KEY POINTS:
Auckland Airport declared itself in play last week with the disclosure of talks with Canada Pension Plan and at least one other party, but it has since played its cards close to its chest.
The market is now assuming at least four parties may be interested in the airport - including CPP and Macquarie Airports - but the names of other potential bidders remain tightly held.
That hasn't stopped speculation concentrating on a handful of likely contenders - globally focused infrastructure funds with a passion for airport acquisition.
One name at the top of that list last week was the world's biggest airport management company BAA, now owned by the giant Spanish infrastructure investor Ferrovial.
Ferrovial took over BAA - which owns London's Heathrow, Gatwick and Stansted airports - last June, in a deal worth more than $26 billion.
In 2002 Ferrovial was tipped as a contender to buy the stake the Auckland City Council was selling.
Other names being bandied about included Australian infrastructure specialist Hastings, which has more than $4 billion of assets, and investment firm Babcock & Brown, with more than $45 billion of funds and assets under management.
The trend towards consortium buyouts means there may be more names involved than there are actual bidders, analysts have warned.
It is also likely that however many parties were involved in the original talks with the airport, more will have had their interest piqued by news that some sort of ownership change is brewing.
As one analyst bemoaned last week, more detailed guidance on the structure of proposals the airport is considering would probably be more useful to investors than the disclosure of more company names.
Auckland Airport shares closed at $3.21 on Friday - up 13 per cent on its close a week earlier.
