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 … unrelated to competitive harms, such as when a merger changes expectations that one or more rivals will be “in play” (i.e., a …

There is a growing concern that U.S. merger control may have been too lenient, but empirical evidence remains limited … reviewing the use and challenges of event studies in merger analysis, I use a novel application of Hoberg-Phillips (2010, 2016 ….S. mergers between 1997 and 2017. I document that following a merger announcement, the most likely competitors experience on …