CoStar Files $1B Copyright Suit Against Zillow as Stock Ranks 360th in Trading Volume

On July 30, 2025, CoStar Group (CSGP.O) rose 0.69% with a trading volume of $0.34 billion, ranking 360th in market activity. The stock’s movement coincided with a high-profile legal dispute involving the real estate data provider. CoStar filed a lawsuit against Zillow Group (ZG.O), alleging the use of over 46,979 of its copyrighted real estate photographs without authorization. The complaint seeks unspecified compensatory and punitive damages, which CoStar estimates could exceed $1 billion. The suit claims Zillow leverages these images—including many watermarked—to enhance its rental listings business, potentially generating revenue through advertising and property management tools.

The case highlights CoStar’s aggressive defense of its intellectual property, a strategy that has previously yielded significant financial results. In 2019, the company secured a $500 million judgment against Xceligent over similar copyright violations. This time, the lawsuit also implicates third-party platforms like Realtor.com and Redfin, which Zillow is alleged to have syndicated the images to. CoStar’s CEO has warned of further legal action if those platforms fail to remove the content. The litigation underscores the competitive dynamics in the real estate tech sector, where data ownership and monetization are critical battlegrounds.

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