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Practice Area: Antitrust
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Berger Montague, a leading national plaintiffs’ law firm, is investigating potential antitrust claims on behalf of commercial real estate brokers, firms, and other professionals who purchased commercial real estate listing or information services from CoStar Group, Inc., including LoopNet, at any time during the past four years.
It is alleged that CoStar used exclusionary contracts, technological barriers, and aggressive enforcement tactics to eliminate competition and lock customers into its platforms. These practices allegedly allowed CoStar to raise prices dramatically, limit customer choice, and force brokers into bundled, higher-cost subscriptions for services that were previously available separately or at significantly lower prices.
CoStar’s alleged conduct may violate federal antitrust laws and may have harmed brokers and firms by requiring them to pay supracompetitive prices for essential commercial real estate listing and data services, often with no practical alternative.
If you or your company paid for CoStar or LoopNet services at any time in the last four years, your legal rights may have been violated — and we want to hear from you.
Please use the form on the right hand side to contact us, email us at info@bergermontague.com or call us at 1-800-424-6690.
Berger Montague is one of the nation’s preeminent law firms focusing on complex civil litigation, class actions, and mass torts in federal and state courts throughout the United States. With more than $2.4 billion in 2025 post-trial judgments alone, the Firm is a leader in the fields of complex litigation, antitrust, consumer protection, defective products, environmental law, employment law, securities, and whistleblower cases, among many other practice areas. For over 55 years, Berger Montague has played leading roles in precedent-setting cases and has recovered over $50 billion for its clients and the classes they have represented. Berger Montague is headquartered in Philadelphia and has offices in Chicago; Malvern, PA; Minneapolis; San Diego; San Francisco; Toronto, Canada; Washington, D.C., and Wilmington, DE.
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Berger Montague Investigating Antitrust Claims Against CoStar FAQs
How do I know if I’m eligible to participate in this investigation?
You may be eligible if you or your company paid for CoStar or LoopNet services at any time in the last four years, including subscriptions or paid listing, advertising, or information services. Eligibility does not depend on the size of your firm or how much you paid.
I feel “locked in” to CoStar. Does that matter?
Yes. Many complaints describe being locked into CoStar contracts because:
- Competitors lack comparable listings or data
- Cancelling would harm deal flow or visibility
- Contracts automatically renew unless cancelled far in advance
What happens after I submit my information?
Your information will be reviewed by our legal team. If you appear to be eligible, a member of our team will contact you to discuss next steps, explain the investigation in more detail, and answer any questions you may have.
Will my information be kept confidential?
Yes. Any information you provide will be kept confidential and used only for purposes related to this investigation, in accordance with applicable privacy and ethical obligations.
Does submitting my information mean that I’m suing CoStar or LoopNet?
No. Submitting your information does not mean you are filing a lawsuit or becoming a party to a case. It simply allows us to evaluate whether you may have a potential claim and whether you may be eligible to participate if litigation moves forward.
Do I have to pay to speak with an attorney?
No. An initial consultation is free of charge. If you qualify to participate in a case, you will not be required to pay any upfront legal fees.
Experiencing CoStar or LoopNet issues?
If you’ve searched online for:
- “CoStar monopoly”
- “LoopNet price increase”
- “Can’t cancel CoStar”
- “CoStar contract auto renewal”
- “Is CoStar illegal?”
- “CoStar antitrust lawsuit”
- “LoopNet alternatives don’t work”
You are not alone. We want to hear from you.
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