Does my cost base reset when I become a tax resident?
In most systems that tax on residence, property you already hold when you arrive is generally treated as acquired at its value on that day. The effect is that the growth from the year you bought it to the day you landed sits outside the new country's reach, and only what happens afterwards is measured there. Two limits are worth knowing. The reset applies to what you actually hold at arrival, so anything sold beforehand is a transaction in the old system instead. And some categories of property are excluded in some countries, so the rule has to be confirmed asset by asset rather than assumed.
What proof do I need of my assets' value on arrival day?
Something contemporaneous, dated, and from a source you did not create. For listed holdings, broker or custodian statements spanning the arrival date do the work, along with the closing prices for that day. For bank and deposit accounts, statements either side of it. For real property, an appraisal instructed at the time rather than a market estimate recalled later. For private company shares, a valuation with its assumptions written down and the financial statements it relied on. Keep the currency conversion source as well. The evidence is cheap to obtain in the weeks around arrival and expensive or impossible to obtain years later.
Which exchange rate applies to property I owned before moving?
The reset fixes a value on a particular day, so the conversion has to be to that day too, not to the rate when you bought the asset and not to an average for the year. In practice you need the value in its own currency at the arrival date and a published rate for the same date, kept with the rest of the file. Where the asset is later sold, the gain is the difference between two converted figures, so the currency movement between arrival and disposal forms part of what the new country measures. That is why the arrival-day rate is recorded at the time.
Does the step-up apply to property I bought after arriving?
No. Anything acquired once you are resident has its own cost and its own history inside the new system, and nothing needs to be reset. The distinction matters when a portfolio is held in one account across the move, because a later statement shows a single line for a holding that was partly bought before arrival and partly added afterwards. Separating the two at the time, rather than reconstructing them at the first disposal, is the whole of the work. A schedule prepared in the arrival year that marks each holding as pre-arrival or post-arrival will still be usable a decade later.
How do I value a private company on my arrival date?
By instructing a valuation then, with its basis recorded, rather than negotiating one with a tax authority later. There is no market price to fall back on, so the file has to carry the reasoning: the financial statements used, the method, the assumptions about the company's prospects on that date, and any shareholder agreement affecting what the shares could be sold for. A valuation prepared at the time and never used costs a fraction of a dispute over a figure reconstructed from memory. If the company is likely to be sold within a few years of the move, treat it as the priority item in the arrival file.
I arrived years ago with no valuations — what now?
The reset still applies. What is missing is the evidence for it. The work becomes reconstruction: archived broker statements, historical closing prices for the arrival date, bank records requested from the institution, land registry and comparable sale data, and old financial statements for private holdings. For some assets that produces a defensible figure. For others, particularly private shares and anything unique, the honest answer is that a figure rebuilt after the fact is weaker than one recorded at the time, and the position should be documented with its limitations stated rather than presented as certain.
What is a permanent establishment, and how easily do we create one?
A taxable presence in another country under the treaty — typically a fixed place of business such as an office, branch, factory or workshop, or a dependent agent habitually concluding contracts on your behalf. Some treaties add a services test measured in days. Purely preparatory or auxiliary activity is excluded, but that carve-out is narrower than it sounds: one senior employee working from home in the other country, with authority, has been enough. See business profits and permanent establishment.
Which country do I pay tax to first?
Generally the source country — where the income arises — taxes first, often by withholding before you receive it. Your country of residence then taxes the same income and credits what the source country took. That order is why timing matters: a residence-country return filed before the source-country tax is settled has nothing to credit yet. Getting the sequence right is most of the work. See international tax planning.
