Not-for-profit KiwiSaver provider Simplicity is changing the management of $3 billion of overseas investments to a German-owned investment firm previously accused of greenwashing.
It is shifting the funds from US investment firm Vanguard to German fund manager DWS International, a part of the Deutsche Bank group.
The funds will be set up as New Zealand domiciled, which will mean income earned on overseas investments will pay local tax rates.
"Moving to DWS is in the best interests of members and we now have the scale to do this," Simplicity managing director Sam Stubbs said.
"It's a big transaction. But it's worth the mahi, as we expect that over time the foreign income withholding tax benefits could mean millions more money in our members' pockets."
Stubbs said the move could lift returns by $4 million to $7m a year, which should flow into member returns.
DWS was raided by German financial authorities last year after a whistle blower leaked information about alleged greenwashing within its sustainable investment branches.
The investigation looked at allegations that DWS had tricked customers into buying financial products that were improperly described as sustainable investments, as well as suggestions of false reporting on progress in sustainable finance development.
DWS has rejected the claims, saying it takes great care in preparation of marketing material.
Stubbs said the new overseas portfolios would use customised indices set up to reflect Simplicity's ethical investment principles, and will be implemented in early May.
He said Vanguard had been inspirational in the formation of Simplicity, and the two firms parted as "the best of friends".