MaCCI members Nicolas Schutz and Volker Nocke organized a two-day workshop gathering around twenty researchers to present and discuss empirical and theoretical research on horizontal mergers, common ownership, and other antitrust-related topics. The presenters were Christopher Conlon (NYU), Daniel Ershov (Toulouse), Mitsuru Igami (Yale), Justin Johnson (Cornell), Leslie Marx (Duke), Massimo Motta (Pompeu Fabra), Patrick Rey (Toulouse), Andrew Rhodes (Toulouse), Nicolas Schutz (MaCCI), Kosuke Uetake (Yale), and Xavier Vives (IESE). The discussants were Bernhard Ganglmair (MaCCI), Laura Grigolon (MaCCI), Volker Nocke (MaCCI), Andrew Rhodes (Toulouse), Pasquale Schiraldi (LSE), Philipp Schmidt-Dengler (Vienna), Nicolas Schutz (MaCCI), Anton Sobolev (MaCCI), Yossi Spiegel (Tel Aviv), and Christoph Wolf (Bocconi).