Time Inhomogeneous Multiple Volatility Modeling

Price variations at speculative markets exhibit positive autocorrelationand cross correlation. Due to large parameter spaces necessaryfor joint modeling of variances and covariances, multivariateparametric volatility models become easily intractable in practice.We propose an adaptive procedure that identifies periods ofsecond-order homogeneity for each moment in time. To overcomethe high dimensionality of the problem we transform the multivariateseries into a set of univariate processes. We discuss thoroughlythe implementation of the adaptive technique. Theoretical andMonte Carlo results are given. We provide two applications ofthe new method. For a bivariate exchange rate series we comparethe multivariate GARCH approach with our method and find thelatter to be more in line with the underlying assumption ofindependently distributed innovations. Analyzing a 23-dimensionalvector of asset returns we underscore the case for adaptivemodeling in high-dimensional systems.     

Determinants of Current Account Imbalances in 16 OECD Countries: An Out-Of-Sample Perspective

We employ panel data as well as country-specific models to uncover empirically the determinants of current account imbalances. We find evidence of slope heterogeneity likely rendering the fixed-effect estimator inconsistent. Mean group estimation is followed to overcome the latter difficulty. Both estimation techniques are evaluated by means of in- and out-of-sample criteria. The mean group estimator outperforms the fixed-effect approach and, moreover, only three economic variables are found to impact on the current account balance significantly. These are the government budget balance, the domestic output gap and the changes of the terms of trade. We finally propose a parsimonious dynamic model of the current account, including only these variables and illustrate that it has similar predictive accuracy as country-specific benchmark models. JEL no. F32, C23, C53     

Last resort gambles, risky debt and liquidation policy

This paper develops a real option model in which the interaction between debt, liquidation policy and risky investments is studied. We consider a manager who owns the firm and faces the opportunity to invest in risky projects which may boost current profits at the cost of bankruptcy if they turn out to be unsuccessful. These investments are “last resort gambles” in the sense that, if successful, they save the company from insolvency, while, if unsuccessful, they make liquidation unavoidable. It is shown that last resort gambles delay liquidation. We study how the liquidation trigger and the last resort investment decisions are affected by the firm's capital structure.     

Random Advertising and Monopolistic Price Dispersion

We investigate the role of price advertising in a market where consumers are imperfectly informed about prices. We consider a monopolist whose demand depends on price and advertising expenditure. This demand function is derived from optimizing behavior of consumers. Uninformed consumers may pay a cost to visit the seller and obtain price information. Advertising enables the monopolist to increase the number of informed consumers. In equilibrium the uninformed consumers form rational price expectations, and the seller necessarily adopts a random pricing and advertising strategy.     

Analysis of cointegrated VARMA processes

VARMA (vector autoregressive moving average) processes are proposed for modelling cointegrated variables. For this purpose the echelon form is combined with the error correction form. Procedures for estimating the Kronecker indices which characterize the echelon form and for specifying the cointegration rank are discussed. The asymptotic distribution of the coefficient estimators is given. An example based o n US macroeconomic data illustrates the procedure and demonstrates its feasibility in practice.