The Supreme Court of the United States has declined to hear an appeal from Real Estate Exchange Inc. (REX) in its antitrust suit against Zillow Group, Inc. (Zillow) and the National Association of REALTORS® (NAR).

The case had argued that NAR’s so-called “no-commingling” rule (which required MLS listings and non-MLS listings to be shown separately) unfairly disadvantaged non-MLS brokerages like REX and restricted competition on Zillow’s platform. Because the Supreme Court didn’t take the case, the lower court rulings in favor of Zillow and NAR now stand as the final word.

Background

• REX filed the lawsuit in 2021 against Zillow and NAR, challenging NAR’s “optional” no-commingling rule. Under that rule, some MLSs required listings from non-MLS sources to be displayed separately or in a less prominent way.

• Zillow, having joined certain MLSs to access IDX feeds and support its listings inventory, changed its website display so that default listing results showed the MLS-affiliated listings, and non-MLS listings (like REX’s) were moved to a secondary “Other Listings” tab. REX claimed this caused a drastic drop in traffic to its listings.

• The district court dismissed the antitrust claims, the United States Court of Appeals for the Ninth Circuit upheld that ruling, and finally the Supreme Court declined review on October 20, 2025.

• Meanwhile, NAR repealed the optional no-commingling rule in June 2025, though its prior existence and effect remain central to this dispute.

What It Means for Real Estate Sales Professionals

Here are several practical take-aways for real estate professionals:

1. Listing exposure & platform display still matter
   While the specific rule challenged in this case is gone, the decision reinforces that how listings are displayed on major sites like Zillow can have big impact. If you’re an agent working with non-traditional listing channels, keep in mind: traffic and visibility matter.

2. Competition remains open, but legacy rules carry weight
   The ruling signals that optional industry rules (even those from large associations like NAR) may not automatically run afoul of antitrust laws if lower courts find they were truly optional and not enforced as mandatory. That means new business models (discount brokerages, hybrid models) still have room, but must carefully design how they interact with MLSs, platforms and associations.

3. Protect your client’s interests by understanding platforms
   For a typical sales pro: make sure you understand how clients’ listings will appear on major portals. If you work outside MLS-dominated systems, know how listings compare in visibility. You may need to highlight to clients the difference in exposure or adjust marketing to compensate.

4. Associations & regulation aren’t static
   The no-commingling rule may be repealed, but the broader questions of how MLS rules, platform policies and listing display affect competition continue. Agents should stay current on association policy changes, MLS rules and platform behaviors. These can affect how you market, how you differentiate, and how you advise clients.

5. New business models are still viable, but need strategic clarity
   If you’re part of a lower-fee brokerage or trying alternative listing models, this outcome is a reminder: you’re not blocked, but you must build visibility, value and differentiation. REX argued that they were hindered by listing posture; other nontraditional brokerages can learn from that and invest in visibility, client education, and clear value propositions.

Bottom line
For the average real-estate sales professional, the key takeaway is this: visibility = value. Whether you’re listing via traditional routes or emerging channels, how your property appears (and how easily consumers find it) is central to your success. Industry policy and association rules matter, but they don’t solely determine your opportunity. Control what you can (marketing, exposure, client education) and stay alert to how platform design and listing rules evolve.