Zillow Finally Beats REX Antitrust Lawsuit After Supreme Court Decision

Zillow has won a definitive legal victory after the U.S. Supreme Court declined to review an antitrust case brought by former discount brokerage REX Real Estate, effectively ending a years-long legal dispute over how listings appear on real estate portals.

The decision leaves intact a March ruling by the Ninth Circuit Court of Appeals, which upheld a lower court’s dismissal of REX’s 2021 lawsuit challenging the National Association of Realtors’ (NAR) “no-commingling” rule. That rule, which has since been repealed by the NAR, had prohibited MLS and non-MLS listings from appearing together on a single web page.

In a statement to Inman News, a Zillow spokesperson said:

“We’re pleased this matter has reached the conclusion we expected and that the court at every level has affirmed Zillow’s position. Zillow was founded on increasing transparency in real estate and we have a long history of advocating for practices and launching products that do just that. This decision reinforces our long-standing commitment to transparency, innovation and prioritizing consumers.”

The dispute dates back to Zillow’s 2019 decision to join hundreds of multiple listing services (MLSs) to access Internet Data Exchange (IDX) feeds. To comply with NAR’s rule, Zillow introduced a two-tab system in 2021 that separated MLS listings from “Other Listings.” As a discount brokerage which was not a member of MLSs, REX claimed the change caused views of its listings to collapse and ultimately led to the closure of its brokerage 18 months later.

REX argued the rule amounted to an “agreement in restraint of trade” and accused Zillow of participating in an “anti-competitive scheme” with NAR. But courts consistently rejected those claims, finding no violation of antitrust law.

NAR formally repealed the optional no-commingling rule in June 2025, but Monday’s Supreme Court order confirms Zillow’s compliance was lawful and marks a final defeat for the now-defunct brokerage.