Rex Wants The Supreme Court To Reconsider Hearing Its Case

The U.S. Supreme Court may have denied Real Estate Exchange’s (REX) to hear its appeal of the Ninth Circuit Court of Appeals ruling in its long-running antitrust suit against the National Association of Realtors (NAR) and Zillow, but that doesn’t mean REX has given up.

Last Thursday, the firm filed a petition asking the Supreme Court to rehear its writ of certiorari. The Supreme Court denied REX’s petition in late-October. Typically, the Supreme Court chooses cases that have national significance or gives them the opportunity to set an important legal precedent. 

According to REX’s latest petition, the case presents the court with “the exceptionally rare situation of an ‘intervening circumstances of a substantial . . . effect,’” which it claims is an issue the Supreme Court has yet to ever rule on. 

The petition cites a decision made in mid-September by the Seventh Circuit Court of Appeals on the role the enforcement or following of rules labeled “optional” has in determining if something can constitute concerted action.

Thus far, six appeals courts across the country have ruled on this issue and their decisions are split evenly with three saying optional rules can be an example of concerted action and three saying they cannot be. REX claims that if the Supreme Court were to look at the ruling made by the Ninth Circuit in its appeal in comparison with the rulings made by the other appeals courts, they would see that the “Ninth Circuit’s decision lacks legal support.” 

Additionally, REX argues that by ruling on this case, the Supreme Court would resolve the appeals court split on these types of rules and their antitrust implications. 

“This case is exceedingly important. A ruling for REX would foster competition in the multi-trillion dollar residential real estate market while also closing a loophole in antitrust law that other associations of competitors could try to exploit,” the petition states.

“If the loophole remains open, optional rules would become a new type of wink and nod used to achieve the same collusive effect of an express, binding agreement. Stopping concerted action through optional rules is critical. Few antitrust cases have ever been more important.” 

REX concluded its petition by arguing that without this review by the Supreme Court, “not only NAR but trade associations in other industries will restrict competition under the legal theory of optional rules, resetting the structure of the entire U.S. economy.”

Originally filed ​​by REX in March 2021, the lawsuit alleges that NAR and Zillow broke antitrust laws when NAR promulgated its optional no-commingling rule and Zillow redesigned its website in order to follow the rule within the MLSs that adopted it. 

Judge Thomas Zilly, who oversaw the case, dismissed REX’s antitrust claims against NAR and Zillow in a summary judgement ruling. REX appealed this ruling to the Ninth Circuit Court of Appeals, which affirmed the lower court’s ruling. In April 2025, the Ninth Circuit denied REX’s request for a rehearing, leaving REX no choice but to file with the Supreme Court, which it did in late September 2025. 

NAR removed the optional no-commingling rule this past June and the trade group has maintained that the rule does not violate antitrust rules. 

“Both the district court and the 9th Circuit Court of Appeals affirmed this, and the Supreme Court has denied certiorari. Local MLSs play a key role in fostering transparent, competitive, and fair housing markets by delivering consumers the most accurate and up-to-date information on home listings,” a NAR spokesperson wrote in an email. “While the optional rule is no longer in effect, NAR remains committed to protecting the benefits MLSs provide agents, consumers, and the industry.”

Zillow did not immediately respond to HousingWire’s request for comment.