“…In this respect, the use of the specific GARCH(1,1) model is widespread since it sufficiently explains systematic variation of stock return volatility in most cases (e.g., Akgiray, 1989, Andersen and Bollerslev, 1998, Engle, 2001, although several modifications have been proposed in the meantime. While GARCH models are already widely applied for several event studies so far (e.g., Savickas, 2003, Babalan and Constantinou, 2006, Oberndorfer and Ulbricht, 2007, only very few event studies use this approach to analyze the impact of corporate environmental or social performance on stock returns (e.g., Becchetti et al, 2007).…”