Nonlinear exchange rate predictability

We study whether the nonlinear behavior of the real exchange rate can help us account for the lack of predictability of the nominal exchange rate. We construct a smooth nonlinear error-correction model that allows us to test the hypotheses of nonlinear predictability of the nominal exchange rate and nonlinear behavior on the real exchange rate in the context of a fully specified cointegrated system. Using a panel of 19 countries and three numeraires, we find evidence of nonlinear predictability of the nominal exchange rate and of nonlinear mean reversion of the real exchange rate. Out-of-sample Theil’s U -statistics show a higher forecast precision of the nonlinear model than the one obtained with a random walk specification. Although the robustness of the out-of-sample results over different forecast windows is somewhat limited, we are able to obtain significant predictability gains—from a parsimonious structural model with PPP fundamentals—even at short-run horizons.     

Purchasing power parity, unit roots, and dynamic structure

Recent studies of purchasing power parity (PPP) account for the possible presence of unit roots in nominal exchange rates and relative price indices by applying standard unit-root tests to real exchange rates, which are ratios of nominal exchange rates and relative price indices. These studies occasionally find evidence of PPP, but as a whole, the evidence is not definitive. Standard unit-root tests impose a restrictive dynamic structure between nominal exchange rates and relative price indices. I specify and estimate a generalized dynamic structure. I reject the dynamic restrictions implicit in standard unit-root tests of PPP, and find stronger evidence of PPP than do most other recent studies.     

Temporal aggregation and purchasing power parity persistence

This paper uses a unique new monthly US-UK real exchange rate series for the January 1794-December 2009 period to reexamine the academic debate over purchasing power parity (PPP). The consensus view described by Rogoff (1996) is that PPP holds in the long-run, but short-run deviations are very persistent, with half-lives ranging from 3 to 5 years. Most of the literature using long time series relies on the annual data developed by Lee (1976) and Lothian and Taylor (1996), which were both constructed from underlying higher-frequency data sources. Estimates of purchasing power parity persistence using these series may therefore be subject to temporal aggregation bias. We find evidence of aggregation bias which indicates the half-life of PPP deviations has been overestimated in much of the previous literature. We also find that estimates of the half-lives are further reduced once we account for the Harrod (1933)-Balassa (1964)-Samuelson (1964) effect. The result of aggregation bias appears to be robust even when considering the case that real exchange rates exhibit nonlinear dynamics.     

Getting PPP right: Identifying mean-reverting real exchange rates in panels

Recent advances in testing for the validity of Purchasing Power Parity (PPP) focus on the time series properties of real exchange rates in panel frameworks. One weakness of such tests, however, is that they fail to inform the researcher as to which cross-section units are stationary. As a consequence, a reservation for PPP analyses based on such tests is that a small number of real exchange rates in a given panel may drive the results. In this paper we examine the PPP hypothesis focusing on the stationarity of the real exchange rates in up to 25 OECD countries. We introduce a methodology that when applied to a set of established panel unit-root tests, allows the identification of the real exchange rates that are stationary. Our results reveal evidence of mean-reversion that is significantly stronger as compared to that obtained by the existing literature, strengthening the case for PPP.     

A sequential purchasing power parity test for panels of large cross-sections and implications for investors

In this paper we use monthly time series data for not less than 64 countries and a new sequential approach to test for purchasing power parity (PPP). The results are strong in that the evidence in favor of PPP is very weak. In fact, for the US-dollar-based exchange rates the evidence is basically non-existent. In order to eliminate the effect of the base currency, we also apply the sequential PPP test to all pairs of exchange rates, and find similarly weak evidence of PPP. However, for those rates where evidence is found, using a technical trading rule, we find evidence of significant profits. The predictability of the stationary pairs is therefore important for investors.     

Deviations from purchasing power parity under different exchange rate regimes: Do they revert and,if so,how?

We propose an empirical model for deviations from long-run purchasing power parity (PPP) that simultaneously accounts for three key features: (i) adjustment toward PPP may occur via nominal exchange rates and relative prices at different speeds; (ii) different exchange rate regimes may generate regime shifts in the structural dynamics of PPP deviations; (iii) nonlinear reversion toward PPP in response to shocks. This empirical framework encompasses and synthesizes much previous empirical research. Using over a century of data for the G5 countries, we provide evidence that long-run PPP holds, the relative importance of nominal exchange rates and prices in restoring PPP varies over time and across different exchange rate regimes, and reversion to PPP occurs nonlinearly, at a speed that is fairly consistent with the nominal rigidities suggested by conventional open economy models.     

购买力平价理论的实证检验法综述

本文介绍了自 2 0世纪 70年代以来开放经济理论的基石———购买力平价及实际汇率的相关实证检验方法。以发达国家双边汇率作为样本数据进行检验 ,发现在样本期间足够长、样本数量足够多的情况下 ,PPP假设成立。此外 ,由于实际汇率对PPP的均值复归呈现出显著的非线性特征 ,今后的研究方向应当是建立非线性汇率动态模型。     

A test of purchasing power parity for emerging economies

The concept of purchasing power parity (PPP) is examined here for its applicability to the soft currencies of a large group of emerging/developing economies. PPP is tested through the use of the technique of cointegration. Based on data covering the period of 1975–1997, cointegration tests of price indices and exchange rates are conducted for 27 countries (against the U. S.). The results provide relatively strong evidence (for 14 countries) in favor of the long-term applicability of PPP as a cointegration concept. Further tests on real exchange rates indicate that the symmetry and proportionality conditions implied by PPP are rejected in all but one case. The latter tests also show that departures from long-term exchange values can last for several years and that a priori restrictions imposed on the cointegrating vector can lead to a false rejection of the PPP concept.     

Long-run purchasing power parity,prices and exchange rates in transition: The case of six Central and East European countries

This paper presents empirical results on the hypothesis of long-run purchasing power parity (PPP) with respect to the exchange-rate regimes in six Central and East European countries. The analysis employs cointegration theory to examine the movements of prices and exchange rates in transition to a market economy. Our results are based on system estimation procedures developed by Stock and Watson (1993) and Johansen (1991). We find moderate evidence to support long-run equilibria, however, the cointegrating vector values do not yield to easy interpretation and violate the symmetry and proportionality conditions suggested by PPP. We provide an explanation for such behavior and find that it is consistent with the existing literature on transition and foreign exchange markets.     

Persistence in law of one price deviations: Evidence from micro-data

Using an extensive micro-price panel, we find a positive cross-sectional relationship between LOP persistence and the distribution margin, which we measure using sectoral U.S. data, as suggested by the classical dichotomy. The median level of persistence (across goods) is low, and there is no evidence of a border effect: the half-life of a deviation is about 19 months across OECD cities and just 1 month lower across cities in the U.S. Aggregating our micro-data using a variety of weighting methods shows PPP persistence to be in the range of 1-2 years, over the 1990-2005 period. These results challenge three widely held views: (i) the classical dichotomy is irrelevant; (ii) high persistence is a robust feature of aggregate real exchange rates; and (iii) border crossings necessarily generate greater real exchange rate persistence.     

Foreign exchange risk pricing and equity market segmentation in Africa

This work is the first to investigate simultaneously the occurrence of unconditional currency risk pricing and equity market segmentation in Africa’s major stock markets. The multi-factor asset pricing theory provides the theoretical framework for our model. We find strong evidence suggesting that Africa’s equity markets are partially segmented. However, we find insufficient evidence to reject the hypothesis that foreign exchange risk is not unconditionally priced in Africa’s stock markets. This result is robust to alternative foreign exchange rate-adjusted return measures. These findings suggest that international investors can diversify into Africa’s equity markets without worrying about unconditional risks associated with foreign exchange rate fluctuations.     

Searching for evidence of long-run PPP from a post-Bretton Woods panel: separating the wheat from the chaff

This paper reexamines the issue of long-run PPP using multiple panel tests in the framework of confirmatory analysis. Application of six panel tests under competing null hypotheses to the real exchange rates of 21 industrial countries yields seemingly contradictory evidence on the parity during the post-Bretton Woods period. Regardless of numeraire currency, four I(1) panel tests unanimously reject the null hypothesis in favor of long-run PPP, whereas two I(0) panel tests lend little support to the parity at conventional significance levels. Confirmatory analysis suggests that this puzzling result can be explained either by nonlinear dynamics of the real exchange rates or by a mixture of I(0) and I(1) series in the panel. Monte Carlo experiments indicate that potential mix of I(0) and I(1) series is more relevant to the empirical finding. The use of a sequential classification method sorts out six real exchange rates which exhibit most persistent deviations from long-run equilibrium. Systematic behavior of these series can be characterized better by country specific factors than by observable macroeconomic variables.     

Impact of speculation and economic uncertainty on commodity markets

We examine the interactions between commodity futures returns and five driving factors (financial speculation, exchange rate, stock market dynamics, implied volatility for the US equity market, and economic policy uncertainty). Nonlinear causality tests are implemented after controlling for cointegration and conditional heteroscedasticity in the data over the period May 1990 – April 2014. Our results show strong evidence of unidirectional linear causality from commodity returns to excess speculation for the majority of the considered commodities, in particular for agriculture commodities. This evidence casts doubt on the claim that speculation is driving food prices. We also find unidirectional linear causality from energy futures markets to exchange rates and strong evidence of nonlinear causal dependence between commodity futures returns, on the one hand, and stock market returns and implied volatility, on the other hand. Overall, the new evidence found in this paper can be utilized for policy and investment decision-making.     

Real exchange rates and time-varying trade costs

This paper re-examines the empirical modeling of Purchasing Power Parity (PPP) deviations in the presence of commodity market frictions. First, we show that a specific type of smooth transition models can closely approximate the functional form of the theoretical adjustment mechanism derived by Dumas (1992) [Dynamic Equilibrium and the Real Exchange Rate in a Spatially Separated World, Review of Financial Studies,5:2153-180] for the case of constant as well as changing trade costs. Second, we develop, for the first time, an empirical model of the real exchange rate which allows for changes in the degree of market integration. By employing a long span of data on the Dollar-Sterling real exchange rate and a micro-founded proxy for trade frictions, we provide novel evidence of a significant relationship between the persistence of the real exchange rate and the level of trade costs. This finding suggests that both the difficulty of detecting PPP and the extend of Rogoff’s puzzle vary over time with the degree of trade restrictiveness. Finally, we highlight policy repercussions of our results.     

Testing the Purchasing Power Parity Hypothesis for the New Member and Candidate Countries of the European Union: Evidence from Lagrange Multiplier Unit Root Tests with Structural Breaks

This paper investigates the validity of purchasing power parity (PPP) for the eleven Central and East European transition countries and three market economy countries, Cyprus, Malta, and Turkey. Unlike previous studies on PPP, this study uses Lagrange multiplier (LM) unit root tests that incorporate structural breaks in the data series. The findings indicate that in cases of one and two structural breaks, for a U.S. dollar-based real exchange rate series, there is little evidence supporting the validity of PPP. For a deutsche mark-based real exchange rate series, for the cases of both one and two breaks, there is evidence of stationarity of real exchange rates for eight sample countries, which is consistent with PPP. The results also indicate that the estimated half-life of a shock to the real exchange rate ranges from 1.25 (15.05 months) to 2.72 (32.72 months) years across countries. The empirical findings may provide direction for policy makers to coordinate monetary policies for the process of European monetary integration.     

A re-examination on dissecting the purchasing power parity puzzle

The purpose of this paper is to examine the source of a real exchange-rate adjustment based on the impulse-response function constructed from local projections when the true data-generating process (DGP) is unknown. This work extends the local-projection method proposed by Jordà [2005. Estimation and inference of impulse responses by local projections. American Economic Review 95, 161-182] to allow for variables that are I(1) and exhibit cointegration. Our paper shows that nominal exchange-rate adjustments dominate in the reversion toward PPP regardless of a nominal exchange-rate shock or a price shock. It is also shown that the half-life of real exchange rates is close to that of nominal exchange rates. Since these results are consistent with those of Cheung et al. [Cheung, Y.W., Lai, K.S., Bergman, M., 2004. Dissecting the PPP puzzle: the unconventional roles of nominal exchange rate and price adjustments. Journal of International Economics 64, 135-150], we therefore conclude that their main findings are robust to possible misspecifications in the true DGP.     

Which Fundamentals Drive Exchange Rates? A Cross‐Sectional Perspective

Standard present‐value models suggest that exchange rates are driven by expected future fundamentals, implying that exchange rates contain information about future fundamentals. We test this key empirical prediction of present‐value models in a sample of 35 currency pairs ranging from 1900 to 2009. Employing a variety of tests, we find that exchange rates have strong and significant predictive power for nominal fundamentals (inflation, money balances, nominal GDP), whereas predictability of real fundamentals and risk premia is much weaker and largely confined to the post–Bretton Woods era. Overall, we uncover ample evidence that future macrofundamentals drive current exchange rates.     

Is the relationship between prices and exchange rates homogeneous?

Empirical tests of purchasing power parity (PPP) are implicitly based on the conditions of symmetry and proportionality of the price coefficients. We investigate a separate condition, which we term homogeneity. Specifically, while there may be factors that drive a wedge between prices and exchange rates, when these factors are held constant we would expect a change in exchange rates to be associated with a proportional, or homogeneous, change in prices. To test for the existence of homogeneity in prices, we conduct two experiments. First, we apply a time-varying-coefficient procedure to nine euro-area countries as well as the euro area as a whole during the (monthly) sample period, 1999:M1 to 2011:M3. Second we apply the same procedure to the same group of countries, plus Canada, Japan and Mexico, over the longer period, 1957:M4 to 2011:M3. We find that averages of the price coefficients, corrected for specification biases, are uniformly homogeneous in the long run, providing strong support for PPP.     

Time-varying risk premia in foreign exchange and equity markets: evidence from Asia–Pacific countries

This paper examines the validity of the risk premia hypothesis in explaining deviations from Uncovered Interest Parity (UIP) and the role of deviations from Purchasing Power Parity (PPP) in the pricing of foreign exchange rates and equity securities in five Asia–Pacific countries and the US. Using weekly data from 1 January, 1988 to 27 February, 1998, I find that conditional variances are not related to the deviations from UIP in any statistical sense based on an univariate GARCH(1,1)-M model. As I consider both foreign exchange and equity markets together and test a conditional international CAPM (ICAPM) in the absence of PPP, I cannot reject the model based on the J-test by Hansen (Econometrica 50 (1982), 1029–1054) and find significant time-varying foreign exchange risk premia present in the data. This empirical evidence supports the notion of time-varying risk premia in explaining the deviations from UIP. It also supports the idea that the foreign exchange risk is not diversifiable and hence should be priced in both markets.     

Was It Real? The Exchange Rate-Interest Differential Relation over the Modern Floating-Rate Period

In this paper, we explore the relationship between real exchange rates and real interest rate differentials in the United States, Germany, Japan, and the United Kingdom. Contrary to theories based on the joint hypothesis that domestic prices are sticky and monetary disturbances are predominant, we find little evidence of a stable relationship between real interest rates and real exchange rates. We consider both in-sample and out-of-sample tests. One hypothesis that is consistent with our findings is that real disturbances (such as productivity shocks) may be a major source of exchange rate volatility.