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Internal Zillow documents put harsh light on CoStar's US real estate data 'monopoly'

By Chris May ( December 23, 2025, 22:00 GMT | Comment) -- CoStar is attempting to replicate its monopoly over commercial real estate data in the residential market by repeating a playbook that includes walled gardens, price hikes and litigation designed to bully and threaten competitors and customers, according to internal Zillow documents revealed during antitrust litigation brought by Compass, Inc.Marketing data and analytics firm CoStar Group is attempting to replicate its monopoly over commercial real estate data in the residential market by repeating a playbook that includes walled gardens, price hikes and litigation designed to bully and threaten competitors and customers, according to internal Zillow documents revealed during antitrust litigation brought by Compass, Inc....

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