Two scenarios are said to explain Antony Catalano's return to Australia's classified real estate market.

Either the head of Australian Community Media could be backing a "third force" against News and Nine interests... or it's "unfinished business" from last year.

Catalano - who previously ran Domain, now a Nine subsidiary - and ACM partner Alex Waislitz are reported have paid $10 million for 26-33 per cent stake in unlisted Realestateview.com.au, and have joined the board.

Combining property listings with those of ACM's regional newspapers would create an online audience of 5.4 million, making it a serious rival to Domain, from which he was ousted.

Max Mason and Michael Bleby on the Nine-owned Australian Financial Review dismiss the move as "unfinished business", saying the major stake is part of a 'Plan B' strategy formulated after he left Domain in 2018. They say discussions with News Corp Australia, News-controlled REA Group and Seven West Media about a "third force" real estate site began mid last year, the rationale being for realestate.com.au to protect market share against Domain.

"Catalano appears to be going ahead with this plan despite the lack of interest from News Corp, REA and Seven," they say.