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. Compass alleges that Zillow's policy banning private home listings that do not appear on Zillow within 24 hours constitutes anticompetitive behavior designed to protect Zillow's monopoly and revenues. The policy, which took effect in late June 2025, requires publicly marketed listings to be submitted to multiple listing services (MLS) within one business day or face removal from Zillow's platform. Compass contends that this “Zillow ban” stifles competition by preventing the display of privately marketed listings shared outside Zillow, undermining market fairness and innovation. Zillow, which operates as both a portal and a brokerage nationwide, denies causing irreparable harm and defends its policy as necessary to maintain transparency and its business model. Compass has also requested a temporary injunction to block enforcement of the ban, citing harm and confusion caused to its business, especially since nearly half of its listings earlier in the year originated as privately marketed listings. This legal battle is part of a broader industry conflict involving Compass, Zillow, the National Association of Realtors (NAR), and the Northwest Multiple Listing Service (NWMLS). Recently, Compass formally withdrew from NAR’s Clear Cooperation Policy, intensifying disputes over how private or “pocket” listings are managed in the U.S. real estate market. The NWMLS has responded by seeking dismissal of Compass’s antitrust suit, accusing Compass of employing a “free-rider strategy.” Meanwhile, Zillow’s CEO Jeremy Wacksman has publicly addressed the industry tensions, emphasizing Zillow’s commitment to market transparency. The ongoing litigation highlights the escalating competition and regulatory scrutiny within the online real estate sector as companies vie for dominance in home search and brokerage services.