When I last wrote about the antitrust lawsuit Compass filed against Zillow in August of last year, the case was headed into a four-day evidentiary hearing on Compass’s motion for a preliminary injunction. Since then, the district court denied the motion, Zillow changed its Listing Access Standards, and Compass voluntarily dismissed the case. On May 12, Zillow hit Compass back with an antitrust lawsuit of its own, prolonging this battle of real estate titans.
Compass v. Zillow
Compass filed a federal antitrust lawsuit against Zillow in June 2025 in the Southern District of New York. The lawsuit attacked Zillow’s Listing Access Standards, which, at the time, required any publicly marketed home to be entered into a multiple listing service and syndicated to Zillow within one business day, or be blocked from appearing on Zillow and Trulia. Compass alleged that the Listing Access Standards in effect created a “Zillow Ban.” Essentially, Compass’ lawsuit claimed that Zillow used its 66% market share of the U.S. real estate audience to force homeowners onto Zillow. Compass also claimed that Zillow had conspired with Redfin and other companies to pressure them to adopt the same rule, effectively squeezing out Compass. Compass asked the court for an order that Zillow’s conduct violated the antitrust laws, and for an injunction blocking Zillow from continuing its policy.
After a four-day hearing, the court denied Compass’ request for an injunction against Zillow. The judge found, among other things, that there was no evidence of an anticompetitive agreement between Zillow and Redfin. Moreover, Compass had not shown that Zillow had the power to exclude competition. While the order was not a final judgment and the case could have proceeded to trial, it signaled that Compass could have a hard time winning the case on the merits. Zillow trumpeted the victory, calling it a “clear victory not just for Zillow, but for consumers, agents, brokerages and the real estate industry at large.”
A few weeks after the court’s order, Compass announced a three-year partnership with Redfin. Under this partnership, Compass’ “Coming Soon” listings would immediately appear on Redfin. Those listings will be displayed on Redfin with no days on market, no price history, and no home valuation estimates. Redfin also announced that it would not ban any listings if they were pre-marketed before being submitted to the MLS.
On March 17, Zillow announced a change to the Listing Access Standards. Under the updated standards, as long as a listing is displayed on a “public-facing website, mobile app, or internet real estate portal,” it is eligible to be listed on Zillow, regardless of whether it is placed on the MLS or another website. If a listing is not accessible to the general public, it is generally not eligible for display on Zillow sites. By expanding the definition to include non-Zillow and non-MLS affiliated sites, Zillow is trying to avoid monopoly implications, since a preview listing can be placed on any public-facing website and be eligible to be later listed on Zillow.
The same day, Zillow also launched a new product called Zillow Preview, which permits participating brokerages to display pre-market listings on Zillow and Trulia before the listings are entered into the MLS.
The day after Zillow revised the Listing Access Standards, Compass filed a notice of voluntary dismissal of its lawsuit, without prejudice. Without prejudice means that Compass would have the option to refile later. While that seemed unlikely at the time, it turns out the fight was just shifting venues.
Zillow Strikes Back
On May 12, Zillow filed its own antitrust lawsuit, this time against Compass and Midwest Real Estate Data LLC (“MRED”), the dominant multiple listing service for the Chicago area. Zillow is now the plaintiff, and it is claiming that Compass and MRED conspired to undermine Zillow’s Listing Access Standards in certain markets.
Zillow’s complaint claims that after Compass lost its preliminary injunction motion in February, it began pursuing a backup plan. Compass holds three of the fifteen seats on MRED’s Board of Managers and is MRED’s largest customer. According to Zillow, Compass leveraged that influence to get MRED to change its listing feed rules in October 2025.
The revised rules state that recipients of MRED’s listing data, like Zillow, cannot exclude listings based on “the identity of any participant, brokerage firm, subscriber, licensee, or representative.” In practical terms, this means Zillow could not apply its Listing Access Standards to Compass listings without risking termination of its access to all MRED listings.
Zillow says this matters because MRED has roughly 98% market share for residential listings in the Chicago area. Losing access to that feed would effectively shut Zillow out of the Chicago market. Faced with that threat, Zillow has not enforced its Standards against Compass listings in the Chicago region. Zillow alleges that on April 24, MRED and Compass announced a national partnership, which was designed to extend MRED’s coercive power beyond the Chicago area, and that Compass reached similar deals with other regional providers. On May 5 and 6, MRED threatened to suspend Zillow’s access to MRED data if Zillow did not restore Compass listings in Florida, Georgia, and California.
Zillow’s complaint alleges that Compass and MRED are improperly denying Zillow listings data in order to coerce Zillow to abandon its Standards. It is asking the court to enjoin Compass and MRED from continuing the alleged conspiracy and block enforcement of MRED’s revised rules.
Interestingly, Zillow’s role has now reversed. In Compass v. Zillow, Zillow argued that it lacked the market power to exclude competition, even with a 66% market share. It now has to explain to the court why MRED has the monopoly power needed to support Zillow’s antitrust claim.
The Compass v. Zillow legal fight may have ended, but the Zillow v. Compass fight is just getting started, and the underlying business dispute will have a big impact on the real estate market.
Pooja S. Nair is a Partner and Chair of the Food, Beverage, and Hospitality Department at Ervin Cohen & Jessup LLP. She represents clients in real estate litigation and complex business disputes involving contracts, employment, intellectual property, and fraud. Her insights have appeared in Law360, Daily Journal, The New York Times, and the Los Angeles Times. Before joining ECJ, she led the Food and Beverage practice at TroyGould and practiced white-collar defense at Foley & Lardner. She also serves on nonprofit boards and has been recognized as one of Los Angeles’s Top Litigators and Trial Attorneys and Most Influential Women Lawyers by the LA Business Journal.
