on the robustness of robustness checks of the environmental kuznets curve hypothesis since its first inception in the debate on the relationship between environment and growth in 1992 the environmental kuznets curve hypothesis ekc hereafter has been subject of continuous and intense scrutiny the most recent line of investigation criticizes the ekc hypothesis on more fundamental grounds in that it stresses the lack of sufficient statistical testing of the empirical relationship and questions the very existence of the notion of ekc attention is in particular drawn on the stationarity properties of the series involved per capita emissions or concentrations and per capita gdp and in case of presence of unit roots on the cointegration property that must be present for the ekc to be a well defined concept only at that point can the researcher ask whether the long run relationship exhibits an inverted u pattern on the basis of panel integration and cointegration tests for sulfur stern 2004 and perman and stern 1999 2003 have presented evidence and forcefully stated that the ekc hypothesis does not exist in this paper we ask whether similar strong conclusions can be arrived at when carrying out tests of system fractional integration and cointegration as an example we use the controversial case of carbon dioxide emissions the results show that more ekcs come back into life relative to traditional integration cointegration tests however we confirm that the ekc hypothesis remains a fragile concept

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

dynamic efficiency in overlapping generations models with stochastic production abstract we consider an overlapping generations economy as in diamond amer econ rev 55 1965 1126 1150 with stochastic production we define two types of efficiency for feasible production consumption allocations using first and second degree stochastic dominance we obtain a complete characterization of inefficiency of type i in this model for each given sequence of strictly concave utility functions for all generations the existence of a competitive equilibrium is proved it is shown that each competitive allocation is short run efficient of type ii

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

national price levels purchasing power parity and cointegration a test of four high inflation economies abstract the time series properties of exchange rates and wholesale prices from four high inflation countries show some evidence in support of purchasing power parity tests for stationarity of real exchange rates and cointegration among price and exchange rate variables are presented for argentina brazil chile and israel during the 1970s and 1980s error correction models describe the mechanism of adjustment to long run equilibrium

asset valuation and production efficiency in an overlapping generations model with production shocks this paper extends the cass criterion for production efficiency to include uncertainty and uses it to show that a stock market equilibrium in an overlapping generations model with production uncertainty is efficient it also develops a no bubbles asset pricing formula results are compared with brock s 1982 infinite lived consumer model and it is shown that the stock market equilibrium in the overlapping generations model has precisely the same asset valuation as brock s infinitely lived agent model

do real exchange rates contain a unit root evidence from turkish data this study explores whether the long run purchasing power parity ppp hypothesis holds for selected real exchange rates from turkish economy during the period 1982m1 2003m12 in addition to conventional unit root tests five different unit root test procedures have been applied including efficient point optimal tests extended m tests and gls detrended variants of df tests to four monthly real exchange rate series defined in terms of both producer and consumer price indices the countries analysed are the usa the uk germany and italy which are major trade partners of turkey mixed evidence is found for the long run ppp hypothesis when real exchange rate is defined in terms of german dm and italian lira however the empirical analysis reveals that the ppp hypothesis holds strongly in the long run for the uk and us based real exchange rates series using either ppi or cpi in corroboration with other studies in the literature the bias correlated half life estimates suggest relatively faster speeds of

the collapse of purchasing power parities during the 1970 s one of the striking facts concerning the relationship beiveen prices and exchange rates during the 1970 s has been the dismal performance of the predictions of the simple versions of the purchasing power parity doctrine ppp that doctrine in its absolute version states that the equilibrium exchange rate between domestic and foreign currencies equals the ratio of domestic to foreign price levels the relative version of the doctrine relates equilibrium changes in exchange rates to changes in the ratio of domestic to foreign prices during the 1970 s short run changes in exchange rates bore little relationship to short run differentials in national inflation rates and frequently divergences from purchasing power parities have been cumulative this paper reviews and analyzes the empirical record of exchange rates and prices during the 1970 s and the analysis is based on the experience of the dollar pound the dollar frecch franc and the dollar dm exchange rates section 2 presents the evidence on ppp during the 1970 s and contrasts it with the evidence from the 1920 s a period during which the doctrine held up reasonably well this analysis is relevant for assessing whether the flexible exchange rate system was successful in providing national economies with an added degree of insulation from foreign shocks and whether it provided policymakers with an added instrument for the conduct of macroeconomic policy the evidence regarding devia tions from purchasing power parities is also relevant for determining whether there is a case for managed float section 3 attempts to explain what went wrong with

maximum likelihood estimation of fractional cointegration with an application to u s and canadian bond rates we estimate a multivariate arfima model to illustrate a cointegration testing methodology based on joint estimates of the fractional orders of integration of a cointegrating vector and its parent series previous cointegration tests relied on a two step testing procedure and maintained the assumption in the second step that the parent series were known to have a unit root in our empirical example of fractional cointegration we illustrate how uncertainty regarding the order of integration of the parent series can be even more important than uncertainty regarding the order of integration of the cointegrating vector when testing for cointegration

stochastic olg models market structure and optimality for a general class of pure exchange olg economies under uncertainty we provide a complete characterization of the efficency properties of competitive equilibria when markets are only sequentially complete and the criterion of efficency is conditional pareto optimality we also consider a particular case in which markets fail to be even sequentially complete and provide a characterization when the criterion of efficency is weakened to ex post pareto optimality

real exchange rates in the short medium and long run abstract this paper uses long horizon autocorrelations and variance ratio statistics to test for long term mean reversion in real exchange rates unlike most previous tests of this hypothesis the tests do reject a random walk for monthly data in the post bretton woods era however the statistics indicate that positively correlated innovations rather than mean reversion are the source of the rejection tests using annual data for the twentieth century also reject the random walk in this case however the rejection can be attributed to mean reversion and confirms that ppp is a long term phenomenon

optimal residual based tests for fractional cointegration and exchange rate dynamics a lagrange multiplier test of the null hypothesis of cointegration in fractionally cointegrated models is proposed the test statistic uses fully modified residuals to cancel the endogeneity and serial correlation biases and standard asymptotic properties apply under the null and under local alternatives with iid gaussian errors the asymptotic gaussian power envelope of all unbiased tests is achieved by the one sided two sided test the finite sample properties are illustrated by a monte carlo study in an application to the dynamics among exchange rates for seven major currencies against the u s dollar mixed evidence of the existence of a cointegrating relation is found

on pricing of credit spread options abstract this paper describes and analyses different pricing models for credit spread options such as longstaff schwartz black das sundaram and duan garch based models the first two models longstaff schwartz and black assume respectively a mean reverting dynamic and a lognormal distribution for the spread and are representative of the so called spread models such models consider the spread as a unique variable and provide closed form solutions for option pricing on the contrary das sundaram propose a recursive backward induction procedure to price credit spread options on a bivariate tree which describes the dynamic of the term structure of forward risk neutral spread and risk free rate this model belongs to the class of structural models which can be used to price a wider range of credit risk derivatives finally we consider the pricing of credit spread options assuming a discrete time garch model for the spread

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

optimality in stochastic olg models theory for tests we consider general olg economies under uncertainty with short maturity assets and with dividend paying assets of infinite maturity and fiat money and study the optimality properties of equilibria with a sequence of asset markets that are sequentially complete we provide necessary and sufficient conditions in terms of asset prices and dividends for equilibria to be conditionally pareto optimal these results provide a theoretical basis for empirical investigation

the cass criterion the net dividend criterion and optimality abstract abel mankiw summers and zeckhauser assessing dynamic efficiency theory and evidence rev econ stud 56 1989 1 20 propose the net dividend criterion as an easy to use sufficient condition for optimality in general stochastic overlapping generations economies with production we provide examples based on the criterion due to cass on capital overaccumulation in the aggregative neoclassical model of economic growth a complete characterization j econ theory 4 1972 200 223 and its extensions the usual tools for such problems to show that the net dividend criterion need not give the right answer we identify the flaw in their proof we also provide an alternative condition which by an argument unrelated to theirs is a sufficient condition for optimality when dividends are nonnegative and then argue that the condition is not innocuous since it cannot be verified in actual economies

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

purchasing power parity over two centuries abstract this paper re examines the purchasing power parity hypothesis for the dollar sterling exchange rate using the two centuries of data from lothian and taylor lt 1996 real exchange rate behavior the recent float from the perspective of the past two centuries journal of political economy 104 3 488 509 unlike lt we conclude that the dollar sterling rer is nonstationary implying a rejection of the long run ppp hypothesis the differences in our conclusions are explained by 1 sensitivity of adf unit root tests to the choice of lag length and or 2 the presence of significant time trends in the adf or phillips perron unit root test equations

purchasing power parity in less developed and transition economies a review paper abstract the concept of purchasing power parity ppp has been the subject of numerous studies many of which have been unable to prove conclusively this core principle of international finance although industrialized countries have received most of the attention studies that focus on less developed and transition economies have also attained mixed results this study surveys trends in this branch of the literature highlighting the econometric advances that have sought to solve this puzzle while pointing out that more needs to be done to address the reasons that might cause ppp not to hold

the power of residual based tests for cointegration when residuals are fractionally integrated abstract we establish divergence rates of various residual based cointegration tests under fractional cointegration and show that the power of these tests is rather poor

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

long run relationships between international stock prices further evidence from fractional cointegration tests the recent empirical literature supports the view that most of the international stock prices are not pairwise cointegrated however by using fractional cointegration techniques this paper shows that france germany hong kong and japan stock prices indices are pairwise fractionally cointegrated with us stock prices equilibrium errors are mean reverting with half life lying between 2 and 12 days it is worthwhile noting that emerging markets like brazil and argentina are not pairwise cointegrated with the us stock market these new results have important implications for asset pricing and international portfolio strategy

long memory and persistence in aggregate output abstract we examine persistence in u s aggregate output by estimating fractionally integrated arima models these models provide better low frequency approximations to the wold representation than previous stochastic specifications and earlier results on the importance of a permanent component emerge as special cases we find evidence of long memory which induces persistence though this long memory need not be associated with a unit root our point estimates indicate that macroeconomic shocks while persistent are distinctly less persistent than many earlier studies suggest however confidence intervals associated with the long run response are quite wide

real exchange rate behavior the recent float from the perspective of the past two centuries using annual data spanning two centuries for dollar sterling and franc sterling real exchange rates we find strong evidence of mean reverting real exchange rate behavior using simple stationary autoregressive models estimated on prefloat data we easily outperform nonstationary real exchange rate models in dynamic forecasting exercises over the recent float such stationary univariate equations explain 60 80 percent of the in sample variation in real exchange rates although the degree of short run persistence may be high the econometric estimates imply a half life of shocks to the real exchange rate of about 6 years for dollar sterling and a little under 3 years for franc sterling

trends random walks and persistence an empirical study of disaggregated u s industrial production unit root and variance ratio tests are used to examine the trend properties and degree of persistence of industrial production in u s industries and comparable aggregates during the post world war ii period the evidence from unit root tests suggests that less than one half of these industries have output that may be characterized as a random walk the variance ratio test results generally support this conclusion consistent with standard economic theory fluctuations in durable goods industries are less persistent than in nondurable goods industries finally tests find relatively greater persistence in the aggregate industrial production data copyright 1992 by mit press

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

bubbles and inefficiencies abstract we study speculative behavior in a stochastic overlapping generations model and we show how the link between the existence of bubbles and dynamic inefficiency which has been established for the deterministic case is broken when risk related factors such as risk premia and capital gains are explicitly taken into account

mean reversion in the real exchange rates abstract robinson s j am stat assoc 89 1994 1420 fractionally based tests for unit roots and other hypotheses are applied to real exchange rate data between u s and five industrialized countries the results indicate that the series are fractionally integrated with mean reversion if the disturbances are autocorrelated

on cross country differences in the persistence of real exchange rates abstract previous findings of long run purchasing power parity come mainly from data for industrial countries raising the issue of whether the results suffer sample selection bias and exaggerate the general relevance of parity reversion this study uncovers substantial cross country heterogeneity in the persistence of deviations from parity the results show that it is more likely rather than less likely to find parity reversion for developing countries than industrial countries although some persistence variations may partly reflect country differences in structural characteristics such as inflation experience and government spending a considerable portion of those variations seems unaccounted for

purchasing power parity in the long run a test of the dollar pound exchange rate 1890 1978 this paper tests the purchasing power parity ppp hypothesis by analyzing t he long run tendency of the dollar pound exchange rate using data sin ce 1890 two different models are considered 1 a na ive model and 2 a modified monetary model the conditions of propor tionality and symmetry cannot be rejected when using the naive model the final results using the monetary model however indicate that t he existence of permanent deviations from ppp cannot be ruled out copyright 1987 by ohio state university press

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

are bilateral real exchange rates stationary evidence from lagrange multiplier unit root tests for india the paper examines the stationarity of india s real exchange rate vis a vis 16 of its major trading partner countries for the period 1960 2000 application of the conventional adf unit root test the lagrange multiplier lm unit root test with one structural break and the lm unit root test with two structural breaks provides evidence that india s exchange rate vis a vis 15 out of 16 countries is stationary implying support for purchasing power parity

are output fluctuations transitory according to the conventional view of the business cycle fluctuations in output represent temporary deviations from trend the purpose of this paper is to question this conventional view if fluctuations in output are dominated by temporary deviations from the natural rate of output then an unexpected change in output today should not substantially change one s forecast of output in say five or ten years our examination of quarterly postwar united states data leads us to be skeptical about this implication the data suggest that an unexpected change in real gnp of 1 percent should change one s forecast by over 1 percent over a long horizon

environmental kuznets curve in an open economy a bounds testing and causality analysis for tunisia the environmental kuznets curve hypothesis posits that in the early stages of economic growth environmental degradation and pollution increase however as a nation reaches a certain level of incom

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

perpetual learning and apparent long memory abstract this paper studies the low frequency dynamics in forward looking models where expectations are formed using perpetual learning such as constant gain least squares we show that if the coefficient on expectations is sufficiently close to unity perpetual learning induces strong persistence that is empirically indistinguishable from long memory we apply this result to present value models of stock prices and exchange rates and find that perpetual learning can explain the long memory observed in the data

social security and risk sharing abstract in this paper we identify conditions under which the introduction of a pay as you go social security system is ex ante pareto improving in a stochastic olg economy with capital accumulation and land we argue that these conditions are consistent with realistic specifications of the parameters of the economy in our model financial markets are complete and competitive equilibria interim pareto efficient therefore a welfare improvement can only be obtained if agents welfare is evaluated ex ante and arises from an improvement in intergenerational risk sharing we also examine the optimal size of a given social security system as well as its optimal reform

on the power of dickey fuller tests against fractional alternatives abstract we examine the properties of dickey fuller unit root tests under fractionally integrated alternatives and find that these tests have quite low power

fractional cointegration analysis of eu convergence traditional cointegration tests do not provide strong evidence of convergence between eu countries in this study fractional cointegration analysis is used to test for convergence between eu members fractional cointegration between inflation and between long term interest rates is found the results indicate that there is nominal convergence but that the equilibrium errors display long memory fractional cointegration analysis gives no evidence of real convergence in output

cointegration how short is the long run abstract when testing for cointegration and faced with short sample periods it is common for researchers to turn to more frequently sampled observations that is to move from annual to quarterly or monthly data in order to increase the number of observations we argue that such a gain in the degrees of freedom is more apparent than real essentially cointegration is a long run concept and hence requires long spans of data to give tests for cointegration much power rather than merely large numbers of observations using monte carlo simulations we demonstrate this for four popular tests for cointegration

on the interaction between risk sharing and capital accumulation in a stochastic olg model with production abstract we analyze the interaction between risk sharing and capital accumulation in a stochastic olg model with production we give a complete characterization of interim pareto optimal competitive equilibrium allocations furthermore we provide tests of pareto optimality suboptimality based on risky rates of return only

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

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

purchasing power parity abstract this paper examines the purchasing power parity henceforth ppp using historical data and the cointegration approach the results indicate that the exchange rate is cointegrated with the wholesale price index wpi ratio but not with the consumer price index cpi ratio the cointegrating vector is close to 0 1 for the cpi based real exchange rates however we cannot reject the random walk hypothesis the findings caution us on the use of general price indexes that give a large weight to nontraded goods and are therefore subject to long run deviations from ppp

credit derivatives with multiple debt issues abstract we evaluate the most actively traded types of credit derivatives within a unified pricing framework that allows for multiple debt issues since firms default on all of their obligations total debt is instrumental in the likelihood of default and therefore in credit derivatives valuation we use a single factor interest rate model where the exponential default frontier is based on total debt and is made coherent with observed bond prices analytical formulae are derived for credit default swaps total return swaps both fixed for fixed and fixed for floating and credit risk options cros price behaviors and hedging properties of all these credit derivatives are investigated simulations document that credit derivatives prices may be significantly affected by terms of debt other than those of the reference obligation the analysis of cros indicates their superior ability to fine tune the hedging of magnitude and arrival risks of default

pricing derivatives on financial securities subject to credit risk this article provides a new methodology for pricing and hedging derivative securities involving credit risk two types of credit risks are considered the first is where the asset underlying the derivative security may default the second is where the writer of the derivative security may default we apply the foreign currency analogy of jarrow and turnbull 1991 to decompose the dollar payoff from a risky security into a certain payoff and a spot exchange rate arbitrage free valuation techniques are then employed this methodology can be applied to corporate debt and over the counter derivatives such as swaps and caps the purpose of this article is to provide a new theory for pricing and hedging derivative securities involving credit risk two sources of credit risk are identified and analyzed the first is where the asset underlying the derivative security may default paying off less than promised this is the case for example with imbedded options on corporate debt the second is the credit risk introduced by the writer of the derivative security who may also default examples include over the counter writers of options on eurodollar futures swaps and swaptions for pricing derivative securities involving credit risk there are currently two approaches the first views these derivatives as contingent claims not on the financial securities themselves but as compound options on the assets underlying the financial securities this is the case for example with the pricing of imbedded options on corporate debt see merton 1974 1977 black and cox 1976 ho and singer 1982 chance 1990 and kim ramaswamy and sundaresan 1993 or the pricing of vulnerable options see johnson and stulz 1987 in practice however this valuation methodology is difficult to use first the assets underlying the financial security are often not tradeable and therefore their values are not observable this makes application of the theory and estimation of the relevant parameters problematic second as in the case of corporate debt all of the other liabilities of the firm senior to the corporate debt must first and simultaneously be valued this generates significant computational difficulties as a result this approach has not

exchange rates and traded goods prices abstract this paper presents a partial equilibrium model of the determination of domestic and export prices by a monopolistic competitive firm the model stresses the role of exchange rate uncertainty and expectations the most important result of the analysis is that the stochastic properties of deviations from the law of one price are crucially affected by the currency of denomination of export prices using data on domestic and dollar export prices of japanese goods i find that deviations from the law of one price are due to exchange rate surprises but also to price staggering and ex ante price discrimination

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

long run versus short run behaviour of the real exchange rates this paper discusses the mean stationarity of real exchange rates by using new time series methods and new tests the question whether the real exchange rates have a unit root or are level reverting is set in the general and flexible framework of fractionally integrated processes the estimations and tests sustain the claim that real exchange rates may be nonstationary and not revert to any short run parity however estimations also suggest that real exchange rates behave differently on the short and on the long run and that they may revert to parity in a century long period

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

purchasing power parity revisited evidence from old and new tests for an oecd panel the objective of this article is to study long run purchasing power parity ppp for a panel of 21 organisation for economic co operation and development oecd countries from the end of the bretton woods era by applying a wide range of the econometric techniques available this will allow us to present a comprehensive up to date examination of the empirical validity of ppp covering the weak and strong versions of the hypothesis with individual and panel analysis including the absence or presence of cross dependency the linear or nonlinear behaviour of the real exchange rates and the degree of persistence overall the results provide evidence in favour of 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

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

banking on currency forecasts how predictable is change in money abstract the paper examines the predictive performance of four structural exchange rate models using both parametric and nonparametric techniques error correction versions of the models are fit so that plausible long run elasticities can be imposed on the fundamental variables of each model a variety of model evaluation statistics are reported our findings confirm that fundamental exchange rate models forecast no better than a random walk model for short term prediction horizons for longer horizons error correction terms can explain exchange rate movements significantly better than a no change forecast for a subset of the models and currencies we consider

the persistence of volatility and stock market fluctuations this paper examines the potential influence of changing volatility in stock market prices on the level of stock market prices it demonstrates that volatility is only weakly serially correlated implying that shocks to volatility do not persist these shocks can therefore have only a small impact on stockmarket prices since changes in volatility affect expected required rates of return for relatively short intervals these findings lead us to be skeptical of recent claims that the stock market s poor performance during the 1970 s can be explained by volatility induced increases in risk premia this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item

cointegration fractional cointegration and exchange rate dynamics multivariate tests due to johansen 1988 1991 as implemented by baillie and bollerslev 1989a and diebold gardeazabal and yilmaz 1994 reveal mixed evidence on whether a group of exchange rates are cointegrated further analysis of the deviations from the cointegrating relationship suggests that it possesses long memory and may possibly be well described as a fractionally integrated process hence the influence of shocks to the equilibrium exchange rates may only vanish at very long horizons in the article by baillie and bollerslev 1989a it is argued that seven different nominal spot and forward exchange rates all contain unit roots in their univariate time series representations at the same time however the spot exchange rates appear to be tied together in the long run through a cointegration type relationship the latter finding of baillie and bollerslev has attracted particular interest and several studies such as those by hakkio and rush 1991 and sephton and larsen 1991 have already addressed this issue using the same data as the baillie and bollerslev article sephton and larsen 1991 describe the evidence for the presence of cointegration as being fragile and note that mixed conclusions are reached by truncating the baillie and bollerslev sample at different points in time diebold gardeazabal and yilmaz 1994 henceforth diebold et al provide interesting evidence that application of the johansen 1988 1991 tests with and without an intercept will result in different inferences on the baillie and bollerslev data set furthermore diebold et al carry out an ex ante forecasting experiment and find that the addition of an error correction term to the martingale model as implied by the standard cointegration paradigm fails to reduce the prediction mean square error when compared to a simple martingale model this therefore leads diebold et al to conclude that there exists substantial uncertainty regarding the existence of cointegration relationships among nominal dollar exchange rates this article provides some additional evidence on the existence of such a long run relationship among the same seven nominal spot exchange rates after further analysis it appears that a form of cointegration does exist between the exchange rates so that they do not drift apart in the long run we argue that this form of cointegration is

a test for rational bubbles in the nasdaq stock index a fractionally integrated approach abstract in this paper we test for the presence of rational bubbles in the nasdaq stock market index over the period 1994 06 2003 11 by means of a methodology based on fractional processes the results suggest that the existence of bubbles depends on the sampling frequency used in the analysis we cannot reject the unit root hypothesis when using monthly data on price dividend ratios which according to the present value model suggests the existence of rational bubbles however we reject this hypothesis in favor of fractional alternatives when using daily and weekly data this might be explained by the temporal aggregation and or the sample sizes used in the application

mean reversion in real exchange rates a modified dickey fuller test which is approximately uniformly most power invariant is employed to examine mean reversion in real exchange rates results from this test provide a wider and more significant support for mean reversion than the standard dickey fuller test

cointegration and tests of purchasing power parity nonstationarity in the levels of spot exchange rates and domestic and foreign price indices makes the use of conventional tests of the absolute version of purchasing power parity ppp inappropriate if ppp is true inter country commodity arbitrage ensures that deviations from a linear combination of spot exchange rates and domestic and foreign price levels should be stationary under these conditions exchange rates and price levels should form a cointegrated system we find the null hypothesis of no cointegration cannot be rejected for all five countries thus violating the long run absolute version of ppp

transactions costs and nonlinear adjustment in real exchange rates an empirical investigation eolquilibrium models of real exchange rate determination in the presence of transactions costs imply a nonlinear adjustment process toward purchasing power parity ppp conventional cointegration tests which ignore the effect of transactions costs may be biased against the long run ppp hypothesis our results using both monthly data for the interwar period and annual data spanning two centuries clearly reject the linear framework in favor of an exponential smooth transition autoregressive process the systematic pattern in the estimates of the nonlinear models provides strong evidence of mean reverting behavior for ppp deviations and helps explain the mixed results of previous studies

informational diversity over time and the optimality of monetary equilibria abstract the temporal realizations of a random state variable in an overlapping generations model create an informational diversity between members of different generations and require a reexamination of the optimality that competitive equilibria might display in such an environment using an optimality criterion that reflects this informational diversity we prove the optimality of competitive equilibrium in a model with a fixed stock of fiat money a single spot market and good endowments that follow a markov process the need for an optimality criterion that incorporates informational diversity is further motivated by studying the same model with the operation of complete contingent commodities markets

social security and demographic shocks an overlapping generations model of social security with shocks to the productivity of labor and capital and demographic shocks is studied we focus attention on stationary long run allocations an allocation is interim optimal if there does not exist another feasible allocation that improves the expected welfare of all generations computed conditionally on the state of the world when they are born we characterize the set of interim optimal allocations and study the equilibria associated with various institutional forms of social security from the point of view of this optimality criterion we obtain the analogs of the two traditional welfare theorems of microeconomic theory assume that there exists a financial asset in fixed quantity which supports some non null intergenerational transfers then the rational expectations equilibrium allocation of this economy is interim optimal conversely any stationary interim optimal allocation can be supported by such an equilibrium with adequate lump sum transfers

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 pricing of credit risk derivatives abstract this paper considers the pricing of derivatives that protect holders of corporate bonds from a reduction in their value because of a deterioration in their credit quality these derivatives are structured as either puts on the bond price or calls on the bond spread above the risk free rate in the context of models developed by merton 1974 and black and cox 1976 the pricing properties of these options are derived using both analytical and numerical methods

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

existence and optimality of currency equilibrium in stochastic overlapping generations models the pure endowment case abstract we consider a pure exchange stochastic overlapping generations economy sufficient conditions for the existence of a monetary equilibrium and a characterization of optimality are provided it is shown that in a monetary equilibrium currency provides partial insurance and that the equilibrium allocation is optimal it is also shown that if an allocation is optimal the contingent claim prices associated with it are such that in an average sense the present value of the social endowment is bounded

safe debt risky capital the author extends the diamond 1965 model of national debt in two directions she first introduces technological uncertainty and then she allows the stock of debt to vary the author studies the dynamical equilibria of the resulting stochastic system and she establishes conditions for the existence of stationary states that are expressed in terms of invariant distributions since conditions that ensure the existence of a stochastic stationary state with positive debt are very restrictive in this model financial instability is a pervasive phenomenon and allocations are in general dynamically inefficient copyright 1994 by the london school of economics and political science

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