Airline industry consolidation and its effect on shareholder value

This paper made use of event study methodology to scan whether horizontal mergers alter the value of the acquiring firm. To evaluate the validity of the results two different models have been estimated, but the similarity of the results suggested that the findings are unbiased to model choice. Additionally, the study used different windows so as to examine the bias of the results on the span of the event period. No evidence was found of cumulative and abnormal return in any event window, apart from only one merger and only when the event window was quite small. At a longer window the abnormal returns seem to disappear. The latter provided evidence of market inefficiency in the short run for the given market, which in turn suggests that investors can gain abnormal returns with the use of publicly available information. In general, the findings indicated that most markets are efficient.