Burgernomics: the economics of the Big Mac standard

In the course of PPP research, much of the debate over the validity has been over the choice of an appropriate ‘basket’ for making purchasing power comparisons. The different compositions of goods and services in these baskets across countries have resulted in arguments against their usefulness for PPP purposes. This problem is augmented by the existence of productivity differentials in traded and non-traded goods across countries. Therefore we consider the use of the Big Mac as the international monetary standard as being a more palatable alternative: It is produced locally in over 80 countries around the world, with only minor changes in recipe and thus has the flavour of ‘the perfect universal commodity’. Our results indicate that the Big Mac Index is surprisingly accurate in tracking exchange rates over the long-term, which is consistent with previous PPP research findings. We subsequently enhance our PPP comparisons by taking into account the productivity differentials between countries and excluding non-traded goods from the Big Mac Index to derive the No-Frills Index.     

The ‘laissez faire’ bias of managed floating

The government of a small open economy trying to manage its exchange rate faces a ‘time consistency’ problem. If markets expect implementation of the optimal linear intervention rule, the government will be tempted to ‘defect’: knowing this, markets will expect less activism; and, in the discretionary equilibrium, this is what they get. How far this credibility problem can shift discretionary policy towards a free float is shown in two popular models of floating rates. One way of offsetting the ‘laissez faire’ bias of discretionary policy is to appoint a relatively ‘conservative’ central banker: but, as the time period of policy action and precommitment shrinks towards zero, the required conservative bias is found to go towards infinity. Other institutional features — such as central bank reputation, contracts and intermediate targets — may be crucial for successful exchange rate management.     

Exchange rate mean reversion from real shocks within an intertemporal equilibrium model

The post Bretton Woods era has been characterized by real exchange rates that exhibit mean reversion, with mixed evidence as to whether this reversion is partial (PPP never holds) or essentially complete. This paper generates these stylized facts theoretically by synthesizing a simple intertemporal open economy model with the elasticities approach to the current account. A central feature of the model is the existence of non-traded goods. The model can generate partial or approximately complete mean reversion for the real exchange rate (depending on parameter values) if innovations in output are made up of permanent and temporary components. In addition, temporary output shocks generate a type of hysteresis wherein the short-run path for the exchange rate permanently alters its long-run equilibrium value.     

Exchange rate dynamics under alternative optimal interest rate rules

We explore the role of interest rate policy in the exchange rate determination process. Specifically, we derive exchange rate equations from interest rate rules that are theoretically optimal under a few alternative settings. The exchange rate equation depends on its underlying interest rule and its performance could vary across evaluation criteria and sample periods. The exchange rate equation implied by the interest rate rule that allows for interest rate and inflation inertia under commitment offers some encouraging results — exchange rate changes “calibrated” from the equation have a positive and significant correlation with actual data, and offer good direction of change prediction. Our exercise also demonstrates the role of the foreign exchange risk premium in determining exchange rates and the difficulty of explaining exchange rate variability using only policy based fundamentals.     

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.     

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.     

Exchange rate exposure in the Asian emerging markets

This paper investigates the impact of foreign exchange rate change on stock returns in the Asian emerging markets. The asymmetric exchange exposure framework and real exchange rates are used in this paper to capture the different exposures between currency appreciation and depreciation and the high inflation effect in the emerging markets. My empirical results show that there did exist extensive exchange rate exposure in the Asian emerging markets from 1997 to 2010. Moreover, foreign exchange exposure became more significant or greater during the 1997 Asian crisis and the 2008 global crisis periods, despite the frequent central banks’ interventions during these periods. The greater exchange exposure during the crisis periods can be attributable to net exporters or firms with dollar assets, implying that firms can reduce exchange exposures by decreasing their export ratio or dollar assets holding during times of crisis.     

Testing PPP Hypotheses between Japan and the Six G7 Countries

The paper examines the purchasing power parity(PPP) theory of the foreign exchange rate of the yenagainst the currencies of the six G7 countries. We usethe error-corrected five-dimensional vectorautoregressive (VAR) model with structural changes inthe trend function. The data cover the period of thepost-Breton–Woods floating exchange rate system. Theresults reveal that the PPP relation alone determinesthe exchange rates for the USA, France, Germany, andItaly, while a linear combination of PPP and uncoveredinterest rate parity (UIP) relations determines that for Canada. Ina model without trend breaks, the PPP relations holdonly for Germany, which indicates that a correctspecification of the sampling distribution of data isimportant. The one-step prediction based on the errorcorrection model (ECM) outperforms the random walkmodel. The ECM is useful to predict the out-of-samplebehaviors of the exchange rates.     

On the relationship between exchange rates and equity returns: A new approach

This paper employs a new approach in order to investigate the underlying relationship between stock markets and exchange rates. Current approaches suggest that the relative equity market performance of two countries is linked to their exchange rate. In contrast, this study proposes an alternative approach where one global variable – global equity market returns – is believed to have an effect on exchange rates, with the relative interest rate level of a currency determining the sign of the relationship. Our empirical findings suggest that exchange rates and global stock market returns are strongly linked. The value of currencies with higher interest rates is positively related with global equity returns, whereas the value of currencies with lower interest rates is negatively related with global equity returns.     

The Roles of Nominal Exchange Rate and Relative Price Adjustments in PPP Reversion

This paper investigates the roles of the nominal exchange rate and relative prices in restoring purchasing power parity (PPP) by estimating their dynamics with a bivariate threshold vector error correction model. Our empirical results suggest a threshold cointegrating relationship between the nominal exchange rate and relative prices. However, these two variables play different roles in restoring PPP. The nominal exchange rate adjusts to restore PPP only outside the threshold band. Within the band, PPP is restored mainly through adjustments in relative prices.     

Local persistence and the PPP hypothesis

This paper examines the statistical properties of the bilateral real exchange rates of the U.S. vs. France, Germany, and the U.K. during the Post-Bretton-Woods period, and draws implications on the Purchasing Power Parity (PPP) hypothesis. Contrary to traditional studies that consider only unit root and stationary processes to describe the real exchange rate behavior, this paper considers an in-between process, the locally persistent process. The empirical results demonstrate the following two findings: (1) Locally persistent processes describe the real exchange rate movements better than unit root and stationary processes, which implies that PPP reversion occurs and PPP holds in the long-run. (2) The confidence intervals for half-life deviations from PPP under local persistence tend to be narrower than those obtained by assuming the ADF and the local-to-unity models.     

Why panel tests of purchasing power parity should allow for heterogeneous mean reversion

Recent studies of purchasing power parity (PPP) use panel tests that fail to take into account heterogeneity in the speed of mean reversion across real exchange rates. In contrast to several other severe restrictions of panel models and tests of PPP, the assumption of homogeneous mean reversion is still widely used and its consequences are virtually unexplored. This paper analyzes the properties of homogeneous and heterogeneous panel unit root testing methodologies. Using Monte Carlo simulation, we uncover important adverse properties of the panel approach that relies on homogeneous estimation and testing. More specifically, power functions are low and assume irregular shapes. Furthermore, homogeneous estimates of the mean reversion parameters exhibit potentially large biases. These properties can lead to misleading inferences on the validity of PPP. Our findings highlight the importance of allowing for heterogeneous estimation when testing for a unit root in panels of real exchange rates.     

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.     

Explaining exchange rate volatility: an empirical analysis of ‘the holy trinity’ of monetary independence, fixed exchange rates, and capital mobility

This paper uses a panel of data from twenty-two countries between 1967 and 1992 to explain exchange rate volatility, focusing on potential tradeoffs between fixed exchange rates, independent monetary policy, and capital mobility. I use monetary models to parameterize monetary divergence and factor analysis to measure capital mobility. Exchange rate volatility is loosely linked to both monetary divergence and the degree of capital mobility. Interestingly, exchange rate volatility is significantly correlated with the width of the explicitly declared exchange rate band, even after taking monetary divergence and capital mobility into account.     

Volatile and persistent real exchange rates with or without sticky prices

The flexible-price two-country monetary model is extended to include a consumption externality with habit persistence. Two methodologies are employed to explore this model's ability to generate volatile and persistent exchange rates. In the first, actual data is used for the exogenous driving processes. In the second, the model is simulated using estimated forcing processes. The theory, in both cases, is capable of explaining the high volatility and persistence of real and nominal exchange rates as well as the high correlation between real and nominal rates.     

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.     

A century of purchasing power parity confirmed: The role of nonlinearity

Taylor (2002) claims that Purchasing Power Parity (PPP) has held over the 20th century based on strong evidence of stationary for century-long real exchange rates for 20 countries. Lopez et al. (2005), however, found much weaker evidence of PPP with alternative lag selection methods. We reevaluate Taylor’s claim by implementing a recently developed nonlinear unit root test by Park and Shintani (2005). We find strong evidence of nonlinear mean-reversion in real exchange rates that confirms Taylor’s claim. We also find a possible misspecification problem in using the ESTAR model that may not be detected with Taylor-approximation based tests.     

Why do central banks intervene?

Intervention by central banks, in terms of buying and selling foreign currency, has been a major activity in recent years. This paper investigates the motivations for such policy and the evidence for its effectiveness. We use high quality daily data on the dollar amounts of intervention by the central banks of the US and Germany. We also use information on agreed G7 target levels for the $/DM and $/Yen nominal exchange rates. Daily, nominal dollar exchange rate returns are well described as a Martingale-GARCH process, and we find little evidence that the different types of intervention have had much effect on the conditional mean of exchange rate returns. There is some evidence that intervention is associated with slight increases in the volatility of exchange rate returns. While little evidence is found for the effectiveness of intervention, the motivations are more clear. In particular, from the application of probit analysis we find that the probability of intervention is determined by the magnitude of the deviation of the nominal exchange rate from the agreed target level and, to a lesser extent, by the current volatility of exchange rates.     

The U.S. current account deficit and the expected share of world output

We investigate the possibility that the large current account deficits of the U.S. are the outcome of optimizing behavior. We develop a simple long-run world equilibrium model in which the current account is determined by the expected discounted present value of its future share of world GDP relative to its current share of world GDP. The model suggests that under some reasonable assumptions about future U.S. GDP growth relative to the rest of the advanced countries—more modest than the growth over the past 20 years—the current account deficit is near optimal levels. We then explore the implications for the real exchange rate. Under some plausible assumptions, the model implies little change in the real exchange rate over the adjustment path, though the conclusion is sensitive to assumptions about tastes and technology. Then we turn to empirical evidence. A test of current account sustainability suggests that the U.S. is not keeping on a long-run sustainable path. A direct test of our model finds that the dynamics of the U.S. current account—the increasing deficits over the past decade—are difficult to explain under a particular statistical model (Markov-switching) of expectations of future U.S. growth. But, if we use survey data on forecasted GDP growth in the G-7, our very simple model appears to explain the evolution of the U.S. current account remarkably well. We conclude that expectations of robust performance of the U.S. economy relative to the rest of the advanced countries is a contender—though not the only legitimate contender—for explaining the U.S. current account deficit.     

Intertemporal risk-return trade-off in foreign exchange rates

We investigate the intertemporal risk-return trade-off of foreign exchange (FX) rates for ten currencies quoted against the USD. For each currency, we use three risk measures simultaneously that pertain to that currency; its realized volatility, its realized skewness, and its value-at-risk. We apply monthly FX excess returns and risk measures calculated from daily observations. We find that there is a significant contemporaneous risk-return trade-off for the currencies under investigation. There is no evidence of noncontemporaneous risk-return trade-off. We pay special attention to the risk-return trade-off during the recent financial crisis.