the technology is

pricing and the news vendor problem a review with extensions in the newsvendor problem a decision maker facing random demand for a perishable product decides how much of it to stock for a single selling period this simple problem with its intuitively appealing solution is a crucial building block of stochastic inventory theory which comprises a vast literature focusing on operational efficiency typically in this literature market parameters such as demand and selling price are exogenous however incorporating these factors into the mode l can provide an excellent vehicle for examining how operational problems interact with marketing issues to influence decision making at the firm level in this paper we examine an extension of the newsvendor problem in which stocking quantity and selling price are set simultaneously we provide a comprehensive review that synthesizes existing results for the single period problem and develop additional results to enrich the existing knowledge base we also review and develop insight into a dynamic inventory extension of this problem and motivate the applicability of such models

mean variance portfolio selection of cointegrated assets abstract this paper considers the continuous time mean variance portfolio selection problem in a financial market in which asset prices are cointegrated the asset price dynamics are then postulated as the diffusion limit of the corresponding discrete time error correction model of cointegrated time series the problem is completely solved in the sense that solutions of the continuous time portfolio policy and the efficient frontier are obtained as explicit and closed form formulas the analytical results are applied to pairs trading using cointegration techniques numerical examples show that identifying a cointegrated pair with a high mean reversion rate can generate significant statistical arbitrage profits once the current state of the economy sufficiently departs from the long term equilibrium we propose an index to simultaneously measure the departure level of a cointegrated pair from equilibrium and the mean reversion speed based on the mean variance paradigm an empirical example is given to illustrate the use of the theory in practice

eoq models for a coordinated two level international supply chain considering imperfect items and environmental impact abstract for a two level supply chain models are presented to determine the optimal production shipment policy for items with imperfect quality in three different scenarios a both the vendor and the buyer are in the same country b the vendor and the buyer are in different countries where the stochastic behavior of the exchange rate between the two countries is modeled using a mean reverting process and c environmental impact is incorporated in determining the optimal production shipment policy by taking into account the fixed and variable carbon emission costs the objective is to minimize the total expected cost per unit time for each scenario considering equal shipment size the total expected cost per unit time is derived and the solution procedure is proposed numerical examples are presented and the results are discussed

real exchange rate behaviour evidence from black markets the behaviour of real exchange rates relative to the us dollar is examined using monthly data obtained from the black markets for foreign exchange of eight asian developing countries the data span is 31 years the black market real exchange rates do not show excess volatility during the recent float which is in sharp contrast to the results reported elsewhere unit root tests in heterogeneous panels and variance ratio tests confirm their stationarity thus we find support for ppp but not for the survivorship bias froot and rogoff 1995 there is little evidence of segmented trends issues raised by rogoff 1996 of whether ppp would hold across countries with differing growth experience and lothian and taylor 1996 of whether the degree of relative price volatility may bias results in favour of mean reverting real exchange rates are addressed copyright 2000 john wiley sons ltd

potential pitfalls for the purchasing power parity puzzle sampling and specification biases in mean reversion tests of the law of one price the ppp puzzle is based on empirical evidence that international price differences for individual goods loop or baskets of goods ppp appear highly persistent or even nonstationary the present consensus is these price differences have a half life that is of the order of five years at best and infinity at worst this seems unreasonable in a world where transportation and transaction costs appear so low as to encourage arbitrage and the convergence of price gaps over much shorter horizons typically days or weeks however current empirics rely on a particular choice of methodology involving i relatively low frequency monthly quarterly or annual data and ii a linear model specification in fact these methodological choices are not innocent and they can be shown to bias analysis towards findings of slow convergence and a random walk intuitively if we suspect that the actual adjustment horizon is of the order of days then monthly and annual data cannot be expected to reveal it if we suspect arbitrage costs are high enough to produce a substantial band of inaction then a linear model will fail to support convergence if the process spends considerable time random walking in that band thus when testing for ppp or loop model specification and data sampling should not proceed without consideration of the actual institutional context and logistical framework of markets

the econometrics of damage control why specification matters the contribution of damage control agents to production differs fundamentally from that of standard inputs lands labor capital this paper develops an econometric model based on the key characteristics of damage control agents and examines its properties it demonstrates that standard production function specifications overestimate damage control agent productivity and have erroneous implications for the evolution of damage control agent productivity and use in response to changing environments e g the spread of pest resistance it also proposes several alternative specifications and discusses methods for estimating them

purchasing power parity and unit root tests using panel data abstract this paper reports the results of unit root tests for real exchange rates using a panel framework this panel approach provides greatly improved power compared to conventional univariate time series unit root tests we obtain evidence supporting ppp over the recent flexible exchange rate period for g 6 and oecd countries we show explicitly that failure to find such evidence in previous research was due to the low power of the tests

is purchasing power parity overvalued the purpose of this paper is to re examine the hypothesis of long run purchasing power parity among industrial countries under the current float using the panel data approach we propose a new finite sample panel data unit root test procedure that allows for a general serial correlation structure and arbitrary contemporaneous correlation in model innovations across countries this procedure is then applied to the recently developed panel data unit root tests of im pesaran and shin 1996 and of maddala and wu 1999 the test results show sufficient evidence against the unit root null for most samples by comparing our results with the existing ones in the literature we found that the method of assuming a restrictive serial correlation structure tends to weaken evidence against the unit root null

dollar vs percentage markup pricing schemes under a dominant retailer abstract we investigate two very common pricing schemes for a stackelberg dominant retailer percentage markup and dollar markup we show that when a dominant retailer switches from dollar to percentage markup the channel s overall pie and the retailer s pie piece are both enlarged in contrast the manufacturer will be forced to levy a lower wholesale price thus receiving a smaller pie piece despite the larger pie the preceding statements hold regardless of whether the demand is deterministic or stochastic however the effects of switching to percentage markup on the retail price and sales volume will depend not only on whether the demand is stochastic but also on the assumed demand curve shape and on whether demand stochasticity is additive or multiplicative besides presenting a comprehensive set of answers on the comparative performance of dollar and percentagemarkups our results also highlight the often overlooked importance of choosing between i dollar and percentage markup and ii the formats of the assumed stochasticity and demand curves

joint pricing and procurement of fashion products in the existence of clearance markets abstract this paper focuses on the joint pricing and procurement of fashion products in the existence of clearance markets it is assumed that the expected regular season demand is a linear decreasing function of the price and the end of period excess inventory is sold at a known discounted price in a clearance market where the demand is a random variable that follows a general distribution it is shown that the expected profit function is unimodal and the optimal procurement quantity and price can be found from the first order conditions existence of a clearance market increases the profit price and the procurement quantity in order to prove this the optimal procurement and pricing policy of a price setting retailer who does not have a clearance market is provided as opposed to the literature it is shown that the expected profit function of this problem is unimodal as well a numerical study demonstrating the magnitude of the increase in profit procurement quantity and price is reported

real exchange rate behavior abstract using random simulations with artificial data with identical sample characteristics to the long sample exchange rate data employed by lothian and taylor lothian j r and taylor m p 1996 the recent float from the perspective of the past two centuries journal of political economy 104 488 509 we show that standard unit root tests have extremely low power over sample sizes corresponding to the recent float the probability of rejecting the null hypothesis when it is false is extremely low with 20 years or even 50 years of data and only reaches an acceptable level over much longer spans

mean reversion in g 10 nominal exchange rates according to conventional wisdom industrial country floating exchange rates contain unit roots sur tests on panels of monthly group of ten g 10 log nominal rates reject the null of unit roots for various samples over the current float with significance levels from 0 5 to 15 on average in out of sample forecasts mean reversion models beat random walks significantly in some forecast periods for monthly data the range of expected usd dem appreciation rates exceeds 15 per year in the mean reversion model mean reversion places strong restrictions on international models over the sample period the g 10 had to run monetary policies consistent with stable long run nominal rates

are real gdp levels nonstationary evidence from panel data tests potential nonstationarity of important macroeconomic variables and unit root tests are now a standard procedure in empirical analyses while there are many findings of unit roots in macroeconomic variables using the popular augmented dickey and fuller 1979 test this test has low power against near unit root alternatives recently panel data procedures have been proposed as an avenue to increased power this paper applies panel unit root tests to international real gdp and real gdp per capita data the results overwhelmingly indicate that international real gdp and real gdp per capita levels are nonstationary

on the equilibrium yen dollar rate this paper presents a definition of the long run equilibrium exchange rate that emphasizes the role of supply factors in addition to the more traditional price differential variables using this definition we estimate the long run equilibrium yen dollar rate during the period of 1973 87 this calculation demonstrates that supply factors are in fact very important determinants of the long run movement of the exchange rate despite the central role the exchange rates play in the economy economists seem to doubt their own ability to explain let alone predict exchange rate movements the reason is that in many cases structural exchange rate equations do not significantly outperform various other models that do not appeal to economic theory such as the random walk see for example richard meese and kenneth rogoff 1983 while we also share this pessimism concerning our ability to forecast exchange rates in the short run intradaily to monthly or quarterly we argue that it is possible to reasonably explain if not predict long run movements the long run equilibrium rate is most often thought to be determined by purchasing power parity ppp which tends to focus only on price differentials medium run divergences of the exchange rate from the long run equilibrium are therefore commonly identified with fluctuations in the inflation adjusted real exchange rate this paper demonstrates however that the simple ppp is unsatisfactory because it emphasizes only the inflation differential in the more elaborated theory of purchasing power parity of course the potential importance of supply side real factors as critical determinants of the exchange rate has been well recognized see for example john m keynes 1923 rudiger dornbusch stanley fischer and paul a samuelson 1977 alan stockman 1980 nevertheless in empirical applications and policy discussions these supply side real factors have been curiously ignored to our knowledge an exception is david hsieh 1982 the main point of this paper is to show that these supply side factors actually have been very important determinants of the yen dollar rate over the period of 1973 to 1987

tests for symmetric and asymmetric nonlinear mean reversion in real exchange rates new tests based on smooth transition autoregressive models for mean reversion in time series of real exchange rates are proposed one test forces mean reversion to be symmetric about the integrated process central case while the other permits asymmetry the tests are applied to monthly series of seventeen real exchange rates against the u s dollar and fourteen against the deutsche mark they reveal stronger evidence against the unit root null hypothesis than does the usual dickey fuller test

purchasing power parity and country characteristics evidence from panel data tests abstract we examine long run purchasing power parity ppp using panel data methods to test for unit roots in us dollar real exchange rates of 84 countries we find stronger evidence of ppp in countries more open to trade closer to the united states with lower inflation and moderate nominal exchange rate volatility and with similar economic growth rates as the united states we also show that ppp holds for panels of european and latin american countries but not for african and asian countries our findings demonstrate that country characteristics can help explain both adherence to and deviations from long run ppp

purchasing power parity and the euro area abstract this paper analyzes purchasing power parity ppp for the euro area we study the impact of the introduction of the euro in 1999 on the behavior of real exchange rates we test the ppp hypothesis for a panel of real exchange rates within the euro area over the period 1973 2003 our methodology exploits the cross sectional dependence across real exchange rates and allows for heterogeneity in the rates of mean reversion we present evidence in favor of ppp for the full panel of real exchange rates but we show that accounting for cross country differences within the euro area is essential the unit root hypothesis can be rejected for some real exchange rates but evidence for ppp is weak for others we also investigate ppp between the synthetic euro against several other major currencies over the period 1979 2003 we find support for the ppp hypothesis for the full panel of real exchange rates when the restriction of a common mean reversion coefficient is relaxed we reject the unit root hypothesis for the euro swiss franc rate only we conclude that the process of economic integration in europe has accelerated convergence toward ppp within the euro area

evidence of purchasing power parity for the floating regime period abstract this paper investigates the ppp hypothesis within industrialized countries for the post bretton woods period via two panel unit root tests the df gls sur and the adf sur tests respectively developed by lopez a panel unit root with good power in small samples econometric reviews in press and levin et al 2002 unit root tests in panel data asymptotic and finite sample properties journal of econometrics 108 1 1 24 both approaches allow for data specific serial and contemporaneous correlation while both tests provide ppp evidence for the post 1973 period the more powerful df gls sur test demonstrates consistently stronger results especially for the 1973 1998 period

real exchange rate adjustment in european transition countries abstract in single equation tests real exchange rates show mean reversion for nine of 10 central and eastern european transition countries for the period january 1993 to december 2005 because of the shift from controlled to market economies and accompanying crises failed policy regimes and changes in exchange rate regimes unit root tests for transition countries often require allowance for structural changes accounting for structural breaks gives substantially faster mean reversion speeds than those found for major industrialized countries these fast adjustment speeds are plausible transition countries had perhaps 10 years to make unprecedented adjustments required for accession to the european union a number of papers have applied non linear models to the central and eastern european countries this paper investigates four non linear models and compares them with piece wise linear break models the break models appear superior in detecting mean reversion for the central and eastern european transition countries

own brand and cross brand retail pass through in this paper we describe the pass through behavior of a major u s supermarket chain for 78 products across 11 categories our data set includes retail prices and wholesale prices for stores in 15 retail price zones for a one year period for the empirical model we use a reduced form approach that focuses directly on equilibrium prices as a function of exogenous supply and demand shifting variables the reduced form approach enables us to identify the theoretical pass through rate without specific assumptions about the form of consumer demand or the conduct of a category pricing manager thus our measurements of pass through are not constrained by specific structure on the underlying economic model the empirical pricing model includes costs of all competing products in the category on the right hand side not only the cost of the focal brand and yields estimates of both own brand and cross brand pass through rates our results provide a rich picture of the retailer s pass through behavior we find that pass through varies substantially across products and across categories own brand pass through rates are on average more than 60 for 9 of 11 categories a finding that is at odds with the claims of manufacturers about retailers in general importantly we find substantial evidence of cross brand pass through effects indicating that retail prices of competing products are adjusted in response to a change in the wholesale price of any given product in the category we find that cross brand pass through rates are both positive and negative we explore determinants of own brand and cross brand pass through rates and find strong evidence in multiple categories of asymmetric retailer response to trade promotions on large versus small brands for example brands with larger market shares and brands that contribute more to retailer profits in the category receive higher pass through we also find that trade promotions on large brands are less likely than small brands to generate positive cross brand pass through i e induce the retailer to reduce the retail price of competing smaller products on the other hand small share brands are disadvantaged along three dimensions trade promotions on small brands receive low own brand pass through and generate positive cross brand pass through for larger competing brands moreover small share brands do not receive positive cross pass through from trade promotions on these larger competitors we also find that store brands are similarly disadvantaged with respect to national brands

long memory and nonlinear mean reversion in japanese yen based real exchange rates abstract the extraordinary difficulty in uncovering parity reversion in yen based real exchange rates has often been ascribed to a missing trend variable this study identifies an alternative explanation and shows that the puzzling behavior of real yen rates may stem from long memory dynamics which undermine unit root tests in their ability to detect mean reversion the long memory findings are consistent with the long swings in yen exchange rates during the current float further analysis also reveals evidence of non monotonic reversion toward parity

productivity differentials the relative price of non tradables and real exchange rates abstract this paper reconciles the apparent contradiction between recent panel unit root tests of real exchange rates and the productivity differential model proposing an alternative view that explains the coexistence of such findings real exchange rates and the relative price of non tradables reflect the gradual adjustment of mean reverting and endogenously competing factors supply and demand shocks as well as traded goods arbitrage granger causality and variance decomposition results indicate substantial simultaneity and feedback effects between real exchange rates the relative price of non tradables and productivity differentials

on the failure of purchasing power parity for bilateral exchange rates after 1973 point estimates suggest mean reversion in real exchange rates however it still remains uncomfortable that models without any mean reversion are often compatible with data from the floating period studies with data over longer periods find mean reversion but at the cost of mixing in data from earlier exchange rate arrangements pooling the floating period data potentially mixes country pairs with and without mean reversion we examine tests for mean reversion for individual country pairs where greater power against close alternatives is gained through modeling other economic variables with the real exchange rate by increasing the power of the tests we find strong evidence of mean reversion

does the exchange rate follow a random walk a monte carlo study of four tests for a random walk abstract several authors have urged that real and nominal exchange rates follow a random walk conditions under which the exchange rate follows a random walk are reviewed in this paper many of these do not appear to hold therefore the empirical evidence presents a puzzle some evidence suggets the exchange rate follows a random walk while other evidence suggests the opposite should be true this paper attempts to reconcile the evidence it is argued that the tests for a random walk have low power monte carlo evidence on four tests for a random walk is presented that suppors this claim

option pricing with mean reversion and stochastic volatility many underlying assets of option contracts such as currencies commodities energy temperature and even some stocks exhibit both mean reversion and stochastic volatility this paper investigates the valuation of options when the underlying asset follows a mean reverting lognormal process with stochastic volatility a closed form solution is derived for european options by means of fourier transform the proposed model allows the option pricing formula to capture both the term structure of futures prices and the market implied volatility smile within a unified framework a bivariate trinomial lattice approach is introduced to value path dependent options with the proposed model numerical examples using european options american options and barrier options demonstrate the use of the model and the quality of the numerical scheme

fifteen years of bt cotton in china the economic impact and its dynamics summary even though the economic benefit of bt cotton adoption in the short run has been well documented the dynamics of this benefit remain unclear in particular the possibility of pest resistance build up and secondary pest outbreaks has caused concern regarding the sustainability of this economic benefit in the long run hence this study analyzes the economic impact of bt cotton and its dynamics in china using nationally representative long panel data for 1997 2012 we show that this economic benefit continues 15 years after the commercialization of bt cotton

why panel tests of purchasing power parity should allow for heterogeneous mean reversion recent studies of purchasing power parity ppp use panel tests that fail to take into account heterogeneity in the speed of mean reversion across real exchange rates in contrast to several other severe restrictions of panel models and tests of ppp the assumption of homogeneous mean reversion is still widely used and its consequences are virtually unexplored this paper analyzes the properties of homogeneous and heterogeneous panel unit root testing methodologies using monte carlo simulation we uncover important adverse properties of the panel approach that relies on homogeneous estimation and testing more specifically power functions are low and assume irregular shapes furthermore homogeneous estimates of the mean reversion parameters exhibit potentially large biases these properties can lead to misleading inferences on the validity of ppp our findings highlight the importance of allowing for heterogeneous estimation when testing for a unit root in panels of real exchange rates

pricing and rebate policies for the newsvendor problem in the presence of a stochastic redemption rate abstract this paper develops the pricing rebate ordering policies of a profit maximizing vendor faced with a stochastic rebate redemption rate and a price rebate dependent random demand all within the single period framework of the newsvendor problem the profitability of these policies directly relates to the redemption rate which in turn depends upon the rebate value by itself and relative to the sales price a random element accounts for the uncertainty in the estimation of such rate the decision variables are the sales price the rebate value and the order size a numerical example and various sensitivity analyses illustrate the main managerial insights of the model one of the key results is that the introduction of uncertainty in the redemption rate contrary to what happens when moving from a deterministic to a stochastic demand leads the rebate policy to dominate its price discount counterpart

the choice of numeraire currency in panel tests of purchasing power parity we investigate the implications of the choice of numeraire currency on panel tests of purchasing power parity under the current regime of flexible exchange rates by conducting panel unit root tests with twenty one different base currencies we show that the conditions necessary for numeraire irrelevancy are not supported empirically and that the choice of numeraire currency can and does matter for ppp the evidence of ppp is stronger for european than for non european base currencies distance between the countries and volatility of the exchange rates are the most important determinants of the results

increasing evidence of purchasing power parity over the current float we conduct unit root tests of real exchange rates with the united states dollar and the german mark as base currencies using samples of data which begin in 1973 and end between 1982 and 1996 we find that as the sample is extended the evidence of ppp strengthens with panel but not univariate methods because of the sharp rise and fall of the dollar in the early 1980s rejections of the unit root null do not monotonically increase with the sample size the evidence of ppp is uniformly stronger when the mark is used as the base currency

bounds tests of the theory of purchasing power parity abstract in this paper we test the absolute and relative purchasing power parity ppp hypotheses during the recent flexible exchange rate period using quarterly data for 21 oecd countries in doing so we use a new econometric technique developed by m h pesaran et al bounds testing approaches to the analysis of long run relationships university of cambridge department of applied economics working paper 9907 this approach is particularly interesting as it is capable of testing the existence of long run relations regardless of whether the underlying variables are stationary integrated or mutually cointegrated

panel unit root tests of purchasing power parity for price indices abstract this paper adopts four panel unit root tests to evaluate ppp over the floating period for six different price indices results generally support ppp albeit the speeds of adjustment differ considerably between price indices and test procedures the degree of contemporaneous and serial correlation as well as heterogeneity of the series in the panel affect stationarity and the speed of mean reversion

a joint optimal pricing rebate value and lot sizing model delayed incentives in the form of mail in cash rebates are very popular among manufacturers and more recently among retailers one of the main advantages of rebates is that while they increase demand a small proportion of consumers redeem them in this paper we formulate and solve models for jointly determining the optimal price rebate face value and the optimal order quantity for a price and rebate sensitive deterministic demand the models show that under realistic conditions offering rebates can have significant pricing and inventory policy implications and can lead to a significant increase in profit

the re emergence of ppp in the 1990s abstract in this paper we investigate purchasing power parity ppp in a panel with 17 countries for the period 1972 through 1996 the novel feature of our panel methodology is that results are invariant to the choice of a benchmark on numeraire currency in the panel we allow individual country effects in the relation between prices and exchange rates in this way we can identify the currency pairs for which ppp holds or does not hold we conclude that there is substantive evidence for ppp although not to the same extent for every currency evidence in favor of ppp is strongest for many exchange rates relative to the dmark and weakest for the japanese yen for this currency a trend like variable like productivity growth is missing

the role of rebates in the hybrid competition between a national brand and a private label with present biased consumers abstract over the past years rebates have been increasingly used by national brand nb manufacturers conventional wisdom suggests that rebates are beneficial to firms as long as positive slippage exists based on the present biased preference theory we investigate the performance of nb rebates as a counterstrategy to the retailer s private label pl game theoretic models are developed to characterize channel dynamics involving consumers knowledge levels of the present biased preferences our model reveals multiple insights first a positive slippage rate does not necessarily benefit the nb manufacturer if the rebates fail to expand the demand of the nb second the retailer s commitment to the original nb price plays a positive role in improving the equilibrium profits of both parties third for loss averse consumers under preference uncertainties the nb manufacturer and the retailer prefer a low redemption cost in contrary to the conventional idea that sellers take advantage of consumers with high redemption costs

mean variance asset liability management cointegrated assets and insurance liability abstract the cointegration of major financial markets around the globe is well evidenced with strong empirical support this paper considers the continuous time mean variance mv asset liability management alm problem for an insurer investing in an incomplete financial market with cointegrated assets the number of trading assets is allowed to be less than the number of brownian motions spanning the market the insurer also faces the risk of paying uncertain insurance claims during the investment period we assume that the cointegration market follows the diffusion limit of the error correction model for cointegrated time series using the markowitz 1952 mv portfolio criterion we consider the insurer s problem of minimizing variance in the terminal wealth given an expected terminal wealth subject to interim random liability payments following a compound poisson process we generalize the technique developed by lim 2005 to tackle this problem the particular structure of cointegration enables us to solve the alm problem completely in the sense that the solutions of the continuous time portfolio policy and efficient frontier are obtained as explicit and closed form formulas

village wide effects of agricultural biotechnology the case of bt cotton in india previous studies on impacts of agricultural biotechnology have mostly focused on direct effects we suggest an economy wide framework to analyze income distribution aspects more carefully for a village in india a micro social accounting matrix sam is developed and used to simulate the effects of bt cotton adoption overall the technology is employment generating although family labor in cotton production is saved while substantial benefits are observed for small and large farmers total household income effects are bigger for larger farms this is mostly due to differential opportunity incomes of saved family labor some research and policy implications are discussed

some new stylized facts of floating exchange rates abstract this paper re examines real exchange rate behavior of oecd currencies under the current float using the more extensive dataset that an additional decade s worth of experience has made available what emerges is a new set of stylized facts which suggest that the problems of the current float were not as commonly believed generic to that system but in fact rather specific being largely confined to one sub period the early and mid 1980s and one currency the us dollar this dollar behavior ranks as one of the important puzzles of the past 25 years

a general theory of pass through in channels with category management and retail competition i provide a general formulation of the channel pass through problem as a comparative static of the retail price equilibrium and i analyze the impact of category management and retail competition on pass through focusing on brand and retailer differences and the nature of the cost change being passed through whether it is brand specific retailer specific both or neither with category management a retailer s response to a brand specific cost change is not limited to that brand in general a retailer will also change the prices of other brands the cross brand effect can be positive or negative and depending on its sign it either enhances or attenuates pass through i explain the cross brand effect as an interaction between two forces a demand substitution force that pushes for a negative cross brand effect and a strategic complementarity force that pushes for a positive cross brand effect retail competition adds another layer of strategic complementarity causing other retailers to respond even for retailer specific cost changes and increasing pass through of categorywide cost changes but its effect for brand specific cost changes is ambiguous i apply the theory to two commonly used demand functions linear demand and nested logit and show that they have significantly different pass through properties the paper concludes with a discussion of how the theory relates to the empirical literature including the companion piece by besanko et al besanko d j p duba s gupta 2005 own brand and cross brand retail pass through marketing sci 24 1 123 137

real exchange rates under the gold standard purchasing power parity is one of the most important equilibrium conditions in international macroeconomics empirically it is also one of the most hotly contested numerous recent studies for example have sought to determine the validity of purchasing power parity using data from the post bretton woods float and have reached different conclusions we assert that most such studies are flawed for two reasons first the post 1973 data contain by definition only a very limited amount of the low frequency information relevant for examination of long run parity second the dynamic econometric techniques used to model deviations from parity are typically quite crude with respect to admissible low frequency dynamics both deficiencies are rectified in the present paper with dramatic results we construct a new data set of 16 real exchange rates covering more than a century of the classic gold standard period and we study deviations from parity using long memory models that allow for subtle forms of mean

impact of bt cotton in china abstract a sample of 283 cotton farmers in northern china was surveyed in december 1999 farmers that used cotton engineered to produce the bacillus thuringiensis bt toxin substantially reduced the use of pesticide without reducing the output ha or quality of cotton this resulted in substantial economic benefits for small farmers consumers did not benefit directly farmers obtained the major share of benefits and because of weak intellectual property rights very little went back to government research institutes or foreign firms that developed these varieties farmers using bt cotton reported fewer pesticide poisonings than those using conventional cotton

the politics of technological upgrading international transfer to and adaptation of gm cotton in argentina summary we describe patterns of international transfer to and adaptation of genetically modified gm cotton in argentina and ask whether political bargaining between the technology owner a multinational enterprise mne and host country actors may have influenced upgrading we suggest that the mne was able to use its exclusive capacity to upgrade gm cotton technologies as a negotiation tool to persuade host actors to change the rules that affected its multi lines of business in the country this implies wider policy scope to encourage technology upgrading host actors could negotiate over a wider range of aspects of interest to mnes

multi country evidence on the behavior of purchasing power parity under the current float abstract using panel data for the united states and 22 other oecd countries for the current float this paper presents evidence that despite substantial short term perturbations purchasing power parity actually performed much better than commonly believed average rates of growth of real exchange rates over long horizons bear little relationship either to average rates of growth of nominal exchange rates or to average inflation differentials thus implying a close to one to one relation between average rates of growth of nominal exchange rates and average inflation differentials panel data variants of standard unit root tests suggest that the real exchange rates of these countries can be characterized as mean reverting

real exchange rates and switching regimes abstract we suggest that the real exchange rate between the major currencies in the post bretton woods period can be described by a stationary 2 state markov switching ar 1 model based on the forecast performance we find that this model outperforms two competing models where the real exchange rate is nonstationary we also find that the existence of different regimes as in the markov switching model is consistent with the common finding of unit roots in real exchange rates

bt cotton in india field trial results and economic projections abstract the performance of bt cotton in india is analyzed on the basis of field trial data from 2001 the amounts of pesticides applied during the trials were reduced to one third of what was used in conventional cotton while under severe pest pressure yield gains were 80 productivity effects are modeled econometrically with a damage control specification the first approval for the commercial cultivation of bt hybrids was given in 2002 by 2005 the technology is expected to cover one quarter of total indian cotton area medium term projections show sizeable welfare gains for the overall economy with farmers being the main beneficiaries

how a dominant retailer might design a purchase contract for a newsvendor type product with price sensitive demand abstract a dominant retailer will purchase a newsvendor type product from a manufacturer who incurs a unit manufacturing cost k the expected retail demand is a function of the unit retail price p how should the retailer design her purchase contract for this increasingly prevalent but inadequately studied scenario we propose plausible adaptations of several contract formats that have been widely studied in the dominant manufacturer context for both symmetric k and a symmetric k knowledge situations we present performance results of these contracts our results then reveal that the performance of these contract formats under our scenario differs considerably from what one would surmise from the well known results published for closely related scenarios for example the widely studied buyback and revenue sharing formats turn out to be largely ineffective when implemented by a dominant retailer in contrast the two part tariff format performs well relative to the theoretically optimal menu of contracts our results highlight the need to study purchase contract formats designed specifically for dominant retailer newsvendor product channels

a panel project on purchasing power parity mean reversion within and between countries abstract previous time series studies have shown evidence of mean reversion in real exchange rates deviations from purchasing power parity ppp appear to have half lives of approximately four years however the long samples required for statistical significance are unavailable for most currencies and are potentially inappropriate because of regime changes in this study we re examine deviations from ppp using a panel of 150 countries and 45 annual post wwii observations our panel shows strong evidence of mean reversion that is similar to that from long time series ppp deviations are eroded at a rate of approximately 15 annually i e their half life is around four years such findings can be masked in time series data but are relatively easy to find in cross sections

long run purchasing power parity with short run data evidence with a null hypothesis of stationarity abstract we investigate long run purchasing power parity with data from the current floating exchange rate period by using tests where stationarity and cointegration are the null rather than the alternative hypotheses in most cases we cannot reject either the null hypothesis of stationarity of the real exchange rate or the null of cointegration between the nominal exchange rate and the domestic and foreign price levels this constitutes evidence of long run purchasing power parity because using the same tests we can reject the null of stationarity for the nominal exchange rate confirmation of the results is provided by a monte carlo study

note the role of returns policies in pricing and inventory decisions for catalogue goods manufacturers often use returns policies to encourage retailers to stock and price items more aggressively we focus on the effect that such policies have on both a retailer s and a manufacturer s profits when the retailer must commit prior to the selling season to both a stocking quantity and a price at which to sell an item such a commitment is often necessary for retailers who sell primarily through catalogues

searching for evidence of long run ppp from a post bretton woods panel separating the wheat from the chaff abstract this paper reexamines the issue of long run ppp using multiple panel tests in the framework of confirmatory analysis application of six panel tests under competing null hypotheses to the real exchange rates of 21 industrial countries yields seemingly contradictory evidence on the parity during the post bretton woods period regardless of numeraire currency four i 1 panel tests unanimously reject the null hypothesis in favor of long run ppp whereas two i 0 panel tests lend little support to the parity at conventional significance levels confirmatory analysis suggests that this puzzling result can be explained either by nonlinear dynamics of the real exchange rates or by a mixture of i 0 and i 1 series in the panel monte carlo experiments indicate that potential mix of i 0 and i 1 series is more relevant to the empirical finding the use of a sequential classification method sorts out six real exchange rates which exhibit most persistent deviations from long run equilibrium systematic behavior of these series can be characterized better by country specific factors than by observable macroeconomic variables

the panel purchasing power parity puzzle does long run purchasing power parity ppp hold over the post 1973 floating exchange rate period panel unit root tests provide evidence of ppp that increases with the number of observations the strengthening of the evidence however is highly cyclical when the dollar appreciates at the end of the sample the evidence of ppp strengthens and when it depreciates the evidence weakens while these patterns cannot be explained by the specifications that are normally used to model real exchange rates the strengthening but not the cyclical pattern can be explained by a specifi cation that incorporates ppp restricted structural change

testing purchasing power parity under the null hypothesis of co integration this paper analyzes monthly data on the exchange rates and price indices of the eleven major industrial countries over the modern period of floating exchange rates it presents tests that are based upon the null hypothesis of cointegration the paper finds evidence that most country pairs not involving north american currencies have exchange rates and price indices that are cointegrated it estimates the error correction representation for the series that are cointegrated and it shows that the dynamic adjustment of the relationship between exchange rates and prices is accomplished almost entirely in the market for foreign exchange copyright 1991 by royal economic society

a long run view of the european monetary system abstract this papaer analyzes the exchange rates and consumer price indices of six countries participating in the european monetary system ems during the entire period of floating exchange rates the analysis shows that most of these real exchange rates have unit roots even when one allows for the possibility of a structural break at the time of the advent of the ems further proces and exchange rates are not co integrated during the ems period the data suggest that the 12 realignments of the ems have not served fully too offset the member countries inflation differentials

searching for stationarity purchasing power parity under the current float abstract using panel data methods we investigate long run purchasing power parity by testing for unit roots in real exchange rates of industrial countries under the current float the evidence against the unit root hypothesis is stronger for larger than for smaller panels for monthly than for quarterly data and when the german mark rather than the united states dollar is used as the base currency while we find that accounting for serial correlation considerably weakens the evidence against the unit root null the results as a whole are consistent with long run purchasing power parity

the behaviour of relative prices in the european union a sectoral analysis using multivariate unit root test methods this paper investigates the purchasing power parity ppp hypothesis at the sectoral level across six european countries over the last 17 years evidence of mean reversion towards ppp is found for the relative prices of some sectors and countries mean reversion in relative prices is explained by cross country and cross sectoral characteristics such as the distance between countries nominal exchange rate volatility differences in gdp per capita non tariff barriers research and development advertising industrial concentration and tradeability of the products

model free evaluation of directional predictability in foreign exchange markets we examine directional predictability in foreign exchange markets using a model free statistical evaluation procedure based on a sample of foreign exchange spot rates and futures prices in six major currencies we document strong evidence that the directions of foreign exchange returns are predictable not only by the past history of foreign exchange returns but also the past history of interest rate differentials suggesting that the latter can be a useful predictor of the directions of future foreign exchange rates this evidence becomes stronger when the direction of larger changes is considered we further document that despite the weak conditional mean dynamics of foreign exchange returns directional predictability can be explained by strong dependence derived from higher order conditional moments such as the volatility skewness and kurtosis of past foreign exchange returns moreover the conditional mean dynamics of interest rate differentials contributes significantly to directional predictability we also examine the co movements between two foreign exchange rates particularly the co movements of joint large changes there exists strong evidence that the directions of joint changes are predictable using past foreign exchange returns and interest rate differentials furthermore both individual currency returns and interest rate differentials are also useful in predicting the directions of joint changes several sources can explain this directional predictability of joint changes including the level and volatility of underlying currency returns copyright 2007 john wiley sons ltd

nonlinear trends in real exchange rates a panel unit root test approach abstract we analyze the possibility of nonlinear trend stationarity as the alternative to unit roots in 23 oecd real exchange rates 1974 1998 by adding nonlinear time terms to the cips panel unit root test of pesaran 2007 we follow a thorough bootstrapping approach and propose a technique to adjust statistical significance for the use of multiple tests over several time trend orders the unit root null that all real exchange rates have unit roots is rejected at better than the 0 05 level bootstrapped results from a procedure of chortareas and kapetanios 2009 suggest that the hypothesis that all are stationary is reasonable we argue that nonlinear trend stationarity is the most likely alternative hypothesis for at least some of the real exchange rates because 1 the strongest cips rejection occurs when quadratic trends are specified 2 nonlinear time terms are statistically significant at the 0 10 level 3 the actual cips statistics are more consistent with cips sampling distributions from bootstrapped nonlinear trend stationary processes than from linear trend or mean stationary processes

estimating the impact of transgenic bt cotton on west and central africa a general equilibrium approach summary west and central africa wca s cotton sector is experiencing rising production costs and lower yields reversing decades of growth declining input use soil fertility and inefficient chemical pest controls are contributing factors we evaluate the potential impact of bt cotton on wca using a multiregion general equilibrium model and multicountry estimates of bt induced productivity we find that bt cotton raises growers returns land value and welfare released labor from cotton is shifted to food crops hence reducing labor shortage constraints overall results indicate that potential gross benefits from bt cotton are substantial for wca cotton sector and that the economic costs of nonadoption are equally significant published by elsevier ltd

impact of bt cotton on pesticide poisoning in smallholder agriculture a panel data analysis while substantial research on the productivity and profit effects of bt cotton has been carried out recently the economic evaluation of positive and negative externalities has received much less attention here we focus on farmer health impacts resulting from bt related changes in chemical pesticide use previous studies have documented that bt cotton has reduced the problem of pesticide poisoning in developing countries but they have failed to account for unobserved heterogeneity between technology adopters and non adopters we use unique panel survey data from india to estimate unbiased effects and their developments over time bt cotton has reduced pesticide applications by 50 with the largest reductions of 70 occurring in the most toxic types of chemicals results of fixed effects poisson models confirm that bt has notably reduced the incidence of acute pesticide poisoning among cotton growers these effects have become more pronounced with increasing technology adoption rates bt cotton now helps to avoid several million cases of pesticide poisoning in india every year which also entails sizeable health cost savings

the overvaluation of purchasing power parity abstract recent panel studies of purchasing power parity have reported strong evidence of mean reversion in real exchange rates however these studies fail to control for cross sectional dependence in the data this failure has dramatic consequences raising the significance level of tests with a nominal size of 5 percent to as much as 50 percent it is shown in this paper that controlling for cross sectional dependence no evidence against the random walk null can be found in panels of up to 64 real exchange rates this finding cannot be attributed to low power as there is ample power in panels of this size to reject the unit root null