SCOTUS Punts CoStar Appeal, Clears Way for Antitrust Fight

CoStar Group’s bid to shut down a looming antitrust battle hit a dead end at the highest level.

The U.S. Supreme Court declined to review the data giant’s petition to overturn an appellate ruling that revived monopoly claims brought by rival Crexi, Bisnow reported, setting the stage for a courtroom clash over control of commercial real estate data.

The decision leaves intact a June ruling from the 9th Circuit Court of Appeals, which found Crexi “plausibly” alleged that CoStar’s business practices violate the Sherman Antitrust Act. The appeals court had reversed a lower court dismissal and ordered the case back for reconsideration, reopening a dispute with potentially wide-ranging implications for how listing platforms operate.

The legal fight traces back to 2020, when CoStar sued Crexi for copyright infringement, alleging the upstart platform scraped thousands of its property photos. Crexi countersued, accusing CoStar of wielding its dominance to lock out competition by restricting broker access, limiting listing portability and driving up costs for rivals trying to gain traction.

CoStar argues it has no obligation to share its platform and warned that allowing such claims to proceed could chill investment in proprietary data businesses. But with the Supreme Court declining to intervene, those arguments will now be tested in lower court.

Both sides struck predictable tones after the decision. CoStar signaled it would press ahead with its copyright claims, while Crexi framed the ruling as the end of delay tactics and an opportunity to scrutinize what it calls long-standing anticompetitive behavior.

The case lands at a sensitive moment for commercial real estate, where access to listings, analytics and market data has become a core battleground. A ruling against CoStar could reshape how platforms control — or are forced to share — their data ecosystems with ripple effects for brokers, investors and tech startups alike.

It’s not CoStar’s first brush with antitrust scrutiny. A prior lawsuit from Xceligent fizzled after that rival’s bankruptcy. Regulators have also intervened before, including blocking CoStar’s attempted acquisition of RentPath in 2020.

CoStar has a long history of filing copyright infringement lawsuits, counting more than 30 cases since its founding in 1986.

In July, CoStar sued Zillow, alleging the listing platform improperly used over 46,000 proprietary photographs from CoStar for rental listings on its website.

— Holden Walter-Warner