Term Deposits vs Savings Accounts in NZ: RWT, PIE Funds and What Your Real Return Is

The advertised rate on a term deposit is not what you get. Tax comes off, sometimes at a higher rate than it needs to, and inflation quietly takes another slice. This guide explains how New Zealand savings and term-deposit interest is taxed, when a PIE beats a bank account, and how to compare offers on what actually reaches you.

Savings accounts versus term deposits

A savings account pays a variable rate and lets you withdraw any time; many pay a bonus rate only if you make no withdrawals in the month. A term deposit locks your money for a fixed term — one month to five years — at a fixed rate, and breaking it early usually costs you most of the interest and may need the bank's agreement. The trade is access for certainty. The rule of thumb: emergency fund and money you will need within a few months in savings; money with a known date beyond that in a term deposit matched to the date.

Resident withholding tax

Interest is income, and the bank deducts resident withholding tax (RWT) before paying you. You choose the RWT rate, and it should match your marginal income tax rate: 10.5%, 17.5%, 30%, 33% or 39%. If you have not supplied your IRD number the bank must deduct at 45% — the most common way people overpay. If you have supplied it but never chosen a rate, you may be on a default that is too high or too low. Too high means you lose the use of the money until you file a return; too low means a bill from Inland Revenue at year end. Check the rate on your bank's internet banking under tax details, and update it after a pay change.

What the net return looks like

$20,000 in a one-year term deposit at 4.5% earns $900 gross. At a 30% RWT rate, $270 is deducted and $630 arrives — a net return of 3.15%. If inflation over the year is 2.5%, the real return is about 0.65%: your money bought slightly more at the end than the start, but only slightly. That is not an argument against term deposits; it is the reason to compare them on net-of-tax, net-of-inflation numbers rather than the headline.

PIE cash and term funds

Many banks offer the same deposit inside a portfolio investment entity (PIE). PIE income is taxed at your prescribed investor rate, which is capped at 28%. If your marginal rate is 30%, 33% or 39%, the PIE version of an identical rate delivers more after tax; at 4.5% gross, a 39% taxpayer keeps 2.75% in an ordinary deposit but 3.24% in the PIE. Below the 30% bracket there is no advantage. PIE income also does not count towards some income-tested thresholds, which occasionally matters. Ask your bank whether the deposit you are looking at has a PIE equivalent; the rate is often identical and the choice is a tick box.

Compounding frequency

Interest paid monthly and left in the account compounds; interest paid at maturity does not. Over one year the difference at these rates is small (a few dollars on $20,000), so do not let it override a better rate. Over five years it is worth checking.

Laddering

If you have a lump sum and no fixed date for it, splitting it into several deposits with staggered maturities — say four deposits maturing every three months — gives you access to a quarter of the money every quarter and lets you reinvest at whatever rates are on offer then. It smooths the risk of locking everything in just before rates rise.

Before you lock in

  1. Confirm your RWT rate (or PIR for a PIE) matches your income.
  2. Compare offers net of tax, not gross.
  3. Match the term to when you actually need the money; do not chase a longer-term rate you will have to break.
  4. Check what happens at maturity — many banks auto-reinvest at whatever the rate is then unless you instruct otherwise.
  5. Note the maturity date in your calendar a week early.

The free term deposit calculator shows the gross, after-RWT and after-inflation result for any rate, term and tax rate so the comparison is on the number that matters.

General information, not financial advice. RWT and PIR rates are set by Inland Revenue; example rates are illustrative and not an offer. Deposits are subject to each bank's terms.

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