56 research outputs found
Evaluating "correlation breakdowns" during periods of market volatility
No full textFinancial market observers have noted that during periods of high market volatility, correlations between asset prices can differ substantially from those seen in quieter markets. For example, correlations among yield spreads were substantially higher during the fall of 1998 than in earlier or later periods. Such differences in correlations have been attributed either to structural breaks in the underlying distribution of returns or to "contagion" across markets that occurs only during periods of market turbulence. However, we argue that the differences may reflect nothing more than time-varying sampling volatility. As noted by Boyer, Gibson and Loretan (1999), increases in the volatility of returns are generally accompanied by an increase in sampling correlations even when the true correlations are constant. We show that this result is not just of theoretical interest: When we consider quarterly measures of volatility and correlation for three pairs of asset returns, we find that the theoretical relationship can explain much of the movement in correlations over time. We then examine the implications of this link between measures of volatility and correlation for risk management, bank supervision, and monetary policy making.Stock market ; Risk management
Indexes of the foreign exchange value of the dollar
No full textAt the end of 1998, the staff of the Federal Reserve Board introduced a new set of indexes of the foreign exchange value of the U.S. dollar. The staff made the changeover, from indexes that had been used since the late 1970s, for two reasons. First, five of the ten currencies in the staff's previous main index of the dollar's exchange value were about to be replaced by a single new currency, the euro. Second, developments in international trade since the late 1970s called for a broadening of the scope of the staff's dollar indexes and a closer alignment of the currency weights with U.S. trade patterns. ; The author discusses several practical aspects of the design and implementation of the exchange rate indexes--the choice of index formula, the design of currency weights, and the selection of currencies. The author also reviews the performance of the indexes over the past twenty-five years and discusses three minor methodological changes that the staff has applied to the indexes since their introduction.Foreign exchange rates ; Dollar
Diskursethisches Programm zur kognitiven Begründung der Medienethik. Von der zeitdiagnostischen Qualität der Medienethik und ihrem Beitrag zur Sensibilisierung kommunikativer Kompetenz in mediatisierten modernen Gesellschaften
No full textVon der zeitdiagnostischen Qualität der Medienethik und ihrem Beitrag zur Sensibilisierung kommunikativer Kompetenz in mediatisierten modernen GesellschaftenDer Bedarf an Ethik zur Klärung konkurrierendernormativer Geltungsansprüche im Bereich der Medien ist unbestritten.Angewandte Ethik hat auch in diesem Bereich Konjunktur. Die von Ulrich Saxer seit über 20 Jahren diagnostizierte Nachfrage ist Ausdruck eines Orientierungs-, Steuerungs- und Legitimationsbedarfs (Saxer 1992, 1996,1999). Kontrovers diskutiert wird allerdings die Frage, ob und allenfalls wie (mit welcher methodischen Kompetenz) Ethik einen fruchtbaren Beitrag zum aktuellen Orientierungs-, Steuerungs- und legitimationsbedarf zu leisten vermag. (...)EnglishThe need of ethics clarifying competing normative demands for recognition in the media is undisputed. Applied ethics are booming in this field. Conflicting opinions exist on whether and how (methodologically) ethics can fruitfully contribute to the present-day need for orientation, control and Iegitimation. Whilst for the past two decades research studies, especially those oriented towards the social sciences, have dealt with the function, constituents and efficiency of media ethical and rofessional ethical procedures, philosophical clarifications of the nonnative principles of journalism are becoming increasingly significant again. With reference to Jürgen Habermas\u27s and Karl-Otto Apel\u27s moral conceptions, the author Mattbias Loretan introduces discourse ethics as a programme for the cognitive foundation of normative claims in modern societies. In the field of journalism, procedural moral theory can be made effective as media ethics. It reconstructs normative claims made by public communication in modern societies and also takes on advisory functions in the process of adequately structuring the media as well as resolving normative conflicts in the field. (...
The development of money markets in Asia
No full textThe depth and breadth of money markets in Asia have improved significantly over the past decade, yet many are still characterised by segmentation and a low degree of cross-border integration. Admittedly, the underdevelopment of Asia’s money markets worked to the region’s advantage during the recent turmoil by insulating it to some degree from the shocks that disrupted more developed money markets. Nonetheless, the turmoil provides authorities and market participants in Asia with an opportunity to learn from experiences elsewhere in their efforts to realise the full benefits offered by well functioning money markets.
Estimating Long Run Economic Equilibria
No full textOur subject is econometric estimation and inference concerning long-run economic equilibria in models with stochastic trends. Our interest is focused on single equation specifications such as those employed in the Error Correction Model (ECM) methodology of David Hendry (1987, 1989 inter alia) and the semiparametric modified least squares method of Phillips and Hansen (1989). We start by reviewing the prescriptions for empirical time series research that are presently available. We argue that the diversity of choices is confusing to practitioners and obscures the fact that statistical theory is clear about optimal inference procedures. Part of the difficulty arises from the many alternative time series representations of cointegrated systems. We present a detailed analysis of these various representations, the links between them, and the estimator choices to which they lead. An asymptotic theory is provided for a wide menu of econometric estimators and system specifications, accommodating different levels of prior information about the presence of unit roots and the nature of short-run dynamic adjustments. The single equation ECM approach is studied in detail and our results lead to certain recommendations. Weak exogeneity and data coherence are generally insufficient for valid conditioning on the regressors in this approach. Strong exogeneity and data coherency are sufficient to validate conditioning. But the requirement of strong exogeneity rules out most cases of interest because long-run economic equilibrium typically relates interdependent variables for which there is substantial time series feedback. One antidote for this problem in practice is the inclusion of leads as well as lags in the differences of the regressors. The simulations that we report, as well as the asymptotic theory support the use of this procedure in practice. Our results also support the use of dynamic specifications that involve lagged long-run equilibrium relations rather than lagged differences in the dependent variable. Finally, our simulations point to problems of overfitting in single equation ECM's. These appear to have important implications for empirical research in terms of size distortions that are produced in significance tests that utilize nominal critical values delivered by conventional asymptotic theory. In sum, our results indicate that the single equation ECM methodology has good potential for further development and improvement. But in comparison with the semi parametric modified least squares method of Phillips and Hansen (1989) the latter method seems superior for inferential purposes in most cases.Co-integration, long-run equilibrium, error correction, semiparametric estimation, asymptotic theory, exogeneity
Estimating Long Run Economic Equilibria
No full textOur subject is econometric estimation and inference concerning long-run economic equilibria in models with stochastic trends. Our interest is focused on single equation specifications such as those employed in the Error Correction Model (ECM) methodology of David Hendry (1987, 1989 inter alia) and the semiparametric modified least squares method of Phillips and Hansen (1989). We start by reviewing the prescriptions for empirical time series research that are presently available. We argue that the diversity of choices is confusing to practitioners and obscures the fact that statistical theory is clear about optimal inference procedures. Part of the difficulty arises from the many alternative time series representations of cointegrated systems. We present a detailed analysis of these various representations, the links between them, and the estimator choices to which they lead. An asymptotic theory is provided for a wide menu of econometric estimators and system specifications, accommodating different levels of prior information about the presence of unit roots and the nature of short-run dynamic adjustments. The single equation ECM approach is studied in detail and our results lead to certain recommendations. Weak exogeneity and data coherence are generally insufficient for valid conditioning on the regressors in this approach. Strong exogeneity and data coherency are sufficient to validate conditioning. But the requirement of strong exogeneity rules out most cases of interest because long-run economic equilibrium typically relates interdependent variables for which there is substantial time series feedback. One antidote for this problem in practice is the inclusion of leads as well as lags in the differences of the regressors. The simulations that we report, as well as the asymptotic theory support the use of this procedure in practice. Our results also support the use of dynamic specifications that involve lagged long-run equilibrium relations rather than lagged differences in the dependent variable. Finally, our simulations point to problems of overfitting in single equation ECM’s. These appear to have important implications for empirical research in terms of size distortions that are produced in significance tests that utilize nominal critical values delivered by conventional asymptotic theory. In sum, our results indicate that the single equation ECM methodology has good potential for further development and improvement. But in comparison with the semi parametric modified least squares method of Phillips and Hansen (1989) the latter method seems superior for inferential purposes in most cases
The Durbin-Watson Ratio Under Infinite Variance Errors
No full textThis paper studies the properties of the von Neumann ratio for time series with infinite variance. The asymptotic theory is developed using recent results on the weak convergence of partial sums of time series with infinite variance to stable processes and of sample serial correlations to functions of stable variables. Our asymptotics cover the null of iid variates and general moving average (MA) alternatives. Regression residuals are also considered. In the static regression model the Durbin-Watson statistic has the same limit distribution as the von Neumann ratio under general conditions. However, the dynamic models, the results are more complex and more interesting. When the regressors have thicker tail probabilities than the errors we find that the Durbin-Watson and von Neumann ration asymptotics are the same.Durbin-Watson ratio, von Neumann ratio, serial correlation, dynamic models, time series, asymptotic theory
The Durbin-Watson Ratio under Infinite Variance Errors
No full textThis paper studies the properties of the von Neumann ratio for time series with infinite variance. The asymptotic theory is developed using recent results on the weak convergence of partial sums of time series with infinite variance to stable processes and of sample serial correlations to functions of stable variables. Our asymptotics cover the null of iid variates and general moving average (MA) alternatives. Regression residuals are also considered. In the static regression model the Durbin-Watson statistic has the same limit distribution as the von Neumann ratio under general conditions. However, the dynamic models, the results are more complex and more interesting. When the regressors have thicker tail probabilities than the errors we find that the Durbin-Watson and von Neumann ration asymptotics are the same
Testing Covariance Stationarity Under Moment Condition Failure with an Application to Common Stock Returns
No full textThis paper studies tests for covariance stationarity under conditions which permit failure in the existence of fourth order moments. The problem is important because many econometric diagnostics such as tests for parameter constancy, constant variance and ARCH and GARCH effects routinely rely on fourth moment conditions. Moreover, such tests have recently been extensively employed with financial and commodity market data, where fourth moment conditions may well be quite tenuous and are usually untested. This paper considers several tests for covariance stationarity including sample split prediction tests, cusum of squares tests and modified scaled range tests. When fourth moment conditions fail we show how the asymptotic theory for these tests involves functionals of an asymmetric stable Levy process, in place of conventional standard normal or Brownian bridge asymptotics. An interesting outcome of the new asymptotics is that the power of these tests depends critically on the tail thickness in the data. Thus, for data with no finite second moment, the above mentioned tests are inconsistent. Some new tests for heterogeneity are suggested that are consistent in the infinite variance case. These are easily implemented and rely on standard normal asymptotics. A consistent estimator of the maximal moment exponent of a distribution is also proposed. Again this estimator is easily implemented, has standard normal asymptotics and leads to a simple test for the existence of moments up to a given order. An empirical application of these methods to the monthly stock return data recently studied in Pagan and Schwert (1989a, 1989b) and the daily returns of the Standard and Poors 500 stock index is presented.Asymmetric stable process, characteristic exponent, covariance stationarity, cusum of squares test, maximal moment exponent, sample split prediction test, scaled range, stable Levy bridge, stock returns
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