Robust Event Studies for Derogation from Suspension of Concentrations in Greece during the Period 1995–2008

Abstract

This paper examines the possible effect of the derogation from suspension of concentrations by the Hellenic Competition Commission (HCC) on the stock performance of the requested companies. For this reason, we examined 16 companies listed in the Athens Stock Exchange (A.S.E) that are involved to 13 requested derogations from suspension during the period 1995–2008 by applying and assessing the results of three different event study methodologies (market model, mean adjusted return model and market adjusted return model). From the empirical findings, we conclude that the argument of the requested companies concerning the subsequent negative effect on their stock performance if the derogation from suspension by the HCC is delayed or not granted does not hold. On the contrary, the average abnormal and cumulative returns of the requested companies are positive and statistical significant. In addition, the results of the three event study methodologies are robust.