Capital Gains Tax: What It Would Actually Mean

New Zealand has no comprehensive capital gains tax, one of the few OECD countries without one. It does already tax some gains in specific cases, but there is no single broad regime. Whether that should change is back on the table for the 2026 election, with Labour proposing a 28% tax on gains from investment property. Before weighing any of it, two things help: understanding what a capital gains tax actually is and how one works in practice, and remembering that tax settings rarely stay where they start. This matters most if you own, or plan to own, investment property.

What a capital gains tax actually is

A capital gains tax is a tax on the increase in value of an asset between when you buy it and when you sell it. Buy something for $500,000, sell it later for $700,000, and the $200,000 increase is the capital gain. A capital gains tax takes a percentage of that gain.

It is different from income tax, which taxes money you earn from working or from a business as you earn it. A capital gain is not earned year by year. It builds up silently while you hold the asset and is only realised, turned into actual money, when you sell. Most capital gains taxes work the same way: nothing is payable while you hold, and the tax is triggered by the sale.

The detail is where these taxes get interesting, and where they differ wildly between countries. What counts as an asset? Is the family home included? Is the gain adjusted for inflation, or taxed in full? What happens if you make a loss instead of a gain? Can that loss reduce other tax you owe? The headline rate tells you very little until those questions are answered. A 28% tax that ignores inflation and refuses to recognise your losses can bite harder than a 40% tax that indexes for inflation and lets losses offset gains. Most coverage fixates on the rate. In practice, two less-discussed features, the valuation date the tax measures from and whether it adjusts for inflation, will do more to determine what a property owner actually pays.

Does New Zealand have a capital gains tax already?

New Zealand does not have a comprehensive capital gains tax, but under current Inland Revenue rules several regimes already tax gains in specific cases. Property sold within the bright-line period, currently two years from July 2024, is taxed on the gain. Property bought with the intention of resale is taxable however long it is held. Overseas shares and managed funds above a cost threshold are taxed annually under the Foreign Investment Fund rules, whether or not anything is sold. People who trade shares or property as a business are taxed on their profits as income. There are also entirely legal ways to reduce tax within these rules. So the real question is not whether to tax capital gains. It is whether to widen what already exists, and by how much.

How a capital gains tax works: a simple example

Take an investor who buys a rental for $600,000 and sells it eight years later for $850,000. The capital gain is $250,000. Under a straightforward 28% capital gains tax, ignoring costs and improvements for simplicity, the tax would be $70,000, leaving $180,000 of the gain in the investor's hands.

That looks clean, but two design choices change the picture entirely. The first is inflation. If general prices rose, say, 25% over those eight years, a large part of the $250,000 is not real enrichment. It is the dollar losing value. The property had to climb just to keep pace. A capital gains tax that ignores inflation, as Labour's proposal does, taxes that inflationary portion as though it were genuine profit. The second is what happens with losses, and whether the starting value is the price you paid or some later figure. Both of those matter enormously under the specific proposal on the table, as the next section shows.

What Labour is proposing

Labour's proposal is a 28% tax on gains from residential and commercial investment property, applying to sales from 1 July 2027. The family home, KiwiSaver investments, shares, business assets, and farms are all excluded. The rate matches the company tax rate. Revenue is earmarked for health spending, including free GP visits. Labour has stressed that most New Zealanders would not pay it, because the family home, where most household wealth sits, is out.

Crucially, the tax would not be retrospective. Property would be valued at the start date, and only the gain accruing after that point would be taxed. Gains built up before then are left alone. Capital improvements you fund along the way are added to the cost base, so they are not taxed as gain.

So far, so reasonable. The trouble is that a great deal of the detail is genuinely unsettled, and with tax the detail is where the real outcomes live. Some elements are defined, the 28% rate, the 1 July 2027 start, the exemptions and the valuation-day approach. Others are only signalled, the treatment of losses chief among them. And some, like the exact valuation method and whether interest stays deductible, remain genuine unknowns. Labour has said different valuation options for the switchover are still being worked through. The worked examples below should therefore be read as showing how the proposal would behave if enacted as currently described, not as settled fact.

The choice of what to exclude raises its own fairness questions, and astute readers will already have spotted a few. Because farms, the family home, shares and business assets are all out, a farmer selling an $8 million farm would pay nothing, and so would a successful business owner selling a $15 million home in Herne Bay. Yet a school teacher who owns their own home and a single $700,000 rental would pay the tax on the rental's gain. Whether a tax aimed at fairness should fall on the small investor while leaving far larger fortunes untouched is exactly the kind of question the carve-outs invite, and exactly the kind of detail that tends to be revisited once a tax is in place.

Will you pay capital gains tax in New Zealand?

For most people, no. If you own only your own home, you would pay nothing: the family home is excluded, and so are KiwiSaver, shares, business assets and farms. If you own a residential or commercial investment property, you would potentially pay 28% on the gain that accrues after 1 July 2027, but only when you sell, and only on the increase above the property's value at that date. And if none of this becomes law, which is a real possibility for an election proposal rather than enacted policy, nobody pays anything. The honest position today is that this affects investment property owners, may affect them only in part, and may not arrive at all.

The losing investor the headline forgets

The political framing of a capital gains tax always assumes the investor is sitting on a gain. Plenty are not. Consider someone who bought a $1,000,000 investment property in Auckland near the market peak, and watched it fall to $800,000 by the time the policy takes effect.

Two awkward questions follow, and the proposal as described answers both unkindly.

First, what if they sell at that $800,000, crystallising a $200,000 loss? On the design Labour has described so far, losses would be ring-fenced. They could not be offset against your salary or any other income, only carried forward against future capital gains from housing. So this investor would get no refund and no relief against other tax. If they then exit property investment altogether, having had enough, the $200,000 loss is stranded and worth precisely nothing. The tax shares in your gains but not in your losses. The loss rules are among the details Labour has yet to finalise, so this could change, but it is the treatment the party has signalled.

Second, and worse, consider what happens if they hold on. The valuation at 1 July 2027 sets the base at the depressed $800,000. Suppose the market recovers over the following years, the property climbs back to $1,000,000, which is merely what they originally paid, and then a little further to $1,100,000, at which point they sell. Their real gain, measured against what the property actually cost them, is $100,000. But the tax is not measured against what they paid. It is measured against the $800,000 valuation. The taxable gain is $300,000, and at 28% the tax is $84,000. They make a real gain of $100,000 and hand over $84,000 of it. That is an effective rate of 84% on the gain that actually made them better off, all because the starting line was drawn at the bottom of their personal loss rather than at their purchase price.

This is a particular scenario, not the typical one. Most investors selling well above their valuation-day figure would face something much closer to the headline 28%. The point is not that everyone pays 84%. It is that a tax measured from an arbitrary date, with no inflation adjustment and no recognition of a real-terms loss, can produce results that bear little relation to actual profit. Anyone who bought near the 2021 property market peak and is still underwater when the policy begins sits closest to this trap.

Taxes rarely stay where they start

Even an investor untroubled by the current design should sit with one further point, because it is the most important and the least discussed. A tax introduced narrowly and at a modest rate has a long history of becoming neither narrow nor modest. Two pieces of New Zealand's own tax history make the pattern plain.

1. When income tax arrived in 1891, it was aimed squarely at the wealthy. Individuals earning under £300 a year were exempt, which was most of the population at the time, and the top rate was just 5%. It was sold as a tax the ordinary worker would never pay. Today income tax reaches almost every earner in the country, and the top personal rate is 39%. Both dials moved: the rate climbed, and the share of people caught widened from a small wealthy minority to virtually everyone. Neither shift happened overnight. Each was a series of incremental adjustments by successive governments, none of which felt dramatic on the day, a slow drift that continues today through bracket creep.
2. GST tells a shorter version of the same story. It was introduced in 1986 at 10%, lifted to 12.5% in 1989, and raised again to 15% in 2010. A tax sold at one rate sat at half as much again within a generation.

None of this proves Labour intends to broaden its capital gains tax later. The point is the rate and reach of a tax at introduction tell you very little about where it settles decades on. A 28% tax on investment property, with the family home carved out, is the starting position, not necessarily the destination. The carve-outs that make a tax palatable at launch are exactly the features later governments find easiest to trim. Anyone making a thirty-year investment decision on the strength of today's exemptions is betting those exemptions survive thirty years of fiscal pressure and changing governments. History suggests that is an optimistic bet.

The case on the other side

None of this means a capital gains tax is a bad idea. There is a serious argument for one, and it is worth stating plainly. New Zealand is an outlier among developed economies in having no broad capital gains tax, which means someone who earns a salary is taxed on every dollar while someone whose wealth grows through rising asset values can pay nothing. Taxing those gains can be defended as fairer, as a way to reduce the incentive to pour money into property over more productive investment, and as a means of broadening a tax base that leans heavily on income and GST. Some, like the Green Party, go further still and favour an annual wealth tax rather than a tax triggered only on sale. Reasonable people land in different places on all of this, and an election is the right venue to settle it. The argument here is that its design, and the near-certainty that the design will change over time, deserve far more scrutiny than the headline rate usually receives.

A brief look across the Tasman

Australia offers a live example, and it shows the rate is only ever half the story. Australia has taxed capital gains since 1985. Recent Budget proposals there set out scrapping the 50% discount that investors had enjoyed and replacing it with inflation indexation plus a minimum 30% rate, for gains from 1 July 2027. Indexing for inflation sounds gentler than New Zealand's nominal approach, and for a single rising asset it can be. But losing the discount would mean high earners pay their full marginal rate, up to about 47%, on the indexed gain rather than half their rate on the whole gain. And on the detail published so far, indexation appears to apply to gains but not to losses, which some analysis suggests could leave an investor holding a spread of shares taxed on a paper gain larger than their real, portfolio-wide gain. The package, sold as fairer, looks in several respects harsher. It is a proposal, not yet law, still working through parliament, and may yet be softened.

The lesson for a New Zealand reader is not about the Australian numbers, which depend heavily on individual tax brackets and asset mix. It is that two governments can both call something a capital gains tax and design it so differently that one taxes inflation directly while the other can tax paper gains that are not fully real. The label settles almost nothing. The design settles everything.

What this means for a decision now

Whenever a tax change is floated, the temptation is to act before it exists. We field a version of this constantly: should I sell my rental before 2027 to get ahead of a capital gains tax?

The honest answer is almost always no, not on the strength of a proposal alone. It is not law. It may be amended, traded away in coalition talks, or never reach the statute book. And because only post-2027 gains would be taxed, the gain you have already built is protected whether you sell or not, which weakens the case for a rushed exit. There are genuine reasons to sell, a short holding horizon, a sale already planned, debt or liquidity pressure, but none of them is the proposal itself. The question of whether property is still worth holding turns on the asset and your plan, not on a campaign announcement.

Marcus Mannering, a financial adviser at Become Wealth, puts the trap plainly:

"The investors who get hurt are usually the ones reacting to news flow. Base investment decisions on the merits of the asset, your aims, tolerance for risk, your other assets, and your phase of life, not on the headlines."

What this means in practice

If you own investment property now, do nothing rash. Your gains to date are not affected, and a depressed 2027 valuation could even work against you if you sell into weakness. Make sure you can evidence the property's value at the switchover date when it comes.

If you plan to buy, factor in that future gains on investment property may eventually be taxed, but do not let a tax that is not yet law dictate the purchase. The asset has to stand on its own merits first.

If you are unsure where you stand, model your position under both the current rules and the proposal before acting, rather than reacting to headlines. If helpful, we can run that with you, including how a depressed 2027 valuation or ignored inflation could affect you. Book a complimentary initial consultation to talk it through.

^{Become Wealth Limited (FSP249805) is licensed by the Financial Markets Authority as a DIMS provider and Financial Advice Provider. This is not tax advice, and much of the proposal discussed here is not yet law and may change. Seek advice from a suitably qualified tax professional before acting.}