Infratil is close to selling its stake in Energy Developments.
A private equity consortium is first in line to make a full takeover offer for the company.
Infratil is a majority owner of Energy Developments. It has done a deal with Archer Capital, giving Archer certainty it will gain almost 20% of the company if Infratil likes the offer price.
For the agreement to go ahead, Archer would have to launch a bid for all of the company's shares within 10 weeks.
An analyst says Infratil is unlikely to accept less than $A2 a share for its stake, which values Energy Developments at $A120 million.
Infratil shares were trading up 3 cents at $1.73 on Monday after a trading halt was lifted. Infratil is managed by Morrison & Co.