The New CGT Assessor is an ICM Hub tool that applies the 2026 Budget's transitional rules to a property scenario. The Budget replaces the 50% CGT discount with cost base indexation and a 30% minimum tax from 1 July 2027, and it limits negative gearing on established residential property.
From 1 July 2027, the 50% capital gains tax discount for individuals, trusts and partnerships is replaced by cost base indexation and a 30% minimum tax on real capital gains, according to the Australian Taxation Office's published guidance on the 2026-27 Budget reforms.
Two changes matter most to property owners. The first is the capital gains change. The second is negative gearing, where the Budget limits offsetting rental losses against other income to new builds. Properties held before 7:30pm AEST on 12 May 2026 are grandfathered under the existing negative gearing rules.
The Hub lists the tool with the description "2026 Budget transitional rules" and marks it NEW. It's designed to help owners and buyers model how these changes could apply to them, rather than to give tax advice.
For assets held before 1 July 2027, gains that accrue up to that date keep the 50% discount, and gains after it are taxed under indexation and the 30% minimum tax. You can establish the 1 July 2027 value with a valuation or an ATO apportionment method.
Under the transitional rules, capital gains that accrue before 1 July 2027 keep the 50% discount, while gains that accrue from 1 July 2027 are subject to cost base indexation and a 30% minimum tax.
Here's how the pieces fit:
Sources: ATO reform guidance (2026), Clayton Utz (May 2026), Baker McKenzie (May 2026).
Enter your property's key dates and values, and the assessor applies the transitional rules to estimate how your gain could be split and taxed. You then compare scenarios, such as selling before or after 1 July 2027, to see how timing may affect the result.
Here's the process:
Say you bought an investment property in 2020 for $600,000. Its value on 1 July 2027 is $800,000. You sell in 2032 for $1,000,000. Your gain before 1 July 2027 is $200,000, and under the transitional rules the 50% discount applies to it, leaving $100,000 assessable.
The post-1 July 2027 gain is $200,000 in nominal terms. With inflation of, say, 3% a year over five years, indexation lifts your $800,000 starting value to about $927,000, so the real gain is about $73,000. The 30% minimum tax applies to that real gain.
In this hypothetical example, indexation cuts the taxable post-2027 gain from $200,000 to about $73,000, but the 30% minimum tax means the tax on that portion cannot fall below 30% of the real gain.
The 3% inflation rate is an assumption for illustration only, not a forecast, and the rules may be refined. Treat this as a way to see how the pieces work, not as a tax calculation.
The old and new rules split at 1 July 2027. If you're already thinking about selling, timing may change the tax outcome.
If you're buying an established residential property, negative gearing won't apply to it under the new rules unless it was held before the announcement date. That changes the cash flow maths.
A supported valuation at 1 July 2027 will likely matter for existing assets, so plan for one.
Owners with several properties can compare which to hold and which to sell, using after-tax numbers, not gross gains.
The old system taxes 50% of your gain after a 12-month hold, at your marginal rate. The new system taxes the inflation-adjusted gain, with a 30% minimum rate, on gains that accrue from 1 July 2027. Existing gains keep the old treatment.
| Feature | Current rules (to 30 June 2027) | New rules (from 1 July 2027) |
|---|---|---|
| Gain calculation | Nominal gain | Real gain, using cost base indexation |
| Discount | 50% CGT discount after 12 months | Replaced by indexation |
| Minimum tax | None | 30% minimum tax on real gains |
| Existing gains | 50% discount | Gains accrued before 1 July 2027 keep the 50% discount |
| Negative gearing (residential) | Losses offset other income | Limited to new builds; grandfathering for properties held at 12 May 2026 |
| Who is affected | Individuals, trusts, partnerships | Individuals, trusts, partnerships |
Old vs new CGT: the current system halves your nominal gain, while the new system taxes your inflation-adjusted gain with a 30% floor, so high-growth, low-inflation holds tend to be affected differently from low-growth holds.
Whether you're better or worse off depends on your holding period, growth rate, inflation and tax rate, which is why scenario modelling helps. Don't assume the new rules are better or worse for you until you've run the numbers.
Investors buying established residential property after 12 May 2026 are most affected, because negative gearing is limited to new builds from 1 July 2027. Investors who already held a property by then keep the current rules until they sell it, and new builds retain negative gearing.
Reports indicate excess losses on established residential property can be carried forward and used only against residential property income, rather than other income like wages. That changes cash flow for buyers who relied on tax deductions to make an investment work.
In practice, the "holding cost" maths in our True Cost Calculator matters more under the new rules, because you may fund more of any shortfall yourself. For buyers, that raises the importance of yield, buffers and borrowing structure. Our investor lending service can help you plan.
Details such as what counts as a "new build" and how contracts signed before the cutoff are treated are set out in the ATO's guidance. Read it, and take advice, before you commit.
The assessor puts the new rules into a scenario tool, backed by a brokerage that works with property investors. It gives you a quick picture of the effect on a property, and a broker can connect that to lending, structure and portfolio planning. Tax advice comes from your accountant.
We're brokers, not tax advisers. The assessor helps you ask better questions, and your accountant answers them.
Investors who plan ahead for tax and lending changes tend to have more options. We haven't published a client story on the 2026 changes because the rules only start on 1 July 2027 and no client outcomes can be reported yet.
Until then, the best preparation is practical. Get a clear picture of your cost base, keep records of improvements and purchase costs, and speak with your accountant about how the transitional rules apply to each property you hold. Our investor lending service can then match your lending to the plan you settle on.
The new rules start on 1 July 2027, and transitional details matter. Use the New CGT Assessor to explore scenarios, then take the results to your accountant and your broker.
Call 1800 46 48 10 or email askus@investorschoice.com.au. You can also explore the Equity Effect calculator or all our property calculators.
