GMI currently manages over $1.5 billion, of which $650 million is KiwiSaver related, on behalf of more than 57,000 clients.

GMI will operate as a stand-alone entity under the Kiwibank Wealth and Insurance line of business. Gareth Morgan will remain a major client of the business and a member of the investment strategy team. Both GMI principals, Morgan and Andrew Gawith, will remain directors of GMI alongside two Kiwibank-appointed directors.

The deal will significantly increase the size of Kiwibank's KiwiSaver business, which launched last year after the bank ended its distribution deal with default provider Mercer.  It currently has about 15,000 members.

Kiwibank chief executive Paul Brock described the purchase as "a unique opportunity to rapidly grow our Wealth and KiwiSaver businesses, while remaining true to the values that have built Kiwibank".

"GMI's core values of trust and honesty; transparency; respect for clients' interests; and the continual pursuit of excellence mirror Kiwibank's values of doing what's right; making it easy; and raising the bar."

Mr Brock added "we started our own KiwiSaver scheme just over a year ago and while the growth has been impressive we were aware of the need to extend our investment management capability. Our plan to do this looked very much like what GMI has developed".

"The aligned values of both organisations reinforced the decision to buy rather than build and we are delighted to have GMI as part of the Kiwibank group and the ongoing participation of its principals".

Morgan maintains a high profile outside of the fund management industry and was in the news again this week for his offer to pay for the funeral of "blanket man" Ben Hana.