Bigger is not always better when it comes to KiwiSaver returns, Morningstar data shows.
Analysis of returns through to the end of December shows that some of the country's biggest KiwiSaver providers are among the poorer performers.
ANZ has 16.6 percent of the KiwiSaver market, the largest of all providers. But it was the second-poorest performer over three and five years in the conservative category and the worst over 10 years. It was the second-poorest in the balanced category over three, five and 10 years. And it was the third-poorest in growth over three years and 10 years.
AMP was worst in growth and balanced over 10 years.
ANZ said in a statement that its longer-term results reflected a challenging period for ANZ Investments.
"That is why, over the past two years, we have strengthened our investment team and external partnerships, and made meaningful changes to our portfolios, aimed at delivering better outcomes for investors.
"The results of those changes are beginning to show in our recent performance. ANZ Investments' KiwiSaver Scheme funds all delivered positive returns over the 12 months to 30 April 2026 after fees."
It said that ranged from 3.17 percent for its cash fund, through to 21.82 percent for its high-growth option.
"We are encouraged by the results we have seen recently, including an improvement in our ranking against our peers."
Fisher Funds, with 13.5 percent of the market and the third-largest provider, had the lowest one-year returns in the balanced category and was near the bottom across one, three- five and 10 years in the growth category.
It recently made staffing changes, including chief investment officer Ashley Gardyne moving to a role as head of global equities.
"Ash has made a meaningful contribution to our business in the last 13 years, and I know he is looking forward to this opportunity. I am grateful he has agreed to stay in his current role while we recruit for a new chief Investment Officer," chief executive Simon Power said.
It did not comment on whether that was related to fund performance.
Morningstar head of data Greg Bunkall said he would be cautious about labelling the returns poor performance because a lot of the dispersion in returns was due to differences in portfolio construction, risk settings and investment philosophy rather than manager quality.
"Historically, some of the larger incumbent providers such as ANZ and AMP tended to run somewhat more structurally conservative portfolios within their respective risk categories. In practice, that often meant slightly higher allocations to cash and fixed income, broader diversification, less concentration in US large-cap technology stocks, and conservative risk controls or hedging frameworks.
"Over the past decade, markets strongly rewarded the opposite characteristics - particularly high exposure to global equities, US technology, growth-style investing, and in some periods unhedged offshore assets. Managers that leaned more aggressively into those areas generally performed very well relative to peers.
"It's also worth noting that AMP's more recent performance profile has improved following changes to portfolio construction and investment approach, so the picture is not necessarily consistent across all time periods.
"More broadly, KiwiSaver performance comparisons can sometimes be distorted by differences in actual growth asset exposure within the same category label. Two 'growth' funds, for example, can still have materially different equity weightings and risk settings, which has a significant impact on long-term outcomes."
University of Auckland senior finance lecturer Gertjan Verdickt said active managers who missed out on the recent rally in stocks could have been left behind.
He said bank owned and legacy providers had been able to inherit clients through default channels, so they faced less pressure to perform than newer challengers.
AMP has been approached for comment.
