Forecasting the time-varying beta of UK firms: GARCH models vs Kalman filter method

Abstract

This paper forecast the weekly time-varying beta of 20 UK firms by means of four different GARCH models and the Kalman filter method. The four GARCH models applied are the bivariate GARCH, BEKK GARCH, GARCH-GJR and the GARCH-X model. The paper also compares the forecasting ability of the GARCH models and the Kalman method. Forecast errors based on return forecasts are employed to evaluate out-of-sample forecasting ability of both GARCH models and Kalman method. Measures of forecast errors overwhelmingly support the Kalman filter approach. Among the GARCH models both GJR and GARCH-X models appear to provide a bit more accurate forecasts than the bivariate GARCH model