sequential procurement auctions abstract two auctions are held in sequence with the possibility of learning between the second and the first the buyer optimally chooses to discriminate against the winner of the first auction in the second the optimal mechanism has a discontinuity in the winner s second bid this strictly dominates a sequence of independent sealed bid auctions

determinants of prices increase of agricultural commodities in a global context the main objective of this article is to present the determinants of increase in agricultural commodity prices after 2006 the other specific aim is to show the factors affecting agricultural raw materials and food prices in the global context this article is a review paper of the determinants of recent commodity and food prices spikes however it provides an outlook on these determinants that were the most important for the increases in the last decade the last part of the article conclusions to some extent is a synthesis of considerations and includes the authors opinions concerning determinants and an attempt to identify which ones were the most important in the growth of agricultural commodity prices these increases in agricultural commodity prices resulted from many factors and it is very difficult to separate the individual impact of each of them because they occurred in parallel however it is possible to indicate several main reasons for these price increases which are adverse changes in supply demand relations in agricultural markets increases in oil prices and increases of the volatility of those prices development of biofuel production from agricultural commodities the first generation biofuels dollar depreciation an increase in operations of a speculative nature on commodity markets and improper economic policy that created an environment for the growth of prices of agricultural products

optimal procurement contracts with pre project planning the paper studies procurement contracts with pre project investigations in the presence of adverse selection and moral hazard to model the procurer s problem we extend a standard sequential screening model to endogenous information acquisition with moral hazard the optimal contract displays system atic distortions in information acquisition due to a rent effect adverse selection induces too much infor mation acquisition to prevent cost overruns and too little information acquisition to prevent false project cancellations moral hazard mitigates the distortions related to cost overruns yet exacerbates those related to false negatives the optimal mechanism is a menu of option contracts that achieves the dual goal of providing incentives for information acquisition and truthful information revelation

equilibrium reserve prices in sequential ascending auctions abstract we study a model where bidders have perfectly correlated valuations for two goods sold sequentially in two ascending price auctions the seller sets a reserve price before the beginning of each auction despite the lack of commitment by the seller we characterize an equilibrium and study its properties strategic non disclosure of information takes the form of non participation in the early auction by low valuation bidders while high valuation bidders bid up to their true valuations some buyers who would profitably buy at the reserve price refrain from participating in order to decrease the second auction reserve price

retailers and consumers in sequential auctions of collectibles we analyse an independent private value model where heterogeneous bidders compete for objects sold in sequential second price auctions in this heterogeneous game bidders may have differently distributed valuations and some have multi unit demand with decreasing marginal values retailers others have a specific single unit demand consumers by examining equilibrium bidding strategies and price sequences we show that the presence of consumers leads to more aggressive bidding from the retailers on average and heterogeneous bidders is a plausible explanation of the price decline effect the study of the expected revenue of the seller confirms the interest of auctioneers in inviting different types of bidders nous analysons un modele a valeurs privees independantes dans lequel des encherisseurs heterogenes sont en concurrence pour des objets vendus lors d encheres sequentielles au second prix dans ce jeu heterogene les encherisseurs tirent leurs evaluations de distributions qui peuvent differer et certains les revendeurs ont des demandes multi unitaires avec des evaluations marginales decroissantes alors que les autres les consommateurs ont une demande individuelle specifique l examen des strategies d equilibre et des sequences de prix montrent que la presence de consommateurs conduit en moyenne a des encheres plus agressives de la part des revendeurs et que la presence d encherisseurs heterogenes constitue une explication plausible a la decroissance des prix l etude de l esperance du revenu du vendeur confirme l interet des commissaires priseurs a inviter differentes categories d acheteurs

perfect equilibria in budget constrained sequential auctions an experimental study this article presents an experimental study of bidding behavior in sequential auctions in which there are budget constraints and perfect information our experiments test both the properties of such auctions and the predictive power of a refinement of the nash equilibrium concept we find that budget constraints affect the behavior of bidders and that the trembling hand perfect equilibrium is generally a good predictor of prices

stability and competitive equilibrium in trading networks we introduce a model in which agents in a network can trade via bilateral contracts we find that when continuous transfers are allowed and utilities are quasi linear the full substitutability of preferences is sufficient to guarantee the existence of stable outcomes for any underlying network structure furthermore the set of stable outcomes is essentially equivalent to the set of competitive equilibria and all stable outcomes are in the core and are efficient by contrast for any domain of preferences strictly larger than that of full substitutability the existence of stable outcomes and competitive equilibria cannot be guaranteed

piecewise procurement of a large scale project this paper studies the optimal piecewise procurement of a large scale project in the unique markov perfect equilibrium mpe of the dynamic procurement game it is found that 1 unlike the static setting the procurer s optimal strategy depends on the number of suppliers and more importantly it is nonmonotonic as one more supplier participates in the procurement auction the procurer softens competition in the initial stages by including more cost btypesq while increasing competition in the mature stages 2 this in turn implies that existing suppliers might favor participation of additional suppliers 3 absent scheduling and or resource constraints the procurer prefers to procure the project as one piece if the suppliers technology exhibits constant or increasing returns and no additional suppliers are enticed to bid and 4 the optimal dynamic mechanism can be easily implemented via a sequence of dominant strategy auctions of the vickrey type d 2004 elsevier b v all rights reserved

cost reducing investment optimal procurement and implementation by auctions the authors analyze a model in which potential suppliers invest in research and development r d and then compete for a procurement contract from a buyer if the buyer is able to commit to a procurement mechanism before the investment stage the full information solution can be uniquely implemented by first price and second price sealed bid auction mechanisms when the r d technology exhibits decreasing returns to scale if the procurement mechanisms and the levels of investment are chosen simultaneously the full information solution cannot be implemented the authors discuss how the second best equilibrium contract varies with the number of suppliers copyright 1996 by economics department of the university of pennsylvania and the osaka university institute of social and economic research association

sequential auctions of interdependent objects israeli cable television licenses in israel area cable television catv licenses were auctioned sequentially this paper provides evidence that i there were interdependencies among many of the franchises and that ii subscriber fees for the interdependent franchises decreased over time in this auction

bottom fishing and declining prices in sequential auctions abstract we study standard sequential auctions in which the seller chooses the order of sale and right to choose auctions in which the winner chooses her preferred item from the remaining items empirically prices in sequential auctions tend to decline and sellers often hold right to choose auctions in our setting the right to choose format guarantees declining prices and efficiency in the standard auction a buyer may submit a low bid for the first item bottom fishing despite its being her less preferred item an example shows that the standard auction has declining prices is inefficient and gives lower expected revenue than the right to choose journal of economic literature classification numbers d44 d82

long run purchasing power parity during the recent float abstract this paper examines the relevance of long run purchasing power parity ppp which allows for measurement errors during the recent floating exchange rate period previous empirical studies generally fail to find support for long run ppp over this period in this paper in this paper the cointegration property of exchange rates and prices is examined using maximum likelihood procedure and we find significant evidence favorable to long run ppp further tests for symmetry and proportionality indicate that these two conditions are not generally with the data the results support the hypothesis of long run ppp with measurement errors in prices

repeated auctions of incentive contracts investment and bidding parity with an application to takeovers this article considers a two period model of natural monopoly and second sourcing the incumbent supplier invests in the first period after observing the incumbent s first period performance the buyer may break out in the second period the investment may or may not be transferable to the second source and it may be monetary or take the form of human capital we determine whether the incumbent should be favored at the reprocurement stage and how the slope of his incentive scheme should evolve over time we find that the gains from second sourcing are not so large as one might hope finally we reinterpret the second source as a raider and the breakout as a takeover we discuss the desirability of defensive tactics and obtain a rich set of testable implications concerning the size of managerial stock options the extent of defensive tactics the firm s performance and the probability of a takeover

the purchasing power parity debate originally propounded by the 16th century scholars of the university of salamanca the concept of purchasing power parity ppp was revived in the interwar period in the context of the debate concerning the appropriate level at which to re establish international exchange rate parities broadly accepted as a long run equilibrium condition in the post war period it first was advocated as a short run equilibrium by many international economists in the first few years following the breakdown of the bretton woods system in the early 1970s and then increasingly came under attack on both theoretical and empirical grounds from the late 1970s to the mid 1990s accordingly over the last three decades a large literature has built up that examines how much the data deviated from theory and the fruits of this research have provided a deeper understanding of how well ppp applies in both the short run and the long run since the mid 1990s larger datasets and nonlinear econometric methods in particular have improved estimation as deviations narrowed between real exchange rates and ppp so did the gap narrow between theory and data and some degree of confidence in long run ppp began to emerge again in this respect the idea of long run ppp now enjoys perhaps its strongest support in more than 30 years a distinct reversion in economic thought

purchasing power parity under the gold standard 1 introduction long run purchasing power parity lrppp a mainstay of international economic theory has proved difficult to back up empirically many attempts have been made using various time series of data yet results continue to be mixed a standout exception to these mixed results is presented by diebold husted and rush 1991 whose work has been interpreted as very strong evidence of lrppp because of their across the board rejection of the unit root for a large sample of real exchange rates baillie 1996 p 51 cites diebold husted and rush as reestablishing purchasing power parity as a meaningful long run concept despite the substantial mixed results of other studies these mixed results are usually attributed to the power problems associated with standard unit root tests especially for small samples diebold husted and rush 1991 overcome these shortcomings by loosening the structure of the model to allow a longmemory process diebold husted and rush 1991 model real exchange rate behavior using autoregressive fractionally integrated moving average arfima models in doing so they reject the unit root for 16 real exchange rates from the gold standard era in favor of a fractionally integrated alternative hypothesis a long memory process is essentially a stationary one but where the autocorrelations take far longer to decay than the exponential rate associated with the autoregressive moving average arma class baillie 1996 p 6 this observation implies that purchasing power parity ppp holds but in some cases only in the extreme long run we agree with diebold husted and rush 1991 that the structure of standard unit root tests is overly restrictive however we offer a different solution to this problem from standard unit root tests one must conclude that either all deviations from ppp are permanent or all deviations dissipate over time however there is a third possibility that has both theoretical and empirical support unit root tests do not allow the possibility that while most deviations dissipate a few remain as permanent shocks real exchange rates may show substantial mean reversion but to a changing mean rather than to the constant ppp value this idea which we call quasi purchasing power parity qppp draws support from the balassasamuelson theory which asserts that productivity shocks can have permanent effects on real exchange rates samuelson 1994 p 202 criticizes economists who tried to use ppp as a guide even when substantive microeconomic changes had taken place between the previous putative equilibrium period and the new status quo he cites an example from the 1980s when the actual yen dollar exchange rate was 150 yen per dollar according to ppp the equilibrium exchange rate was 200 yen per dollar yet the rate proceeded to drop to 110 yen per dollar and below in qppp terms this situation would represent not a lack of mean reversion but evidence of an equilibrium that had shifted away from ppp this is a form of the penn effect whereby a rich country in comparison with a poor one will be estimated to be richer than it really is if you pretend that the simplified cassel version of purchasing power parity is correct samuelson 1994 p 201 we assert that this penn effect can occur not just between rich and poor countries but between any two countries if one of these countries is affected by a permanent external shock qppp also supports engel s 1996 p 1 proposition that the real exchange rate evolves as the sum of two processes a stationary but persistent component and a non stationary component it is generally held that while the exchange rate deviates from its long run equilibrium value in the short run it eventually converges to that equilibrium value in the long run the question then is what is that long run equilibrium value some argue it is the ppp level while others argue that there is a complex set of factors determining the long run value including such things as the relative labor productivities at home and abroad engel 1996 p

bundling as an optimal selling mechanism for a multiple good monopolist abstract multiple objects may be sold by posting a schedule consisting of one price for each possible bundle and permitting the buyer to select the price bundle pair of his choice we identify conditions that must be satisfied by any price schedule that maximizes revenue within the class of all such schedules we then provide conditions under which a price schedule maximizes expected revenue within the class of all incentive compatible and individually rational mechanisms in the n object case we use these results to characterize environments mainly distributions of valuations where bundling is the optimal mechanism in the two and three good cases

sequentially optimal auctions abstract in auctions where a seller can post a reserve price but if the object fails to sell cannot commit never to attempt to resell it revenue equivalence between repeated first price and second price auctions without commitment results when the time between auctions goes to zero seller expected revenues converge to those of a static auction with no reserve price with many bidders the seller equilibrium reserve price approaches the reserve price in an optimal static auction an auction in which the simple equilibrium reserve price policy of the seller mirrors a policy commonly used by many auctioneers is computed journal of economic literature classification numbers c78 d44 d82

real and nominal exchange rates in the long run an empirical investigation abstract this paper reports on econometric tests of the hypothesis that purchasing power parity holds as a long run relationship using data on eight industrialized countries during the flexible exchange rate period the empirical work proceeds by i testing whether nominal exchange rates and relative price levels are co integrated and ii conducting impulse response analysis of long run exchange rate and relative price level changes to explain the data keynesian models suggest that shocks during the estimation period were due principally to exogenous shifts in aggregate demand while equilibrium models suggest that monetary factors have been relatively more important

partial pooling at the reserve price in auctions with resale opportunities abstract two features common to many auctions are the use of reserve prices and the existence of secondary markets for the goods being sold even in simple symmetric settings the combination of these features can preclude existence of an equilibrium in symmetric separating bidding strategies with a reserve price sufficiently far below the maximum endogenous valuation a symmetric equilibrium still exists but with some types pooling at the reserve the optimal reserve price depends not only on the joint distribution of bidders information before and after the auction but also on how surplus is divided in the secondary market journal of economic literature classification numbers d44 c7 l1 d82

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

fractional cointegration low frequency dynamics and long run purchasing power parity an analysis of the australian dollar over its recent float a relatively new but generalized concept of fractional cointegration is applied to shed some light on the validity of purchasing power parity ppp as a long run equilibrium condition by examining the long run relationship between quarterly consumer price indices and bilateral exchange rates of the australian dollar and seven major oecd trading partners over australia s recent float the paper demonstrates that relaxing the condition that the residual from the cointegration equation must be a i 0 process provides a wide range of cases of parity reversion with processes that are ci 1 d with 0 d 1 findings tend to suggest that while standard tests of cointegration fail to support cointegration between nominal exchange rates domestic and foreign prices and thus the empirical favour for ppp as a long run phenomenon the fractional cointegration analysis permits deviations from equilibrium to follow a fractionally integrated process and hence captures a much wider class of parity or mean reversion

generalized long memory and mean reversion of the real exchange rate definitive evidence regarding a rapid mean reversion of the real exchange rate is not present when using standard linear methodology including unit root tests and fractional integration to consider the robustness of these results we use an encompassing model the gegenbauer autoregressive moving average garma model which nests as special cases the existing linear methods the garma model accommodates a complete notion of persistence and allows shocks to dissipate slowly in a cyclical manner we find evidence supporting a weak version of purchasing power parity where equilibrium errors are long memory with strongly persistent cycles however this new form of cyclical mean reversion is likely too slow to be economically meaningful the inability to find a strong equilibrium attractor process using a very general encompassing linear methodology provides support for the recent models that allow for a nonlinear attraction process and for shifting real exchange rate equilibria

sequential procurement with subcontracting two symmetric sellers are approached sequentially by fragmented buyers each buyer conducts a second price auction and purchases from the seller who offers the lower price winning an auction affects bidding for future contracts because the sellers have nonconstant marginal costs we assume that the sellers are completely informed and we study the unique equilibrium that survives iterated elimination of weakly dominated strategies if subcontracting between the sellers is impossible the final allocation of contracts is generally inefficient if postauction subcontracting is possible the sellers can be worse off ex ante than when subcontracting is impossible

dissecting the ppp puzzle the unconventional roles of nominal exchange rate and price adjustments the conventional view as expounded by sticky price models is that price adjustment determines the ppp reversion rate this study examines the mechanism by which ppp deviations are corrected nominal exchange rate adjustment not price adjustment is shown to be the key engine governing the speed of ppp convergence moreover nominal exchange rates are found to converge much more slowly than prices with the reversion being driven primarily by nominal exchange rates real exchange rates also revert at a slower rate than prices as identified by the ppp puzzle j econ lit 34 1996 647 c 2003 elsevier b v all rights reserved

the dynamics of incentive contracts the paper studies a simple two period principal agent model in which the principal updates the incentive scheme after observing the agent s first period performance the agent has superior information about his ability the principal offers a first period incentive scheme and observes some measure of the agent s first period performance cost or profit which depends on the agent s ability and unobservable first period effort the relationship is entirely run by short term contracts in the second period the principal updates the incentive scheme and the agent is free to accept the new incentive scheme or to quit the strategies are required to be perfect and updating of the principal s beliefs about the agent s ability follows bayes rule the central theme of the paper is that the ratchet effect leads to much pooling in the first period first for any first period incentive scheme there exists no separating equilibrium second when the uncertainty about the agent s ability is small the optimal scheme must involve a large amount of pooling the paper also gives necessary and sufficient conditions for the existence of partition equilibria and looks at the effect of cost uncertainty

impact of increasing liquid biofuel usage on eu and uk agriculture the biofuels industry in both the uk and the eu as a whole has expanded significantly in recent years in response to various eu biofuel policy initiatives further expansion of biofuel demand will increase the impact of the biofuels sector on agricultural markets this paper examines the impact that increasing levels of first generation biofuel demand to 10 of total transport fuel use in the uk and other eu member states would have on agricultural markets within the eu and specifically the uk using a partial equilibrium modelling system increasing overall biodiesel demand raises demand for vegetable oil and oilseed and in turn their prices the increased grain demand in response to the increased bioethanol demand is mostly sourced from changes in eu net trade

preemptive patenting and the persistence of monopoly this article takes a different tack and inquires whether institutions such as the patent system create opportunities for firms with monopoly power to maintain their monopoly power the results apply to other situations such as brand identification spatial location and capacity expansion which share the characteristic that early or preemptive actions may lower the returns to potential competitors

purchasing power parity over two centuries strengthening the case for real exchange rate stability a reply to cuddington and liang cuddington and liang 2000 purchasing power parity over two centuries journal of international money and finance 19 751 755 examine the long span of sterling dollar real exchange rate data of lothian and taylor 1996 real exchange rate behavior the recent float from the perspective of the past two centuries journal of political economy 104 488 509 and claim to reject long run purchasing power parity by fitting time trends or by considering very high order autoregresssive representations this reply demonstrates however that the central claims of lothian and taylor are in fact strengthened by the implications of cuddington and liang s analysis in that while the economic importance of introducing trend terms is slight this leads to a faster estimated speed of mean reversion c 2000 elsevier science ltd all rights reserved jel classification f31 f41 c22

sequential auctions of stochastically equivalent objects abstract we show that in sequential auctions of a large enough number of stochastically equivalent objects with bounded values prices will on average have a downwards trend

collusion and the choice of auction auctions are used in many different markets including the leasing of a substantial fraction of the natural resources in the united states the procedures used in the auctions conducted by the federal government have been a continuing source of controversy one of the concerns has been the possibility of collusion among bidders this article shows that cartels are stable if the seller uses open ascending bid oral auctions but not if he uses sealed high bid auctions this may help to explain the frequent use of sealed high bid auctions

signal jamming in a sequential auction abstract in a sequence of first price auctions with stable private values bidders strategically conceal their private information until the last auction we characterize equilibrium bidding and explore how such signal jamming affects the dynamics of equilibrium prices

a two stage sequential auction with multi unit demands abstract working within the independent private values paradigm i examine a sequence of two second price auctions where individual bidders have diminishing marginal valuations equilibria are characterized for complete and incomplete informational settings when information is complete allocations can be inefficient and price sequences are constant or decreasing however when information is incomplete and symmetric equilibrium behavior produces efficient outcomes and an expectation of increasing prices these divergent findings are reconciled using an argument based on ex ante bidder asymmetry that can also explain the declining price anomaly finally comparisons to other auctions are made in terms efficiency and revenue generation journal of economic literatureclassification number d44

sequential auctions of endogenously valued objects two completely informed but possibly asymmetric bidders buy or sell identical claims in sequential auctions they subsequently receive monetary prizes that depend upon the final allocation of claims iterated elimination of weakly dominated strategies leaves a unique nash equilibrium for any prize schedule prices weakly decline as the auctions progress and points of strict decline have a simple characterization for one class of prize schedules which arises naturally if duopolists bid for a scarce input the equilibrium is completely characterized many initial allocations generate the same final unequal division of claims which may be interpreted as the natural market structure journal of economic literature classification numbers d43 d44 l11

sequential auctions with informational externalities and aversion to price risk decreasing and increasing price sequences a large body of empirical research has shown that prices of identical goods sold sequentially sometimes increase and often decline across rounds this article introduces a tractable form of risk aversion called aversion to price risk and shows that declining prices arise naturally when bidders are averse to price risk when there are informational externalities there is a countervailing effect which pushes prices to raise along the path of a sequential auction even if bidder s signals are independent the article shows how to decompose the effect of aversion to price risk from the effect of informational externalities

research note optimal selling in dynamic auctions adaptation versus commitment this paper analyzes optimal selling strategies of a monopolist facing forward looking patient unit demand bidders in a sequential auction market such a seller faces a fundamental choice between two selling regimes adaptive selling that involves learning about remaining demand from early prices and commitment selling that forgoes such learning and makes all selling decisions in the beginning of the game a model of the game between the seller and the bidders is proposed to characterize the optimal regime choice the model implies that the relative profitability of the two regimes depends on the expected gains from trade when the expected gains from trade are low commitment dominates adaptation and vice versa

collusion via signalling in simultaneous ascending bid auctions with heterogeneous objects with and without complementarities collusive equilibria exist in simultaneous ascending bid auctions with multiple objects even with large complementarities in the buyers utility functions the bidders collude by dividing the objects among themselves while keeping the prices low in the most collusive equilibrium the complementarities are never realized the scope for collusion however narrows as the ratio between the number of bidders and the number of objects increases

moral hazard with several agents abstract we consider a situation in which a principal hires two agents whose cooperation is technically profitable and study three models that incorporate different assumptions about the agents cooperative behavior we find a close relationship between the agents commitment capacity and the characteristics of the optimal contract a greater capacity to cooperate leads to more efficient outcomes we also show that unless agents form a team the efficient level of mutual help is not achieved in equilibrium

long run purchasing power parity with asymmetric adjustment 1 introduction despite its intuitive appeal there is inconclusive evidence supporting purchasing power parity ppp between countries with low inflation rates during the post bretton woods period for example enders 1988 taylor 1988 and macdonald 1993 use various forms of cointegration tests called stage three tests and find that real exchange rates exhibit large fluctuations with slow rates of decay toward a long run mean froot and rogoff s 1995 literature review presents a consensus estimate that deviations from long run ppp have a half life of about three years this is somewhat disappointing since stage three tests seem to be well suited to the task they require no assumptions concerning exogeneity and they imply a sensible dynamic relationship among price levels and the exchange rate the vast literature on ppp is indicative of the importance of the issue and the ambiguity of the findings it is well recognized that standard cointegration tests have low power to reject the null hypothesis of no cointegration this observation is especially relevant for ppp since any mean reversion in real rates is very gradual and the length of the post bretton woods period sample period is relatively short efforts to increase the power of unit root and stage three tests have had mixed success for example lothian and taylor 1996 and mark 1990 have tried to circumvent the low power of stage three tests by using long spans of time series data unfortunately the use of long time spans raises the possibility of structural changes occurring during the period being examined panel unit root tests are generally more supportive of ppp than are bilateral tests of real exchange rate behavior for example oh 1996 wei and parsley 1995 and wu 1996 have used panel data in order to enhance the power of standard unit root tests although these particular articles are supportive of ppp panel studies must deal with the thorny issues of cross sectional correlation and the choice of the nations to include in the panel papell 1997 finds that allowing for serial correlation substantially weakens the evidence in favor of long run ppp o connell 1998 applies generalized least squares to panel data to eliminate any contemporaneous correlation in the error structure and finds no evidence supporting ppp the second problem with the standard unit root and cointegration tests is that they implicitly assume symmetric adjustment however official intervention in the foreign exchange market means that nominal exchange rate adjustment may be asymmetric under a managed float for example one of the monetary authorities might be more willing to tolerate currency appreciation than depreciation similarly a currency band mitigates exchange rate movements until the level of the band is altered furthermore the slow adjustment of real exchange rates is often explained by the stickiness of national price levels for example in the well known dornbusch 1976 overshooting model prices and the exchange rate move in the same proportion as the money supply in the very long run however in the short run prices are sticky and monetary shocks cause ppp deviations since the exchange rate moves proportionately more than prices rhee and rich 1995 and madsen and yang 1998 provide empirical evidence corroborating the implications of the asymmetric price adjustment models the key point to note is that if prices are primarily sticky in the downward direction there is no reason to presuppose that real exchange rate adjustment is symmetric in spite of the evidence supportive of asymmetric exchange rate and price adjustments there are only a few nonlinear tests of ppp although they do not explicitly test for ppp michael nobay and peel 1997 and taylor and sarno 1998 estimate real exchange rates as smooth transition threshold adjustment processes enders and falk 1998 formally apply various nonlinear unit root tests to real exchange rates and find little evidence of ppp

sequential auctions theory and evidence from the seattle fur exchange we develop a model that incorporates salient features of the seattle fur exchange identical lots of furs are auctioned sequentially bids must be raised by specified increments and the winner of a lot has the privilege of beginning the bidding on the subsequent lot predictions of the theory are consistent with the data revenue implications of the theory are also explored

procurement auctions with entry of bidders abstract in procurement auctions with a fixed number of bidders there is a tradeoff between cost efficiency and rent extraction an optimal mechanism therefore entails distortions of effort laffont and tirole 1987 if potential suppliers must sink an entry investment before they can participate in the auction then decreasing the firms rent may imply reduced entry we show that if potential bidders are uninformed before entry commitment to a plain nondistortive auction is optimal in contrast if potential bidders learn all their private information before entry the optimal mechanism entails the same distortions as in laffont and tirole s static model

a model of the evolution of duopoly does the asymmetry between firms tend to increase or decrease this paper is an attempt to identify some of the factors that affect the evolution of market structure in a model of dynamic competition between two firms the stochastic evolution of the state of competition depends on the respective effort rates of the firms the question is whether the current leader works harder than the laggard does the gap between firms tend to increase or decrease we show that several effects are at work the state tends to evolve in the direction where joint payoffs are greater since joint payoffs are related to joint product market profits less joint effort costs there are two classes of effect the joint profit effect and various joint cost effects the latter result in part from the pattern of profits and in part from endpoint effects that give relief from efforts asymptotic expansions illuminate these influences moreover we show by numerical simulation that there is another kind of joint cost effect the pattern of joint effort costs can influence the pattern of evolution of market structure and the evolution of the pattern of market structure can influence the pattern of efforts in a mutually self reinforcing manner in particular there may be equilibria in which this last effect means that the laggard works harder than the leader even though all the other effects work in favour of the leader

the declining price anomaly abstract data from wine auctions indicate that identical products sold sequentially typically follow a decreasing pattern of prices known as the declining price anomaly this is explained for both first and second price auctions by appealing to risk averse bidders earlier bids are then equal to expected later prices plus a risk premium associated with the risky future price we show that this logic rests on the assumption of nondecreasing absolute risk aversion which is necessary for pure strategy equilibrium bidding functions to exist thus decreasing absolute risk aversion implies ex post inefficiency with positive probability data from wine auctions are used to confirm the existence of the declining price anomaly journal of economic literature classification numbers d43 d44 d81 d82 l81

multivariate cointegration analysis and the long run validity of ppp this paper tests the long run validity of ppp using johansen s multivariate cointegration methodology on exchange rates and domestic and foreign price levels monthly data covering the recent flexible exchange rate period of the dm vis a vis 15 currencies le ad to the following conclusion ppp seems to hold in the long run for s ix european currencies the pound lira norwegian krone schilling escudo and peseta however ppp has to be rejected for the united states and the canadian dollar as well as for the belgian franc and the danish krone nevertheless the authors analysis is more favorable to ppp as a long run property of exchange rates than the recent work applying the engle granger regression methodology copyright 1993 by mit press

the purchasing power parity persistence paradigm abstract rogoff journal of economic literature 1996 34 647 668 describes the remarkable consensus of 3 5 year half lives of purchasing power parity deviations among studies using long horizon data these studies however focus on rejections of unit roots in real exchange rates and do not use appropriate techniques to measure persistence our half life estimates explicitly account for serial correlation sampling uncertainty and most importantly small sample bias calculating confidence intervals as well as point estimates for long horizon and post 1973 data we find that even though most of the point estimates lie within the 3 5 year range univariate methods provide virtually no information regarding the size of the half lives

dynamic auction environment with subcontracting this article provides evidence on the role of subcontracting in the auction based procurement setting with private cost variability and capacity constraints we demonstrate that subcontracting allows bidders to modify their costs realizations in a given auction as well as to control their future costs by reducing backlog accumulation restricting access to subcontracting raises procurement costs for an individual project by 12 and reduces the number of projects completed in equilibrium by 20 the article explains methodological and market design implications of subcontracting availability

how auctions work for wine and art interview auctioneers and even to buy a little wine in the meantime i have also had the opportunity with john abowd 1988 to observe and collect data on the auction sale of impressionist and contemporary paintings this paper reports on some of the empirical regularities that i and others have observed in the actual operation of the auction markets for these items in view of the rich and diverse array of theoretical literature on auctions it seems high time economists began to spell out precisely what facts it is meant to explain 2

to build or not to build normative and positive theories of public private partnerships abstract this paper analyzes whether the two tasks of building infrastructures which are socially useful in providing public services and managing these assets should be bundled or not when performance contracts can be written both tasks should be performed altogether by the same firm if a better design of the infrastructure helps also to save on operating costs otherwise tasks should be kept apart and undertaken by different units in incomplete contracting environments we isolate conditions under which either the traditional form of public provision of services or the more fashionable public private partnership emerges optimally the latter dominates when there is a positive externality and the private benefits from owning assets are small enough finally we take a political economy perspective and study how incentive schemes are modified under the threat of capture of the decision makers much of the gains from bundling may be lost in this case

bertrand competition with subcontracting we investigate how the possibility of subsequently subcontracting production to each other influences rivals initial competition for a contract or a market as a two stage game in its first stage the two firms engage in price competition to supply a contract or a market in the second stage the firms may subcontract production to each other it is supposed that the firms produce the identical product with the same strictly convex cost function the incentive for subcontracting comesfrom the strictly convex production costs a firm is obliged to supply the entire quantity demanded at its quoted price our analysis discloses that if the winner of the game s first stage determines the terms of the subcontract in its second stage there exists a unique subgame perfect nash equilibrium spne in pure strategies in which the firms bid the same price in the first stage and both receive zero profits on the other hand if the loser of the game s first stage sets the terms of the subcontract in the second stage there exists a unique spne in pure strategies in which the firms bid the same price in the first stage and both receive positive profits the presence of the possibility of subcontracting supports a unique spne in pure strategies even though no actual subcontracting may occur the spne price is below the socially optimal price in the first case and is above it in the second case we also consider other modes of sharing the gains from subcontracting between the two firms such as the nash bargaining solution

the evolution of market structure when there is a sequence of innovations the paper explores the question of how market structure evolves when there is a sequence of opportunities to innovate does one firm extend its technological superiority to become increasingly dominant or does technological leadership constantly change hands in a process of actionreaction a simple duopoly model is proposed in which the answer to this question depends upon the nature of product market behaviour in that model highly competitive product market behaviour leads to increasing dominance whereas cournot behaviour may lead to action reaction

a fractional cointegration analysis of purchasing power parity a generalized notion of cointegration called fractional cointegration is introduced to examine the long run purchasing power parity ppp hypothesis by allowing deviations from equilibrium to follow a fractionally integrated process the fractional cointegration analysis can capture a wider range of mean reversion behavior than standard cointegration analyses this gain is flexibility in modeling subtle mean reverting dynamics is found to be important for a proper evaluation of long run ppp empirical results based on historical data for the 1914 1989 period show that ppp reversion exists and can be characterized by a fractionally integrated process in three out of five countries studied the results support ppp as a long run phenomenon though significant short run deviations from ppp can exist

incumbency and entry in license auctions the anglo dutch auction meets another simple alternative the existence of ex ante strong incumbents may constitute a barrier to entry in auctions for goods such as licenses favoring the allocation to entrants is a way to induce entry and thus create competition designs such as the anglo dutch auction have been proposed with this goal in mind we first show that the anglo dutch auction does indeed foster entry and increases the revenues of the seller however we argue that a more effective way could be to stage the allocation of the good so that each stage reveals information about the participants we show that a sequence of english auctions with high reserve prices in early rounds fulfils this property and is more efficient than any one stage entry auction moreover it also outperforms the anglo dutch auction in terms of seller s revenues

threshold cointegration and purchasing power parity in the pacific nations the paper uses a threshold cointegration methodology to explore the properties of long run purchasing power parity ppp in the pacific nations using japan and the usa as base countries it is shown that long run ppp holds for most asian countries but that the adjustment mechanism is asymmetric in contrast to symmetric error correction models it is found that asymmetric adjustments of nominal exchange rates play an important role in eliminating deviations from long run ppp

measuring the persistence of deviations from purchasing power parity with a fractionally integrated star model abstract empirically elements of both fractional long memory and threshold non linearity are present in the real exchange rates of the g 7 countries against the us notably in the eu countries estimated half lives of deviations from ppp using median unbiased corrections to conventional linear autoregressive models corroborate existing evidence related to the ppp paradox as half lives range from at least four years to an infinite number of years in contrast for each eu country accounting for threshold non linearity results in estimated half lives that can be less than three years even with the allowance for fractional long memory

sequential common value auctions with asymmetrically informed bidders we study an in nitely repeated rst price auction with common values we focus on one sidedincomplete information in which one bidder learns the objects value which itself does not change overtime learning by the uninformed bidder occurs only through observation of the bids the proprietaryinformation is eventually revealed and the seller extracts essentially the entire rent for large discountfactors both players pay offs tend to 0 as the discount factor tends to 1 however the uninformed bidderdoes relatively better than the informed bidder we discuss the case of two sided incomplete informationand argue that under a markovian re nement the outcome is pooling as information is revealed onlyinsofar as it does not affect prices

bundling decisions by a multiproduct monopolist with incomplete information this paper analyzes bundling decisions of a rnultiproduct monopolist facing uncertain demand the monopolist sells his products using an auction mechanism and the market is analyzed as a game with incomplete information in which the buyers as well as the seller are strategic agents with a small number of buyers a profit maximizing seller will bundle all his output this makes buyers uniformly worse off compared to the case where the same monopolist does not bundle in the sense that any buyer is worse off regardless of his demand for the monopolist s outputs with a larger number of buyers the seller will have a tendency to unbundle his output and high demand buyers are worse off than they would be if the monopolist bundled his output low demand buyers on the other hand are always better off when the monopolist unbundles his output regardless of the number of competing buyers despite the fact that high demand buyers are the typical purchasers of the monopolist s output the net effect of increasing the number of buyers is greater market efficiency since bundling creates market inefficiencies both ex post and ex ante

auctions with endogenous valuations the persistence of monopoly revisited it is shown that the standard arguments for a monopoly to persist break down when many units of capacity become available sequentially the reason is that deterring entry at one st age affects the cost of doing so in later stages this force can be so powerful that entry is deterred only at the final stage the persistence of monopoly or its erosion over time depends on the timi ng of arrival of capacity the size of early versus subsequent capacity availability the length of the capacity acquisition stage relative to the life of the industry and the discount factor copyright 1993 by american economic association

coalitions incentives and risk sharing abstract this paper analyzes the effects of coalitional behavior in principal multiagent relationships with moral hazard and identifies cases where the principal prefers agents to form a coalition via side contracting it is shown that the principal can implement given efforts via non individualistic incentive contracts at a lower cost when the agents can monitor each other s efforts perfectly and hence coordinate their effort choice than when the agents behave independently permitting the principal to utilize more complex communication mechanisms does not alter the result for there is no coalition proof revelation mechanism improving the principal s welfare journal of economic literature classification number d82

an empirical examination of long run purchasing power parity using cointegration techniques this paper presents an empirical analysis of long run purchasing power parity ppp for five major exchange rates using recently developed econometric techniques on the cointegration of economic time series our empirical results are extremely unfavourable to the ppp hypothesis as a long run equilibrium condition even with an allowance made for measurement error and or tranportation costs in particular we are unable to reject the hypothesis of non cointegration of the exchange rate and relative prices for any of the countries concerned far from finding a stable long run proportionality between exchange rates and relative prices our results therefore suggest that they tend to drift apart without bound

sequential auctions price trends and risk preferences abstract we analyze sequential auctions in a general environment where bidders are heterogeneous in risk exposures and exhibit non quasilinear utilities we derive a pure strategy symmetric equilibrium for the sequential dutch and vickrey auctions respectively with an arbitrary number of identical objects for sale when bidders are risk averse preferring the equilibrium price sequences must be downward upward drifting the declining price anomaly is thus evidence of bidder risk aversion in this general environment these results derive from a key assumption that bidders marginal utilities are log supermodular in payment and type

risk allocation and the costs and benefits of public private partnerships we study the agency costs of delegated public service provision focusing on the link between organizational forms and uncertainty at project implementation we consider a dynamic multitask moral hazard environment where the mapping between efiort and performance is ex ante uncertain but new information may come along during operations our analysis points out at the e ciency gains that bundling planning and implementation as under public private partnerships can bring in terms of better project design and lower operational costs bundling also results in increasingly better performance as uncertainty is reduced by growing experience in the sector bundling should instead be viewed with caution when the private sector seeks to radically innovate on public service provision or to introduce new services but lacks the knowledge and expertise to anticipate the impact of the innovative design procedure technology on the cost of operations the compounding of asymmetric information ex post plus moral hazard and renegotiation may generate diseconomies of scope in agency costs which for high operational risk can make unbundling optimal in this context the use of private flnance can help re establishing the beneflt of bundling only if lenders have su cient expertise to help assessing project risks

reserve prices without commitment abstract when potential bidders in an auction have to incur a cost to prepare their bids and thus to learn their valuations imposing a reserve price and announcing that in case no bid is submitted there will be another auction without a reserve price is both revenue and welfare improving reserve prices that induce less than maximum entry in the first auction may be optimal also entry fees are not necessarily better instruments than reserve prices journal of economic literatureclassification number d44

primary commodity prices co movements common factors and fundamentals the behavior of commodities is critical for developing and developed countries alike this paper contributes to the empirical evidence on the co movement and determinants of commodity prices using nonstationary panel methods we document a statistically significant degree of co movement due to a common factor within a factor augmented var approach real interest rate and uncertainty as postulated by a simple asset pricing model are both found to be negatively related to this common factor this evidence is robust to the inclusion of demand and supply shocks which both positively impact on the co movement of commodity prices

the shill bidding effect versus the linkage principle abstract the analysis of second price auctions with externalities is utterly modified if the seller is unable to commit not to participate in the mechanism for the general symmetric model introduced by milgrom and weber p milgrom r weber a theory of auctions and competitive bidding econometrica 50 1982 1089 1122 we characterize the full set of separating equilibria that are symmetric among buyers and with a strategic seller being able to bid in the same way as any buyer through a so called shill bidding activity the revenue ranking between first and second price auctions is different from the one arising in milgrom and weber the benefits from the highlighted linkage principle are counterbalanced by the shill bidding effect

confidence intervals for half life deviations from purchasing power parity existing point estimates of half life deviations from purchasing power parity ppp around 3 5 years suggest that the speed of convergence is extremely slow this article assesses the degree of uncertainty around these point estimates by using local to unity asymptotic theory to construct confidence intervals that are robust to high persistence in small samples the empirical evidence suggests that the lower bound of the confidence interval is between four and eight quarters for most currencies which is not inconsistent with traditional price stickiness explanations however the upper bounds are infinity for all currencies so we cannot provide conclusive evidence in favor of ppp either

purchasing power parity in brazil a test for fractional cointegration the purpose of this paper is to test the validity of the purchasing power parity ppp doctrine in brazil historical data for the period 1855 1996 are considered the period 1855 1990 is also analysed in order to compare the results with those obtained by zini and cati 1993 using the conventional cointegration analysis this article uses fractional cointegration analysis a flexible methodology which allows for more subtle forms of mean reversion the tests performed are those of geweke and porter hudak 1983 and of hurvich and ray 1995 the critical values for both tests are generated by simulation because they are non standard the empirical results do not support the absolute ppp hypothesis but the relative ppp holds in the long run

bundling decisions in procurement auctions with sequential tasks abstract this paper investigates the principal s bundling decision during a procurement auction for a project consisting of two sequential tasks in which task externality exists and information arrives sequentially we show that although increasing the number of bidders in the market for the second task always tilts the principal s choice toward unbundling increasing the number of consortiums that can perform both tasks tilts the principal s preference toward bundling if the externality is negative

a comparative analysis of multi unit sequential auction under optimal reserve abstract we consider sequential auction of two identical objects under the second price rule when reserves are set optimally we find that bidders bid more in the sequential auction when they are risk averse cara than when they are not the expected revenue is higher under the vickrey rule than under the uniform price rule hence the sequential auction generates higher expected revenue than both the vickrey auction and uniform price auction when bidders have constant absolute risk aversion

equilibrium price paths in sequential auctions with stochastic supply abstract in many sequential auctions supply is unknown ex ante consequently price formation depends on information regarding supply uncertain supply reduces the option value and yields declining prices however prices increase if it becomes known that supply falls short of expectations

simultaneous vs sequential auctions with risk averse bidders abstract in this paper we ask a basic question that is interesting for auctioneers and regulators when multiple units are on sale should multiple identical units be sold simultaneously through a single shot auction or sequentially we consider the risk effect of such a decision on bidders and show that in the independent private values setting the answer unambiguously depends on the pricing rule a bidder s payoff uncertainty increases when the sale is sequenced under a pay as bid rule but decreases under the vickrey rule we find that as a result the sequential auction is less desirable from revenue and ex post efficiency points of view under the pay as bid rule and more desirable under the vickrey rule when the reserves in all auctions are set revenue optimally

econometrics of first price auctions in this paper we propose an estimation method for the empirical study of theoretical auction models we focus on first price sealed bid and descending auctions and we adopt the private value paradigm where each bidder is assumed to have a different private value only known to him for the object that is auctioned following mcfadden 1989 and pakes and pollard 1989 our proposed method is based on simulations specifically the method relies on a simulated nonlinear least squares objective function appropriately adjusted so as to obtain consistent estimates of the parameters of interest we illustrate the proposed method by studying a market of agricultural products where descending auctions are used our analysis takes into account heterogeneity of the auctioned objects and the fact that only the winning bid is observed we estimate the parameters that characterize the distribution of the unobserved private values for each auctioned object

volatility spillovers between food and energy markets a semiparametric approach previous literature on volatility links between food and energy prices is scarce and mainly based on parametric approaches this article examines these links by using a semiparametric garch model recently proposed by long et al 2011 which is essentially a nonparametric correction of the parametric conditional covariance function the analysis focuses on price links between crude oil ethanol and sugar prices in brazil results suggest strong volatility links between the prices studied parametric approximations of the conditional covariance matrix may lead to misleading results that can be improved upon by using nonparametric techniques

research note strategic bid shading and sequential auctioning with learning from past prices this paper analyzes sequential auctioning of single units of an indivisible good to a fluctuating population composed of overlapping generations of unit demand bidders two phenomena emergent in such a market are investigated forward looking bidding strategies and closed loop selling strategies that involve learning from past prices the buyers shade their bids down i e bid less than they would in a single isolated auction whenever they expect the seller to sell another unit of the good in the near future unlike in exogenous sequences of auctions the optimal bidding strategy thus depends on the seller s selling strategy the converse dependence also occurs the seller can learn about current demand from past realized prices and sell only in periods with high enough demand such learning depends on the extent of bid shading because the seller needs to invert the bidding strategy to learn in equilibrium buyer bid shading persists even when the seller does not sell in every period but it is self regulating in that it eventually vanishes when the existence of the market is threatened by low seller profits in this sense auction markets have a self preservation instinct general properties of learning about current demand from past auction prices are also investigated and characterized

parity reversion persistence in real exchange rates middle income country case this article investigates purchasing power parity ppp in the specific context of middle income countries to circumvent the low power of traditional stationarity tests augmented dickey fuller and phillips perron tests it performs variance ratio and fractional integration tests in addition to perron s test that accounts for potential structural changes in real exchange rate processes beyond estimating half life shocks to ppp this article attempts to explain these estimates using a set of country specific variables as suggested by economic theory the evidence suggests that reversion to parity tends to be faster in high inflation countries and that productivity improvement leads to a higher level of persistence openness to trade tends to reduce the extent of deviations from parity but this result does not appear to be statistically robust evidence shows also that deviations are less persistent under a fixed exchange rate regime and under unrestricted capital mobility

generalized long memory processes failure of cointegration tests and exchange rate dynamics this paper presents evidence that the equilibrium relationship in a system of nominal exchange rates is best described as a stationary garma process the implementation of the garma methodology helps explain conflicting and puzzling results from the use of linear cointegration and fractional cointegration methods furthermore we use monte carlo analysis to document problems with standard cointegration tests when the attraction process is distributed as a long memory garma process copyright 2006 john wiley sons ltd

on the maximum likelihood cointegration procedure under a fractional equilibrium error abstract this paper examines the usual maximum likelihood procedure under fractional cointegration the lagrange multiplier test poses the ability of detecting cointegration relations when deviations from equilibrium are persistent however the estimates of the long run relations are severely biased

three bubbles and a panic an explanatory review of recent food commodity price events abstract this paper is a summary of the behaviour of food commodity prices in 2007 2008 and a review of the causes of the price increases extracted from a report to the chief scientific advisor to her majesty s government thirtle c piesse j 2008 an explanatory review of the world food commodity price events of 2007 2008 a report to the chief scientific advisor department for innovation universities and skills london the historical background shows that the price spike was much less severe than in the 1970s the conventional wisdom that prices of the main food commodities were falling prior to 2006 is questioned most ceased falling and were quite stable from the 1980s the paper separates the causes of the spike from the underlying changes driving the long run trends the literature on the causes of the spike is critically reviewed and summarised there is a reasonably broad consensus on most of the causes but much less on the impact of the depreciation of the us dollar there are also concluding speculations on the future

auctions with imperfect commitment when the reserve may signal the cost to re auction if bidders are uncertain whether the auctioneer sticks to the announced reserve they respond with strategic non participation speculating that the auctioneer may revoke the reserve however the reserve inadvertently signals the auctioneer s type which drives multiplicity of equilibria eliminating belief systems that violate the intuitive criterion yields a unique equilibrium reserve price equal to the seller s consumption value paradoxically even if bidders initially believe that the auctioneer is bound by his reserve almost with certainty commitment has no value commitment is a shorthand for a high cost to re auction which may reflect a concern for reputation several variations of the model assess the robustness of our results

budget constrained sequential auctions with incomplete information i study a budget constrained private valuation sealed bid sequential auction with two incompletely informed risk neutral bidders in which the valuations and income may be non monotonic functions of a bidder s type multiple equilibrium symmetric bidding functions may exist that differ in allocation efficiency and revenue the sequence of sale affects the competition for a good and therefore also affects revenue and the prices of each good in a systematic way that depends on the relationship among the valuations and incomes of bidders the sequence of sale may affect prices and revenue even when the number of bidders is large relative to the number of goods if a particular good say is allocated to a strong bidder independent of the sequence of sale then auction revenue and the price of good are higher when good is sold first