CoStar Group, the company behind Homes.com, has filed an amicus brief in Zillow Group, Inc. v. Midwest Real Estate Data LLC accusing Zillow of demanding open access to competitors’ listings while locking up pre-market inventory of its own.
In mid-May, Zillow sued Midwest Real Estate Data (MRED), a Chicago-area multiple listing service (MLS), along with the brokerage Compass. Zillow said it competes with both MRED and Compass and that it stood to lose MRED’s feed of Chicagoland MLS listings because MRED objected to Zillow’s policy of banning pre-MLS listings — specifically those offered by Compass. Zillow asked the federal court to grant it unconditional access to MRED’s full listing database while keeping its own ability to ban pre-MLS listings.
According to CoStar’s brief, Zillow’s complaint leaves out a key fact. Roughly two months ago, weeks after Zillow declared victory for “equal access” in a related dispute against Compass, the company launched its own pre-market listing product, Zillow Preview. CoStar says Zillow built the product through exclusive agreements that locked up pre-market inventory from approximately 60 major brokerages, and that Zillow then entered an exclusive horizontal agreement with Realtor.com. As a result, the brief states, competitors such as Homes.com cannot obtain the pre-MLS listings from those brokerages — including RE/MAX and Keller Williams — and Zillow will not share them.
On the first page of its MRED lawsuit, Zillow wrote: “It is basic economics that the free flow of information supports an efficient and competitive marketplace. In the world of residential real estate sales, the most important information for all market participants is listings.”
The central claim in CoStar’s amicus brief is that Zillow’s conduct mirrors or exceeds the anticompetitive behavior Zillow attributes to its opponents. CoStar argues that while Zillow calls for the “free flow” of listings, Zillow Preview listings remain exclusive to Zillow and Realtor.com and do not flow to other platforms. According to the brief, those listings stay inside Zillow Preview for an indefinite exclusive period that could run days, weeks, or months, and some may never reach the MLS or any competing platform. CoStar contends this is the same arrangement as Compass’s “coming soon” pre-market listings.
Compass also offers a second type of pre-MLS listing — “Phase 1” or “private exclusive” listings — which, according to Zillow, are available only to those who choose to engage with Compass. CoStar argues this does not help Zillow’s case. Just as Phase 1 listings are available only to those who choose Compass, the brief states, “Zillow Preview listings are available only to those who choose to visit Zillow and its partner websites — which is not a neutral public venue, but rather the top of the funnel into the Zillow ecosystem.”
CoStar argues that despite Zillow’s stated support for openness, Zillow walls off Preview listings from other platforms, requiring consumers to engage with Zillow even if they would prefer a platform such as Homes.com. The brief states: “Consumers who engage with Zillow Preview are drawn into that [Zillow] ecosystem, where they are subject to lead diversion, mortgage steering, and other practices that benefit Zillow at consumers’ expense. That is not neutral public access; it is access conditioned on exposure to Zillow’s integrated monetization apparatus.”
CoStar characterizes exclusive pre-market listings as the entry point for a set of practices it says extract value from consumers throughout the homebuying process. The brief notes that several of those practices are the subject of pending consumer class action lawsuits.
CoStar’s brief argues that Zillow’s claims should be rejected. It states that the harm Zillow alleges is self-inflicted, because Zillow only loses access to the MRED feed as a result of its own ban on rival pre-market listings — the Zillow Access Standards — which it maintains while promoting its own pre-market product. The brief further argues that Zillow cannot seek the unrestricted right to others’ listings while banning competitors such as Homes.com from accessing its own pre-MLS listings.
According to CoStar, granting Zillow full access to MRED’s listings while Zillow bars competitors from its own pre-market listings would create an asymmetric market structure rather than a free flow of information.
CoStar and other industry commentators have characterized the MRED suit as part of a broader effort by Zillow to replace the current MLS system, which Zillow describes as a competitor. The brief and commentators frame the case as a warning to MLSs nationwide to provide Zillow access to their listings or risk litigation, even as Zillow gatekeeps the pre-MLS listings it has called the “most valuable.”
Breitbart News previously reported that Zillow bizarrely added “climate change risk data” to house listings.
Lucas Nolan is a reporter for Breitbart News covering issues of AI, free speech, and online censorship.