Exchange-rate return predictability and the adaptive markets hypothesis: Evidence from major foreign exchange rates

This study examines return predictability of major foreign exchange rates by testing for martingale difference hypothesis (MDH) using daily and weekly nominal exchange rates from 1975 to 2009. We use three alternative tests for the MDH, which include the wild bootstrap automatic variance ratio test, generalized spectral test, and Dominguez–Lobato consistent tests. We evaluate time-varying return predictability by applying these tests with fixed-length moving sub-sample windows. While exchange rate returns are found to be unpredictable most of times, we do observe a number of episodes of statistically significant return predictability. They are mostly associated with the major events such as coordinated central bank interventions and financial crises. This finding suggests that return predictability of foreign exchange rates occurs from time to time depending on changing market conditions, consistent with the implications of the adaptive markets hypothesis.     

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.     

Nonlinear trends in real exchange rates: A panel unit root test approach

We analyze the possibility of nonlinear trend stationarity as the alternative to unit roots in 23 OECD real exchange rates, 1974–1998, by adding nonlinear time terms to the CIPS panel unit root test of Pesaran (2007). We follow a thorough bootstrapping approach and propose a technique to adjust statistical significance for the use of multiple tests over several time trend orders. The unit root null that all real exchange rates have unit roots is rejected at better than the 0.05 level. Bootstrapped results from a procedure of Chortareas and Kapetanios (2009) suggest that the hypothesis that all are stationary is reasonable. We argue that nonlinear trend stationarity is the most likely alternative hypothesis for at least some of the real exchange rates because: (1) the strongest CIPS rejection occurs when quadratic trends are specified; (2) nonlinear time terms are statistically significant at the 0.10 level; (3) the actual CIPS statistics are more consistent with CIPS sampling distributions from bootstrapped nonlinear trend stationary processes than from linear trend or mean stationary processes.     

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.     

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.     

Bivariate relative city price convergence in the United States: 1918-1997

As in international tests of purchasing power parity, panel unit root tests have been successful in rejecting a unit root process in U.S. city relative prices over the period 1918-1997. However, there is an empirical question of what the rejection of a ‘panel unit root’, particularly with respect to real exchange rates, means. This paper employs a variety of univariate unit root and cointegration tests which have recently come to the fore. These tests improve the power and reduce size distortion found in standard unit root and cointegration tests such as the Dickey-Fuller and Phillips-Perron tests. I find considerable evidence for rejecting a unit root process in the majority of U.S. city relative prices over the entire sample period and two subperiods. Less successful are stationarity tests conducted on regions of the U.S.     

An extensive analysis on the Japanese markets via S. Taylor's model

Applying S. Taylor's approach (1986), we make an extensive analysis on the Japanese stock market, foreign exchange market and the Japanese Government Bond Futures market. The purpose of this paper is to empirically reveal the structure of the Japanese markets via Taylor's model rather than to propose a new model. For this reason, we include a variety of analyzed data particularly for the Japanese stock market and the foreign exchange market because the results can be used in a different manner. The paper consists of three parts. But each part can be read separately. Part 1: Overshooting hypothesis for Japanese stock prices Part 2: A trend movement in daily/weekly Yen-Dollar exchange rates Part 3: Price variations of Japanese Government Futures. In the first part, the stock prices are shown to over-respond to new information, which is different from the behaviors of stock prices in other markets. In Part 2, a trend movement is revealed in Yen-Dollar exchange rates. In Part 3, a strategy in the Japanese Government Bond futures markets is shown to perform better than a buy and hold strategy.     

RESPONSE OF FINANCIAL MARKETS TO ANNOUNCEMENTS OF THE AUSTRALIAN CURRENT ACCOUNT BALANCE

This paper documents the response of exchange rates, interest rates and stock prices to monthly announcements of the Australian current account balance. Survey data on market participants' expectations and forecasts generated from ARIMA time series models are used to identify the unexpected component of the announcements. The study also controls for day-of-the-week effects that have been documented in the Australian equity market The results support the efficient market hypothesis and show a significant depreciation of the Australian dollar in foreign exchange markets and a significant rise in both short- and long-term interest rates to announcements of larger than expected current account deficits. The study was, however, unable to find evidence of a significant stock price response to the current account announcements.     

Temporal aggregation and unit roots in nominal foreign exchange rates

Extant empirical evidence on the logarithm of the daily and weekly spot exchange rates indicates the presence of unit roots. At a lower frequency, however, there is evidence that monthly spot rates do not have a unit root, although the autocorrelation coefficient may be close to one in absolute value. Unlike earlier studies, the present article applies various tests to data with different frequencies and reports evidence suggesting that exchange rates may not have unit roots. Absence of nonstationarity in the observations implies that econometric models may not have to apply any differencing.The authors gratefully acknowledge Hashem Dezhbakhsh for helpful suggestions. Comments are welcome.     

Do Interest Rates Follow Unit-Root Processes? Evidence from Cross-Maturity Treasury Bill Yields

Abstract. It is widely reported in the literature that interest rates follow integrated processes. Many empirical studies have, in fact, taken this result as a maintained hypothesis. This article demonstrates that the failure to reject the hypothesis that interest rates contain a unit root may be due to the severe power problem of standard test procedures in small samples. We analyze a panel of cross-maturity Treasury-bill yield series by employing a panel-based test. This test exploits cross-maturity variations of the data to improve estimation efficiency and is more powerful than standard tests for unit roots. The critical values of the test statistics are computed by Monte Carlo simulations tailored to our samples. It is found that the null hypothesis that each yield series contains a unit root can be decisively rejected. Our findings cast some doubt on previous studies that rely on the nonstationarity assumption of interest rates.     

Equity market integration in the NAFTA region: Evidence from unit root and cointegration tests

This study examines integration of the three participating equity markets before and after the 1993 passage of NAFTA based on daily, weekly, and monthly data. As expected, unit root tests for the overall period 1988-2001 and the two subperiods, 1988-1993 (pre-NAFTA) and 1994-2001 (post-NAFTA), indicate that stock prices are non-stationary but stock returns are generally stationary for all three markets for all three periods. However, daily, weekly, and monthly equity prices in the three NAFTA countries are cointegrated only for the post-NAFTA period. Similarly, US stock prices are more integrated with both Canadian and Mexican stock prices after the passage of NAFTA. This evidence of increased financial integration and co-movement in NAFTA equity markets after the passage of NAFTA has important implications for policymakers and managers.     

The random-walk hypothesis revisited: new evidence on multiple structural breaks in emerging markets

We examine whether stock prices in 18 emerging markets follow random-walk or mean-reversion processes in the presence of sudden and gradual multiple structural breaks. Our tests endogenously determined the structural shifts and are more powerful than either the traditional random-walk (unit root) tests or the single structural break tests. In all emerging markets, we find strong evidence for multiple structural breaks. When we use single break tests, the random-walk hypothesis is rejected. However, when we use tests of double level shifts in the mean and make due allowance for multiple structural breaks, the results are consistent with the random-walk hypothesis in the vast majority of the sampled markets. The evidence proves robust to using price indexes whether denominated in U.S. dollars, in local currencies or in real terms, and also to using fractional integration tests. Our results contradict some previous studies for emerging markets which restrict structural breaks to only one-time shift.     

MULTIVARIATE COINTEGRATION TESTING OF THE EFFICIENCY OF AUSTRALIA'S SPOT FOREX MARKET

Efficiency in Australia's spot FOREX market is tested using daily, weekly and four-weekly data subsequent to the floating of the dollar in 1983. Earlier research using pairwise cointegration tests of currency markets has suggested little evidence of market inefficiencies. However, multivariate cointegration tests carried out in the paper, based on canonical transformation of the exchange rate data, suggest the existence of long run equilibrium relationships among the spot rates, implying the existence of market inefficiency in the FOREX market.     

Unbiasedness of the Forward Exchange Rates

This paper derives an error correction model under the assumption that the spot and the forward rates are cointegrated, the first difference of forward rates is stationary, and the first order autocorrelation in the forecast error is allowed. When tests of the unbiasedness hypothesis are conducted with an error correction model using generalized methods of moments [GMM], the unbiasedness hypothesis cannot be rejected. Furthermore, the multivariate GMM estimation supports the hypothesis of unbiasedness of the forward exchange rates and the absence of a risk premium in the foreign exchange markets.     

Testing the Expectations Hypothesis on the Term Structure of Volatilities in Foreign Exchange Options

This article tests the expectations hypothesis in the term structure of volatilities in foreign exchange options. In particular, it addresses whether long-dated volatility quotes are consistent with expected future short-dated volatility quotes, assuming rational expectations. For options observed daily from December 1, 1989 to August 31, 1992 on dollar exchange rates against the pound, mark, yen, and Swiss franc, we are unable to reject the expectations hypothesis in the great majority of cases. The current spread between long- and short-dated volatility rates proves to be a significant predictor of the direction of future short-dated rates.     

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.     

THE TERM STRUCTURE OF INTEREST RATES AS A COINTEGRATED SYSTEM: EMPIRICAL EVIDENCE FROM THE EUROCURRENCY MARKET

In this paper I examine the term structure of Eurocurrency interest rates from six countries (with maturities of one, two, three, and six months) using unit root tests and cointegration tests that are robust to departures from independent and identically distributed errors. The main conclusions are: (1) Eurocurrency interest rates have one (and only one) unit root when viewed individually, and (2) for each of the countries examined, Eurocurrency interest rates are cointegrated—with one equilibrium relationship—when viewed jointly. These conclusions are consistent with the weak form of the efficient market hypothesis and suggest that in efficient markets arbitrage generally prevents rates on different maturities of a given asset from drifting too far for an extended period.     

Arbitrage, Risk Premium, and Cointegration Tests of the Efficiency of Futures Markets

This article provides a new perspective on the efficiency of futures markets in a cointegration framework. Under the conventional risk premium hypothesis, if futures and spot prices are non-stationary, they must be cointegrated if futures markets are efficient. Alternatively, the cost-of-carry model implies that there should be a cointegration relationship among spot prices, futures prices and interest rates assuming all the series contain a unit root. Market efficiency further implies specific parameter restrictions under these two models. Using data on the futures markets for gold, silver, palladium and platinum, this article first establishes that interest rates, spot and futures prices are unit root non-stationary. The evidence on cointegration is somewhat mixed: the gold futures market is consistent with the cost-of-carry model, and the silver futures market satisfies the risk premium hypothesis, but the evidence for the other two markets is inconclusive.     

Financial integration in the pacific basin region: RIP by PANIC attack?

We exploit advances in panel data econometrics to test whether real interest parity holds in the Pacific Basin region. We test for a unit root in the difference between either the US, Japanese or Euro area real interest rate and the real interest rates from a panel of eleven Pacific Basin economies. Unlike extant studies that test for RIP using panel data, we use Bai and Ng’s (2004) PANIC test which allows for a very general model of cross-section dependence, including the possibility of cross-unit cointegration. Ignoring the possibility of cross-unit cointegration can lead to severe size distortions and to an over-rejection of the null hypothesis of a unit root. We overturn earlier findings based on first-generation panel tests, and demonstrate that cross-unit cointegration leads to incorrect conclusions. We find that RIP holds in the Pacific region. Real interest rates converge to the US rate. We find no support for the hypothesis that Pacific Basin real interest rates converge to either the Japanese or Euro area rates.     

Are Asian stock markets efficient? Evidence from new multiple variance ratio tests

This paper tests for the martingale hypothesis in the stock prices of a group of Asian markets. We use new multiple variance ratio tests based on the wild bootstrap and signs. These are non-parametric finite sample tests, which do not rely on large sample theories for statistical inference. This paper also presents Monte Carlo results that these non-parametric tests show superior small sample properties to those of the conventional Chow–Denning test. Both weekly and daily data from 1990 are considered, while moving sub-sample windows are used for the latter to control the sensitivity of the results to a particular sample period. It is found that the Hong Kong, Japanese, Korean and Taiwanese markets have been efficient in the weak-form. The markets of Indonesia, Malaysia and Philippines have shown no sign of market efficiency, despite financial liberalization measures implemented since the eighties. We have also found evidence that the Singaporean and Thai markets have become efficient after the Asian crisis. In general, the results point toward the notion that the pricing efficiency of a market depends on the level of equity market development as well as the regulatory framework conducive of transparent corporate governance.