Template-type: ReDIF-Paper 1.0 Author-Name: Ole E. Barndorff-Nielsen Author-Email: oebn@mi.aau.dk Author-Workplace-Name:The Centre for Mathematical Physics and Stochastics (MaPhySto), University of Aarhus, Denmark Author-Name: Bent Nielsen Author-Email:bent.nielsen@nuf.ox.ac.uk Author-Workplace-Name: Nuffield College, Unviersity of Oxford, Oxford, UK Author-Name: Neil Shephard Author-Email:neil.shephard@nuf.ox.ac.uk Author-Workplace-Name: Nuffield College, Unviersity of Oxford, Oxford, UK Author-Name: Carla Ysusi Author-Email:ysusi@stats.ox.ac.uk Author-Workplace-Name: Dept of Statistics, Unviersity of Oxford, Oxford, UK Title: Measuring and forecasting financial variability using realised variance with and without a model Abstract: We use high frequency financial data to proxy, via the realised variance, each day's financial variability. Based on a semiparametric stochastic volatility process, a limit theory shows you can represent the proxy as a true underlying variability plus some measurement noise with known characteristics. Hence filtering, smoothing and forecasting ideas can be used to improve our estimates of variability by exploiting the time series structure of the realised variances. This can be carried out based on a model or without a model. A comparison is made between these two methods. Keywords:Kalman filter; Mixed Gaussian limit; OU process; Quadratic variation; Realised variance; Realised volatility; Square root process; Stochastic volatility. Length:32 pages Creation-Date: 2002-10-07 Number:2002-W21 File-URL:http://www.nuff.ox.ac.uk/economics/papers/2002/w21/jim.pdf File-Format: application/pdf Handle: RePEc:nuf:econwp:0221