Antitrust enforcement has recently surged in hot-button areas like big tech and labor, and we can now add housing to the mix. In the past two years, the private bar has brought at least eight lawsuits challenging various practices by multiple listing services (MLSs) in the residential real estate brokerage industry. The Department of Justice (DOJ) has also increased its investigation of such practices. These enforcement actions apply both traditional and novel antitrust concepts to one of the most important financial transactions people make in their lives.