CGT Rules Are Changing: Property Investors Need a Valuation Now

More than 2.5 million investment properties may need independent valuations before landmark capital gains tax changes take effect next year.

Australian property investors have under a year to understand exactly what their holdings are worth before landmark capital gains tax changes take effect — and the cost of getting it wrong could run to tens of thousands of dollars. With markets diverging sharply across the country and investor demand already softening in several cities, the case for acting early is strong.

What's Changing From 1 July 2027

The federal budget legislated sweeping changes to how investment property gains are taxed. From 1 July 2027, the existing 50 per cent CGT discount on assets held for more than 12 months will be replaced by cost-base indexation and a minimum 30 per cent tax on net capital gains. At the same time, negative gearing will be restricted to newly built properties, removing a key tax benefit for owners of established investment properties.

Australian Broker reports that property valuation firm Opteon estimates around 2.5 million residential, commercial and agribusiness properties are potentially affected by these changes.

The reason an independent valuation matters comes down to how the ATO plans to calculate capital gains at the transition. Scott Chapman, Opteon managing director Australia and New Zealand, explained the issue directly: 'The ATO method applies a standard formula across the period you've owned the property, but property values don't grow evenly year to year.' If the ATO formula distributes growth evenly across your full ownership period, it can significantly overstate how much gain accrued after the July 2027 cutover — and tax you on gains you did not actually make in the new regime.

By contrast, an independent valuation conducted before the transition date establishes a firm market value at that point, giving the ATO a real number rather than an interpolated estimate. In one modelled example, Opteon estimated a Hawthorn property owner could save more than $22,000 in capital gains tax by obtaining an independent valuation rather than relying on the ATO's apportionment method. Valuation firm JLL has separately estimated the gap between a professional valuation and the ATO's formula could cost some investors as much as $58,000.

Diverging Markets Sharpen the Stakes

The need for a property-specific valuation is made more acute by how unevenly Australian markets have performed — and how much that uneven performance matters under the new rules.

Opteon's July 2026 Property Pulse Check, as reported by Australian Broker, revealed sharp divergences: Melbourne dwelling values fell 2.6 per cent over the June quarter, while Perth values rose 23.9 per cent over the past year. Adelaide recorded no growth in June after a strong prior run, and Sydney's metro market weakened through the quarter while regional NSW continued to outperform on affordability.

Chapman noted that properties which saw most of their growth before July 2027 could face a disproportionately higher tax under the ATO's standard formula than under an independent valuation. The formula doesn't distinguish between when growth actually happened. A property in Melbourne that surged between 2020 and 2022 and has since flatlined looks very different from one in Perth that has appreciated strongly and recently — yet a blanket apportionment calculation may treat them similarly.

The variation in outcomes can be substantial. If your investment property is in a market that moved sharply before 2025 and has since gone sideways or declined, embedded gains may be attributed partly to the post-2027 period under the ATO formula, generating a higher tax bill than an independent valuation would produce.

How Investor Behaviour Is Already Shifting

The effects of the policy change are already visible in market activity. In the ACT, Opteon's state director reported that CGT-related changes weighed on investor demand and confidence from May, contributing to broader softening in the Canberra market. South Australia has seen a similar dynamic, with some investors exiting the established property market altogether. In South East Queensland, agents have noted a pullback in enquiry from investors at the entry level of the market.

Opteon recorded a 30 per cent jump in valuation enquiries in July as some investors begin to act. Chapman's message is measured: owners don't need to rush, but they do need to understand their position before the deadline arrives.

That urgency is compounded by the rate environment. With three of the Big Four banks now expecting another RBA cash rate increase before year-end, the cost of carrying an investment property on a variable-rate loan is likely to rise further. Investors managing both a higher mortgage bill and a looming tax change have good reason to review their full position now — including how their financing is structured.

What Investors Should Consider Before July 2027

If you hold an investment property, a few practical steps are worth taking well before the July 2027 transition:

First, consider commissioning an independent valuation before the deadline. The cost of a professional valuation is modest relative to a potential tax saving estimated at $22,000 to $58,000 in the scenarios cited above. With enquiry volumes already rising, advisers suggest not leaving it to the final months of 2026–27, when demand for valuations will likely spike.

Second, review your financing. If your investment property loan is sitting on a rate you haven't examined recently, check what's currently available via our investor home loan comparison page. Our borrowing power calculator can help you model how further rate changes would affect your overall position, including your ability to hold the property through the transition period.

Third, speak to a qualified tax professional who understands the CGT transition rules in detail. The changes are material, and the evidence you gather now — including a properly dated valuation report — could be the difference between an efficient tax outcome and a costly one.