The European Commission is currently revising its Merger Guidelines. In this context, MaCCI, in collaboration with the Chief Economist Team of the European Commission, organized a workshop addressing key issues in the revision process. Members of the Chief Economist Team at DG Competition engaged in discussions with MaCCI researchers Jens-Uwe Franck, Volker Nocke, Martin Peitz, and Nicolas Schutz, as well as with external academics Igor Letina, Nate Miller, Markus Reisinger, and Joel Stiebale.