Analysts said the announcements held out some other possibilities, including:
That SIA's 8.3-per-cent stake could be in addition to the 16.7 per cent it is seeking from Brierley Investments Limited (BIL), which has indicated that SIA is its favoured partner;
That SIA was probably going in with a strategic partner that could be either Lufthansa -- with which it has been working closely lately -- or with Virgin Atlantic -- in which it already owns 49 per cent.
Or less likely:
That SIA has only managed to get half of the 16.7 per cent of Air NZ "B" shares that it was seeking from BIL.
One analyst said: "SIA knows that it does not make sense to fragment the Australian domestic market further. That could partly explain its reluctance to back the no-frills airline planned by Richard Branson.
"This is pure conjecture. But going in with Virgin for a stake in Ansett serves well both SIA and Virgin's purposes of entering the Aussie market."
Foreigners can own up to 49 per cent of Air NZ by holding all the unrestricted Class B shares, but New Zealand law limits a single overseas airline to a maximum 25-per-cent stake.
That means SIA's moves could be coordinated with another investor that works closely with it, most likely an airline.
The 8.3 per cent, combined with BIL's 16.7 per cent, would take it to the 25-per-cent cap.
Aviation specialists said this may well be the scenario.
"That is because, in the past, the airline turned down an offer for 10 per cent of China Airlines, saying the stake was not meaningful enough," one analyst said.
BIL said last month that negotiations over Air NZ were frozen until Air NZ had completed its acquisition of Ansett.
The Straits Times Singapore