CoStar Hit With Antitrust Suit Alleging Data Monopoly

By Grace Dixon · May 21, 2026, 8:00 PM EDT

A Washington, D.C., brokerage has filed a proposed class action against CoStar in federal court, alleging a decades-long anticompetitive scheme designed to maintain a monopoly over commercial real estate listing services...

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Case Information

Case Title

ONE REAL ESTATE LLC v. COSTAR GROUP, INC. et al

Case Number

1:26-cv-01735

Court

District Of Columbia

Nature of Suit

Anti-Trust

Date Filed

May 20, 2026