Template-Type: ReDIF-Paper 1.0 Author-Name: Adriana Bruscato Bortoluzzo Author-Name-First: Adriana Bruscato Author-Name-Last: Bortoluzzo Author-Name: Pedro A. Morettin Author-Name-First: Pedro A. Author-Name-Last: Morettin Author-Name: Clelia M. C. Toloi Author-Name-First: Clelia M. C. Author-Name-Last: Toloi Title: Time-Varying Autoregressive Conditional Duration Model Abstract: The main goal of this work is to generalize the autoregressive conditional duration (ACD) model applied to times between trades to the case of time-varying parameters. The use of wavelets allows that parameters vary through time and makes possible the modeling of non-stationary processes without preliminary data transformations. The time-varying ACD model estimation was done by maximum likelihood with standard exponential distributed errors. The properties of the estimators were assessed via bootstrap. We present a simulation exercise for a non-stationary process and an empirical application to a real series, namely the TELEMAR stock. Diagnostic and goodness of fit analysis suggest that time-varying ACD model simultaneously modelled the dependence between durations, intra-day seasonality and volatility. Length: 22 pages Creation-Date: 2009 Order-URL: https://repositorio.insper.edu.br/handle/11224/5758 File-URL: https://repositorio.insper.edu.br/handle/11224/5758 File-Format: text/html File-Function: Full text Number: 059 Handle: RePEc:aap:wpaper:059