KiwiSaver investments grew to more than $76 billion at the end of December, following a strong rebound for sharemarkets.
The quarterly survey by research firm Morningstar showed assets under management rose by 7 percent - $5.4b over the quarter in the three months ended December, and by $13b on the year before.
"The strong finish to the year may be attributed to the continued progress in the distribution of vaccines and further monetary and fiscal support from policymakers," Morningstar director of manager research Tim Murphy said.
Sharemarkets in developed economies had strong finishes to the year, particularly in November, with several including the NZX hitting record highs.
"KiwiSaver funds generally reflected the strong underlying market conditions experienced over the December quarter. The average multisector category returns ranged from 2 percent for the conservative category to 8.8 percent for the aggressive category," Murphy said.
The more conservative the fund the more New Zealand assets they held, while the most aggressive funds chased higher returns overseas.
The survey showed about 45 percent of the funds invested were in income-generating assets with 55 percent in growth assets.
The best performers were Milford in the conservative sector, Aon Russell Lifepoints Moderate, CareSaver in the balanced group, JUNO KiwiSaver for growth funds, and SuperLife High Growth in the aggressive niche.
The largest provider was ANZ with more than $17.55b, followed by ASB with $13.4b.