In a supplemental post-hearing brief filed by defendants Midwest Real Estate Data (MRED) and Compass, the defendants argue that Zillow is not entitled to relief because “any harm, if it exists at all, is self-inflicted.”
“If Zillow wants MRED’s feed, the ‘lifeblood’ of its business that it receives virtually for free, all Zillow has to do is not subjectively ban listings,” they claim.
The 40-page filing, submitted to Judge John J. Tharp Jr. in the Northern District of Illinois, frames the dispute as “two sets of rules at war with each other”—Zillow’s Listing Access Standards, which the defendants call a “ban,” and MRED’s display rules, which bar what MRED considers non-objective filtering of its listing data.
Because Zillow’s motion turns on an alleged horizontal group boycott, the defendants argue that there was no agreement at all. Compass and MRED “may have moved in similar directions,” but say each acted unilaterally in its own interest in response to Zillow’s threats.
Both sides had two days to present their case, with Zillow showing communication between MRED and Compass’s respective CEOs, Rebecca Jensen and Robert Reffkin, and Compass’s and MRED’s legal counsel focusing on Zillow’s “listing access standards” and whether or not they did suffer “immediate and irreparable harm.”
The defendants cite a previous court case, in which the Supreme Court held that “something more than evidence of complaints is needed” to infer a conspiracy. Compass’s complaints that the ban violated MRED’s rules, the defendants argue, cannot by themselves establish a coordinated effort.
Jensen testified that “when we suspended Zillow’s feed, we acted completely on our own,” after a year of explaining to Zillow that its ban violated MRED rules, or did not use objective criteria. Jensen said she was “flabbergasted” when she first learned of the standards in April 2025.
The defendants also argue that the “per se illegal group boycott” categorization cannot apply because Compass and MRED are not horizontal competitors.
Their expert, Dr. Debra Aron, characterized the two as complements rather than substitutes—Compass creates and markets listings; MRED aggregates and distributes them. Courts in the Seventh Circuit and elsewhere, the brief notes, review MLS conduct rules under the rule of reason.
Under that standard, the defendants say Zillow failed to define a relevant market or show market power, and cannot demonstrate that private listings or MRED’s neutral data rules harm competition rather than a single competitor.
The brief also attacks Zillow’s stated rationale: Zillow’s ban does not apply to truly secret “office exclusives” that are shared within a brokerage—only to listings publicly marketed off-MLS—and lifts if a seller fires the original agent and hires a new one. That carve-out, defendants argue, shows the standards exist to “penalize” agents who market outside the MLS, not to promote transparency.
They also point to Zillow’s own internal deliberations, citing documents in which the company weighed “hardline” tactics and described private listings as a “contagion.”
The defendants say Zillow offered Compass “$1.3 to $1.6 billion of annual revenue uplift” and a path to doubling its market share if Compass abandoned its three-phased marketing strategy. Reffkin testified that the company declined.
On irreparable harm, the defendants argue Zillow’s injury is self-inflicted, speculative and fully compensable through antitrust treble damages. They note Zillow never enforced the ban in MRED’s primary service area yet has not experienced the “downward spiral” it warns of, and that Zillow waited 13 months after MRED first objected before suing.
Also, the defendants argue the injunction Zillow seeks against Compass—barring it from “conspiring”—is an impermissible “obey the law” order.
MRED suspended Zillow’s feed on May 20; the court’s temporary restraining order (TRO) restored it within two days.
