Airports operator BAA could soon be at the centre of a bidding war, according to reports.
Australian bank Macquarie has begun talks with potential finance partners with a view to launching a bid for BAA, the Sunday Times and Reuters said.
The news comes a month after Spain's Grupo Ferrovial said it was considering a bid, which speculation suggests could come as early as this week.
BAA, which owns seven UK airports, declined to comment on the reports.
Macquarie, which recently dropped its pursuit of the London Stock Exchange, has interests in a number of airports.
It already owns Bristol Airport in a joint venture with Ferrovial.
According to reports, the Australian firm is currently in talks with US private equity firm Blackstone and Canada's Ontario Teachers' Pension Plan about funding a takeover of BAA.
Macquarie was unavailable for comment.
Separately, a Financial Mail report said BAA would ask the Takeover Panel to impose a bid deadline on Ferrovial, unless it launches an offer this week.
Analysts have said they expect the Spanish group to make an initial offer of 800 pence per share.
However, market talk suggests any bid would have to be around 900p, valuing the firm at £9.5bn, for shareholders to accept the offer.
As well as owning Heathrow, Stansted and Gatwick in the UK, BAA also has a stake in 13 overseas airports, including operations in the US, Australia, Italy and Hungary.