Domain Holdings mulls $2.7b takeover offer from US firm

Nine Entertainment, which owns a 60.1 per cent stake in Domain, was up 22 per cent to a one-year high of $1.67, while Realestate.com.au owner REA Group had dropped 10.2 per cent to $239.30 on the possibility of a well-funded competitor entering the Australian market.

Domain said Nasdaq-listed CoStar Group, whose subsidiaries include Apartments.com and Homes.com in the US and OnTheMarket in the UK, has tentatively offered to acquire it for $4.20 per share.

Domain shares had risen above that level on Friday morning, changing hands around a nearly two-year high of $4.355, indicating some traders anticipate a better offer.

Domain said its board was assessing CoStar's proposal and there was no certainty it would result in a transaction.

CoStar said it had already acquired a 19.99 per cent stake in Domain.

E&P analyst Entcho Raykovski said CoStar had around $US2.1 billion ($A3.3 billion) in net cash, which would comfortably fund the acquisition.

Shares in Mayne Pharma were meanwhile changing hands at $7.205 after it agreed to be acquired by Cosette Pharmaceuticals for $7.40 per share, or $672 million.

The New Jersey and North Carolina-based company is backed by private equity firm Avista Healthcare Partners and funds managed by Hamilton Lane.

Mayne's products include a next-generation oral contraceptive pill, Nextstellis, and other women's health and dermatology products, two fields that Cosette also operates in.

"This acquisition marks a transformational step for Cosette, adding patented, high-growth products to solidify our leadership in women's health in the US and expanding our reach globally," said Cosette president and chief executive Apurva Saraf.

The deal will combine Cosette's strong portfolio with Mayne Pharma's proven commercial expertise, Mr Saraf said.

Mayne Pharma chairman Frank Condella said the board was unanimous in recommending the deal, which is expected to be completed by June.