The recent merger between US Airways and American Airlines was approved by federal and state antitrust authorities … anticompetitive effects from this merger. The economics literature offers many reasons why such stock-market event studies should not … be used to infer competitive effects from mergers. For example, abnormal returns for rivals might arise for reasons …

of selling and buying airlines, thus contributing to the literature on mergers and acquisitions (M&As) in emerging … obtain abnormal returns that are statistically significant after the announcement of the M&A. However, when the merger is not …