Under the deal, CP2 boosted its shareholding in the firm to 27 per cent.
ConnectEast is the owner and operator of Melbourne's EastLink transport network.
"This type of asset strongly matches our clients' long-term liability profiles and is a strong fit with CP2's strict risk-adjusted investment criteria," CP2 chief executive Peter Doherty said.
"There is a natural fit between pension funds seeking reliable long-term returns and infrastructure assets capable of delivering those returns."
CP2 manages about $3 billion in investments in infrastructure on behalf of pension and endowment funds, including the Harvard Management Company in the United States, the Universities Superannuation Scheme and Railpen in the United Kingdom, ATP in Denmark and the New Zealand Superannuation Fund.
The firm already has investment stakes in Transurban Group, Drive, Capital Beltway Project, Zurich Airport and Sydney's airport rail link.
