Compass Inc., the largest U.S. residential real estate brokerage by sales volume, has filed an antitrust lawsuit against Zillow Group Inc., the nation's leading online real estate portal, in the U.S. District Court for the Southern District of New York. The lawsuit alleges that Zillow's policy banning privately marketed home listings that do not appear on Zillow within 24 hours constitutes anticompetitive behavior and violates federal antitrust laws. Compass claims this “Zillow ban” is designed to protect Zillow's monopoly and revenues by restricting competition and undermining market dynamics. The ban, which took effect recently, requires publicly marketed listings to be submitted to multiple listing services (MLS) within one business day or risk removal from Zillow's platform. Compass argues that nearly half of its listings earlier this year started as privately marketed listings, and the policy threatens its business model and market access. Zillow has responded by stating that Compass faces no irreparable harm from the ban and defends its stance on maintaining transparency and openness in property listings. The dispute is part of a broader conflict involving Compass, Zillow, the National Association of Realtors, and the Northwest Multiple Listing Service (NWMLS), with ongoing litigation and challenges over listing policies and market practices. Additionally, Compass has distanced itself from the National Association of Realtors’ Clear Cooperation Policy, escalating tensions in the real estate market. Industry figures have expressed varied opinions on the implications of these policies and lawsuits for competition and market innovation.