Wisconsin-based Alliant said – in a broad statement on its various international investments issued in the US yesterday – that it "continues to evaluate the various alternatives to monetise its New Zealand investments".

Dow Jones Newswire reports Simon Young, chief executive of Alliant Energy's New Zealand unit, as saying monetising this investment did not necessarily involve an outright sale of its NZ$500 million stake in Trustpower.

Alternative methods of raising cash included issuing redeemable preference shares or borrowing against assets, Young said.

But NZ analysts have said an Alliant sale could trigger a takeover offer for Tauranga-headquartered TrustPower, the smallest one of the big five NZ generator-retailers.

Alliant has said its NZ are worth US$340 million (NZ$500 million) based on trading prices and exchange rates at June 30.

TrustPower's other big shareholders are NZSX-listed infrastructure company Infratil (35% equity) – whose investment agreement with Alliant gives it some pre-emptive rights – and the Tauranga Energy Consumer Trust (28%).

TrustPower shares were flat yesterday at NZ$6.00, close to the year-high of NZ$6.01, while Infratil was up 5c to NZ$3.95.