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1 July 2027 CGT Cost Base Reset: Worked Examples

The 1 July 2027 reset gives every property held on 30 June 2027 a new starting point — its market value at the end of 30 June 2027, just before 1 July. Two methods can set that value: a dated, independent valuation, or the Treasurer’s free apportioning method. These three worked examples show, in round dollars, when each method wins. All figures are illustrative — not quotes, not predictions, not advice.

See where a valuation pays off

How the two methods split the gain
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Both methods divide your total gain into a pre-2027 slice (still under the old 50% discount rules) and a post-2027 slice (under the new CPI indexation plus a 30% minimum tax rate on that gain):

  • Dated valuation — uses the actual market value at the end of 30 June 2027. Pre-2027 gain = that value − your original cost base. Post-2027 gain = sale price − that value.
  • The Treasurer’s apportioning method — compounds one constant growth rate across the time you owned the property; the portion of the holding period falling after 1 July 2027 is the post-2027 slice. (We use simple time-apportionment to illustrate; the Treasurer’s method compounds instead, and is still an exposure draft — confirm the final instrument with your accountant.)

For individuals, gain in the pre-2027 slice generally keeps the 50% discount, so a higher, well-evidenced 1 July 2027 value tends to place more gain there and less in the new regime — but only where the growth genuinely happened before the date. Where it did not, the formula can be the better call (see when the formula wins).

Illustrative tax assumptions. For the tax lines below: an individual on a 47% marginal rate; the 50% discount applies to the pre-2027 slice (so ≈ 23.5% of that gain in tax); the post-2027 slice is taxed at the 47% marginal rate (above the 30% floor), ignoring CPI indexation, which would reduce the post-2027 figure. Real outcomes depend on your rate, indexation, eligibility and circumstances. Illustrative only, not tax advice.

These three examples are being revised. They apportion the gain evenly across the ownership period. Treasury’s exposure draft instead compounds one constant daily growth rate, which credits less value to 30 June 2027 than an even split — so each example understates the gap between the two routes, and the case for a dated valuation is stronger than shown here, not weaker. The figures below are left in place until they are recomputed rather than quietly removed. Recorded 30 August 2026.

Example A — steady-growth apartment
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An apartment bought for $600,000 in July 2017 and sold for $1,000,000 in July 2037 (a 20-year hold), with even growth throughout. Its actual value at the halfway point, 1 July 2027, is about $800,000.

Method1 July 2027 valuePre-2027 gainPost-2027 gainIllustrative tax
Dated valuation$800,000$200,000$200,000≈ $141,000
Apportioning method$800,000$200,000$200,000≈ $141,000

Verdict: with even growth, time-apportionment lands almost exactly on the real value. The free formula gives essentially the same answer, so here it is the simpler, cheaper choice — a valuation adds little. Honest is honest.

Example B — a suburb that boomed before 2027
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Same $600,000 purchase in July 2017, but the suburb boomed early: by 1 July 2027 the property is worth about $1,050,000, then growth flattens and it sells for $1,150,000 in July 2037.

Method1 July 2027 valuePre-2027 gainPost-2027 gainIllustrative tax
Dated valuation$1,050,000$450,000$100,000≈ $153,000
Apportioning method$875,000*$275,000$275,000≈ $194,000

*The formula never states a value — it apportions the $550,000 total gain 50/50 over the 20-year hold. The $875,000 is what that implies.

Verdict: the boom happened before the reset, but the time-based formula can’t see that — it averages the gain across 20 years and pushes $275,000 into the new post-2027 regime, versus just $100,000 under the dated valuation. That’s $175,000 more gain taxed under the less generous rules, and on these assumptions about $41,000 more tax. This is the case a dated valuation is built for.

Example C — a renovated property
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Bought for $700,000 in July 2015, with a $200,000 renovation in 2026 (an element 4 capital improvement), giving a cost base of $900,000. The renovation lifts the 1 July 2027 value to about $1,350,000; it sells for $1,450,000 in July 2035 (a 20-year hold; 8 of those years fall after the reset, so the formula’s post-2027 share is 40%).

Method1 July 2027 valuePre-2027 gainPost-2027 gainIllustrative tax
Dated valuation$1,350,000$450,000$100,000≈ $153,000
Apportioning method$330,000$220,000≈ $181,000

Verdict: the renovation created a step-up in value before 2027, but the formula spreads the whole gain evenly over time and can’t recognise it. A dated valuation captures the improved property as at the reset date, keeping more gain in the pre-2027 slice — about $28,000 less tax on these assumptions. The lesson pairs up: keep the renovation invoices and a dated 1 July 2027 value that reflects the finished work.

When the free formula wins
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A dated valuation is not always the answer. If your property’s growth came mostly after 1 July 2027, its actual value on that date is low — a valuation would then set a low starting point and expose a larger slice to the new regime, while the formula’s even apportionment assigns less. Where growth was flat or even, the formula lands close (Example A) and saves you the cost. The point is not that one method always beats the other — it is that the choice is elective, and worth checking against your property’s real history with your accountant.

Try your own numbers
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Illustrative general information, not tax advice. Excludes buying/selling costs, the CGT discount calculation, indexation, exemptions and your marginal rate; SMSFs and companies are excluded from the reform for property acquired on or after 20 September 1985 (pre-CGT property is deemed sold whoever holds it). Confirm with your accountant.

Where to go next#

Register interest
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We use your details to prepare your valuation and to contact you about it. If you engage us, we also create and keep a long-term record of the property's documents and condition as at 30 June 2027, so that you, your accountant, or a valuer you appoint can use it when the property is eventually sold; and we keep property information after your personal details are removed, to improve our valuation reference data. See our privacy policy; you can ask us to delete your details at any time.

Common questions
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Can you show a 1 July 2027 cost base reset example?
Yes — see three above. In short, a $600,000 property worth $1,050,000 on 1 July 2027 gets a $450,000 pre-2027 gain (old 50% discount) and only a small post-2027 gain, whereas the free time-formula would split the gain evenly and tax more of it under the new rules. Figures illustrative.
Is the Treasurer's free apportioning method always worse than a valuation?
No. Where growth was even, the formula lands close and is the cheaper choice (Example A); where growth came after 2027 it can beat a valuation. A dated valuation mainly helps when your growth was concentrated before 1 July 2027. See when the formula wins.
How does the apportioning method work?
It derives one constant daily growth rate from your purchase price and your eventual sale price, then applies it forward to 30 June 2027 — a compounding curve, not a straight line. Because that curve is convex it credits less value to 30 June 2027 than an even split would; the portion of that period after 1 July 2027 is taxed under the new rules. We illustrate with simple time-apportionment; the Treasurer's method compounds instead, and is still an exposure draft — confirm the final instrument with your accountant.
Why can a dated value beat the free formula?
Because the formula assumes even growth. If your property boomed or was renovated before 2027, its real 1 July 2027 value is higher than an even split implies, so a dated valuation keeps more gain under the old 50% discount rules. See Example B.
Do the examples include the CGT discount and my tax rate?
The tax lines are illustrative, using a 47% marginal rate and the 50% discount on the pre-2027 slice, and they ignore CPI indexation (which would lower the post-2027 figure). Your actual result depends on your circumstances — confirm with your accountant.
Are SMSFs or companies covered by these examples?
Not for property acquired on or after 20 September 1985 — pre-CGT property is deemed sold whoever holds it (s 112-175). Otherwise SMSFs and companies keep their existing CGT settings for property acquired on or after 20 September 1985, so these individual-focused examples don't apply to them. Foreign and temporary residents are a different case and are **not** outside the reform: they are excluded from the 1 July 2027 deemed sale (s 112-155(1)(d)), so they get no cost-base reset, and they are denied the replacement indexation (s 114-25). That is a worse position, not an exemption. Check your own structure with your adviser.

General information only — not tax, financial or legal advice. All dollar figures are illustrative and rounded. Any indicative appraisal is automated and is not a certified or ATO-suitable valuation; the signed valuation is provided separately.