Booster vs Simplicity KiwiSaver 2026: Fees, Returns and Who Each Suits (NZ)

Booster's active, advised approach versus Simplicity's low-cost index model. Fees, returns, fund range, ownership and who each suits.

TL;DR: Booster is an actively managed, advised provider; Simplicity is a low-cost, not-for-profit index manager. On the Growth funds, Simplicity's total annual fund charge is about 0.24% against Booster's roughly 1.23-1.28% (plus a $36/yr member fee), so Booster costs roughly a percentage point more. Simplicity suits cost-focused, hands-off members; Booster suits those valuing active management, an SRI range and adviser support.

Booster vs Simplicity KiwiSaver is really a choice between two opposite philosophies. New Zealanders now hold $123.1 billion in KiwiSaver across 3.38 million members, paying an average fee of 0.7% of funds under management. ¹ Booster and Simplicity sit at almost opposite ends of that fee and philosophy spectrum: one backs human managers to beat the market; the other tracks it cheaply.

This guide compares the two on fees, on performance, on what you actually get, and on who each one suits. Figures are point-in-time, drawn from the September 2025 quarterly fund updates and current provider disclosures; specific as-at dates are noted where they matter.

What is the core difference between Booster and Simplicity?

The whole comparison turns on one decision: active management versus low-cost index tracking.

Simplicity is a passive, index-based manager. It buys broad slices of global and New Zealand markets and aims to match them at the lowest possible cost. It is also 100% owned by the not-for-profit Simplicity Foundation, which donates 15% of its management fee revenue to charity, and runs around $11.3 billion in funds across roughly 193,935 members. ⁷ Its Growth fund is one of the government-appointed default KiwiSaver funds.

Booster is a privately held, New Zealand-owned independent provider that leans active. Its managers make deliberate calls about what to hold and when, which is why its fee sits well above the index crowd. Booster also runs a well-developed Socially Responsible Investment (SRI) range and a broader product set, including the well-known Booster Tahi (private growth assets) options that index-only providers simply do not offer.

Neither approach is "right". Active management can add value or subtract it; index tracking guarantees you the market return minus a small fee. The question is which trade-off fits you.

How do the fees compare, and what do they cost over 30 years?

Fees are the one variable you control with certainty, and over a working lifetime they compound hard.

On the Growth funds, the Simplicity KiwiSaver Growth fund charges a total annual fund charge of about 0.24% with no fixed annual membership or admin fee. ⁸ The Booster KiwiSaver Growth fund charges a total annual fund charge of roughly 1.23-1.28% — Booster's own fees page quotes 1.28% on balances up to $200,000, while Mindful Money/Disclose data shows about 1.23% — plus a $36 per year ($3/month) member fee (not charged on balances under $500). ⁹ So on a like-for-like total-charge basis, Booster's Growth fee is roughly a full percentage point higher than Simplicity's, not merely double.

To put that gap into context: across the whole scheme, providers collected $868.5 million in fees in the year to 31 March 2025. ² Small percentages move large dollars.

Worked example: the fee gap on an $80,000 balance over 30 years

Scenario: Mere is 35 with $80,000 in KiwiSaver and contributes nothing further. To isolate the fee drag, assume an identical 5% gross return on both funds. The comparison uses Booster's total annual fund charge at the 1.26% midpoint of its 1.23-1.28% range.

On these illustrative assumptions, the lower fee leaves Mere roughly $82,000 better off after 30 years, purely from the fee difference (and before Booster's $36/yr member fee, which widens the gap slightly further). All balances are rounded; treat them as illustrative, not precise quotes. That is the cost Booster has to justify through active outperformance and the extras it offers, which is why it is worth checking the actual returns rather than assuming.

You can run any two funds against each other on fees and returns using Sorted's Smart Investor tool, ¹⁰ or use a free KiwiSaver fund comparison.

How has each provider performed across fund types?

Fees only matter relative to what you get back. The Simplicity KiwiSaver Growth fund reported a 5-year average annual return of 8.12% after fees and tax (as at 30 September 2025). ⁸ Note this is an after-fee, after-tax figure to that date — different from any current before-tax number a provider's live site may show — so compare like with like. That is a strong number for an index fund, and it sets the bar Booster's active approach has to clear after its higher fee.

A few honest things about comparing returns:

• Match the risk category. Compare Growth with Growth, Balanced with Balanced. A Booster Balanced fund will look "worse" than a Simplicity Growth fund simply because it holds fewer shares, not because the manager is weaker.
• Use after-fee, after-tax returns. That is what lands in your account. Headline gross numbers flatter higher-fee funds.
• Five years is the minimum useful window. One good year tells you almost nothing; KiwiSaver is a 30-to-40-year product.

The cleanest way to see live, like-for-like figures is the official fund pages: Simplicity Growth (FND697) and Booster Growth (FND1280). ¹⁰ Across the scheme as a whole, KiwiSaver generated $6.4 billion in net investment returns in the most recent reporting year, so even the difference between two solid Growth funds is meaningful at scale. ²

What about fund range, ethical options and KiwiSaver extras?

This is where the two providers genuinely diverge, and where Booster's higher fee starts to earn its keep for some members.

Simplicity keeps it deliberately simple: a tight ladder of diversified funds (Conservative, Balanced, Growth and a high-growth option) built from low-cost global and NZ index exposure, with ethical screens applied across the range. There is little to fiddle with, which is the point. It also reinvests in NZ through its own residential lending and build-to-rent programme.

Booster offers more choice: actively managed diversified funds, a dedicated Socially Responsible Investment (SRI) range, geographic and asset-class options, and access to private growth assets through its Tahi vehicles. Booster is also strongly adviser-supported, so if you want a human walking you through fund choice, contributions and first-home withdrawals, that channel is built in.

Whichever you choose, the surrounding KiwiSaver rules are the same for both, and 2026 brings several changes worth knowing:

Many members finish the KiwiSaver year a few hundred dollars short of the full government contribution, and the match rate halved to 25c per dollar from 1 July 2025. The provider you pick doesn't change that, but a quick check does. Run yours through the KiwiSaver health check.

Who actually runs your money: ownership and structure?

Simplicity is owned by a not-for-profit foundation; Booster is a privately held, New Zealand-owned company. Structure is not just trivia — it tells you who the provider answers to.

• Simplicity is 100% owned by the not-for-profit Simplicity Foundation. ⁷ There are no external shareholders extracting profit, and a slice of fee revenue goes to charity. The model is built around keeping costs down for members.
• Booster is owned by Booster Financial Services Limited, a New Zealand-owned, privately held independent provider. ¹⁰ It is a commercial business, but a local and independent one, which funds the research and active-management capability behind its funds.

Both are New Zealand-owned and both are well-established managers, so this is about philosophy and incentives rather than safety. Your money is held by an independent supervisor and custodian in either case.

Comparison table: Booster vs Simplicity at a glance

_Source: Sorted Smart Investor; Simplicity and Booster September 2025 quarterly fund updates and current provider disclosures (fees compared on a like-for-like total-annual-fund-charge basis)._ ⁸⁹¹⁰

Who should pick which, and when is neither the answer?

Pick Simplicity if you are fee-focused, comfortable being hands-off, and happy to accept the market return minus a very small cost. For a younger member with decades to run and no desire to tinker, that ~0.24% Growth fee is a powerful long-term advantage. ⁸

Pick Booster if you want active management, value the SRI range or private-asset options, or simply want a provider with strong adviser support behind it. The ~1.23-1.28% fee buys a different proposition, not just a more expensive version of the same thing. ⁹

Neither may be the answer if your real issue is something the provider choice cannot fix. Two common ones:

• You're in the wrong fund type. A retiree-aged member sitting in Growth, or a 25-year-old parked in Conservative since auto-enrolment, will lose far more to the wrong risk setting than to any fee gap between providers.
• A different provider fits better. Booster and Simplicity aren't the only serious options. Members weighing active managers often also look at Milford or Generate; if that's you, our Generate vs Milford comparison is a useful next read. Kernel and Fisher Funds are also worth a look depending on your priorities.

One more thing that applies to both: get your PIR right. If your PIE Prescribed Investor Rate is too high you overpay tax inside the fund, and if it's too low you'll owe at year-end. The tiers are 10.5%, 17.5% and 28% depending on your income — most working members end up on 28%. ¹¹

How does an independent review settle it for your situation?

The Booster-versus-Simplicity decision is close, and the right answer depends on facts about you, not headline fees. Your timeframe, your appetite for active versus index, whether SRI matters to you, your contribution rate, and your PIR all change the maths.

An independent adviser who does not sell their own KiwiSaver product can run both providers, and the rest of the market, against your actual goals. That is the point of a KiwiSaver review: the comparison is done properly, once, by someone with no stake in the result.

Frequently asked questions

Is Booster or Simplicity cheaper? Simplicity is cheaper on fees. Its Growth fund charges a total annual fund charge of about 0.24% with no member fee, while Booster's Growth fund charges a total annual fund charge of roughly 1.23-1.28% plus a $36/yr member fee — close to a percentage point higher overall. ⁸⁹ Whether the lower fee wins overall also depends on after-fee returns.

Is Simplicity's index approach better than Booster's active management? Neither is universally better. Index tracking locks in the market return minus a small fee; active management can beat or trail the market. Compare the after-fee, after-tax returns over at least five years for the same risk category before deciding. ¹⁰

Is my KiwiSaver safe with a privately owned provider like Booster? Yes. Your money is held by an independent supervisor and custodian, separate from the manager. Booster is a New Zealand-owned, privately held provider; Simplicity is owned by a not-for-profit foundation. Ownership affects incentives and fees, not the safety of your balance. ⁷

How much do I need to contribute to get the full government contribution in 2026? You need to contribute at least $1,042.86 in the KiwiSaver year to receive the full government contribution, which is now capped at $260.72 (matched at 25c per $1). Members earning over $180,000 taxable income are no longer eligible. ³⁴

Are KiwiSaver contribution rates changing in 2026? Yes. The default minimum employee and employer rate rises from 3% to 3.5% from 1 April 2026, then to 4% from 1 April 2028. A temporary opt-down to 3% (for 3 to 12 months) is available, with applications from 1 February 2026. ⁵⁶

What PIR should I be on? Your PIE Prescribed Investor Rate is 10.5%, 17.5% or 28% depending on your income — and most working KiwiSaver members are on 28%. In short: 10.5% if your taxable income is up to $15,600 (and total income up to $53,500), 17.5% if taxable income is up to $53,500 (total up to $78,100), and 28% otherwise. Getting it wrong means overpaying tax or owing at year-end. ¹¹

General information, not personalised financial advice. Seek advice tailored to your situation before acting. Craig Smith Business Services Ltd (FSP712931), trading as Smiths Financial, holds a Class 2 licence issued by the Financial Markets Authority and is a member of the Financial Dispute Resolution Service (FDRS). Written by Henry Smith, Financial Adviser; reviewed by Craig Smith, Principal Adviser. Last reviewed 16 June 2026.