CoStar Files Apartments.com.au Trademark Claim, Despite Existing Australian Portal

CoStar Group is attempting to trademark Apartments.com.au in Australia, according to a filing published on the IP Australia register earlier this month. The application, lodged under CoStar UK Limited and handled by Melbourne law firm Corrs Chambers Westgarth, is a figurative mark pairing the wordmark with a five-quadrilateral star, the same star device CoStar uses on its US portals Apartments.com and Homes.com. The application is currently awaiting examination.

The complication is that Apartments.com.au is already a live Australian portal. Third Door Ventures, the proptech group led by Mike Bird and George Glover, rebranded its off-the-plan platform Urban.com.au to Apartments.com.au in July 2025, after buying the domain from Darren Pateman, the former Finbar Group managing director who had held it privately for more than two decades. The cash-and-equity deal was reported as one of Australia's top-10 URL transactions.

The trademark filing rounds out a pattern. In the US, CoStar owns both Apartments.com, acquired for $585 million in 2014, and Homes.com, bought from Dominion Enterprises for $156 million in 2021. In Australia, CoStar picked up the Homes.com.au domain from developer Pat Carbone for a reported A$22.8 million shortly after agreeing a roughly A$3 billion takeover of Domain Holdings, which closed on the 27th of August 2025. Andy Florance has said the Homes.com.au domain gives CoStar "optionality" around "flanking brands" or a rebrand of Domain.

Asked on stage at the recent Property Portal Watch Bangkok event whether his company had anticipated CoStar's Australian entry when it targeted apartments.com.au, Mike Bird replied: "It would have been good foresight, but I can't say that that was the case."

When contacted for comment, a CoStar Group spokesperson told Online Marketplaces: "This filing was a part of CoStar Group’s routine efforts to protect its intellectual property rights around the globe."