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Global Mobility programmes often involve a combination of salary, allowances, benefits, equity, and assignment-related support.
While these elements may appear straightforward from a policy perspective, their tax treatment can vary significantly depending on how compensation is structured, where services are performed, and how long an employee is present in a particular jurisdiction.
The second session in AIRINC & Andersen’s Mobility Tax: The Essentials Refresher series focused on Tax and Mobile Compensation, building on the first session’s discussion of allowances and expenses, gross-up, and mobility payroll.
This session examined how compensation structure, assignment duration, equity, corporate tax considerations, and cost modelling can all affect the overall tax position and employer cost.
How Can Compensation Structure Affect Mobility Tax?
One of the central themes of the session was that the tax treatment of a benefit may depend not only on its value, but also on how it is delivered.
Housing is one example. In China, housing paid directly to a third party or supported by qualifying receipts can currently receive different tax treatment from a cash allowance. The session also considered moving expenses and per diems, where local rules may determine whether an amount can be provided on a tax-advantaged basis or must be treated as taxable compensation.
These differences can be significant when viewed across an entire assignment.
Compensation structuring may therefore involve considering whether a benefit should be provided in cash or in kind, whether an expatriate tax concession is available, whether host or shadow payroll is required, and whether local employment or posted worker requirements affect the proposed arrangement. The timing of payments and the duration of the assignment may also influence the tax outcome.
The key point is that compensation design and tax should be considered together. A policy may define the benefit an employee is entitled to receive, but the method of delivery can materially affect the employer’s overall cost.
How Does Assignment Length Affect Tax?
Assignment length can be an important factor in determining whether an employee is taxable in the host jurisdiction.
Certain short-term assignments may qualify for an income tax treaty exemption where the relevant conditions are satisfied. These conditions often include a day-count test, together with requirements relating to which entity pays or bears the employee’s compensation and whether a permanent establishment is involved.
The often-cited 183-day threshold should not, however, be considered in isolation.
An employee who spends fewer than 183 days in a host country may still be taxable there if the other treaty conditions are not met. The employment structure, allocation of costs, and the employee’s residence position under the applicable treaty all need to be considered.
Some jurisdictions also offer specific concessions for qualifying expatriates, such as an exclusion for part of an employee’s income or a preferential tax rate.
For Mobility teams, this means assignment duration should be considered alongside the employment and compensation structure rather than treated as a standalone test.
Poll #1: How Are Companies Structuring Mobility Allowances?
During the session, we asked participants:
Does your company vary the pay delivery of allowances in order to take advantage of certain tax concessions?
- Yes 31%
- No 23%
- I’m not sure 47%
These results show that programs are mixed when it comes to tax planning on pay delivery, or it's an unknown. Tax planning on how a certain benefit is provided to the employee can be a useful tax savings tool for mobility programs.
How Can Companies Better Manage International Assignment Tax Costs?
Managing assignment tax costs starts with planning.
The session highlighted the importance of clarifying expected expenditure at the outset, communicating anticipated costs to the relevant Business Unit, obtaining budget approval, and establishing an appropriate accrual with Finance.
That process should continue throughout the assignment.
Assignment costs can change as a result of tax rates, compensation changes, exchange rates, assignment extensions, family circumstances, or changes in local rules. For that reason, assumptions made at the beginning of an assignment should be reviewed regularly.
The session also highlighted several common areas of risk, including assuming that a local-to-local arrangement will necessarily be the lowest-cost option, overlooking social security costs, or assuming that costs will remain consistent from year to year.
A further point was that effective cost management begins with a coherent mobility policy.
Where exceptions or additional commitments are agreed by the business before Mobility and Tax are involved, the organisation may have fewer opportunities to manage the resulting cost efficiently.
Why Is Equity So Complicated for Mobile Employees?
Equity can create particular challenges for mobile employees because the lifecycle of an award may span several jurisdictions.
An award may be granted while an employee is working in one country, continue to vest after a move, be exercised in another location, and ultimately be sold after a further transfer.
This can create differences in both the timing and sourcing of taxable income.
The session considered the key stages of an equity award — grant, vesting, exercise, and sale — and the questions that arise where an employee has performed services in more than one jurisdiction during that period.
Depending on the countries involved, home and host jurisdictions may not tax the award at the same point. They may also apply different sourcing rules.
This means employers may need to consider when the award becomes taxable, how income should be allocated between jurisdictions, whether a treaty applies, whether trailing awards remain taxable after departure, and whether reporting, withholding, or individual filing obligations arise.
In some cases, pre-move planning may also be relevant, particularly where the timing of an exercise or other taxable event could affect the outcome.
What Are the Employer’s Responsibilities for Mobile Employee Equity?
The technical tax treatment of an equity award is only one part of the issue.
Employers also need to ensure that the appropriate operational processes are in place.
This may involve determining the correct amount of tax to withhold globally, coordinating payroll and stock plan administration, identifying employees who require specialist reporting, and ensuring that payroll systems can accommodate any necessary adjustments.
Employee communication is also important.
Equity income can be difficult for employees to understand even in a domestic context. Where multiple jurisdictions are involved, it becomes particularly important to explain what has been reported, where tax has been withheld, and whether additional filing obligations remain.
Ultimately, the employer is responsible for meeting its reporting and withholding obligations. Reliable employee tracking and coordination between Mobility, Payroll, Tax, and equity administration are therefore critical.
Poll #2: Which jurisdiction will generally assess tax on equity compensation?
During the session, we asked participants:
Which jurisdiction will generally assess tax on equity compensation?
- Issuing country 13%
- Host country 3%
- Not taxable in any jurisdiction 1%
- Possibly home and host countries 72%
- I don’t know 11%
For international assignments spanning the life-cycle of an equity award, the answer is likely both the home and host jurisdictions, but it also depends on local regulations, the type of award, and possible treaty relief.
What Corporate Tax Risks Can Mobile Employees Create?
Employee mobility can also create tax and compliance considerations for the organisation itself.
The session covered issues including permanent establishment, transfer pricing, entity-level questions around which company benefits from the employee’s services, payroll compliance, social security coordination, posted worker requirements, and pay equity.
Remote workers and commuters have made these issues increasingly relevant.
An employee may begin performing services in a jurisdiction where the business does not otherwise expect to have a workforce presence. Depending on the facts, that may create corporate, payroll, or reporting obligations in addition to the employee’s personal tax position.
This reinforces the need for coordination between Mobility, Tax, Payroll, Finance, HR, Legal, and the business when cross-border working arrangements are established or changed.
Why Do Cost Projections Matter?
Cost projections are not simply budgeting tools. They can also support decision-making before an assignment structure or policy exception is approved.
The session focused on four areas where projections can add value: comparing structures, supporting budgeting and accruals, improving alignment between Tax and Finance, and modelling the impact of policy exceptions.
The benefit of scenario modelling is that it allows the organisation to assess the full cost of a decision before committing to it.
That is particularly important where tax equalization or gross-up applies, because the face value of a benefit does not necessarily reflect its cost to the employer.
How Can Benefit Delivery Change the Total Assignment Cost?
The session concluded with a practical scenario involving a long-term assignment from Houston to Beijing for a family of four, running from January 2027 to December 2028.
Under the initial scenario, housing was provided directly by the company and the projected assignment cost was USD1,536,989.
The scenario was then recalculated on the basis that the same housing benefit would instead be provided as a cash allowance.
The revised projected assignment cost increased to USD1,647,365.
The difference was USD110,376, driven by the additional tax cost associated with the change in delivery method.
The example illustrates why seemingly small policy or delivery changes should be modelled before approval.
The value of the employee benefit may be unchanged, but the total employer cost can be materially different.
Want the Full Discussion?
This article highlights some of the principal themes discussed during the webinar, but each area involves additional technical and practical considerations.
The full session explores the interaction between compensation structure, assignment duration, equity, employer obligations, corporate tax considerations, and cost modelling in more detail.
CRP/GMS Credit
This webinar was eligible for 1 CRP/GMS credit. If you watch the webinar recording, you can download the certificate for claiming CRP/GMS credits here.
Coming Next: Tax Considerations for Different Assignment Types
The next session in the Mobility Tax: The Essentials Refresher series will look at how tax considerations change across different types of mobility.
Session 3: Tax Considerations for Different Assignment Types
November 17 | 10:00 AM Boston / 4:00 PM Brussels
The session will cover tax equalization and tax protection, short-term assignees, business travelers and remote workers, the application of tax treaties, and social security and totalization agreements.
Presenters:
Patrick Jurgens, Director of Global Tax, and Jeremy Piccoli, Director of Global Tax Solutions at AIRINC, with Adam Schwartz, Director and Global Mobility Tax Transformation & Technology Lead, and Lynda Ngo, Director of Global Mobility at Andersen.
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