Commercial Real Estate Exchange Inc. (CREXi) has urged the U.S. Supreme Court to decline CoStar Group Inc.’s petition for certiorari, contending that the Ninth Circuit’s decision to revive CREXi’s antitrust counterclaims does not warrant further review. CREXi argues that CoStar’s disagreement with the appellate court’s interpretation of the allegations does not constitute a substantial legal question meriting the Supreme Court’s attention.
The dispute originated when CoStar filed a lawsuit against CREXi in 2020, alleging copyright infringement related to the unauthorized use of property images and information. In response, CREXi counterclaimed, accusing CoStar of monopolistic practices in the commercial real estate listing services market. CREXi alleged that CoStar engaged in anticompetitive conduct by entering into de facto exclusive agreements with brokers and implementing technological barriers that hindered brokers from collaborating with competitors.
Initially, the U.S. District Court for the Central District of California dismissed CREXi’s antitrust counterclaims. However, in June 2025, the Ninth Circuit Court of Appeals reversed this decision, allowing the counterclaims to proceed. The appellate court found that CREXi had plausibly alleged that CoStar possessed monopoly power and had engaged in anticompetitive behavior that could harm competition in the commercial real estate markets.
In December 2025, CoStar petitioned the Supreme Court to review the Ninth Circuit’s ruling, arguing that the decision could lead to an increase in baseless antitrust claims, thereby stifling innovation and imposing unnecessary litigation costs. CoStar contended that the appellate court’s acceptance of a “de facto” exclusive-dealing claim, absent explicit contracts or policies, was a departure from established antitrust principles.
In response, CREXi filed a brief opposing CoStar’s petition, asserting that the Ninth Circuit’s decision aligns with existing legal standards and does not present a novel legal issue warranting the Supreme Court’s intervention. CREXi emphasized that CoStar’s petition is essentially an attempt to re-litigate factual determinations already addressed by the appellate court.
The Supreme Court’s decision on whether to grant certiorari will have significant implications for the commercial real estate industry, particularly concerning the enforcement of antitrust laws in the context of digital platforms and data services. Legal professionals and industry stakeholders are closely monitoring the case, as it may influence the competitive dynamics and regulatory landscape of the sector.
As of February 17, 2026, CoStar Group Inc. (CSGP) shares are trading at $45.74, reflecting a slight increase from the previous close. The company’s stock performance remains a point of interest amid the ongoing legal proceedings.