MLCIM replaces Aviva Australia, following the acquisition of Aviva by National Australia Bank (NAB).
Aviva Australia was supported in its investment decisions by Mercer, which acted as an investment consultant to the company. This contract has also been terminated.
MLCIM indicated it would not make any immediate changes to the underlying investment managers of the fund range.
Standard & Poor's Fund Services (S&P) has placed the Pre Select range on hold following the announcement.
"Given the takeover of Aviva Australia by the National Australia Bank Group in 2009 and the capabilities of MLCIM within the group, we were expecting some changes in the organisation to be made," S&P analyst Toby Lewis said.
"S&P has a high regard for the multi-management capability of MLCIM, but the change precipitates the need for a rating review."
MLCIM has not yet provided details of the selection criteria or investment strategy that will be introduced for the fund range, and Lewis said he needed to see more details before he would review the ratings.
