An international assignment changes your tax position on the date you arrive, rather than at the end of the tax year, and for most assignees it creates obligations in two countries at once. This guide is meant for relocating employees and expats to help them understand tax residency, filing timing across ten common destinations, what an employer tax policy typically covers, and which party to approach for each type of question. It sits alongside, and does not replace, advice from the assignment tax adviser appointed for your move.

This guide is written for relocating employees and expats. For the employer-facing counterpart covering programme obligations, shadow payroll and compliance frameworks, see our expatriate tax compliance guide for HR and finance teams.

Tax residency and what changes on arrival

Tax residency is the legal test that determines which country holds primary taxing rights over your income. It is the single factor that drives most other outcomes in an assignment, including where tax is withheld, where returns are filed, and which reliefs are available.

Many countries anchor the test around a day count, commonly at or near 183 days in a twelve month period. Several layers in further tests covering whether a home remains available to you, where your family is based, and where your centre of vital interests sits. Arriving in a host country does not automatically end residency at home, and dual residency is common in the year of the move. Where both countries have a double tax treaty in force, tie breaker provisions in that treaty determine which one takes precedence.

Two positions sit outside the general pattern. Citizens and green card holders of the United States remain taxable on worldwide income regardless of where they live, so a US assignee files at home every year of an assignment. Assignees moving to or from Australia and India encounter tax years that do not follow the calendar, which affects how the arrival year is split.

For a full overview of how international employee moves are structured from the employer side, see our guide on how to move employees from one country to another.

Filing deadlines across common assignment destinations

Filing deadlines are set by each host country tax authority and run to a local tax year that does not always follow the calendar. The table below sets out the general position in ten destinations that appear regularly in assignment programmes.

Country	Tax year end	Usual individual filing deadline	Point assignees most often miss
Germany	Calendar year	31 July following the tax year, extended where a registered tax adviser files	Host taxation can be triggered on short assignments where assignment cost is recharged to the German entity
Netherlands	Calendar year	1 May following the tax year, extension available through a registered adviser	Arrival and departure years are usually split-year filings rather than full-year ones
France	Calendar year	May to June following the tax year, staggered by department for online filing	Tax is withheld at source during the year, and the annual return still has to be filed
United Arab Emirates	Not applicable for personal income tax	No individual income tax return	End of service gratuity and, for GCC nationals, social security obligations still apply
Japan	Calendar year	15 March following the tax year	Employer year end adjustment does not cover assignees with foreign source income, who file separately
Canada	Calendar year	30 April following the tax year	Departure from Canada can trigger a deemed disposition of certain assets in the year of the move
Australia	30 June	31 October, later where a registered tax agent lodges on your behalf	The tax year runs to 30 June, so arrival timing splits the first return differently from calendar year countries
India	31 March	31 July following the financial year for individuals not subject to audit	Residency is assessed on day count within the April to March year, and foreign asset reporting applies to residents
Brazil	Calendar year	Late April following the tax year	A definitive exit communication and exit return are required on departure, otherwise worldwide taxation continues
Singapore	Calendar year	18 April following the tax year for electronic filing	Tax clearance must complete before final salary is released on departure

Deadlines move where a registered tax adviser or tax agent files on your behalf, and several countries operate extension regimes that apply automatically in that situation. Filing dates are also revised periodically, so the assignment tax adviser appointed for your move confirms the date that applies to your circumstances and the year in question.

For a full breakdown of the visa and work permit process in each of these destinations, see our guides for Germany, the Netherlands, France, the UAE, Japan, Canada, Australia, India, Brazil and Singapore.

Tax equalisation, tax protection and hypothetical tax

Tax equalisation, tax protection and laissez faire are the three policy approaches that determine how tax cost is shared between an employer and an assignee. The approach that applies to your move is set at programme level and stated in the assignment letter.

Under tax equalisation, the aim is to leave you in broadly the same tax position you would have held had you remained at home. The employer meets the actual home and host tax liability on assignment income, and a notional home country amount known as hypothetical tax is deducted from your pay across the assignment. This is the reason gross and net figures on an assignment payslip differ from those of a comparable domestic role. A reconciliation follows each tax year and can produce a balance owed in either direction. For a full breakdown of what relocation cost estimates should cover, see our guide on the importance of cost estimates in talent mobility and relocation.

Tax protection caps the downside for the assignee while allowing you to retain the benefit where host country tax turns out to be lower. Under laissez faire, the tax outcome rests with the assignee, whether favourable or otherwise. Questions about which approach applies, and what it covers, go to the global mobility team rather than to payroll.

For a full breakdown of how relocation policies are structured and what each type covers, see our guide on understanding relocation policies.

Social security contributions and coverage certificates

A coverage certificate is documentary evidence that social security contributions remain payable in your home country for the duration of an assignment. Within the European Union, the European Economic Area and Switzerland this is the A1 certificate. Under bilateral totalisation agreements elsewhere, the equivalent is a certificate of coverage.

Certificates are applied for by the employer and secured before departure. Where one is not in place, social security can fall due in both countries on the same income, which in several jurisdictions represents a larger cost than income tax. Continuity of contributions also affects your state pension record and, in some countries, healthcare entitlement. The global mobility team confirms certificate status.

Which party to approach for each tax question

Responsibility for assignee tax questions divides across the assignment tax adviser, the employer global mobility team, home and host payroll, and any personal adviser you appoint yourself. The table below maps common questions to the party that holds the answer.

Question	Party to approach
Your host country tax return, residency position and any correspondence from the host tax authority	The assignment tax adviser appointed by your employer
Which tax policy applies to your assignment and what the assignment letter covers	Your employer global mobility team
A deduction or figure you do not recognise on your host payslip	The host country payroll provider
Hypothetical tax shown on your home payslip and how the amount was calculated	Home payroll for the deduction itself, and the assignment tax adviser for the calculation basis
Whether your A1 or certificate of coverage has been issued	Your employer global mobility team, working with the payroll function
Registering for a host country tax number	The assignment tax adviser, who files or supports the registration
Visa conditions or permit changes that affect how long you can remain in the host country	The immigration lawyer engaged by your employer
Rental income, investments, cryptoassets, property sales, inheritance and estate planning	A personal tax adviser you appoint, in most cases at your own cost
Income your spouse or partner earns in the host country	A personal tax adviser, unless the assignment letter states otherwise

For a full breakdown of what rights a partner holds in the host country, see our guide on what happens to your dependent’s visa when you relocate for work.

Tax matters that sit outside the assignment package

Assignment tax support covers income and benefits arising from the assignment itself, and does not extend to personal financial affairs. The distinction is set out in the assignment letter and is worth reading closely before the move.

Matters that ordinarily fall to the assignee include rental income from a property retained at home, investment and dividend income, gains on cryptoassets, property sale proceeds, inheritance, and estate planning. Income earned by a spouse or partner in the host country also sits outside the package in most programmes. Some employers fund a limited personal consultation with the assignment tax adviser, with the scope defined in the assignment documentation.

Documentation to retain across the assignment

Assignment tax filings depend on records that are considerably simpler to keep as the assignment proceeds than to reconstruct at year end. The following items are requested most frequently by assignment tax advisers.

• The assignment letter and any amendments or extensions
• The record of the pre assignment tax briefing
• The A1 certificate or certificate of coverage
• Payslips from both home and host payroll for every month of the assignment
• A travel record showing days spent in each country, including business travel to third countries
• Host country tax registration details and any correspondence from the tax authority
• Tax returns filed in both countries for the years covered by the assignment

For a full pre-departure preparation framework, see our expat checklist.

Repatriation and tax clearance

Tax clearance is a departure process operated in several countries that must be completed before final payments are released to a departing employee. In Singapore, the employer files a clearance return ahead of departure and withholds final salary until the position is settled. In Brazil, a definitive exit communication and an exit return are required, and worldwide taxation continues where these are not filed.

Obligations continue after the move home. Host country returns for the final assignment year fall due after repatriation, equalisation settlements are often finalised well into the following year, and departure from Canada can trigger a deemed disposition of certain assets. The assignment tax adviser normally remains engaged through this trailing period, and the end date of that engagement is worth confirming before departure.

For HR and mobility teams managing the tax coordination dimension of international assignments, MOVEPLUS™ supports the programme through our consultancy services helping organisations design compliance frameworks, coordinate with tax advisers, and maintain visibility across the full assignment lifecycle.

Get in touch to discuss how MOVEPLUS™ can support your programme.

Frequently asked questions

1. Do assignees pay tax in two countries at the same time?

Filing in two countries is common during an assignment, and paying full tax twice on the same income is not the intended outcome where a double tax treaty applies. Treaty provisions allocate taxing rights between the two countries and give credit for tax already paid. Where an employer operates tax equalisation, the employer meets the actual liability in both countries on assignment income.

2. When does an assignee become a tax resident in the host country?

Residency is determined by the host country test, which commonly combines a day count with further factors such as availability of a home and location of family. The threshold sits at or near 183 days in many countries, and several apply residency from the date of arrival where the move is clearly permanent. The assignment tax adviser confirms the position for a specific move.

3. Who files the host country tax return for an assignee?

In most assignment programmes the employer appoints an assignment tax adviser who prepares and files the host country return on the assignee behalf. The assignee supplies the underlying information and signs the return. Personal income outside the assignment package is filed by the assignee, in many cases with a personal adviser.

4. What is a hypothetical tax on an assignment payslip?

Hypothetical tax is a notional home country tax amount deducted from pay under a tax equalisation policy. It replaces the actual home country deduction that would have applied in a domestic role, and the employer then meets the real home and host liability. The amount is reconciled after each tax year.

5. What happens if an A1 certificate or certificate of coverage is not obtained?

Without a valid certificate, social security contributions can become payable in both the home and the host country on the same income, and recovering contributions paid in error is a lengthy process in most jurisdictions. Certificates are applied for by the employer before departure, and their status is confirmed by the global mobility team.

6. Do tax obligations end when an assignment ends?

Obligations continue after repatriation in most cases. A final host country return falls due after the move home, tax equalisation settlements are often finalised in the following year, and several countries operate departure clearance or exit filing requirements. The engagement period of the assignment tax adviser should cover this trailing phase.