The Hidden Costs of Term Deposits in New Zealand

The main disadvantages of term deposits in New Zealand have less to do with the product itself and more to do with how they are used. Bank deposits are well designed for one job: holding capital with certainty over a short period. They are poorly designed for almost any other use, and yet rolling term deposits remain the default home for a large share of household wealth, particularly among retirees and anyone with a lump sum they are not sure what to do with.

When we review new clients' holdings at Become Wealth, we often find the bulk of someone's liquid wealth sitting in rolling term deposits, typically because a rate locked in during 2023 or 2024 felt attractive at the time and no maturity notice ever prompted a rethink. Years on, the rate environment has shifted, the Depositor Compensation Scheme has changed the safety calculus, and the original logic no longer fits.

What follows is seven disadvantages worth weighing before you roll another deposit on autopilot. Each is independent of the others. Taken together, they explain why term deposits are a specific-purpose tool rather than a general-purpose one.

1. The invisible erosion of purchasing power

The first and most consequential disadvantage is the one most savers never see on a statement. A bank deposit's nominal balance only goes up. The statement tells a reassuring story of steady progress. What the statement cannot show you is what those dollars actually buy.

With the December 2025 quarter CPI at 3.1% and top twelve-month deposit rates around 4.0%, the maths is unforgiving. A saver in the 33% tax bracket keeps 2.68% after tax. Against 3.1% inflation, the real return is negative. A saver in the 39% bracket keeps 2.44%, further in the red. Full worked examples, across all tax brackets and a ten-year compounding view, are laid out in our piece on the negative real rate of return on term deposits.

The effect is slow and invisible, which is what makes it dangerous. A visible loss prompts action. An invisible one prompts nothing, and the compounding runs unchecked for years.

2. Tax treatment among the least efficient available

Interest on a standard term deposit is taxed at the investor's full marginal rate via Resident Withholding Tax. For anyone earning over $78,100, the rate is 33%. Over $180,000, it is 39%. Every dollar of interest, whether or not it exceeds inflation, is taxed as income.

Very few other investment returns in New Zealand face this treatment. PIE-structured funds, including most KiwiSaver Schemes and the bulk of managed funds, cap tax at the investor's Prescribed Investor Rate of 28%. Capital gains on most shares and investment property held for the long term sit outside the income tax net entirely. Even PIE-structured cash funds, which invest in similar short-term instruments to a term deposit, cap their tax at 28%.

For a higher-income investor, the gap is 5 to 11 percentage points on every dollar of return. On a $500,000 balance earning 4%, the difference between a standard term deposit taxed at 39% and a PIE cash fund taxed at 28% is roughly $2,200 per year. The money is the same. The structure is what changes the outcome.

3. The opportunity cost of forgone compounding

Every year capital sits in a rolling deposit is a year it is not compounding inside a diversified portfolio. For short-term money, this is a non-issue. For long-term money, the gap accumulates.

Consider two $100,000 balances, both held for ten years. The first rolls at 4.0% per year, taxed at 33%, with 3.1% inflation. The second sits in a balanced portfolio with a long-run nominal return of around 7% per year, PIE-structured so tax caps at 28%. The rolling deposit ends the decade with real purchasing power close to where it started. The balanced portfolio ends the decade with real purchasing power roughly $30,000 to $40,000 higher, depending on how much of its return comes as capital gain rather than taxable income. Actual outcomes vary, and the balanced portfolio will have negative years along the way. The broad direction is what compounds.

This suggests capital with a long-term job should not be in a vehicle designed for a short-term one. The cost is real, measurable, and grows each year the default sits unexamined.

4. Concentration above the Depositor Compensation Scheme cap

Since 1 July 2025, New Zealand has had a Depositor Compensation Scheme protecting up to $100,000 per depositor, per licensed deposit taker. This is a welcome development. It brought New Zealand into line with most OECD nations after decades without any form of deposit insurance.

Two points are worth keeping in mind. The $100,000 cap is lower than in comparable countries. Australia covers A$250,000 per depositor, the United Kingdom covers £85,000, and the United States covers US$250,000. A New Zealand household with $500,000 held at a single institution has $100,000 protected and $400,000 sitting within that bank's credit risk.

The second point concerns the Reserve Bank's Open Bank Resolution policy, which remains in place alongside the Depositor Compensation Scheme. In the event of a major bank failure, deposits above the protected threshold could face a haircut as part of the resolution process. The probability of a large New Zealand bank failing is remote. But between 2006 and 2012, more than fifty New Zealand finance companies failed, erasing retirement savings for thousands of investors, and in 1989 the Bank of New Zealand required a government bailout. Concentration risk above the scheme cap is not a theoretical worry.

By contrast, assets held through publicly offered KiwiSaver Schemes and most managed funds must sit in a bare trust, legally separate from the fund manager. If the manager fails, the underlying assets are ring-fenced and a replacement manager is appointed. A bank deposit sits on the bank's own balance sheet.

5. Reinvestment risk in a falling rate environment

When rates are rising, a maturing term deposit rolls into a higher one. Savers reinvesting in 2022 and 2023 benefited from this. When rates are falling, the same mechanism works against you.

A one-year deposit placed in late 2023 at 6% would typically have rolled into something closer to 3.7% by late 2025. For a retiree relying on interest income to fund living costs, that is a near-halving of income, inflicted by the calendar rather than by any decision on their part. The deposit itself was never at risk. The income it produced was slashed.

Bonds handle this differently. A five-year bond purchased at 5% continues paying 5% for the full term, regardless of what the Reserve Bank does subsequently. The trade-off is that bonds carry price risk if sold before maturity, whereas a term deposit always returns principal at face value. Neither is better in all environments, and the right mix depends on time horizon and income needs. The mechanics of the comparison are laid out in our piece on bonds versus term deposits.

The reinvestment risk matters most for investors who rely on interest for income. Locking everything into the same maturity compounds it. Laddering across several maturities smooths it, though it does not eliminate it.

6. The break-fee economics and auto-rollover trap

A term deposit locks funds for the agreed period. Life does not always wait. Medical bills, family obligations, and business opportunities arise without consulting the maturity date.

Breaking a deposit early typically costs the full accrued interest, sometimes with an additional administrative fee. At ANZ, ASB, BNZ, and Westpac, a thirty-one-day notice period applies before a break can be processed, unless the depositor can demonstrate hardship. New Zealand-owned banks such as Kiwibank, TSB, and SBS do not currently enforce the notice period. In every case, the rate on any broken portion is usually cut to the at-call savings rate, which can wipe the interest earned to date.

At maturity, most banks automatically roll the deposit into a new term at the prevailing rate unless the holder acts within a short grace window, typically seven to ten business days. Maturity notices are sent, but they are easy to miss, and the rolled rate can be materially lower than the original. Auto-rollover is the mechanism by which a decision made two years ago quietly becomes a decision made today, without anyone actively choosing to make it.

PIE cash funds and conservative managed funds generally offer daily or next-day liquidity at comparable yields, with no break penalties and no rollover mechanic. For capital with any prospect of being needed at short notice, the liquidity profile is meaningfully different.

7. No pricing power against inflation

The final disadvantage is structural. A term deposit's return is fixed at the headline rate for the term. It cannot rise to reflect a change in the cost of living, a lift in corporate earnings, or a strengthening economy. Whatever happens to the broader economic picture, your deposit earns what was agreed at the start.

Productive assets work differently. A well-run business can raise its prices to offset inflation; economists call this pricing power, and it is the reason equity returns have historically outpaced cash over long periods. Property rents can be increased when market conditions allow. A diversified portfolio of shares, bonds, and property has several mechanisms by which its real return can keep pace with, or exceed, inflation over time.

A term deposit has none. Its nominal return is locked. Its real return is whatever is left after tax and inflation do their work, and in the current environment, what is left is usually nothing.

When term deposits still make sense

None of the above is an argument against term deposits as a category. It is an argument against using them as a default for purposes they are not designed to serve. Bank deposits are a useful tool in three specific situations.

1. ‍Capital with a known short-term spending purpose. A house deposit due in eighteen months. A planned renovation. A known tax bill. The certainty of principal outweighs the low real return, because the alternative is exposing a near-term commitment to market volatility.‍
2. Part of an emergency fund. Some households prefer to hold a portion of their emergency reserve in a short-term deposit rather than an at-call savings account, accepting reduced liquidity for a marginally higher rate. A laddered structure can work here.‍
3. A deliberate small allocation within a diversified portfolio. As a cash layer providing stability and drawdown support, particularly for investors in retirement, a modest deposit holding plays a role in portfolio construction. The key word is modest.

The common thread: term deposits are a parking place for money with a short and defined purpose. They are a tool for capital preservation over months, not years. They are not a wealth-building instrument, and treating them as one is where the real cost accumulates.

Consider two people each holding $200,000 in rolling deposits. One is buying a house in fourteen months and needs the full amount at settlement. Deposits are the right tool. The other inherited the money three years ago and has no defined use for it. For the second person, each year the funds remain in rolling deposits, the gap between where the money is and where it could be widens. Both hold the same product. Only one is using it well.

Frequently asked questions

Do I pay tax on term deposit interest even if I do not file a tax return? Yes. Resident Withholding Tax is deducted by the bank at source. If your RWT rate is lower than your marginal rate, you may owe additional tax when Inland Revenue reconciles your income. If it is higher, you may receive a refund.

Can I spread deposits across several banks to extend my Depositor Compensation Scheme coverage? Yes. The $100,000 cap applies per depositor, per licensed deposit taker. Holding $100,000 at three different licensed banks means $300,000 is covered. Holding $300,000 at a single bank means only $100,000 is protected.

Are online-only or non-bank deposit takers covered by the scheme? Only deposits held with institutions licensed under the Deposit Takers Act 2023 qualify. The Reserve Bank maintains a register of licensed deposit takers. Check before assuming coverage applies.

What are the main alternatives to term deposits in New Zealand? PIE-structured cash funds offer similar stability with better tax treatment and daily liquidity. Conservative or balanced managed funds offer higher expected returns with more volatility. KiwiSaver Schemes cover savings earmarked for retirement. Bonds and bond funds sit between cash and growth assets. The right mix depends on time horizon, income needs, and tolerance for short-term fluctuation.

What happens if I want to break a term deposit early? Most banks require a thirty-one-day notice period (with exceptions for hardship) and apply a penalty that reduces the interest rate to the at-call savings rate on the broken portion. In some cases the penalty wipes the interest earned to date. The specific rules vary by institution and by product.

What this means for your term deposits

The core question for any New Zealand saver holding a significant deposit balance is straightforward. Does this money have a job to do within the next one to three years? If the answer is yes, a term deposit remains a sensible vehicle. If the answer is no, or is "I'm not sure," the combination of tax, inflation, and forgone compounding creates a cost that grows every year it goes unaddressed.

"Most of the cost we see comes from not revisiting the deposit at maturity, not from opening it in the first place. People made a reasonable decision two or three years ago and then let the rollover happen on autopilot. Once we sit down and separate the cash that has a short-term job from the cash that does not, the conversation becomes much easier." Nik Velkovski, financial adviser, Become Wealth.

If you hold a meaningful balance in rolling term deposits and are unsure how much of it has a genuinely short-term purpose, the team at Become Wealth can help you quantify the current position and map out what a more considered structure would look like. Get in touch to start that conversation.