Grabar Law Office Is Investigating Potential Antitrust Violations by CoStar on Behalf of Commercial Real Estate Brokers

Grabar Law Office is actively investigating whether CoStar Group, Inc. has engaged in unlawful monopolistic conduct affecting commercial real estate (“CRE”) brokers nationwide. Our investigation focuses on whether CoStar has used its dominant market position—through the CoStar Platform, LoopNet, and related CRE data services—to restrict competition, lock brokers into costly contracts, and inflate prices in violation of federal and state antitrust laws.

If you are a commercial broker who pays CoStar directly, you may have valuable legal rights and the ability to participate in this investigation and any ensuing litigation.

Who May Be Affected:

You may have been impacted if you are a Commercial Real Estate Broker who meets the following criteria:

• You pay CoStar directly for a CoStar Platform license.
• You first signed your CoStar agreement before February 5, 2025.
  • (Renewals qualify; CoStar often makes renewals subject to original terms.)
• You purchased a LoopNet advertising package before February 5, 2025.
• You are located anywhere in the United States.

Why CoStar Is Under Antitrust Scrutiny:

Publicly filed allegations assert that CoStar has maintained and expanded monopoly power in commercial real estate listing, information, and auction markets through:

1. Exclusionary Broker Contracts

CoStar allegedly uses long-term, restrictive, and sometimes de facto exclusive agreements that limit brokers’ ability to work with competing platforms such as CREXi or others.

2. Technological Blockages

Competitors allege that CoStar imposes restrictions that prevent rival platforms from accessing listing data, syndicating content, or integrating with broker websites—functioning as technological barriers to entry.

3. Aggressive IP and Litigation Tactics

CoStar has been accused of asserting baseless or inflated copyright claims and initiating costly litigation against emerging competitors as a means of discouraging brokers from using rival services.

4. Inflated Subscription Prices

Due to reduced competition, brokers allegedly pay supra-competitive prices for the CoStar Platform (over $1 billion in annual revenue) and LoopNet (over $250 million in annual revenue). Estimated damages to brokers may exceed $100 million per year.

These allegations—many of which were dismissed at the trial court—have recently been allowed to proceed, opening the door for brokers to pursue claims.

Potential Financial Impact on Brokers:

If the alleged anticompetitive conduct is proven, commercial brokers may be entitled to:

• Monetary damages for overcharges on CoStar Platform subscriptions
• Recovery of inflated LoopNet advertising costs
• Potential treble damages under federal antitrust law
• Injunctive relief requiring CoStar to revise or eliminate restrictive practices
• Monetary incentive or service awards as approved by the relevant court.

How Grabar Law Office Can Help:

Grabar Law Office has extensive experience representing businesses and professionals in complex antitrust and commercial disputes. We are currently evaluating claims on behalf of brokers nationwide and can provide a confidential, no-obligation review of your CoStar contracts and payment history.

You may be able to recover damages as well as a court approved incentive award at no cost to you whatsoever.

If you believe you may have been affected by CoStar’s conduct—or wish to learn more about your rights—please contact Joshua H. Grabar at jgrabar@grabarlaw.com or call us at (267) 507-6085.

You may be entitled to significant compensation at no cost to you. Your participation can help restore fairness and competition to the commercial real estate marketplace.