Retrospective Property Valuation (Backdated)

A retrospective valuation (also called a backdated valuation or a historical valuation) assesses what a property was worth at a specific date in the past — not what it is worth today. It is one of the most common valuation types accountants and lawyers request, because tax and legal outcomes often hinge on market value at a particular historical moment.

A property that sold for $850,000 in 2019 and would fetch $1.3 million today has two different market values. Which one you need is set by your circumstances rather than by choice, so the date is the first thing to establish.

What a retrospective valuation is — and what it is not

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A retrospective valuation is a qualified valuer’s signed opinion of market value as at a stated past date, formed from the evidence that existed at that date and set out with the method shown.

Three things are frequently mistaken for one another, and the difference matters when someone tests the figure:

• An agent’s appraisal is not a valuation. It is a marketing estimate, usually free, given by someone who would like to sell the property. The Australian Property Institute is explicit that an appraisal cannot be relied on for tax, legal or financial decisions.
• An automated estimate is not a valuation. A price generated by an algorithm from sales data has nobody standing behind it, and no professional has formed a view on the property.
• A valuation is signed. A named, qualified valuer takes professional responsibility for the figure, states the method, and can be asked to explain it years later.

That matters most for a past date. Nobody can go back and inspect the property as it stood in 2019. What a report can do is show which evidence was used, why it was chosen, and what was assumed — which is what makes a number defensible.

When you need a backdated valuation

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• Date of death (deceased estate / probate). The property’s market value at the date of death typically sets the cost base for beneficiaries. See our deceased estate valuation guide.
• Your home first earned income. When a main residence first becomes a rental, the CGT cost base can become its market value at that first income date — often years before anyone thinks to get evidence.
• Family law separation. Settlements frequently need a defensible value as at separation or another agreed date.
• Related-party transfers and gifts. Stamp duty and CGT can both require market value at the transfer date, and a transaction between related parties attracts more scrutiny than one at arm’s length.
• SMSF related-party dealings. Where a fund buys from, sells to or leases to a member, an auditor will look for an independent figure, and the date that matters is the transaction date.
• 1 July 2027 CGT cost base reset. If the reform applies to you and the date has passed without a contemporaneous valuation, a retrospective valuation as at the end of 30 June 2027 can still establish the reset value. See valuing for 1 July 2027 after the date below.
• Insurance disputes and financial audits, where a historical value has to be established from records rather than from the property as it stands.

Retrospective valuations for 1 July 2027: can you value it after the date?

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Yes. The law fixes the date the value speaks to, not the date the valuation has to be prepared. A valuation prepared after 30 June 2027, stating the market value at the end of that day, is a retrospective valuation like any other. What changes with time is how much evidence survives.

Why 1 July 2027 matters

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The Treasury Laws Amendment (Tax Reform No. 1) Act 2026 (Act No. 49 of 2026, assented to 26 June 2026) changes how capital gains are taxed. The Budget 2026–27 describes it as replacing the 50 per cent CGT discount with a discount based on inflation from 1 July 2027, and says the reforms will only apply to gains arising after that date.

To split the gain at that point, the Act treats an individual who holds a property on 30 June 2027 as having sold it just before 1 July 2027 and bought it back straight afterwards (s 112-155(2)). The sale happens on 30 June 2027 and the reacquisition on 1 July 2027. The amount is the property’s market value just before 1 July 2027, unless you choose an apportioning method instead (s 112-155(3)). The Budget’s tax explainer describes that value as the cost base for gains from 1 July 2027 onwards.

Not every property is treated the same way. The Act has separate rules for trusts and for pre-CGT assets, and it carves out new residential dwellings and affordable housing and treats foreign and temporary residents differently. Whether the reset applies to your property is a question for your tax adviser.

Valuing after the date, or around it

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Nothing in section 112-155 sets a date by which a valuation must be prepared. The choice between market value and the apportioning method is made later: the Act’s note says you “do not have to make a choice until the day you lodge your income tax return for the income year in which the realisation event happens” (s 112-155(4), Note 2). That is usually the year you sell.

So there are two ways to hold a market value for the reset, and both are legitimate:

• Around the date. A valuation prepared soon after 30 June 2027, while the comparable sales are recent and the property is still as it was. This is the cleanest evidence you can hold.
• After the date. A retrospective valuation prepared years later, stating the market value at the end of 30 June 2027. The valuer has to rebuild that market from older sales, and reconstruct the property’s condition from records, which is harder and costs more.

The second is a fallback, not a problem. The risk is the same as for any backdated valuation: a thinly evidenced figure is easier to challenge, and the challenge tends to arrive when the property is sold. If you renovate after 30 June 2027, the valuer will need to know what was there before, so a dated property evidence record made around the date is worth keeping either way.

Two routes, and neither is “ATO-approved”

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1. A market valuation stating the value just before 1 July 2027. This is the default under s 112-155(3)(a).
2. The apportioning method, a method the Minister determines by legislative instrument under s 112-185. On 4 August 2026 the Treasurer released a draft instrument for consultation covering real property and assets without a readily ascertainable market value; consultation closed on 21 August 2026. As at early October 2026 no final determination appeared on the Federal Register of Legislation, so the method can still change. The Budget’s tax explainer says the ATO will provide tools to estimate the value.

There is no “ATO-approved” valuation, and the method is not set by the ATO: the Act gives the power to set it to the Minister. Which route suits you depends on the property and the numbers, and the comparison is set out on the sister site’s valuation vs formula page and its is there a deadline? page.

What a valuer needs for a past date

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The ATO’s market valuation guidance says a valuation must be objective and supported with appropriate evidence, that valuations by professional valuers are more credible, and that a report should state, among other things, its purpose and scope, the date it was conducted, whether it is a retrospective valuation, the date of inspection if there was one, and the records that explain the basis of the value. It also says to keep the report, because you will need those records if your tax affairs are later reviewed.

For a 30 June 2027 value that means:

• Comparable sales from around 30 June 2027, listed, with the reasoning shown.
• A stated method, including the assumption that the property is valued as it was on that date.
• An independent, qualified valuer who signs the report and can explain it later.
• Records of the property at the date: dated photographs, leases, rental appraisals, renovation invoices and council approvals.

How that evidence is used is set out in how a retrospective valuation works below. To reserve a valuation around the date, the sister site takes 1 July 2027 valuation reservations through our specialist CGT service, which prices reset valuations separately. Tell us the purpose and the date when you enquire, and we will say which level fits and why before you commit to anything.

This section is general information, not tax advice. Whether the reset applies to you, and which route suits your property, should be confirmed with a registered tax professional.

What level of valuation advice does a past date need?

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The answer changes both the price and what the report can be used for.

In August 2026 the Australian Property Institute published its Levels of Property Valuation Advice guide, setting out four levels:

Two of the guide’s positions matter here. A desktop report is never a valuation compliant with the International Valuation Standards, because nobody inspected the property. And where a figure will be tested by someone else — the ATO, a court, a co-owner, a beneficiary — the guide points to a Level 1 comprehensive report.

A retrospective assignment sits awkwardly against that. An inspection today establishes the property’s condition today. It cannot establish its condition in 2019. So a full inspection is valuable — it tells the valuer what the property is and grounds the comparable analysis — but it does not, on its own, answer the retrospective question.

That is why the level for a backdated valuation is a professional judgement rather than a rule, and why we ask the valuer to make it rather than deciding it for them. In practice a retrospective CGT assignment is commonly scoped as a Level 1 or Level 2 report with the retrospective basis stated, and with the report saying plainly what could and could not be established about the property as at the valuation date.

Tell us the purpose and the date when you enquire, and we will say which level fits and why before you commit to anything.

How a retrospective valuation works

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The valuer reconstructs the market as it was, rather than adjusting today’s market backwards.

Comparable sales from around the effective date. The core evidence is what similar properties in the area actually sold for at the time — not indexed estimates derived from current prices. The valuer selects comparables, states why each was chosen, and adjusts for differences in land size, condition, position and improvements.

The property’s condition and features at that date. This is the part that decays. A kitchen renovated in 2021 has no bearing on a 2019 value, and a valuer needs to know it was not there. Council approvals, renovation invoices, old listing photographs, rental appraisals, insurance records and dated photographs all help establish what existed when.

Market conditions at the date. Interest rates, local supply, and whether that specific suburb was rising, flat or falling at that specific time.

A stated method. The report sets out the approach, the evidence, the assumptions and any special assumptions — including, for a retrospective assignment, the assumption that the property is valued in the condition it was in at the valuation date rather than its condition today.

How far back can a valuation be dated?

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Many years. Retrospective valuations for deceased estates and CGT are routinely prepared for dates a decade or more in the past, and pre-1985 dates arise where a property’s capital-gains history reaches back to the introduction of CGT.

The limit is not a rule but the evidence. Sales records survive well; the property’s own history often does not. A 2005 date with good documentation is more straightforward than a 2020 date with none.

What makes a retrospective figure hard to challenge

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If the number is ever questioned — in an audit, a settlement, or a dispute between beneficiaries — the report is what answers. Four things carry the weight:

1. A named, qualified valuer who signed it and can explain it.
2. Comparable evidence from the period, listed, with the reasoning shown.
3. A documented view of the property at the date, rather than assumptions about it.
4. Assumptions stated openly, so a reader can see what was taken as given.

The third is the one owners can influence, and it is the one that disappears with time. If a date in the future will matter — 1 July 2027, for instance — a dated photographic record made now costs very little and is worth a great deal later. Our property evidence record exists for exactly that.

Why earlier is easier

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Sales evidence goes cold. The further back the date, the harder it is to establish condition and find clean comparables — which can mean more work, more cost and more room for a number to be challenged. If you know a past date will matter, get the valuation sooner rather than later.

A contemporaneous valuation — one prepared around the date itself — is always the cleanest evidence you can hold. Retrospective is the fallback, and a legitimate one, but it is a fallback.

Retrospective property valuation cost

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A retrospective valuation is quoted separately: it costs more than a current-date valuation of the same property, because the valuer has to rebuild the market as it stood on that date. The choice of level is the same as for any valuation:

• On-site. A valuer attends the property. This is the level to use where the ATO or a court may test the figure.
• Desktop. No inspection. Appropriate for lower-stakes purposes such as updating or monitoring an earlier figure — and, per the API guide above, not a valuation compliant with the International Valuation Standards.

The final scope depends on the property, how far back the date is, and what evidence exists for that period. A 2003 date on a renovated rural property is more work than a 2023 date on a suburban unit, and the quote reflects that. You get a fixed price before you proceed — there is no hourly meter.

Will the ATO accept a retrospective valuation?

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There is no “ATO-approved” valuation. No such status exists.

What the ATO’s market-valuation guidance looks for is objective and supportable evidence, a clear methodology, and a qualified, independent valuer. A signed retrospective report prepared on that basis is ordinary, accepted practice — retrospective valuations are used every day for deceased estates, CGT and family law.

The risk is not that retrospective valuations are disallowed. It is that a thinly evidenced one is easier to challenge, and the challenge tends to arrive years later, when reconstructing the evidence has become harder still.

What to gather before you enquire

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You do not need all of this, and we will tell you what helps for your date. It speeds things up considerably:

• The effective date you need the value as at, and why — the purpose changes the scope.
• The property address, and the title reference if you have it.
• Anything documenting its condition at that date: photographs, old listings, leases or rental statements, renovation invoices, council approvals, building plans.
• The purchase contract, if the date relates to acquisition.
• Who will rely on the report — you, an accountant, a court, a co-owner — because that affects how it is addressed and which level is appropriate.

How to get one

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1. Tell us the date and the purpose. Those two facts determine everything else.
2. We confirm the scope and a fixed price, including which level of advice fits and why.
3. A qualified valuer is instructed, with the retrospective basis and any assumptions agreed in writing before the work starts.
4. You receive a signed report stating the market value as at your date, the evidence, the method, and what could and could not be established about the property at that time.

Common questions

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Related guides: CGT valuations · deceased estates · desktop vs on-site · property evidence record.

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General information only — not tax, financial or legal advice. The signed valuation is provided by a qualified valuer.