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Becoming or ceasing to be a U.S. person happens on a specific date, and everything is measured against it. Moving in, your Australian assets arrive with their historic basis and their old holding periods. Moving out, exit rules test your wealth and five years of compliance, and can deem your assets sold. Both directions reward planning the date.
The questions arrive in plain clothes. Do I pay U.S. tax on gains from before I moved? Does my super come with me? Can I just mail the green card back when I leave?
Behind all of them sits one mechanism: U.S. person status attaches on a date and detaches on a date, and the tax system measures everything against those two days. Your assets never change. The measuring system does.
Moving In: The Day the Clock Starts
Residency begins under status tests, not feelings. A green card starts the clock from your first day as a permanent resident. Physical presence starts it through a weighted 183-day formula that counts parts of earlier years. Publication 519 governs the tests, the start-date rules, and the first-year elections that can shift them.
The arrival year itself is usually a dual-status return: nonresident rules for the months before the start date, resident rules after, with its own restrictions on how the two halves are filed. It is the one return where the calendar matters more than the numbers, because the date decides which system each event belongs to.
The split is not cosmetic. Deductions, filing status, and which income each half captures all differ across the line, married filers meet extra restrictions, and an election can sometimes treat the whole year as resident, which is a choice with a price. Income earned before the start date generally stays outside the U.S. net, which is why the placement of a bonus, a property settlement, or a fund sale against that date is real money. The reporting duties switch on at the date too, not at the first April.
Your Assets Do Not Get a Fresh Start
Here is the surprise that costs the most. Assets generally arrive with their historic basis, so decades of Australian growth can become U.S.-taxable gain the day you sell, even though most of it happened before you ever landed. Holding periods travel too, which makes pooled investments dangerous: the PFIC default regime counts your whole ownership history, and first-year elections are time-sensitive. The largest pre-existing asset is usually the super fund, and its classification question arrives with you.
Roles arrive as well: the family trust seat, the Pty Ltd shares, the appointor backup nobody remembered. And pending currency events keep their fuse, because an AUD mortgage repaid after the start date is measured inside the U.S. system, whenever it was borrowed.
A Tale of Two Arrival Dates
Two colleagues transfer from the same Sydney office. One lands late in the year, one early in the next. Between the weighted presence formula and a first-year choice, their residency start dates end up months apart, in different tax years.
The first, briefed before flying, sold her managed funds, stopped her voluntary super top-ups, and settled a small property matter, all before her date. Her first U.S. return starts clean: fresh gains only, no pooled-fund history dragging behind, elections made on time.
The second did the same things after his date, because nobody framed the date as a boundary. Same employer, same assets, same suburb. His first return inherits pre-move gains, a PFIC history counted from the original purchase, and an election window already narrowing. The difference between them was never wealth. It was sequence.
The two directions, side by side.
| Question | Moving Into the System | Moving Out of the System |
| The date that matters | The residency start date under the status tests. | The expatriation date: renunciation or green card end. |
| The return that year | Often a dual-status return, split in two. | A final-year filing plus the expatriation statement. |
| Your Australian assets | Arrive with historic basis. No fresh start. | Can face a deemed sale under the exit tax. |
| The compliance test | Prior years are usually not the IRS’s concern. | Five years of certified compliance required. |
| What is plannable | The start date, and steps taken before it. | The exit date, and the cleanup before it. |
| Measurement | Measures presence and status, day by day. | Measures wealth, tax history, and compliance at the exit. |
Moving Out: Leaving Is an Event, Not a Fade
The system does not let go by silence. Renouncing citizenship, or ending a green card held long enough, triggers the expatriation rules, and the exit is documented on Form 8854. Mailing the card back, or letting it expire in a drawer, is not the clean non-event people imagine.
The rules sort leavers with three tests, and failing any one makes you a covered expatriate:
- A net worth test, set at USD 2 million.
- An average tax liability test, indexed annually.
- A certification test: five prior years of full U.S. tax compliance, sworn on the way out.
- Green card holders are inside these rules after holding status in 8 of the last 15 years.
Covered expatriates face the exit tax: a deemed sale of worldwide assets on the day before expatriation, with an indexed exclusion sheltering part of the gain, and special regimes for deferred arrangements, including super. The quiet trap is the third test. People of ordinary wealth become covered expatriates purely because unfiled years made certification impossible.
Super deserves its own warning on the way out. Deferred arrangements do not simply ride through the deemed sale; they meet special exit treatment of their own, and depending on the analysis, that can mean withholding regimes on later payments or amounts treated as received at exit. The fund that followed you in quietly does not follow you out quietly.
What the Treaty Does Not Do Here
The treaty does not move the dates, waive the tests, or soften the exit computation for U.S. persons. Where the U.S.-Australia treaty genuinely helps, and where it quietly does not, is its own analysis, and transition years are where people over-trust it most.
Common Transition-Year Mistakes
- Assuming assets get a fresh basis on arrival. The U.S. generally inherits your history, gains and all.
- Missing first-year elections on pooled investments, then meeting the default PFIC regime later.
- Letting trust roles and company shares ride into residency unexamined.
- Selling the home or repaying the mortgage just after the start date when just before was available.
- Treating a returned or expired green card as a tax non-event.
- Discovering the five-year certification requirement at the exit, with unfiled years behind it.
Planning the Date Instead of Discovering It
Both directions have the same structure: a date, a set of tests, and a window before the date when facts can still be arranged. Sales, restructures, elections, and cleanups all price differently on the two sides of the line, and the line itself is often movable by weeks or months.
Inbound, the review reads like a checklist in prose: what to realize or restructure before the date, which elections belong in year one, which trust and company roles to resign or document, and where the mortgage timing sits. Outbound, it is the mirror image: filings brought to certify-ready condition first, then the tests measured honestly. Positioning steps ahead of the tests exist and can be legitimate, and aggressive versions invite scrutiny. Part of the review is knowing which is which.
For leavers with missing years, the certification test makes cleanup a precondition, not an option, and multi-year gaps are resolved through a structured catch-up path before the exit date is chosen.
Mapping your assets and roles against the date, in either direction, is the work of a Personal CPA Tax Resolution Case Analysis. Ed Parsons, CPA runs transition reviews for people moving between the Australian and U.S. systems, inbound and outbound, wherever they sit today.
