Theodore Simos

The exact discrete model of a system of linear stochastic differential equations driven by fractional noise

This paper derives the exact discrete model (EDM) of a kth-order system of stochastic differential equations driven by a vector fractional noise under fixed initial conditions. The EDM can be used for the Gaussian estimation and forecasting with long-memory discrete-time equispaced data. Detailed formulae which are necessary for the construction and numerical evaluation of the Gaussian likelihood under two observation schemes are established. State variables can be observed either at equispaced points in time or as integrals over the observational interval. Copyright 2008 The Author. Journal compilation 2008 Blackwell Publishing Ltd

Contagion Effects on Stock and FX Markets: A DCC Analysis Among USA and EMU

Purpose - – This paper aims to investigate the contagion effects of stock and FX markets for the USA and european monetary union (EMU) during the US subprime crisis of 2007-2009. Design/methodology/approach - – The data sample is daily comprising a weighted Morgan Stanley Capital Index (MSCI) for US and EMU equity markets, as well as EUR/USD exchange rate and 3-month US and EMU interest rate indices. The authors model, simultaneously, the dynamic conditional correlations (DCC) for the triplet: US, EMU equity markets and euro – USD uncovered interest rate parity (UIP) via a multivariate GARCH(1,1)-DCC model. The authors also test for a level shift increase of DCCs during the crisis period by incorporating a dummy variable in a GARCH(1,1) model. Findings - – Our results suggest the presence of contagion for the US stock market and UIP. These results indicate that possibilities for portfolio diversification exist even in periods of severe financial turmoil. This can be explained by the different monetary policies that followed during the crisis. While USA increased liquidity through stimulus packages in early 2009, EMU preferred a strict monetary policy and fiscal austerity measures. Consequently, the EUR/USD exchange rate was less volatile than the EMU equities, resulting in their weak co-movement. Originality/value - – These findings confirm a specific pattern of contagion that provide important implications for international investors and policy-makers.

Monetary Union Effects on European Stock Market Integration: An International CAPM Approach with Currency Risk

This paper explores the evolution of European stock markets integration with the US stock market, after the formation of European Monetary Union (EMU). To this end, we employ a dynamic version of international CAPM in the absence of purchasing power parity. The conditional covariance matrix of asset returns is estimated employing a parsimonious diagonal BEKK multivariate GARCH-in-mean model. The data sample is daily extending from June 1994 to June 2009. The introduction of world-wide information variables into the system reveals that the formation of monetary union has not exerted positive influence on EMU markets integration with US stock market. Moreover at the same time rolling estimates show that member states domestic or idiosyncratic risks have exhibited a lower volatility level.

International portfolio diversification: an ICAPM approach with currency risk

This article investigates international stock market integration in four major developed economies, namely the United States, the Economic and Monetary Union of the European Union, Japan and the United Kingdom, and two Asian emerging, countries namely China and India, over the period from June 1994 to June 2009. To model stock market integration we estimate a dynamic version of the international capital asset pricing model (CAPM) in the absence of purchasing power parity. Conditional variance is modelled via a multivariate GARCH specification. To investigate the evolution of integration overtime we estimate the CAPM in sub-periods. In addition, we connect our results to the timing of world financial crises. Our findings show that the stock markets tend to move in parallel after June of 2002, although from 2002 to 2006 there have not been crises events. These results support the increasing globalization and interdependence of both emerging and developed markets in the recent decade, reducing the benefits of portfolio diversification.

The Exact Discrete Model Of A Third-Order System Of Linear Stochastic Differential Equations With Observable Stochastic Trends

The objective of this paper is to develop closed-form formulae for the exact discretization of a third-order system of stochastic differential equations, with fixed initial conditions, driven by observable stochastic trends and white noise innovations. The model provides a realistic alternative to first- and second-order differential equation specifications of the time lag distribution, forming the basis of a testing and estimation procedure. The exact discrete models, derived under two sampling schemes with either stock or flow variables, are put into a system error correction form that preserves the information of the underlying continuous time model regarding the order of integration and the dimension of cointegration space.