BNP Paribas won what UniSuper described as an "extensive tender and review process" that involved a number of custodians.
"We determined that BNP Paribas was best placed to meet UniSuper’s evolving custody needs and were highly impressed with the overall depth and quality of its service offering for both core custody and back/middle office functions," said UniSuper head of portfolio analysis and implementation Dharmendra Dayabhai.
UniSuper chief executive Kevin O'Sullivan said BNP Paribas' information delivery systems will both satisfy regulatory requirements and allow the fund to "expand in-house investment management activities".
BNP Paribas Securities Services acting head Ian Perkins, who will be replaced by David Braga in a permanent capacity in May, said: "UniSuper appreciated our understanding of their current as well as future requirements and how we will meet them with our full service offering, global scale and local efficiency, supported by world-leading technology."
BNP Paribas Securities Services global chief executive Patrick Colle said UniSuper is a "globally significant" client for the firm.
"As one of the world’s strongest banks, we are extremely well positioned to protect their members’ assets," Mr Colle said.
The review and tender was conducted by UniSuper’s internal team, led by Mr Dayabhai, in conjunction with Drew Vaughan from Dymond, Foulds & Vaughan, an independent consulting firm specialising in custody review services.