Zillow Accuses Rivals of Conspiracy in Data Access Dispute

Zillow alleged an "unlawful conspiracy" by Midwest Real Estate Data (MRED) and Compass to cut off its access to Chicagoland listing data, according to post-hearing briefs filed on Monday. These filings are part of an ongoing antitrust dispute stemming from a lawsuit Zillow initiated in mid-May. The listing portal claims MRED conspired with Compass to expand nationwide and suspend Zillow's listing data feed by updating MRED's IDX display "objective criteria" policy.

Zillow contends that this policy update would cause Zillow to violate its own listing access standards policy in the Chicagoland area. Zillow's policy, introduced in April 2025, prohibits listings publicly marketed for more than one business day before appearing on IDX or VOW feed powered websites. In its reply brief, Zillow asserted that MRED and Compass attempted to "minimize isolated parts of their conspiracy" and offered "self-serving denials" contradicted by their own testimony and documents.

Compass and MRED countered in their own briefs that Zillow's alleged harm is "self-inflicted." The parties participated in a two-day hearing regarding Zillow's preliminary injunction motion, which seeks to prevent MRED from suspending its listing data feed. Zillow argues that the alleged horizontal group boycott between Compass and MRED constitutes a per se violation of antitrust law and would prevail even under the rule of reason test due to substantial anticompetitive effects and a lack of pro-competitive justifications.