Zillow Sues Chicago Listing Network and Brokerage Over Alleged Collusion

On Wednesday, Zillow abruptly lost access to thousands of property listings in the Chicago area after filing a lawsuit accusing a private listing network owner of colluding with the nation’s largest brokerage to harm consumers by hiding homes.

According to the Chicago Sun-Times, hopeful Chicagoland home buyers browsing Zillow and Trulia suddenly saw significantly fewer listings. On Zillow, a nearly 5,000-home market dropped to about 1,700.

Thorough home buyers diligently checking every possible resource can still turn to other platforms, like Redfin and Realtor.com, which currently host between 5,000 and 8,000 listings, the Sun-Times noted.

But in an antitrust lawsuit filed last week, Zillow claimed that everybody buying or selling a home will be harmed if the alleged collusion goes unchecked.

Specifically, Zillow alleged that Midwest Real Estate Data LLC (MRED) and Compass, two “powerful players in the real estate industry,” have conspired to create “barriers to information that harm or threaten harm to sellers, buyers, and competitors by hiding real estate listings behind a velvet rope in a Private Listing Network (PLNs).”

As Zillow has alleged, MRED—Chicago’s multiple listing service (MLS) provider—“entered into a conspiracy” with Compass—Chicago’s dominant brokerage—to block platforms like Zillow from taking steps to increase transparency of available listings in the area.

“Rather than share all of its listings transparently—as its competitors do—Compass has sought to anticompetitively benefit from its dominance by hiding listings from anyone who is not working with a Compass agent in a PLN,” Zillow’s complaint alleged.

This allegedly “allows Compass to lure prospective home buyers to its brokerage with the promise of access to listings hidden behind a registration wall” and then maximize opportunity for profit by engineering “deals where its agents represent both sides of the transaction.”

In a statement to Ars, Zillow said that “Chicagoland home buyers and sellers today have far worse access to the housing market than they had yesterday, because their local MLS decided one mega-brokerage’s profits mattered more than their ability to achieve the American Dream.”

Zillow has requested a preliminary injunction to end the suppression of listings and other unlawful attempts to allegedly manipulate the home-buying market to disadvantage platforms that are pushing for more transparency.

Firms defend private listings

Challenging that, MRED has recently moved to force the legal fight into arbitration, alleging that Zillow’s antitrust claims are “meritless” and amount to little more than a contract dispute. The company also claimed that Zillow’s alleged harms are “self-inflicted,” since the platform knew that choosing to block nine listings of previously hidden homes would trigger a violation cutting off access to 43,000 listings.

In a press release, MRED said that Zillow lost access to its listings due to breaching its contract. The company also criticized Zillow, writing that “in a striking lesson in irony, Zillow has chosen not to display 43,000 MRED listings because it demands the right, and has filed a federal antitrust lawsuit to secure that right—to exclude nine listings it disfavors.”

Asked for comment, Compass told Ars that the legal fight “is about whether homeowners have a choice in how they market their homes, or whether Zillow can set a one-size-fits-all policy for the industry.”

“Restricting listing visibility and penalizing agents for exercising lawful and strategic marketing options undermines consumer choice,” Compass said.

Defending sellers’ choice in how they market their homes, Compass said that it commends MRED for “enforcing policies that protect both consumer choice and the fiduciary obligations agents owe their clients. Buyers in Chicago should not be deprived of access to listings because a platform disagrees with how a homeowner chooses to market their property.”

Zillow Preview launch complicates fight

The real estate industry fight escalated in April 2025, when Zillow claimed that it “took a competitive stand” to protect consumers by adopting new Listing Access Standards designed to throw a wrench in schemes like the alleged MRED/Compass conspiracy.

Zillow hoped that by threatening to block “listings that had been previously marketed privately to only a select group of buyers and were withheld from all market participants” from appearing on its websites, the market might shift to hide fewer listings.

But after Compass failed to secure an injunction blocking Zillow’s new policy, Compass and MRED allegedly teamed up “to threaten loss of access to all of MRED’s listings if a competitor did not display one of MRED’s or Compass’s competing PLN listings,” Zillow claimed. They did this, Zillow alleged, understanding that Zillow cannot afford to lose access to all Chicago-area listings and would have to revert to its prior standards.

And they soon followed through on that threat. In early May, after Zillow suppressed nine listings for failing to adhere to its Listing Access Standards, Zillow got a warning threatening to terminate its access to MRED’s listing feed “if Zillow did not display” some of the Compass listings that violated Zillow’s policies.

In its motion to compel arbitration, MRED accused Zillow of filing the lawsuit out of its “dissatisfaction” with its contract terms and “insecurity about continuing to generate revenue.” The company claimed that any harm that Zillow experienced is “completely self-inflicted, readily avoidable, and can be remedied at any time by simply complying with the same clear and longstanding license agreements under which it has operated for years.”

Reached for comment, MRED’s spokesperson also pointed to an article calling out Zillow’s seeming hypocrisy for challenging MRED’s private listing network while launching Zillow Preview, a pre-market listing network.

But Zillow insists that Zillow Preview is “not at all the same” as MRED’s alleged scheme. In a statement to Ars, Zillow defended its pre-market listing product as “available for any buyer to see and aligned with our transparency standards.”

“Private listings networks are just that—private, and only available to buyers working with a specific brokerage or agent,” Zillow said. “The goal of Preview is to help sell the house. The goal of PLNs is to hide the house to force more buyers into working with your brokerage.”

Home buyers in the US have in the past few years faced hardships, including “persistently high mortgage rates and home prices,” since the housing inventory has never returned to pre-pandemic levels, a 2026 Experian forecast said. While inventory is expected to modestly increase this year, Zillow’s legal fight suggests some brokerages may be motivated to increasingly hide new listings to increase profits.

Zillow worries that the MRED/Compass plan will inevitably block platforms that are promoting more transparency from competing with powerful private listings network providers. That will disadvantage both buyers and sellers in major markets like Chicago, Zillow alleged.

“Defendants’ conspiracy harms home buyers and sellers by incentivizing brokerages to withhold listings from the market only until the listing fails to sell privately, thus erecting barriers to information, exacerbating the accessibility and affordability crisis, and reducing the pool of buyers and listings that makes the real estate market efficient and competitive,” Zillow alleged.

In its complaint, Zillow said that MRED and Compass “control over 99 percent of the market for Chicagoland real estate listing platforms.” Allegedly, they’ve worked “in lockstep” and “in secret” to “leverage MRED’s monopoly power and control over Chicagoland listing feeds to force competitors like Zillow to display unwanted private listings, abandon pro-consumer listings policies, and block nascent competing offerings that preference access over exclusivity.

“MRED and Compass have colluded to turn back the clock on consumer transparency at the exact moment American families can least afford it, cutting off competition, hiding homes and engineering a market that extracts more from buyers and sellers so Compass can pocket more on every deal,” Zillow told Ars.