Despite how the question is usually put, the enacted 2027 rules do not simply oblige every property owner to commission a physical valuation by 30 June 2027. What the law sets up is a transition — and a 30 June 2027 market value is one of the methods for separating gains taxed under the old rules from gains taxed under the new ones, not a blanket requirement to hire a valuer.

The core of the transition is one sentence with one important word in it:

Property held on 30 June 2027 is treated as sold and reacquired at market value just before 1 July 2027 — or an apportionment method can be used instead (s112-185).

That “or” is the whole point of this guide. The market value is the default route through the transition, set in the enacted law itself; an apportionment method under section 112-185 is the alternative. That alternative’s detailed method sits in an enabling legislative instrument the Minister may make but had not yet made as at July 2026.

Do the new rules require a valuation by 30 June 2027?

On the enacted law available as at July 2026, not as a blanket requirement. The Treasury Laws Amendment (Tax Reform No. 1) Act 2026 — royal assent 26 June 2026 — applies to CGT events on or after 1 July 2027. A “CGT event” is the trigger that crystallises a capital gain or loss, most commonly the sale of an asset.

For an asset you still hold on 30 June 2027, the enacted law’s default (sections 112-155, 112-165 and 112-175, depending on the type of asset) is that it is treated as sold just before 1 July 2027 at its market value just before that date, and reacquired just after for the same amount — so gains built up before the changeover keep their old treatment. That market value is the figure the law itself uses to draw the line between the two periods: it is the deemed basis, not a direction to commission a physical valuation, though a taxpayer can support the figure with one. The Act also names an apportioning method under section 112-185 as an alternative to that market-value default.

What the enacted words leave open is the apportioning alternative. Section 112-185 lets the Minister set that method by legislative instrument, and as at July 2026 none had been made — so exactly how the apportioning method works, and when it would suit a holding better than the market-value default, is not yet on the public record. As at July 2026, no such instrument has been registered on the Federal Register of Legislation — check the Register before relying on this alternative.

So the honest answer to “why do I need a valuation” is that the law does not require you to commission one. It sets a market value at the changeover as the default basis and offers an apportioning method as the alternative, with that alternative’s detail still being filled in.

Tax outcomes depend on your circumstances — speak with a registered tax agent before acting.

What a 30 June 2027 market value actually does

The transition exists to separate two periods of ownership so each is taxed under the rules in force at the time. Under the market-value method, a value fixed just before 1 July 2027 is what draws that line.

Broadly, as at July 2026, the two sides fall out like this:

Period	Broad treatment
Gains up to 30 June 2027	Old rules — the pre-1 July 2027 regime
Gains from 1 July 2027	New rules — indexation and the Division 119 floor

On the old side, the settings that applied to CGT events before 1 July 2027 continue for the pre-changeover portion. On the new side, the enacted reform brings CPI indexation of the cost base back for most cost base elements and ends the 50% discount for individuals, trusts and partnerships. The discount is retained for new residential dwellings and qualifying affordable housing, and complying super funds keep the 33.33% discount. A new Division 119 also applies a minimum 30% tax to residential and non-residential capital gains, with new dwellings excluded.

How much of a gain lands in each period is exactly what the transition governs. The market-value default is set in the Act; the apportioning alternative’s detailed method is part of the guidance still to be published. So this section is a summary of the settings, not a worked formula.

Market value or apportionment: it is a choice, not a single rule

The Act sets out two routes, and it is worth being clear that they are options rather than a fixed instruction. One route uses a market value just before 1 July 2027. The other uses an apportioning method under section 112-185 — a mechanism that does not turn on a physical valuation at all.

Neither is presented here as the “right” choice. Which suits a particular holding depends on the property, the timing and figures no general article can supply — and, as above, the apportioning method’s rules were not yet finalised as at July 2026, even though the market-value default is set in the Act. A registered tax agent and the ATO’s transitional guidance are the places to confirm how the choice works for a specific property.

The apportioning alternative is a substantial topic in its own right — the general idea is that it splits the gain by reference to time held on each side of 1 July 2027, rather than by reference to a valuation. Because the calculation can favour one holding and disadvantage another, it is not a step to generalise about.

Why property records matter through the transition

Whichever transitional method ends up applying, the ordinary CGT record-keeping rules do not change. As at July 2026, the ATO requires property CGT records to be kept for the whole period you own the property, plus at least 5 years after you dispose of it.

Recording a market value when a property’s tax position changes is already a normal part of that paper trail. The ATO, for example, expects a market value to be recorded when a home first becomes income-producing — an existing rule, unrelated to the 2027 changes.

None of this points to a single action for a particular reader. Which rules apply to a future sale depends on when the CGT event occurs, and complete records make whichever calculation applies easier to substantiate. The timing and value questions are ones to work through with a registered tax agent, not from a general guide.

How does this apply to fractional interests like Brix?

The settings above describe how the transition treats a CGT asset such as a directly held property. A Brix is a different kind of asset. A Brix is a fractional economic interest in a property — a financial product under Chapter 7 of the Corporations Act 2001 (Cth), not ownership of the property and not a loan — and the owner remains the registered legal owner of the home.

As at July 2026, no ATO guidance and no registered legislative instrument set out how the 2027 transition — including any 30 June 2027 market value or the section 112-185 apportionment method — applies to fractional or indirect interests in residential property. This guide does not fill that gap. How the transition treats a Brix is a question for a registered tax agent and for the Product Disclosure Statement, not something to infer from the rules for directly held property.

Under the MyBrix Product Disclosure Statement current as at July 2026 (version 4.0), each property is divided into 10,000 Brix representing all of its economic benefits — future net sale proceeds and, where applicable, net rental proceeds.

Where the detail will be confirmed

The transition is enacted law; the working detail — including the section 112-185 apportionment method — is being filled in through ATO guidance and legislative instruments that were still pending as at July 2026. The amending Act and the ATO’s guidance on the reform are the primary sources to watch, and a registered tax agent can confirm how any of it applies to a specific property.

For the CGT basics this builds on, see our guide to how capital gains tax is calculated on property.