How PIE Tax Works on Your KiwiSaver NZ (2026): Why It's Capped at 28%

KiwiSaver is a PIE, so your returns are taxed at your PIR — capped at 28%, below the top 39% income tax rate. Here is how PIE tax works and who it saves money.

Your KiwiSaver fund is a portfolio investment entity, or PIE. That single technical fact changes how your investment returns are taxed — and for a lot of New Zealanders, it quietly works in their favour. Instead of paying your normal marginal income tax rate on what your fund earns, you pay your prescribed investor rate (PIR), which tops out at 28% even when your salary is taxed at 33% or 39%.

This guide explains, in plain English, what a PIE is, how the tax is calculated and deducted, why the rate is capped, and when the cap actually saves you money.

TL;DR: KiwiSaver is a PIE, so the income your fund earns is taxed at your prescribed investor rate (PIR) — 10.5%, 17.5% or a maximum of 28% — not your salary tax rate. Because the top PIR is capped at 28% while personal income tax goes to 39%, anyone on a 30%, 33% or 39% marginal rate pays less tax on KiwiSaver returns. ¹²⁴

What is a PIE, and why is KiwiSaver one?

A portfolio investment entity (PIE) is a special type of investment fund that pays tax on your behalf at your prescribed investor rate rather than your personal marginal tax rate. Nearly all KiwiSaver schemes and retail managed funds in New Zealand are structured as PIEs — Simplicity, Milford, Generate, Booster, Kernel, Fisher Funds, ANZ, BNZ, Westpac and Kiwibank funds included.

The key consequence is this: the income your fund earns is treated as "excluded income." You do not put it in a tax return, and the PIE tax deducted by your provider is the final tax on that income. ¹ There is no end-of-year reconciliation against your salary tax — the two systems run separately. ¹

That is different from, say, money sitting in a term deposit, where the bank deducts resident withholding tax (RWT) at your full marginal rate and the interest is added to your taxable income.

How is PIE income taxed differently from your salary?

Your salary is taxed on a sliding scale that climbs as you earn more. PIE income is taxed at one of just three flat rates, set by your circumstances over the last two years.

For resident individuals there are three PIRs — 10.5%, 17.5% and 28% — and 28% is the maximum. ² The rate you should be on is set by your income across the last two tax years:

PIR thresholds effective 1 April 2025. ³

Note that the default and highest PIR is 28%. If you never told your provider your PIR — or you opened a fund before 1 April 2018 with no IRD number on file — you are almost certainly being taxed at 28% regardless of what you actually earn. ² ANZ and Westpac both confirm pre-1 April 2018 investments with no IRD number sit at the top 28% rate. Low earners who should be on 17.5% can spend years overtaxed at 28% simply because nobody asked them for a PIR, and the rate corrects once the missing IRD number is added.

If you are not sure which rate you are on, our free KiwiSaver health check walks through your provider, fund and PIR in plain English, no login required — and for the rate itself we keep a dedicated guide on what PIR you should be on.

Why is the top PIR capped at 28% when income tax goes to 39%?

This is the part most people miss. The PIR scale was deliberately designed to top out at 28% — the company tax rate — rather than follow personal income tax up to 39%.

Personal income tax in New Zealand runs to a top marginal rate of 39% on income over $180,000, with 33% from $78,101 to $180,000. ⁴ But the highest PIR you can ever be put on is 28%. So if your salary is taxed at 30%, 33% or 39%, the income inside your KiwiSaver is still only taxed at 28%. You pay less tax on a dollar of fund return than you would on a dollar of bank interest. ⁴

Marginal tax vs PIR on KiwiSaver returns

The gap is easiest to see side by side. Take $1,000 of investment income earned for someone on the top tax bracket:

Source: IRD income tax rates and PIR thresholds, 2025/26. ⁴²

That 11-cent-in-the-dollar saving is why providers like Kiwibank market their PIE funds on a "maximum tax rate of 28%" — a 30% or 33% taxpayer keeps more. It is also why a KiwiSaver review checks your PIR first: it has significant tax impact and is easy to get wrong.

How PIE tax works on KiwiSaver, step by step

You never write IRD a cheque for PIE tax. Your provider handles it, and the mechanics are worth understanding.

Attributed income and daily unit pricing

A PIE works out its total taxable income, tax credits and losses, then attributes a slice to you based on the units you hold each day — this is your "attributed income," and it flows through your fund's daily unit price. ¹ In practice your provider is running a small tax calculation on your balance every single day of the year.

The tax is then collected at one of three trigger points: ¹

• At the end of the tax year (31 March) — most investors pay then, with the deduction usually processed in April; ¹
• On a full withdrawal (for example when you take your money out at 65); or
• When you transfer to another provider or the fund closes — at which point the tax is "crystallised."

Providers collect it by cancelling units equal to the tax owed. AMP, for instance, sums each day's PIE tax or rebate across the year and collects it by cancelling units at 31 March, on full withdrawal or on transfer — and notes it may collect earlier (tested monthly) if your balance risks being too small to cover the bill. ¹

One genuinely counter-intuitive point: you can owe PIE tax even in a year your fund lost value. Tax follows your share of the fund's attributed taxable income and credits — dividends, interest and deemed returns — not the change in your balance. ⁹ Distributions the fund pays out are themselves not taxed. ⁹

If your fund holds international shares, the tax is generally worked out under the Foreign Investment Fund (FIF) rules: tax is assessed as if your average balance earned a 5% deemed annual return, multiplied by your PIR. At the top 28% PIR that works out to roughly 1.40% of your average balance per year, before any foreign tax credits. ⁸ Kernel's growth funds are a clear worked example of this.

What about the end-of-year square-up?

Since the rules changed, IRD now auto-calculates your end-of-year PIE position. If you used a PIR that was too high, you get a refund. If you used one that was too low, you get a bill. ¹ PIE income is pre-populated into myIR, and your annual PIE tax certificate shows the income, tax credits, tax paid and the PIR used. This is why getting your PIR right matters more than it used to — being on the wrong rate now reliably gets caught.

Does PIE tax affect your KiwiSaver withdrawals?

No — and this trips a lot of people up as they approach 65. KiwiSaver withdrawals are not taxed as income. ⁷ When you take your lump sum out at 65, there is no income tax on the withdrawal itself.

PIE tax applies only to the investment income earned inside the fund during your membership — the dividends, interest and deemed returns the fund generates along the way — not to the money you eventually withdraw. ⁷ Because PIE income is excluded income and the PIE tax is the final tax, by the time you withdraw, the tax has already been dealt with year by year. ¹⁷

There is one practical wrinkle: a full withdrawal triggers a final PIE tax calculation on any income earned since the last square-up, settled before the money lands in your account. ¹ But that is the tax on the fund's earnings, not a tax on your savings. Planning the timing of withdrawals is something we cover under retirement planning.

When is PIE tax an advantage — and when does it not matter?

The PIE structure is an advantage precisely when your marginal tax rate is above 28%. If you earn enough that your salary is taxed at 30%, 33% or 39%, the 28% cap is a genuine, automatic tax saving on your KiwiSaver returns compared with holding the same investments directly. ⁴

At worst it is neutral: because there is no 28% personal tax bracket, a 28% PIR never costs you more than holding the same investments directly in your own name, and for most people it costs less.

Where the cap does not help is at the bottom. If you genuinely qualify for the 10.5% or 17.5% PIR, the cap is irrelevant — what matters is making sure you are actually on the lower rate and not defaulted to 28%. Being overtaxed at 28% when you should be on 17.5% is a common and easily fixable mistake. Getting that right is part of KiwiSaver advice.

This is also the year the government contribution halved. From 1 July 2025 the match dropped from 50c to 25c per $1, and the annual maximum fell from $521.43 to $260.72 — you now need to contribute $1,042.86 of your own money between 1 July and 30 June to get the full $260.72. ⁵⁶ With a smaller government contribution, getting your PIR right matters more.

Your PIE tax checklist

1. Check your current PIR with your provider — if you have never set one, you are likely on the default 28%. ²

2. Work out your correct PIR using the two-year income test: 10.5%, 17.5% or 28%. Our free KiwiSaver health check runs this for you in a couple of minutes. ³

3. Confirm your IRD number is on file — a missing IRD number forces the 28% default, even for low earners. ²

4. Update your PIR directly with your provider if it is wrong; the change takes effect going forward.

5. Keep your annual PIE tax certificate — it shows the PIR used, income, credits and tax paid. ¹

6. Watch the FIF effect if you are in international-share funds — roughly 1.40% of balance per year at 28%. ⁸

7. Review it after any income change — a pay rise, a year of parental leave or a side business can all move your correct PIR.

Frequently asked questions

What is a PIE in KiwiSaver? A portfolio investment entity is a fund structure where the fund pays tax on your investment income at your prescribed investor rate (PIR) instead of your marginal income tax rate. Almost all KiwiSaver schemes are PIEs, and the PIE tax deducted is the final tax — you do not declare that income in a tax return. ¹

Why is the top PIR only 28% when income tax goes to 39%? The PIR scale was deliberately capped at 28% (the company tax rate) rather than following personal income tax up to 39%. So anyone on a 30%, 33% or 39% marginal rate pays less tax on their KiwiSaver returns than on equivalent directly-held interest. ²⁴

What happens if I'm on the wrong PIR? IRD now auto-calculates your end-of-year PIE position. If your PIR was too high you get a refund; if it was too low you get a bill. The most common error is being defaulted to 28% when you actually qualify for 17.5% — fixable by giving your provider the correct PIR. ¹²

Do I pay tax when I withdraw my KiwiSaver? No. KiwiSaver withdrawals are not taxed as income. PIE tax applies only to the investment income your fund earns during membership, not to the lump sum you take out at 65. ⁷

Can I owe PIE tax if my fund lost money? Yes. PIE tax follows your share of the fund's attributed taxable income and credits each day — dividends, interest and deemed returns — not the change in your balance. So a fund can fall in value over a year and still generate a tax bill. ⁹

How is the tax actually deducted? Your provider attributes income to you daily through the fund's unit price, then collects the tax by cancelling units — usually at 31 March, on a full withdrawal, or when you transfer. You never pay IRD directly. ¹

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.