Two model averaging approaches are used and compared in estimating and forecasting dynamic factor models, the well-known BMA and the recently developed WALS. Both methods propose to combine frequentist estimators using Bayesian weights. We apply our framework to the Armenian economy using...

Risk assessments often encounter extreme settings with very few or no occurrences in reality.Inferences about risk indicators in such settings face the problem of insufficient data.Extreme value theory is particularly well suited for handling this type of problems.This paper uses a multivariate...

We consider the question whether top tennis players in a top tournament (Wimbledon) employ an optimal (efficient) service strategy.We show that top players do not, in general, follow an optimal strategy, and we provide a lower bound of the inefficiency.The inefficiency regarding winning a point...

Consider the nonparametric regression model Y = m(X)+e, where the function m is smooth, but unknown.We construct tests for the independence of e and X, based on n independent copies of (X; Y ).The testing procedures are based on differences of neighboring Y 's.We establish asymptotic results for...

AMS classifications: 62G08, 62G10, 62G20, 62G30; 60F17.

Many researchers use GARCH models to generate volatility forecasts. We show, however, that such forecasts are too variable. To correct for this, we extend the GARCH model by distinguishing two regimes with different volatility levels. GARCH effects are allowed within each regime, so that our...

Most economists intuitively consider purchasing power parity (PPP) to be true. Nevertheless, quite surprisingly, the empirical literature is not very supportive for PPP. In this paper, however, we find evidence in favor of PPP using a new test. The test is embedded in a Markov regime-switching...

We analyze the time-dependence of exchange rate correlations using a new multivariate GARCH model. This model consists of two parts. First, we transform the exchange rate changes into their principal components and specify univariate GARCH models for all components. Second, we use the inverse of...

The random walk is often used to model exchange rates. According to the Lucas critique, however, policy shifts may lead to breaks in the trend of exchange rates and hence to long swings. We use a Markov regime-switching model to allow for such swings and we reject the random walk in favor of the...

The riskless nature in real terms of inflation-linked bonds has led to the conclusion that inflation-linked bonds should constitute a substantial part of the optimal investment portfolio of long-term investors.This conclusion is reached in models where investors do not receive labor income...