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We discuss the development of dynamic factor models for multivariate nancial time series, and the incorporation of stochastic volatility components for latent factor processes. Bayesian inference and computation is developed and explored in a study of the dynamic factor structure of daily spot exchange rates for a selection of international currencies. The models are direct generalisations of univariate stochastic volatility models, and represent speci c varieties of models recently discussed in the growing multivariate stochastic volatility literature. We also discuss connections and comparisons with the much simpler method of dynamic variance discounting that, for over a decade, has been a standard approach in applied nancial econometrics in the Bayesian forecasting world. We review empirical ndings in applying these models to the exchange rate series, including aspects of model performance in dynamic portfolio allocation. We conclude with comments on the potential practical utility of structured factor models and future potential developments and model extensions.

Our object in writing this book is to present the main results of the modern theory of multivariate statistics to an audience of advanced students who would appreciate a concise and mathematically rigorous treatment of that material. It is intended for use as a textbook by students taking a first graduate course in the subject, as well as for the general reference of interested research workers who will find, in a readable form, developments from recently published work on certain broad topics not otherwise easily accessible, as, for instance, robust inference (using adjusted likelihood ratio tests) and the use of the bootstrap in a multivariate setting. The references contains over 150 entries post-1982. The main development of the text is supplemented by over 135 problems, most of which are original with the authors. A minimum background expected of the reader would include at least two courses in mathematical statistics, and certainly some exposure to the calculus of several variables together with the descriptive geometry of linear

This paper proposes a Bayesian approach to a vector autoregression with stochastic volatility, where the multiplicative evolution of the precision matrix is driven by a multivariate beta variate. Exact updating formulas are given to the nonlinear filtering of the precision matrix. Estimation of the autoregressive parameters requires numerical methods: an importance-sampling based approach is explained here.

This paper introduces a novel class of Bayesian models for multivariate time series analysis based on a synthesis of dynamic linear models and graphical models. The models are then applied in the context of financial time series for predictive portfolio analysis providing a significant improvement in performance of optimal investment decisions.

This dissertation introduces new simulation-based analysis approaches, including both sequential and off-line learning algorithms, for various Bayesian time series models. We provide a Markov Chain Monte Carlo (MCMC) method for an autoregressive (AR) model with innovations following exponential power distributions using the fact that an exponential power distribution is a scale mixture of normals. This model has application in signal processing, specifically image processing, with orthogonal wave...

This paper develops a Bayesian procedure for estimation and forecasting of the volatility of multivariate time series. The foundation of this work is the matrix-variate dynamic linear model, for the volatility of which we adopt a multiplicative stochastic evolution, using Wishart and singular multivariate beta distributions. A diagonal matrix of discount factors is employed in order to discount the variances element by element and therefore allowing a flexible and pragmatic variance modelling approach. Diagnostic tests and sequential model monitoring are discussed in some detail. The proposed estimation theory is applied to a four-dimensional time series, comprising spot prices of aluminium, copper, lead and zinc of the London metal exchange. The empirical findings suggest that the proposed Bayesian procedure can be effectively applied to financial data, overcoming many of the disadvantages of existing volatility models.

This dissertation develops Bayesian theory and computation to address important issues in two main socio-economic areas: financial modeling and institutional assessment. The first part focusses on computational developments for model fitting and forecasting of multiple series of crude oil futures prices. The methodology is motivated by the central role that the stochastic behavior of commodity prices plays in the evaluation of commodity-related securities. A class of Bayesian multivariate dynamic linear models for oil future prices is developed based on a theoretical financial model that assumes two latent factor processes: a notional equilibrium price level and a process representing short-term deviations from equilibrium levels. A customized Markov Chain Monte Carlo (MCMC) sampling scheme is developed for inference and analysis of such model. In addition, several structures on the observational variance are explored including the challenging case of a singular variance matrix. Relevant

We introduce and explore a new class of stationary time series models for variance matrices based on a constructive definition exploiting inverse Wishart distribution theory. The main class of models explored is a novel class of stationary, first-order autoregressive (AR) processes on the cone of positive semi-definite matrices. Aspects of the theory and structure of these new models for multivariate “volatility ” processes are described in detail and exemplified. We then develop approaches to model fitting via Bayesian simulation-based computations, creating a custom filtering method that relies on an efficient innovations sampler. An example is then provided in analysis of a multivariate electroencephalogram (EEG) time series in neurological studies. We conclude by discussing potential further developments of higherorder AR models and a number of connections with prior approaches. 1. Introduction. Modeling

Bayesian time series and forecasting is a very broad field and any attempt at