Investment intensity of currencies and the random walk hypothesis: Cross-currency evidence

This paper studies the cross-currency and temporal variations in the random walk behavior in exchange rates. We characterize currencies with relatively large investment flows as investment intensive and conjecture that the more investment intensive a currency is, the closer its exchange rate adheres to random walk. Using 29 floating bilateral USD exchange rates, we find that the higher the investment intensity, the less likely it is to reject random walk and the smaller the deviation from random walk is. However, the effect of investment intensity is non-monotonic. Application of threshold models shows that after investment intensity reaches the estimated thresholds, the level of investment intensity has no further effect on the deviation from random walk. These findings help reconcile the previous conflicting results on the random walk in exchange rates by focusing on the effect of cross-currency and temporal variations in investment intensity.     

Structural models of exchange rate determination

This study compares the forecasting accuracy of state space techniques based on the monetary models of exchange rate with univariate and random walk models for four countries. It is found that these structural models outperform ARIMA and random walk models for all four countries. A state space vector that contains variables based on the monetary model easily outperforms random walk as well as ARIMA models for France, Germany, UK, and Japan during the sample period of this study.     

Nonlinear dynamics in foreign exchange rates

This paper investigates whether the behavior of real and nominal foreign exchange rates as well as interest rates are governed by nonlinear dynamics; it also explores whether observed deviations from parity conditions exhibit nonlinear dependence. Standard statistical tests for randomness, such as autocorrelation tests, have low power against a large class of deterministic, nonlinear processes. Discerning nonrandomness of innovations in exchange rates is important for a variety of reasons. For example, many models of international asset pricing assume exchange rates to follow a random walk. Furthermore, nonlinear patterns in deviations from various exchange rate parities have implications for the existence of a time-varying foreign exchange risk premium. With the use of the BDS statistic and a correlation dimension analysis, this paper's primary findings are that (1) foreign exchange markets have become increasingly complex and therefore less amenable to forecasting over time; (2) although forward exchange risk premia are statistically significant and display a deterministic structure, this structure is complex and therefore not easily discernible; and (3) innovations in real exchange rates are consistent with a Purchasing Power Parity equilibrium.     

Random walk and monetary causality in five exchange markets

Time series behavior of monthly spot exchange rates for the French franc, the Deutsche mark, the Italian lira, the Japanese yen, and the UK pound, all priced in relation to the US dollar, shows the robustness of the random walk hypothesis. Incremental efficiency is investigated by a new test procedure, based on the reduction of the forecast error variance, which is a direct implementation of the definition of Granger causality. Exchange markets are found to be not only money efficient, but also monetary efficient in that they are efficient with respect to real income and market interest rates in addition to money stock.     

Some evidence of random walk behavior of Euro exchange rates using ranks and signs

This study utilises recently developed tests based on ranks and signs, in addition to the traditional variance ratio test, to examine the behavior of Euro exchange rates. We show that adjustments for multiple tests must be employed in order to avoid size distortions. Overall, such adjustments provide evidence consistent with random walk behavior of Euro exchange rates.     

On market efficiency of Asian foreign exchange rates: evidence from a joint variance ratio test and technical trading rules

This study employs a joint variance ratio test and technical trading rules to examine the random walk behavior for nine Asian foreign exchange rates for the period 1988–1995. The joint variance ratio test results suggest that there is little evidence of serial correlations in the daily exchange rate series. The results also indicate that, in general, the moving average and channel trading rules do not generate significant, positive profits.     

GDP growth and currency valuation: The case of the dollar

One popular view on the strength of the US dollar around the turn of the century is that the higher growth in the US compared to Europe had stimulated foreigners to buy American assets, thereby driving up the exchange rate. In this paper a modified portfolio balance model is presented, in which it is shown that the impact of output growth on the exchange rate depends crucially on the origin of this growth. An improvement of the output gap is shown to actually depress the exchange rate whereas an increase in potential output growth leads to an appreciation, especially if this improvement is likely to be persistent. In an empirical example, it is shown that the equilibrium real dollar rate is indeed positively affected by high trend growth in the US, whereas it is negatively affected by a positive output gap. The model outperforms the random walk in forecasting future real dollar rates one to eight quarters ahead.     

Exchange Rates and Fundamentals: A General Equilibrium Exploration

Engel and West (2005) show that the observed near random‐walk behavior of nominal exchange rates is an equilibrium outcome of a partial equilibrium asset approach when economic fundamentals follow exogenous first‐order integrated processes and the discount factor approaches one. In this paper, I argue that the unit market discount factor creates a theoretical trade‐off within a two‐country general equilibrium model. The unit discount factor generates near random‐walk nominal exchange rates, but it counterfactually implies perfect consumption risk sharing and flat money demand. Bayesian posterior simulation exercises, based on post‐Bretton Woods data from Canada and the United States, reveal difficulties in reconciling the equilibrium random‐walk proposition within the canonical model; in particular, the market discount factor is identified as being much smaller than one. A relative money demand shock is identified as the main driver of nominal exchange rates.     

Tests of the hypothesis of the existence of risk premium in the foreign exchange market

This paper tests for a risk premium in the foreign exchange market. The null hypothesis of the test is the random walk hypothesis in the foreign exchange market. The alternative hypothesis is that biases of current spot rates (or forward rates) from future spot rates are systematically related to a set of economic variables on which a risk premium may depend. This paper provides firm evidence for a risk premium in the foreign exchange market. The risk premium explains 10–20% of the total variance in future spot rates when the US dollar/mark quarterly rates are used. The magnitudes are smaller (less than 10%) for monthly rates.     

An examination of real interest rates in the United States, Canada, France, and Germany during the recent floating exchange rate period

This study reexamines the international linkage of ex-ante real interest rates using the theory of cointegrated processes. The univariate unit root tests suggest the existence of a nonstationary real interest rate in the United States, Canada, and (the former) West Germany. An ex-ante real interest rate is obtained by subtracting estimates of inflation from the nominal interest rate. The expected inflation rates are obtained by modeling changes in monthly CPI values as autoregressive moving average (ARMA) processes. A multivariate test for unit roots indicates that there are two cointegrating vectors, or one common stochastic trend, for the system of three nonstationary real interest rates. In addition, the log-likelihood ratio test fails to reject the null hypothesis that, in the long run, real interest rates in the United States are equal to those in Canada and West Germany.     

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.     

Exchange rate determination and inter-market order flow effects

The dependence of foreign exchange rates on order flow is investigated for four major exchange rate pairs, EUR/USD, EUR/GBP, GBP/USD and USD/JPY, across sampling frequencies ranging from 5 min to 1 week. Strong explanatory power is discovered for all sampling frequencies. We also uncover cross-market order flow effects, e.g. GBP exchange rates are very strongly influenced by EUR/USD order flow. We proceed to investigate the predictive power of order flow for exchange rate changes, and it is shown that the order flow specifications reduce RMSEs relative to a random walk for all exchange rates at high-frequencies and for EUR/USD and USD/JPY at lower sampling frequencies.     

The Taylor Rule and Forecast Intervals for Exchange Rates

In this paper, we examine the Meese–Rogoff puzzle from a different perspective: out‐of‐sample interval forecasting. While most studies in the literature focus on point forecasts, we apply semiparametric interval forecasting to a group of exchange rate models. Forecast intervals for 10 OECD exchange rates are generated and the performance of the empirical exchange rate models are compared with the random walk. Our contribution is twofold. First, we find that in general, exchange rate models generate tighter forecast intervals than the random walk, given that their intervals cover out‐of‐sample exchange rate realizations equally well. Our results suggest a connection between exchange rates and economic fundamentals: economic variables contain information useful in forecasting distributions of exchange rates. We also find that the benchmark Taylor rule model performs better than the monetary, PPP and forward premium models, and its advantages are more pronounced at longer horizons. Second, the bootstrap inference framework proposed in this paper for forecast interval evaluation can be applied in a broader context, such as inflation forecasting.     

On the short-term predictability of exchange rates: A BVAR time-varying parameters approach

In this paper we propose a Bayesian vector autoregressive model with time-varying parameters (BVAR-TVP) to examine the short-term predictability of exchange rates. An important contribution of the paper is the application of the BVAR-TVP model, for the first time, to daily data using information from financial markets. Another contribution is the production of forecasts in real time at the very short horizon of one-trading day-ahead typically used by traders and investors in financial markets. We employ financial criteria and recently developed statistical tests to assess the exchange rate predictability. We find that the BVAR-TVP model outperforms the random walk for all exchange rates. These forecast gains are due primarily to the time-variation of coefficients, and secondly to information from other financial markets. It is shown that international investors could have made statistically significant excess profits if they had followed an inter-day trading strategy based on the buy/sell signals generated by the model’s one-day-ahead exchange rate forecasts, even after allowing for transaction costs and risk factors.     

Exchange rates,innovations and forecasting

In this paper an ex-post forecasting experiment is performed on the basis of a version of the ‘news’ model of exchange rate determination. For several exchange rates the ‘news’ formulation of monetary exchange rate models leads to relatively accurate ex-post exchange rate forecasts at a number of forecasting horizons. For a majority of the exchange rates studied, however, the results do not compare favorably with those obtained from the naive random walk forecasting rule. Thus, the findings in this article provide mixed evidence with regard to a suggestion in the literature that the finding by Meese and Rogoff that structural models do not even outperform the random walk in an ex-post forecasting experiment, may be due to the fact that these models were not properly tested in a ‘news’ framework.     

Investigating nonlinearities in real exchange rate adjustment: Threshold cointegration and the dynamics of exchange rates and relative prices

Motivated by growing evidence of nonlinear mean-reverting behavior in real exchange rates, this paper investigates the underlying dynamics in the context of a threshold vector error correction model (TVECM) of nominal exchange rate and relative prices. Unlike univariate models, our nonlinear multivariate framework takes into explicit account the joint behavior and individual dynamics of the nominal exchange rate and relative prices when these two key variables are threshold cointegrated. Our empirical application unravels their relative contribution to mean reversion and underscores the importance of capturing their interactions in investigating the nonlinear adjustment toward purchasing power parity.     

Do currency exchange rates impact gold prices? New evidence from the ongoing COVID-19 period

We apply the nonlinear autoregressive distributed lag method to examine the relationships between seven leading currency exchange rates and gold prices using daily data from January 2017 to April 2021. The results reveal that in the short term, while negative United States dollar (USD) to United Kingdom pound, negative USD to Canadian dollar, negative USD to Japanese yen, negative USD to Danish krone, and positive USD to euro exchange rates increase gold prices, a lagged positive USD to euro and lagged positive USD to Danish krone exchange rates decrease gold prices. A test of the pre-pandemic normal period reveals that the uneven and unpredictable impacts of six exchange rates on gold prices are particularly due to COVID-19. We find efficiency in the gold market, in line with the market efficiency hypothesis and random walk theory. Our findings indicate that gold acts as a safe-haven asset for investors during COVID-19.     

A Unifying Microstructure Framework for Modeling Intraday and Interday Asset Pricing Dynamics: the Case of Exchange Rates

A model of the dynamics of intradaily exchange rates is presented. The current Over‐The‐Counter (OTC) exchange rate is the quote of the quoting bank.Two polar cases are considered: (i) If each bank is able to observe the noises relative to the orders of its own clients, then the OTC exchange rate is shown to obey a random walk with a constant conditional variance. (ii) If each bank is not able to observe the noises relative to the orders of its own clients, the OTC exchange rate is no more a random walk and conditional heteroskedasticity appears.
     

Common Stochastic Trends in a System of Exchange Rates

Univariate tests reveal strong evidence for the presence of a unit root in the univariate time-series representation for seven daily spot and forward exchange rate series. Furthermore, all seven spot and forward rates appear to be cointegrated; that is, the forward premiums are stationary, and one common unit root, or stochastic trend, is detectable in the multivariate time-series models for the seven spot and forward rates, respectively. This is consistent with the hypothesis that the seven exchange rates possess one long-run relationship and that the disequilibrium error around that relationship partly accounts for subsequent movements in the exchange rates.     

A Variance-Ratio Test of Random Walks in Foreign Exchange Rates

The separate variance-ratio tests under homoscedasticity and heteroscedasticity both provide evidence rejecting the random walk hypothesis, using five pairs of weekly nominal exchange rate series over the period from August 7, 1974 to March 29, 1989. The rejections cast doubt on the random walk hypothesis in exchange rates, which has received support in the existing literature. Furthermore, since the rejections are robust to heteroscedasticity, they suggest autocorelations of weekly increments in the nominal exchange rate series, which may be consistent with the exchange rate overshooting or undershooting phenomenon.