Am I a dual-status alien if I moved mid-year?
Usually yes, if the move changed your US residence status during that year. A dual-status year is one where you were a non-resident for part of it and a resident for the rest, which is why it arises most often in the year of arrival or the year of departure. The return then covers both periods on different rules, so the first task is not the arithmetic but the date: what fact made your status change, and what evidence fixes it. Once the split date is settled, each item of income is assigned to the side of the year it falls in. Get the date wrong and everything downstream is wrong with it.
Which tax year is my dual-status year?
The year your status changed, and not the years on either side of it. Before it you were a non-resident for the whole year; after it you are a resident for the whole year. Only the transition year carries the two sets of rules at once. People sometimes assume the dual-status treatment continues into the following year because the move itself was spread over months, and that is not how the year is characterised. It is the change of status that matters, and the year in which it happened. If you moved late in one year and settled in the next, work out which year the status actually changed in before filing either.
Does income earned before I arrived in the US count?
It is not ignored, but it is looked at under the rules that applied while you were still a non-resident, which reach a narrower field than the rules for the resident part of the year. So the question is really one of allocation: which side of the split date does each amount fall on, and on what basis, whether that is when it was earned, when it was paid or when it vested. Employment income, investment income and a gain on a sale can each answer that differently. This is the part of a dual-status return worth doing slowly, with the documents in front of you, because it is also the part an authority can most easily test later.
Why not just file as a US resident for the whole year?
Because it changes what is inside the return. A full-year resident return applies resident rules to the months you were not a resident, which pulls in income from before you arrived or after you left. You may then spend the rest of the return claiming relief for foreign tax on income that did not need to be there in the first place. In some situations a full-year treatment is available and sensible, and in others it is simply the wrong characterisation of the year. It is a decision to take deliberately, with both treatments worked out in front of you, rather than a default.
What if I already filed the wrong way for that year?
It can be corrected. The usual sequence is to establish what the year should have looked like, document the split date and the allocation behind it, and then put the corrected position in. Two things make that easier. The first is contemporaneous evidence of the move: travel records, a lease or a sale, an employment start date. The second is consistency, because the same date and the same reasoning should appear in whatever you file on the other side of the border for the same period. A position explained one way in one country and another way in the other is the thing most likely to draw a question.
Does a dual-status US year affect my Canadian return?
It affects how the two returns sit together, yes. Canada decides your residence on its own tests and its own dates, and those dates do not have to match the US split date. So the same calendar year can contain a period each country treats as its own, a period neither does, or a period both do. None of that is unusual. What causes trouble is filing the two returns as if they were unconnected, so that a month of income is reported on a resident basis twice, or is quietly left out of both. Prepare them together and reconcile the periods before either is sent.
How would a foreign tax authority know I am resident there?
Mostly from information you or your bank already provided. Account-opening forms ask you to self-certify tax residence, and that certification is reported between authorities under the Common Reporting Standard or, for US accounts, under the FATCA framework. Beyond that: employer and payroll filings, property registries, immigration records and the tax filings of anyone who paid you. The realistic planning assumption is that the data arrives. See FATCA and information reporting.
Which countries have a tax treaty with the United States?
Around sixty, including Canada, the United Kingdom, India, Australia and most of western Europe — but the list matters less than the terms, because each treaty caps rates and allocates income differently. Two countries with treaties can produce opposite answers on the same pension or the same royalty. What decides your position is the specific article covering your income type. See our country guides.
