KiwiSaver strategy: fund selection, active vs passive, and how it fits your broader portfolio

KiwiSaver has been one of the genuinely successful policy interventions in New Zealand personal finance. The combination of employer contributions, government contributions, and the default enrolment mechanism has brought a large proportion of the working population into long-term saving who would not otherwise be there. That is worth acknowledging before criticising anything about how it works in practice.

The criticism is this: most New Zealanders are in the wrong fund, paying the wrong fee, and on the wrong tax rate. Not through any fault of their own — the system makes all three errors easy to make and difficult to notice. By the time the compounding effect becomes visible, it is often decades later and the damage is done.

The three most common KiwiSaver mistakes

In roughly 19 years of working in NZ financial services, I have seen the same mistakes repeated across a wide range of investors at all levels of financial literacy. The three most costly ones, in order of frequency:

The PIR issue is worth checking first because it requires no investment decision and takes about 60 seconds to resolve.

Fund type: the most important decision first

Before you think about which provider to use or whether active or passive is better, get the fund type right. KiwiSaver funds are categorised by risk profile: defensive, conservative, balanced, growth, and aggressive. The general principle is straightforward: the longer your investment horizon, the more equity exposure you can sustain, and the more you should be in a growth or aggressive fund.

A 30-year-old in a conservative KiwiSaver fund is not playing it safe. They are systematically giving up decades of compounding for the comfort of avoiding short-term volatility they will never need to access.

Active vs passive: what the NZ data shows

The active vs passive debate in KiwiSaver is more nuanced than the global literature might suggest, for a specific reason: New Zealand has a small number of active managers with genuinely long track records, and some of them have outperformed their benchmarks after fees over meaningful time periods.

The data worth looking at is net returns after fees over five and ten years. Morningstar and the FMA's Smart Investor tool both publish this data for NZ KiwiSaver funds. The pattern that emerges is broadly consistent with the global literature: most active funds underperform their benchmark after fees over the long term, but a small number of NZ active managers have delivered genuine outperformance.

Milford is the most frequently cited example. Over the ten years to 2024, Milford's Active Growth fund delivered net returns that comfortably exceeded passive alternatives at a comparable risk level, despite charging fees of around 1.05%. The question is whether past outperformance predicts future outperformance. The honest answer is that it is a better predictor for some NZ active managers than the global literature would suggest, but it is not a guarantee.

The fee impact: concrete numbers

The fee difference between a low-cost passive fund and a mid-tier active fund in NZ is typically around 0.6% to 0.8% per year. On a $50,000 balance growing at 7% gross over 30 years, that difference in annual fees produces a terminal balance difference of more than $130,000. On a $100,000 balance, it doubles.

Those numbers are not arguments against active management in every case. They are arguments for making the fee decision with full awareness of what it costs over time, rather than defaulting to whichever fund your bank offered you when you first enrolled.

How KiwiSaver fits your broader portfolio

Most personal finance advice treats KiwiSaver as a separate question from broader investment strategy. That separation is administratively convenient but strategically wrong. KiwiSaver is part of your total portfolio, and the right asset allocation across KiwiSaver and your personal investments should be considered together, not independently.

A few practical implications. If your KiwiSaver is in a growth fund with high global equity exposure, and your personal investment portfolio is also heavily weighted to global equities, your total portfolio may be less diversified than either account looks in isolation. The government contribution of up to $260.72 per year requires a minimum $1,042.86 contribution from you between 1 July and 30 June — 25 cents for every dollar you contribute, up to the maximum. Getting the full government contribution should be the first priority for most investors before deploying additional capital elsewhere.

KiwiSaver is part of your total portfolio. The right asset allocation should be considered across both accounts together, not independently. Most people do not think about it this way.