Last month, the Australian newspaper reported that IFM Investors is preparing a competing bid for Infratil to the one put forward by AustralianSuper.
IFM, which has around A$148 billion ($156.8b) under management, grew out of the infrastructure-focused Development Australia Fund, founded in 1990.
Today, it is collectively owned by 27 pension funds, including AustralianSuper.
Infratil's board, and one of its largest investors, Fisher Funds, have flatly rejected AustralianSuper's $5.37b offer for the ASX/NZX-listed infrastructure company, saying it undervalues its assets by a large margin.
The company owns a majority stake in Wellington Airport, half of Vodafone NZ, half of Trustpower, half of fast-growing CDC Data Centres and a number of clean-energy assets.
Shares in Tilt last traded at $6.30, having gained 76.7 per cent over the last 12 months. Infratil last traded at $7.39, up 38.6 per cent over the 12 months.