Australian Cost Base Reset for Returning Expats: CGT Guide

The Australian Cost Base Reset: The Quiet Rule That Works in Your Favour (For Once) & Can Save Returning Expats Thousands

Most tax rules are designed to take money off you. This one can, for once, be on your side.

When an Australian who has been living overseas becomes a tax resident again, a quiet provision buried in the capital gains rules can wipe years of investment growth out of the Australian tax net. Not defer it. Not discount it. Remove it, cleanly, as if those gains never happened for Australian purposes. On a portfolio that has done well over a decade abroad, that can be the difference between a comfortable tax bill and a brutal one, and many people coming home have never heard of it.

It is called the cost base reset, and it is the rare piece of tax law that rewards the organised. The catch, and there is always a catch, is that it only works properly if you understand what it does and do not accidentally sabotage it on the way in. Here is how it works, who it helps, and the handful of ways people quietly throw the benefit away.

What actually happens when you become a resident again

Start with the ordinary rule, because the reset is an exception to it.

For an Australian resident who is not a temporary resident, overseas investment assets generally come inside Australia’s capital gains tax net. That creates an obvious question when you already owned those assets before Australian residency resumed: where should the Australian calculation start?

For many eligible assets, the answer is market value on the day you become resident. The Australian CGT starting point resets, and the law treats you as having acquired the asset at that time. In practical terms, the appreciation or decline that occurred before the reset generally drops out of the later Australian calculation. Any later capital gain or loss starts from that reset value, measured for Australian tax purposes in Australian dollars, so exchange-rate movements after the reset can matter too.

This is not a loophole or an aggressive position. It is the statutory treatment for eligible assets when Australian residency begins. The real questions are whether a particular asset qualifies, what the market value was on the reset date, and whether another rule changes the result. The trap is not that the reset is risky. The trap is that people do not realise it is there, do not capture what they need to prove it, or hold assets the reset does not touch.

Which assets get the reset, and which do not

Here is where the “most of your assets” I have been careful to say starts to matter, because the reset is generous but not universal.

Broadly, the ordinary reset applies to post-CGT assets you own just before Australian residency resumes that are not taxable Australian property at that time. That often captures overseas shares, foreign investments and other offshore holdings, giving them a fresh market-value starting point.

What does not get the ordinary residency reset is an asset that was already taxable Australian property immediately before you became resident. Australian real property is the obvious example. Certain indirect interests in Australian real property, and assets used in carrying on a business through an Australian permanent establishment, can also stay inside the Australian net. Certain employee share scheme interests have their own rules, and people who become Australian residents while still temporary residents for tax purposes run on a different track again.

Pre-CGT assets are another separate category. They do not receive this residency reset. Assets still held into the new regime from 1 July 2027 have their own transitional treatment, so the old shorthand that pre-CGT assets simply sit outside capital gains tax forever no longer tells the whole story.

The practical point is that sorting your assets into “resets” and “does not reset” is not a two-minute job you do from a blog article. Whether a particular holding, especially an indirect interest, an interest in a trust, or something with an Australian connection, is genuinely outside the net is exactly the kind of question that looks simple and is not, because an ordinary shareholding in an Australian company is not automatically taxable Australian property, while some less obvious interests are. Get the classification wrong and every calculation downstream is wrong with it. This is the first thing worth having checked rather than assumed.

The trap for people who left Australia the smart way

Now for the part that catches the well-advised, which is a particular kind of painful.

When you originally left Australia, the departure capital gains rules may have treated certain assets as disposed of at market value as you ceased residency. You could instead choose to disregard those departure gains and losses. That choice was not an asset-by-asset menu: it applied across the assets caught by the departure event. If the choice was made, the affected assets remained inside Australia’s capital gains net while you were away, so that no tax fell due on departure.

That matters when you return. Because those assets were still treated as taxable Australian property immediately before residency resumed, they do not receive the ordinary homecoming market-value reset. Their cost base continues under the ordinary rules rather than being refreshed to the value on your return date, which can be a much lower starting point where the asset has appreciated, with that intervening growth still very much on Australia’s radar. The reset that is quietly enriching the person beside you, who simply held ordinary overseas shares, does not apply to the assets you made that departure choice on.

This is not a reason to regret the deferral, which may have been exactly the right call at the time. It is a reason to work out, before you sell anything, which of your assets reset and which are still tethered to their old cost base by a choice you made on the way out. The two categories are taxed completely differently, and treating them as one is one of the more expensive mistakes a returning expat can make. If you made that departure choice, this needs to be untangled asset by asset, and it is precisely the sort of thing worth paying to get right.

The second clock nobody sees: the discount

The reset does something else that is easy to miss. It does not just give the asset a new market-value starting point. For Australian capital gains purposes, it also gives the asset a new acquisition date, and that date matters more than people expect.

Australia gives resident individuals a capital gains tax discount, broadly halving the taxable gain on an asset held long enough. Under the rules applying to gains before 1 July 2027, a gain generally only qualifies for that discount if the asset was acquired at least twelve months before you sell. Here is the catch: because the reset treats you as acquiring the asset on your residency date, the twelve-month clock starts again then. Come home in January, sell the reset shares in September, and your ten years of overseas ownership do not rescue you. For Australian purposes, you acquired those shares in January.

There is an upside to the very same rule. The foreign-resident years before the reset do not ordinarily dilute the discount on a properly reset asset, because they sit before the new Australian acquisition date. That is the reverse of what many expats fear, and it is one of the reasons the reset is worth understanding rather than guessing at.

There is also another date now sitting on the calendar. Under the Treasury Laws Amendment (Tax Reform No. 1) Act 2026, the ordinary 50 per cent discount is generally replaced from 1 July 2027 by cost-base indexation for eligible gains, with a 30 per cent minimum-tax regime that can also apply in some cases, and transitional rules for assets already held. For returning expats, some of the rules dealing with foreign, mixed and temporary-resident cases are still being developed in later legislation, so anyone whose residency may change again after 1 July 2027 is dealing with a moving target. Either way, the answer depends on when your residency resumed, when you sell, and what happens to your residency afterwards. Those are dates to model before a sale, not to explain to yourself afterwards.

The cheapest time to solve the evidence problem is now

Here is the single most important practical thing in this entire article, and it is almost boringly simple.

The law gives you the market-value reset whether or not your records are tidy. The practical problem is proving the number. That value becomes the Australian capital gains starting point for the asset, so the stronger your evidence at the residency date, the more defensible every later calculation becomes. If the evidence is poor the reset does not disappear, but establishing the right starting point years later can become much harder and more expensive.

For widely traded listed investments, contemporaneous market data usually makes the exercise relatively straightforward, though even there, thin trading, unusual volatility or a corporate event around the date can mean a single displayed price is not the whole story. For everything else, unlisted investments, private company shares, a stake in a family business, foreign property, an interest in a managed vehicle that does not publish a daily price, establishing a defensible market value as at your residency date is a real exercise, and it is dramatically easier to do at the time than to reconstruct years later when you are trying to sell.

This is one of the more frustrating problems we see. Someone comes home, sells a reset asset four years later, and discovers they have no reliable evidence of what it was worth on the day that mattered. The entitlement was real. The proof was never captured. And a value reconstructed years after the fact can be much harder and more expensive to support, particularly for an asset that does not trade publicly. For listed investments, capturing the evidence may cost almost nothing. For harder assets, proper valuation work may cost real money even when commissioned promptly. The expensive mistake is waiting until the sale to discover that the number your entire calculation depends on was never properly supported.

So what should a returning expat actually do?

Without handing over a map you should not be driving with, the shape of getting this right looks like this.

Someone establishes the exact date your residency resumes, because for the ordinary returning-resident reset that date is critical and, as we cover in our returning to Australia tax reset checklist, it is not always the day you land. Your assets are then separated into those that reset and those that do not, including anything affected by a departure capital gains choice. Market-value evidence is captured for each reset asset as at your residency date, with proper valuation work obtained where the asset genuinely requires it. And the whole position is documented so that a sale years later starts with evidence rather than archaeology.

That is a handful of sentences describing work that can be extremely valuable on a substantial portfolio. It is also work that is far cheaper and more effective done around the time you come home than reconstructed under pressure when a sale is looming or a query has landed.

The mistakes we see, so you can dodge a few

A short catalogue, offered so you can dodge a few of them.

Assuming every asset resets, including Australian property and other assets that never left the Australian capital gains net, and building a plan on a foundation that was never there. Forgetting that assets affected by a departure capital gains choice do not receive the ordinary return-date reset, then being blindsided by the gain. Selling a reset asset too soon and discovering that the Australian twelve-month holding clock restarted when your residency did. Ignoring the new capital gains rules commencing from 1 July 2027. And the big one, the one that costs the most for the least reason: coming home, doing nothing, and only thinking about market-value evidence years later when the asset is being sold and the day that mattered is long gone.

The short version

When you become an Australian tax resident again, many of your overseas investment assets can receive a fresh Australian capital gains starting point at market value, removing years of pre-reset growth from the later Australian gain. It is one of the genuinely good rules for returning expats, and it can be worth serious money. But not every asset resets: departure choices, taxable Australian property, temporary-resident rules and some employee share scheme interests can change the answer. The reset also gives an eligible asset a new Australian acquisition date, which matters for the twelve-month discount rule, and the broader capital gains landscape changes again from 1 July 2027. The practical value of the reset depends heavily on being able to support the market value at the residency date.

The reset rewards the organised and quietly punishes the casual. The first questions are which assets qualify, what the reset date actually is, and what evidence supports the market value on that date. Getting those questions answered at the right time can prevent a much more expensive problem later.

If you are coming home, or you are recently back and holding overseas assets you have not yet dealt with, book a consultation with our specialist expat tax team. We will pin down your residency date, sort your assets into what resets and what does not, make sure the market-value evidence is captured while it still can be, and set the whole thing up so that when you eventually sell, the tax calculation starts from a properly supported position. We work with Australians in over one hundred countries, many of whom hold exactly the sort of assets this rule is about, and we quote upfront before any work begins. For the wider picture on coming home, see our full returning to Australia tax guide.

Frequently asked questions

What is the cost base reset?

When Australian residency begins, many eligible capital gains assets that were outside Australia’s tax net immediately beforehand are treated as having been acquired at their market value at that time. That becomes the new Australian capital gains starting point, so the later Australian capital gain generally starts from that reset value rather than from your original acquisition cost.

Does the reset apply to all my assets?

No. Taxable Australian property does not receive the ordinary reset. Australian real property is the obvious example, but certain indirect Australian property interests and assets connected with an Australian permanent establishment can also fall into that category. Pre-CGT assets, some employee share scheme interests and temporary-resident cases have separate rules again. This is why the asset classification comes before the calculation.

What if I chose to defer my capital gains tax when I left Australia?

If you made the departure capital gains choice when you left, the affected assets were kept inside Australia’s capital gains net while you were a foreign resident. They therefore do not receive the ordinary market-value reset when residency resumes. Their cost base continues under the ordinary rules rather than being refreshed to the value on your return date. This is a point we regularly see missed by returning expats, and those assets need to be identified and treated separately.

How do I prove the market value on the day I became a resident?

For widely traded listed investments, contemporaneous market data will often provide strong evidence of value. Private companies, unlisted investments, business interests and foreign property can require much more work. The important thing is to capture defensible evidence around the residency date rather than trying to reconstruct it years later, which is harder, more expensive and more dependent on whatever records happen to survive.

Will I still get the 50 per cent capital gains discount when I sell a reset asset?

It depends on when you sell. For a genuinely reset asset, the reset date becomes the Australian capital gains acquisition date. Under the rules applying to gains before 1 July 2027, that means the ordinary twelve-month holding period starts again from that date, so selling too soon after coming home can cost you the discount even on an asset you have owned for years. The foreign-resident years before the reset do not ordinarily reduce the discount, because they sit before that new acquisition date. From 1 July 2027, legislated reforms generally replace the ordinary discount with cost-base indexation for eligible gains and introduce a 30 per cent minimum-tax regime that can apply in some cases. Transitional rules apply, and further legislation is still being developed for some foreign, mixed and temporary-resident situations, so the reset date, the sale date and your later residency history all matter.

When should I deal with all this?

Ideally around the time you become a resident again, and certainly before you sell anything. The reset hangs off your residency date, the evidence is easiest to capture at the time, and the decisions are far cheaper to get right upfront than to repair once a sale is in motion or a query has arrived.

General information only. This article is current as at 13 September 2026 and does not take your personal circumstances into account. It is not tax, financial or legal advice. Your residency, the assets affected by the cost base reset, and the capital gains consequences when you sell all depend on your specific circumstances and can change over time. Speak with our specialist expatriate tax team before acting.