Zillow says conspiracy, MRED and Compass say Zillow did this to itself

After exchanging post-hearing briefs late last week in their ongoing antitrust dispute, Zillow, Midwest Real Estate Data (MRED) and Compass filed replies to each others’ briefs on Monday. 

In briefs filed last Thursday, Zillow alleged an “unlawful conspiracy” to cut off its access to Chicagoland listing data while defendants Compass and MRED countered that the company’s harm is “self-inflicted.”

These briefs come after the parties took part in a two-day hearing regarding Zillow’s preliminary injunction motion seeking to prevent MRED from suspending its listing data feed. The motion is part of a larger antitrust lawsuit filed by Zillow in mid-May, in which the listing portal claims that MRED conspired with Compass to not only expand nationwide, but to cut off its listing feed to Zillow, by updating its IDX display “objective criteria” policy so that Zillow would be in violation of the policy if it enforced its listing access standards policy in the Chicagoland area. Under the policy, which Zillow debuted in April 2025, any listing that is publicly marketed for more than one business day prior to being available for display on IDX or VOW feed powered websites is banned from the listing portal. 

Zillow responds

In its response to MRED and Compass’s post-hearing briefs, Zillow claimed that the lawsuit’s two defendants used their filings to “minimize isolated parts of their conspiracy and offer self-serving denials flatly contradicted by their own testimony and contemporaneous documents.” 

“Nothing in Defendants’ briefs rebuts Zillow’s showing that it is likely to prevail on the merits,” Zillow response claims.

The company goes on to claim that the horizontal group boycott it has alleged between Compass and MRED is a per se violation of antitrust law and that even under the rule of reason test, Zillow would prevail as it has “shown substantial anticompetitive effects flowing from the boycott.” 

The plaintiff argues that due to the lack of pro-competitive justifications made by Compass and MRED for its alleged group boycott, the court should grant its preliminary injunction motion. 

“Absent relief, Zillow faces irreparable harm from the false choice that Defendants have engineered, the erosion of Zillow’s brand, goodwill and competitive position, and the injury to nascent platform product Zillow Preview,” Zillow’s filing states.

Who has the monopoly?

For its part, MRED claimed in its filing that Zillow cannot prove MRED has monopoly power because brokers can provide listings directly to Zillow, which already receives direct feeds covering a significant portion of the Chicagoland market and that MRED’s objective criteria rule promotes competition by preventing listings from being withheld. Additionally, MRED maintained that its enforcement of the objective criteria rule and its national expansion strategy were legitimate business decisions rather than the result of a conspiracy with Compass or attempts to exclude Zillow, meaning that the MLS feels Zillow is unlikely to succeed on its monopolization claim.

In addition to this, in a joint reply brief, both MRED and Compass claim that Zillow is trying to use this lawsuit to “shield itself from the consequences of its own anticompetitive tactics.” 

“Zillow manufactured a listing ban to thwart consumer choice by punishing homesellers and agents who privately market homes— blacklisting them until sellers fire their agents and hire new ones,” the filing states. “The ban violates MRED’s procompetitive display rules, which prohibit all feed recipients from filtering listings using nonobjective criteria, such as agent identity, and misrepresenting listings.”

The filing goes on to claim that Zillow’s listing access standards policy is specifically targeted to Compass and the response by the defendants to Zillow’s policy and alleged threats were not a conspiracy, but “unilateral defenses against Zillow’s anticompetitive attacks.” 

“Zillow paints itself as an innocent transparency advocate, too weak to protect itself from the ‘dominant’ Defendants,” the defendants’ reply states. “The facts show exactly the opposite. Zillow is trying to wield its power, using the ‘largest audience of buyers on the internet’ to force homesellers and agents into immediate public marketing.”

Due to this, the defendants reiterate their argument that Zillow’s preliminary injunction should not be granted. 

Judge John Tharp Jr., who is overseeing the lawsuit, will take all of these arguments as well as those the parties made during the two-day hearing on the motion earlier this month into consideration as he contemplates his decision. It is unknown how long the court will take to rule on the motion, but it may take weeks if not months for the parties to have an answer.