temporal aggregation of an estar process some implications for purchasing power parity adjustment nonlinear models of deviations from ppp have recently provided an important theoretically well motivated contribution to the ppp puzzle most of these studies use temporally aggregated data to empirically estimate the nonlinear models as noted by taylor 2001 if the true dgp is nonlinear the temporally aggregated data could exhibit misleading properties regarding the adjustment speeds we examine the effects of different levels of temporal aggregation on estimates of estar models of real exchange rates our monte carlo results show that temporal aggregation does not imply the disappearance of nonlinearity and that adjustment speeds are significantly slower in temporally aggregated data than in the true dgp furthermore the autoregressive structure of some monthly estar estimates found in the literature is suggestive that adjustment speeds are even faster than implied by the monthly estimates

natural resources curse or blessing are natural resources a curse or a blessing the empirical evidence suggests that either outcome is possible this paper surveys a variety of hypotheses and supporting evidence for why some countries benefit and others lose from the presence of natural resources these include that a resource bonanza induces appreciation of the real exchange rate deindustrialization and bad growth prospects and that these adverse effects are more severe in volatile countries with bad institutions and lack of rule of law corruption presidential democracies and underdeveloped financial systems another hypothesis is that a resource boom reinforces rent grabbing and civil conflict especially if institutions are bad induces corruption especially in nondemocratic countries and keeps in place bad policies finally resource rich developing economies seem unable to successfully convert their depleting exhaustible resources into other productive assets the survey also offers some welfare based fiscal rules for harnessing resource windfalls in developed and developing economies

it only takes a few moments to hedge options abstract we propose a novel non structural method for hedging european options relying on two model independent results first under suitable regularity conditions an option price can be disentangled into a linear combination of risk neutral moments second there exists an explicit approximate functional form linking the risk neutral moments to the futures price of the underlying asset and the related variance swap contracts we show that s p 500 call prices are mainly explained by two factors that are related to level and volatility of the underlying index we empirically compare the performance of two strategies where the vega exposure is adjusted either by a direct position in a variance swap contract or indirectly through an at the money call while both strategies ensure effective immunization in periods of market turmoil taking direct exposure on variance swaps is not optimal during extended periods of subdued volatility

the minimum variance hedge ratio under stochastic interest rates in an environment where interest rates are stochastic we examine the case of a pure hedger endowed with a fixed position in a long term bond in contrast to conventional wisdom according to which the difference between hedging through forward contracts and futures is immaterial it turns out that the minimum variance hedge ratio using forwards comprises two terms instead of one only when using futures the magnitude of the difference between the two hedge ratios may be important under some plausible assumptions this result is due to the presence of additional interest rate risk that bears on the profit and loss statement associated with the forward position this sheds some additional light on the respective features of forward and futures contracts written on interest rate sensitive securities

commodity windfalls democracy and external debt we examine the effects that windfalls from international commodity price booms have on external debt in a panel of 93 countries during the period 1970 2007 our main finding is that increases in the international prices of exported commodity goods lead to a significant reduction in the level of external debt in democracies but to no significant reduction in the level of external debt in autocracies to explain this finding we show that in autocracies commodity windfalls lead to a statistically significant and quantitatively large increase in government consumption expenditures in democracies government consumption expenditures did not increase significantl

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

examining dynamically changing timber market linkages market integration has been widely studied in the past to gain a better understanding of how different markets for the same good interact with one another traditional cointegration tests have been used to perform these analyses however these tests can only reveal the presence of stable or average long term relationships to evaluate market dynamics over time we modify a time varying smooth transition autoregressive tv star model to examine pine stumpage markets in the us south the proposed model incorporates an economic indicator and allows us to evaluate market integration as it changes throughout a specified time period the potential significance of this work is twofold first market integration can be observed as a function of an economic indicator and secondly the proposed model will allow us to draw inference about market integration at specific time points

nonlinear purchasing power parity under the gold standard 1 introductionrecent theoretical analysis of purchasing power deviations see e g dumas 1992 sercu uppal and van hull 1995 and o connell and wei 1997 demonstrates how transactions costs or the sunk costs of international arbitrage induce nonlinear adjustment of the real exchange rate to purchasing power parity ppp globally mean reverting this nonlinear process has the important property of exhibiting near unit root behavior for small deviations from ppp since small deviations from ppp are left uncorrected if they are not large enough to cover the transactions costs or the sunk costs of international arbitrage a parametric nonlinear model suggested by the theoretical literature that captures the nonlinear adjustment process in aggregate data is the exponential smooth transition autoregression model estar of ozaki 1985 a smooth rather than discrete adjustment mechanism is motivated by the theoretical analysis of dumas 1992 also as postulated by terasvirta 1994 and demonstrated theoretically by berka 2002 in aggregate data regime changes may be smooth rather than discrete given that heterogeneous agents do not act simultaneously even if they make dichotomous decisions 1 recent empirical work e g michael nobay and peel 1997 taylor peel and sarno 2001 peel and venetis 2002 has reported empirical results that suggest that the estar model provides a parsimonious fit into a variety of data sets particular for monthly data for the interwar and postwar floating period as well as for annual data spanning 200 years as reported in lothian and taylor 1996 in addition nonlinear impulse response functions derived from the estar models show that although the speed of adjustment for small shocks around equilibrium will be highly persistent larger shocks mean revert much faster than the glacial rates previously reported for linear models rogoff 1996 in this respect the estar models provide some solution to the ppp puzzle outlined in rogoff 1996 2the estar model can also provide an explanation of why ppp deviations analyzed from a linear perspective appear to be described by either a nonstationary integrated i 1 process or alternatively described by fractional processes see e g diebold husted and rush 1991 taylor peel and sarno 2001 and pippenger and goering 1993 show that the dickey fuller tests have low power against data simulated from an estar model michael nobay and peel 1997 and byers and peel 2003 show that data that is generated from an estar process can appear to exhibit the fractional property that this would be the case was an early conjecture by acosta and granger 1995 given that the estar model has a theoretical rationale whereas the fractional process is a relatively nonintuitive one the fractional property might reasonably be interpreted as a misleading linear property of ppp deviations granger and terasvirta 1999 whereas the empirical work employing estar models provides some explanation of the glacially slow adjustment speeds obtained in linear models there is one aspect of the empirical work that is worthy of further attention a second way of explaining the rogoff puzzle raised by rogoff himself 3 is to relax the assumption that the equilibrium real exchange rate is a constant see e g canzoneri cumby and diba 1996 and chinn and johnston 1996 theoretical models such as that of balassa 1964 and samuelson 1964 imply a nonconstant equilibrium in the real exchange rate if real productivity growth rates differ between countries 4 nonlinear models that incorporate proxies for these effects are found to parsimoniously fit post bretton woods data for the main real exchange rates see venetis paya and peel 2002 and paya venetis and peel 2003 naturally models that ignore this effect may generate misleading speeds of ppp adjustment to shocks in this regard the empirical results of hegwood and papell 2002 for the gold standard period are particularly interesting

reading pibor futures options smiles the 1997 snap election abstract in this paper we compare various methods that extract a risk neutral density rnd out of pibor interest rate futures options and we investigate how traders react to a political event our benchmark model derives from a brace d gatarek m musiela mathematical finance 7 1997 127 155 we also consider a mixture of log normals as in w r melik c p thomas journal of financial and quantitative analysis 32 1997 91 116 an hermite expansion as in p abken d b madan s ramamurtie estimation of risk neutral and statistical densities by hermite polynomial approximation with an application to eurodollar futures options federal reserve bank of atlanta 1996 and a method based on maximum entropy according to p buchen m kelly journal of financial and quantitative analysis 31 1996 143 159 we take care of the early exercise feature and we show how to approximate rnds for a fixed time to maturity the various methods generate similar rnds a daily panel of options running from february 1997 to july 1997 reveals that operators expected the snap election a few days before the official announcement was made and that a substantial amount of political uncertainty subsisted even a month after the elections uncertainty evolved with polls forecasts of the future government

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

democracy and development the devil in the details does democracy promote economic development this paper reviews recent attempts to address this question that exploited within country variation it shows that the answer is largely positive but also depends on the details of democratic reforms first the sequence of economic vs political reforms matters countries liberalizing their economy before extending political rights do better second different forms of democratic government lead to different economic policies and this might explain why presidential democracy leads to faster growth than parliamentary democracy third it is important to distinguish between expected and actual political reforms taking expectations of regime change into account helps identify a stronger growth effect of democracy

quadratic hedging schemes for non gaussian garch models abstract we propose different schemes for option hedging when asset returns are modeled using a general class of garch models more specifically we implement local risk minimization and a minimum variance hedge approximation based on an extended girsanov principle that generalizes duan s 1995 delta hedge since the minimal martingale measure fails to produce a probability measure in this setting we construct local risk minimization hedging strategies with respect to a pricing kernel these approaches are investigated in the context of non gaussian driven models furthermore we analyze these methods for non gaussian garch diffusion limit processes and link them to the corresponding discrete time counterparts a detailed numerical analysis based on s p 500 european call options is provided to assess the empirical performance of the proposed schemes we also test the sensitivity of the hedging strategies with respect to the risk neutral measure used by recomputing some of our results with an exponential affine pricing kernel

tax base variability and procyclical fiscal policy in developing countries abstract based on a sample of 56 countries we show that fiscal policy in the g7 countries appears to be acyclical while fiscal policy in developing countries is procyclical i e fiscal policy is expansionary in good times and contractionary in bad times to explain this puzzle we develop an optimal fiscal policy model in which running budget surpluses is costly because they create pressures to increase public spending given this distortion a government that faces large fluctuations in the tax base as is the case for developing countries will find it optimal to run a procyclical fiscal policy

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

a new analysis of the determinants of the real dollar sterling exchange rate 1871 1994 the high persistence of both ppp deviations and the proxy variables for the equilibrium real rate might create a problem of spurious coefficient significance within recently applied nonlinear models to illustrate we consider the real dollar sterling exchange rate over the period 1871 1994 a nonlinear estar process with a time varying equilibrium seems to parsimoniously fit the data appropriate significance levels are obtained using the wild bootstrap method to adequately capture the conditional heteroskedasticity in the data our results provide further evidence for the nonlinear model and the implied speed of adjustment is found to be substantially faster than previously reported in the literature

the commodity terms of trade unit roots and nonlinear alternatives a smooth transition approach market price dynamics for north american oriented strand board markets are examined specifically the role of transactions costs are examined vis a vis the law of one price weekly data for the january 3rd 1995 through april 14th 2006 period are used in the analysis nonlinearities induced by unobservable transactions costs are modeled by estimating smooth transition autoregressions stars results indicate that nonlinearity is an important feature of these markets and that the parity relationships implied by economic theory are generally supported by the star models implications for the efficiency of spatial market linkages are examined by estimating generalized impulse response functions

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

external debt capital flight and political risk abstract this paper explains the simultaneous occurence of large external debts private capital outflows and low domestic capital formation we consider a general equilibrium model in which two government types with conflicting distributional goals randomly alternate in office uncertainty over the fiscal policies of future governments generates capital flight and small domestic investment and induces the government to overaccumulate external debt the model also predicts that left wing governments are more inclined to restrict capital outflows than right wing governments finally we examine how political uncertainty affects the risk premium and how debt repudiation may occur after a regime change

the process followed by ppp data on the properties of linearity tests recent research has reported the lack of correct size in stationarity test for ppp deviations within a linear framework however theoretically well motivated nonlinear models such as the estar appear to parsimoniously fit the ppp data and provide an explanation for the ppp puzzle employing monte carlo experiments we analyze the size and power of the nonlinear tests against a variety of nonstationary hypotheses we also fit the estar model to data from high inflation economies our results provide further support for estar specification

international commodity prices growth and the outbreak of civil war in sub saharan africa to learn more about the effect of economic conditions on civil war we examine whether sub saharan civil wars are more likely to start following downturns in the international price of countries main export commodities the data show a robust effect of commodity price downturns on the outbreak of civil wars we also find that sub saharan countries are more likely to see civil wars following economic downturns in their main oecd export destinations

purchasing power parity over two centuries trends and nonlinearity in two recent contributions lothian and taylor and cuddington and liang produced empirical evidence that annual data for the dollar sterling real exchange rate spanning two centuries exhibited a non linear deterministic trend this trend could be proxying harrod balassa samuelson effects lothian and taylor showed that a linear stationary autoregressive mode which embodied a cubic trend implied much faster mean reversion of the real exchange rate to shocks than a model that excluded the trend this article shows that both non linearity and a deterministic trend can be allowed for in a theoretically appealing manner and that the fitted models provide a parsimonious explanation of both the dollar sterling and franc sterling real exchange rates over the two centuries of data generalized impulse response function analysis of the models demonstrates that the speed of adjustment to shocks can be even faster when trends are considered

output value risk for commodity producers the uncertain benefits of diversification summary commodity price volatility has long been recognized as a main risk for commodity producers welfare and has led to diversification efforts less noticed has been the importance of commodity correlations and their increase after 2006 in the risk faced by producers to assess their impact we perform an empirical analysis of the market value of commodity producers output in a sample of 56 countries producing 26 commodities we find that diversification and correlations strongly explain output value volatility during 1987 2006 producers effectively specialized in a single commodity had an average output value volatility of 27 0 while producers of three or more commodities had a 12 7 volatility in this period average correlation was 8 and diversification was very effective in the 2007 12 period correlations averaged 26 and output volatilities for specialized and diversified commodities were 30 4 and 19 5 respectively thus reducing the benefit of diversification at a time of macroeconomic distress in 2013 16 output volatilities reverted to levels close to those in 1987 2006 as commodities decorrelated again our findings should be relevant to policy makers embarking in diversification efforts and in the analysis of macroeconomic risk of commodity producers

generalized risk premia abstract this paper develops an optimal trading strategy explicitly linked to an agent s preferences and assessment of the distribution of asset returns the price of this strategy is a portfolio of implied moments and its expected excess returns naturally accommodate compensation for higher order moment risk variance risk and the equity premium approximate it to first order and it nests cross sectional asset pricing models such as the linear capital asset pricing model capm an empirical study in the us index market compares the investment behavior of an agent with recursive long run risk preferences to one who merely uses an identically independently distributed time series model and takes market prices as given the two agents exhibit very similar behavior during crises and can be distinguished mostly during calm periods

optimal delta hedging for options abstract as has been pointed out by a number of researchers the normally calculated delta does not minimize the variance of changes in the value of a trader s position this is because there is a non zero correlation between movements in the price of the underlying asset and movements in the asset s volatility the minimum variance delta takes account of both price changes and the expected change in volatility conditional on a price change this paper determines empirically a model for the minimum variance delta we test the model using data on options on the s p 500 and show that it is an improvement over stochastic volatility models even when the latter are calibrated afresh each day for each option maturity we also present results for options on the s p 100 the dow jones individual stocks and commodity and interest rate etfs

hedging using simulation a least squares approach abstract this paper presents a new and flexible computational approach to derivative hedging it is based on the use of least squares regression in order to compute the hedging portfolio this nonparametric methodology can be readily applied to any derivative contract written on a single underlying risky asset in a complete market with continuous markov price paths we illustrate this technique computing sensitivities on plain vanilla and exotic options with both european and american exercise style the achieved numerical accuracy is always comparable with the best simulation and semianalytic techniques presented in the literature

oil rents corruption and state stability evidence from panel data regressions abstract we examine the effects of oil rents on corruption and state stability exploiting the exogenous within country variation of a new measure of oil rents for a panel of 30 oil exporting countries during the period 1992 2005 we find that an increase in oil rents significantly increases corruption significantly deteriorates political rights while at the same time leading to a significant improvement in civil liberties we argue that these findings can be explained by the political elite having an incentive to extend civil liberties but reduce political rights in the presence of oil windfalls to evade redistribution and conflict we support our argument documenting that there is a significant effect of oil rents on corruption in countries with a high share of state participation in oil production while no such link exists in countries where state participation in oil production is low

resource windfalls and public debt a political economy perspective abstract can natural resource windfalls increase public debt in democracies adopting a political economy perspective we show that the answer is in the affirmative resource windfalls increase both the government s income and wealth the former mitigates the need to borrow whereas the latter encourages further borrowing as it improves its terms implying an ambiguous pure effect of resource windfalls on debt re election considerations shorten political time horizons and give rise to political myopia we show that higher political myopia induced by more stringent institutional re election restrictions magnifies the wealth effect turning positive the effect of resource windfalls on debt we test the model s predictions using a panel of u s states over the period 1963 2007 our identification strategy rests on constitutionally entrenched differences in gubernatorial term limits that provide plausibly exogenous variation in re election prospects and geographically based cross state differences in natural endowments our baseline estimates indicate that a resource windfall of 1 induces an increase of approximately 20 in the public debt of states with more stringent re election restrictions

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

do natural resources fuel authoritarianism a reappraisal of the resource curse a large body of scholarship finds a negative relationship between natural resources and democracy extant cross country regressions however assume random effects and are run on panel datasets with relatively short time dimensions because natural resource reliance is not an exogenous variable this is not an effective strategy for uncovering causal relationships numerous sources of bias may be driving the results the most serious of which is omitted variable bias induced by unobserved country specific and time invariant heterogeneity to address these problems we develop unique historical datasets employ time series centric techniques and operationalize explicitly specified counterfactuals we test to see if there is a long run relationship between resource reliance and regime type within countries over time both on a country by country basis and across several different panels we find that increases in resource reliance are not associated with authoritarianism in fact in many specifications we generate results that suggest a resource blessing

the quality of political institutions and the curse of natural resources we propose a theoretical model to explain empirical regularities related to the curse of natural resources which emphasises the behaviour and incentives of politicians we extend the standard voting model to give voters political control beyond the elections this gives rise to a new restriction that policies should not give rise to a revolution our model clarifies when resource discoveries might lead to revolutions namely in countries with weak institutions it also suggests that for bad political institutions human capital depends negatively on natural resources while for high institutional quality the dependence is reversed this finding is corroborated in cross section regressions

the voracity effect abstract we analyze an economy that lacks a strong legal political institutional infrastructure and is populated by multiple powerful groups powerful groups dynamically interact via a fiscal process that effectively allows open access to the aggregate capital stock in equilibrium this leads to slow economic growth and a voracity effect by which a shock such as a terms of trade windfall perversely generates a more than proportionate increase in fiscal redistribution and reduces growth we also show that a dilution in the concentration of power leads to faster growth and a less procyclical response to shocks jel f43 o10 o23 o40

why is fiscal policy often procyclical many countries especially developing ones follow procyclical fiscal policies namely spending goes up taxes go down in booms and spending goes down taxes go up in recessions we provide an explanation for this suboptimal fiscal policy based upon political distortions and incentives for less than benevolent government to appropriate rents voters have incentives similar to the starving the leviathan classic argument and demand more public goods or fewer taxes to prevent governments from appropriating rents when the economy is doing well we test this argument against more traditional explanations based purely on borrowing constraints with a reasonable amount of success

the factor structure in equity options principal component analysis of equity options on dow jones rms reveals a strong factor structure the rst principal component explains 77 of the variation in the equity volatility level 77 of the variation in the equity option skew and 60 of the implied volatility term structure across equities furthermore the rst principal component has a 92 correlation with sp g12 g13

index arbitrage with heterogeneous investors a smooth transition error correction analysis abstract the traditional index arbitrage model assumes a constant threshold mispricing between the futures and cash prices for all investors allowing for heterogeneity in investors transaction costs objectives and capital constraints we model the intraday mispricing of djia futures as a smooth transition autoregressive star process with the speed of adjustment toward equilibrium varying directly with the mispricing we show that the observed mean reversion in mispricing changes is induced by heterogeneous arbitrageurs instead of a statistical illusion infrequent trading of index portfolio stocks we further use a star error correction model to describe the nonlinear dynamics between the djia futures and index this model describes not only which market is more informationally efficient than the other but also the legging process the nonsimultaneous establishing of cash and futures positions

do real exchange rates follow a nonlinear mean reverting process in developing countries in an effort to fight relatively high inflation many developing countries try to manage their nominal exchange rates through official intervention in addition developing countries tend to have high transportation costs tariffs and nontariff barriers these factors are among the sources of generating nonlinearity in real exchange rates and hence some nonlinear adjustment toward purchasing power parity ppp in developing countries in this paper we employ monthly real effective exchange rate reer data of 88 developing countries and test the null of nonstationarity versus an alternative of linear stationarity by the means of a conventional unit root test and compare the results with those obtained from a new test in which the null is the same but the alternative hypothesis is nonlinear stationarity the latter test supports the ppp theory in more developing countries compared with the former test suggesting that nonlinear adjustment toward ppp in developing countries is an important phenomenon reported country characterizations indicate that reversion in reer occurs more often for high inflation countries and for countries with high flexibility in their exchange rates

tractable hedging an implementation of robust hedging strategies abstract this paper analyzes tractable robust hedging strategies in diffusion type models including stochastic volatility models a robust hedging strategy avoids any losses as long as volatility stays within a given interval it does not depend on the exact specification of the volatility process and therefore mitigates problems caused by model misspecification a tractable hedging strategy is defined as the sum over black scholes strategies for a convex concave payoff the cheapest robust hedge is given by a bs hedge at the upper lower volatility bound thus it is tractable for all other payoffs one has to solve a black scholes barenblatt equation and the cheapest robust hedge is not tractable a tractable hedge can then be found by decomposing the payoff into a convex and a concave function each of which is hedged separately we first give the decomposition that minimizes the initial capital second we show that it may be even cheaper to hedge a dominating payoff and we show explicitly how to determine the optimal dominating payoff we illustrate our results by two examples

institutions and the resource curse countries rich in natural resources constitute both growth losers and growth winners we claim that the main reason for these diverging experiences is differences in the quality of institutions more natural resources push aggregate income down when institutions are grabber friendly while more resources raise income when institutions are producer friendly we test this theory building on sachs and warner s influential works on the resource curse our main hypothesis that institutions are decisive for the resource curse is confirmed our results contrast the claims of sachs and warner that institutions do not play a role

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

dynamic persistence of primary commodity prices this article examines the persistence of shocks to international commodity prices from 1900 to 2008 using the updated grilli yang index the main innovation of this study is that it determines whether commodity prices are characterized by multiple changes in persistence specifically bootstrap methods are used to estimate persistence and the associated half life shocks are calculated we find that the persistence of shocks can vary widely depending on the individual commodity and the time period the results suggest that policy makers need to exercise caution when introducing measures to cushion the effect of shocks to world commodity prices

are windfalls a curse abstract a puzzling feature of temporary terms of trade booms is that some countries have responded to such windfalls by running current account deficits furthermore those countries that ran current account deficits failed to attain greater post boom growth rates indicating the deficits were consumed or invested in low quality projects the point we make is that the structure of the fiscal process is critical in determining outcomes if fiscal control is unitary then the consumption smoothing effect is operative and representative agent models of the current account have predictive power however if control is divided among several fiscal claimants a voracity effect appears which counteracts the consumption smoothing effect leading to a deterioration of the current account in response to a positive temporary shock we model the interaction among fiscal claimants as a dynamic game and show that in equilibrium aggregate appropriation increases more than the windfall itself this results in a deterioration of the current account we also show that all the windfall is dissipated with the country experiencing no increase in welfare 1998 elsevier science b v

north american oriented strand board markets arbitrage activity and market price dynamics a smooth transition approach price dynamics for north american oriented strand board osb markets are examined the role of transactions costs are explored vis a vis the law of one price weekly data february 3rd 1995 through october 9th 2009 are used in the analysis nonlinearities induced by unobservable transactions costs are modeled by estimating time varying smooth transition autoregressions tv stars results indicate that nonlinearity and structural change are important features of these markets price parity relationships implied by economic theory are generally supported by the estimated models implications for the efficiency of spatial market linkages and the dynamics associated with price adjustments are also examined

trade institution quality and income inequality summary we examine the effect of trade on income inequality in small developing countries we use two well accepted trade cost variables for identification one is based on baltic dry index and another is commodities price index our main finding is that trade leads to a significant reduction increase in income inequality in autocracies democracies to explain such different effects we provide supporting evidence that autocracies export more primary commodities and may follow the stolper samuelson theorem in ho framework while democracies active in manufacturing outsourcing may follow feenstra and hanson 1996 task model

model free hedge ratios and scale invariant models a price process is scale invariant if and only if the returns distribution is independent of the price measurement scale we show that most stochastic processes used for pricing options on financial assets have this property and that many models not previously recognised as scale invariant are indeed so we also prove that price hedge ratios for a wide class of contingent claims under a wide class of pricing models are model free in particular previous results on model free price hedge ratios of vanilla options based on scale invariant models are extended to any contingent claim with homogeneous pay off including complex path dependent options however model free hedge ratios only have the minimum variance property in scale invariant stochastic volatility models when price volatility correlation is zero in other stochastic volatility models and in scale invariant local volatility models model free hedge ratios are not minimum variance ratios and our empirical results demonstrate that they are less efficient than minimum variance hedge ratios

financing vs forgiving a debt overhang abstract this paper examines the tradeoffs facing creditors of a country whose debt is large enough that the country cannot attract voluntary new lending if the country is unable to meet its debt service requirements out of current income the creditors have two choices they can finance the country lending at an expected loss in the hope that the country will eventually be able to repay its debt after all or they can forgive reducing the debt level to one that the country can repay the post 1983 debt strategy of the imf and the us has relied on financing but many current calls for debt reform call for forgiveness instead the paper shows that the choice between financing and forgiveness represents a tradeoff financing gives the creditors an option value if the country turns out to do relatively well creditors will not have written down their claims unnecessarily however the burden of debt distorts the country s incentives since the benefits of good performance go largely to creditors rather than itself the paper also shows that the tradeoff itself can be improved if both financing and forgiveness are made contingent on states of nature that the country cannot affect such as oil prices world interest rates etc

hedging options under transaction costs and stochastic volatility in this paper we consider the problem of hedging contingent claims on a stock under transaction costs and stochastic volatility extensive research has clearly demonstrated that the volatility of most stocks is not constant over time as small changes of the volatility can have a major impact on the value of contingent claims hedging strategies should try to eliminate this volatility risk we propose a stochastic optimization model for hedging contingent claims that takes into account the effects of stochastic volatility transaction costs and trading restrictions simulation results show that our approach could improve performance considerably compared to traditional hedging strategies

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

political foundations of the resource curse in this paper we argue that the political incentives that resource endowments generate are the key to understanding whether or not they are a curse we show 1 politicians tend to over extract natural resources relative to the efficient extraction path because they discount the future too much and 2 resource booms improve the efficiency of the extraction path however 3 resource booms by raising the value of being in power and by providing politicians with more resources which they can use to influence the outcome of elections increase resource misallocation in the rest of the economy 4 the overall impact of resource booms on the economy depends critically on institutions since these determine the extent to which political incentives map into policy outcomes countries with institutions that promote accountability and state competence will tend to benefit from resource booms since these institutions ameliorate the perverse political incentives that such booms create countries without such institutions however may suffer from a resource curse

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

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

explaining ethiopia s growth acceleration the role of infrastructure and macroeconomic policy summary ethiopia has experienced an impressive growth acceleration over the past decade this was achieved on the back of an economic strategy emphasizing public infrastructure investment supported by heterodox macro financial policies this paper identifies the drivers of ethiopia s recent growth episode and examines the extent to which they were typical or unique it combines country specific information with the results of a cross country panel regression model we find that ethiopia s growth is explained well by factors correlating with growth in a broad range of countries in recent decades including public infrastructure investment restrained government consumption and a conducive external environment on the other hand we argue that the policy mix that supported very high levels of public investment in ethiopia was to some extent unique interestingly macroeconomic imbalances due to this heterodox policy mix only moderately held back growth which helps explain why ethiopia was able to grow so fast in spite of their presence their negative effects were quantitatively much less important than the positive growth drivers they helped to achieve the results suggest that getting infrastructure right may outweigh moderate shortcoming in the macro framework at early stages of development we further relate this country specific finding to the recent growth literature