A federal judge in Chicago denied Zillow’s bid for a preliminary injunction against the Chicago-area multiple listing service and the brokerage Compass, dissolved the temporary restraining order that had kept Zillow’s listing feeds switched on since May, and sent the core of the case to private arbitration.
U.S. District Judge John J. Tharp Jr. issued two memorandum opinions on Sept. 15 in Zillow Group, Inc. v. Midwest Real Estate Data LLC, No. 1:26-cv-05451, in the Northern District of Illinois. The first denied Zillow’s injunction motion; the second granted Midwest Real Estate Data’s motion to compel arbitration and stayed the entire action, including the claims against Compass, which is not a party to the arbitration agreement.
What the fight is about
Zillow adopted what it calls its Listing Access Standards in April 2025. Under those standards, according to the opinion, Zillow will not display a listing that was previously marketed through a brokerage’s private listing network or other off-market inventory, unless the seller changed agents.
Compass markets listings through a multi-phase strategy whose first phase places a home, with the seller’s approval, on its own private listing network, branded Compass Private Exclusives. When those homes later reached the MRED multiple listing service, Zillow declined to show some of them.
MRED distributes its listing data through MLS Grid, a licensing and distribution platform built by a consortium of MLSs. MRED concluded that Zillow’s refusal violated MLS Grid’s licensing rules. Those rules, the opinions say, allow listings to be excluded only on a defined set of objective criteria β list price, location, property type and the like β and the identity of the listing brokerage is not among them. On May 21, 2026, MRED cut off Zillow’s Internet Data Exchange and Virtual Office Website feeds for the Chicago area.
Zillow had sued on May 12, alleging that MRED and Compass conspired to boycott it under Sections 1 and 2 of the Sherman Act. It won a temporary restraining order on May 22 that restored the feeds by agreement while requiring Zillow to display listings that had previously appeared in MRED’s feeds or that sat in a ZIP code where MRED had at least one listing during the prior year. The court held a two-day evidentiary hearing on July 1 and 2.
Why the injunction failed
Tharp found Zillow had not made the “strong showing” of likely success that a preliminary injunction requires on either antitrust count. On the monopolization claim, the opinion says Zillow “has not sufficiently established monopoly power in a cognizable relevant market, has not sufficiently shown willful maintenance of monopoly power, and has not established antitrust injury.”
The opinion is blunt about Zillow’s theory of harm. Zillow argued that losing the feeds would leave it with a less comprehensive inventory and with “stale” listings that buyers had already seen elsewhere. “That makes no sense,” Tharp wrote, reasoning that consumers viewing a listing on Zillow have no way of knowing whether it previously appeared on a private network unless they saw it there β and that a consumer checking several portals is not relying on Zillow for comprehensiveness.
The judge also found the alleged injury avoidable by Zillow’s own choice: the company loses feed access only if it enforces the listing ban, so “harm resulting from loss of access to the listing feeds is therefore entirely avoidable.” He noted testimony that Zillow has never actually enforced the standard in the Chicago market, and that the company had presented no evidence of the “downward spiral” it predicted.
On money, the court concluded damages after a final judgment could make Zillow whole, pointing out that Zillow’s business model converts site traffic into advertising revenue and that traffic and ad rates are measurable.
The arbitration ruling
The second opinion is the one with the longer reach. Tharp held that the rights and obligations in the dispute arise under the MLS Grid license agreement, which contains an arbitration clause covering disputes “arising out of or relating to” the agreement. Applying Delaware’s broad-scope standard, he found Zillow’s claims fall squarely within it, that Zillow had refused to arbitrate, and that the Federal Arbitration Act therefore required him to enforce the clause.
He then stayed the Compass claims as well, writing that to say the issues overlap with what arbitration will decide “is an understatement” because the two defendants are alleged to be coconspirators.
One qualification matters for what happens next: the court said compelling arbitration does not moot the request for provisional relief, since the Seventh Circuit permits injunctions “in the face of arbitration.” Under a June 4 order, the restraining order was to last until either the injunction ruling or an arbitrator’s decision on emergency relief under the American Arbitration Association’s emergency measures rules. The injunction ruling came first, and the order lapsed with it.
The wider context
The rules at the center of the case predate the portal wars. The “objective criteria” requirement MRED enforced traces to a 2008 Justice Department consent judgment against the National Association of Realtors. NAR’s Clear Cooperation Policy, in force from 2019 until March 2025, required listings to reach the MLS within one day of public marketing; after a DOJ challenge, NAR amended it to let brokers delay MLS distribution with seller consent β the opening through which private listing networks grew.
Zillow has been settling on other fronts. It settled the Federal Trade Commission’s antitrust case with Redfin in August, and it signed a new MLS data license with Realtracs that set terms for AI use of listing data. Compass, for its part, settled its own antitrust suit against Northwest MLS in Washington state this month.
For agents in Chicagoland, the practical question now is whether Zillow begins enforcing a standard it has so far declined to enforce there, and whether MRED moves again to cut the feeds if it does. The court has left that contest to an arbitrator.
