An empirical application of stochastic volatility models

This paper studies the empirical performance of stochastic volatility models for twenty years of weekly exchange rate data for four major currencies. We concentrate on the effects of the distribution of the exchange rate innovations for both parameter estimates and for estimates of the latent volatility series. The density of the log of squared exchange rate innovations is modelled as a flexible mixture of normals. We use three different estimation techniques: quasi-maximum likelihood, simulated EM, and a Bayesian procedure. The estimated models are applied for pricing currency options. The major findings of the paper are that: (1) explicitly incorporating fat-tailed innovations increases the estimates of the persistence of volatility dynamics; (2) the estimation error of the volatility time series is very large; (3) this in turn causes standard errors on calculated option prices to be so large that these prices are rarely significantly different from a model with constant volatility

A Bayesian analysis of the unit root in real exchange rates

We propose a posterior odds analysis of the hypothesis of a unit root in real exchange rates. From a Bayesian viewpoint the random walk hypothesis for real exchange rates is a posteriori as probable as a stationary AR(1) process for four out of eight time series investigated. The French franc/German mark is clearly stationary, while the Japanese yen/US dollar is most likely a random walk. In contrast, classical tests are unable to reject the unit root for any of these series

Big news in small samples

Univariate time series regressions of the forex return on the forward premium generate mostly negative slope coefficients. Simple and refined panel estimation techniques yield slope estimates that are much closer to unity. We explain the two apparently opposing results by allowing for both additive and multiplicative news. No arbitrage arguments imply that the multiplicative news component must be identical across all exchange rates at a given point in time. Cross section estimates reveal that the movements in the multiplicative news component are so large that a negative slope coefficient for the post Bretton Woods time series regressions is not inprobable

A Bayesian Panel Data Approach to Explaining Market Beta Dynamics

We characterize the process that drives the market betas of individual stocks by setting up a hierarchical Bayesian panel data model that allows a flexible specification for beta. We show that combining the parametric relationship between betas and conditioning variables specified by economic theory with the robustness of an autoregressive specification delivers superior estimates of firm-specific betas. Our model also improves the accuracy of beta forecasts, which we use to construct optimal portfolios subject to target beta constraints. We further provide empirical support for the prediction of conditional asset pricing theory that individual stocks exhibit different risk dynamics. Finally, we document strong cross-sectional heterogeneity in firm-specific betas within the 25 size-B/M portfolios that are commonly used to test asset pricing models

Effcient Estimation of Firm-Specific Betas and its Benefits for Asset Pricing Tests and Portfolio Choice

We improve both the specification and estimation of firm-specific betas. Time variation in betas is modeled by combining a parametric specification based on economic theory with a non-parametric approach based on data-driven filters. We increase the precision of individu

Price Discovery on Foreign Exchange Markets with Differentially Informed Traders

This paper uses Reuters exchange rate data to investigate the contributions to the price discovery process by individual banks in the foreign exchange market. We propose multivariate time series models as well as models in tick time to study the dynamic relations between the quotes of individual banks. We investigate the hypothesis that German banks are price leaders in the deutschmark/dollar market. Our empirical results suggest an important but not exclusive role for German banks in the price discovery process. There is also a group of banks, German and non-German, that lags behind the market and does not contribute to the price discovery process. In contrast to Peiers~(1997) we do not find evidence for stronger price leadership of Deutsche bank on days with suspected Bundesbank interventions in the foreign exchange market