Employees working abroad: US employer duties
Reviewed by Mellow Editorial Team, HR & payroll content team
US employers remain responsible for certain tax, payroll, and compliance obligations when an employee works abroad — but the exact duties depend on where the employee works, for how long, and whether a tax treaty applies.
What triggers your obligations
The moment an employee moves their work location to another country, two sets of rules come into play simultaneously: US law and the law of the host country. Neither automatically waives the other.
On the US side, American citizens and permanent residents are subject to US federal income tax on worldwide income regardless of where they physically work. That means you generally continue withholding federal income tax unless the employee claims the Foreign Earned Income Exclusion (FEIE) on their personal return and instructs you accordingly. Withholding doesn't stop automatically just because someone boards a plane.
FICA obligations — Social Security at 6.2% (employee and employer each) up to the annual wage base, plus Medicare at 1.45% each side — typically continue for US employees working abroad, unless a totalization agreement applies (see below). There is no blanket overseas exemption.
Totalization agreements and why they matter
The US has totalization agreements with several dozen countries. These treaties exist to prevent double Social Security taxation: when a covered agreement is in place, the employee pays into one country's system, not both.
If your employee is working in a country with a US totalization agreement, you need to determine which country's system covers them. For short-term assignments (often under five years), the employee usually remains covered under the US system and you continue FICA. For longer stays, coverage may shift to the host country, and you stop withholding US Social Security and Medicare taxes.
Get a Certificate of Coverage from the Social Security Administration before you stop FICA withholding. Operating without one leaves you exposed if the IRS audits the payroll later.
Host-country payroll and permanent establishment risk
Working abroad doesn't eliminate host-country obligations — it often creates new ones. Many countries require employers to register locally and run payroll through a local entity once an employee works there beyond a certain threshold. Some countries set that threshold as low as a few months.
Even before payroll registration is required, an employee working in another country can inadvertently create a "permanent establishment" — a taxable presence — for your company under local corporate tax rules. This is one of the most commonly overlooked risks of remote-abroad arrangements. The specifics depend entirely on the host country's domestic law and any applicable tax treaty with the US.
Practically, this means that before an employee relocates or extends a stay beyond a short trip, you need local legal or tax advice in that country — not just a review of US rules.
Reporting and documentation
US reporting obligations don't pause for overseas employees. You still file Form 941 quarterly and issue Form W-2 by January 31, showing wages paid and any US tax withheld. If you reduce or stop withholding because of a totalization agreement or FEIE claim, document the basis carefully.
The employee has their own obligations too — particularly if they hold foreign bank accounts or financial assets above certain thresholds, which triggers FBAR and FATCA reporting on their personal returns. That's not your direct burden as an employer, but being aware of it helps you support employees who may not realize what they've signed up for.
If you're also engaging workers abroad as independent contractors rather than employees, the test for classification is the same as it is domestically: it's about the nature of the working relationship, not the worker's location. Misclassification carries the same penalties overseas that it does at home. Contractors who are not US persons generally don't require a Form W-2 or 1099-NEC for services performed entirely outside the US, but the classification question has to be answered correctly first.
Practical steps before an employee goes abroad
Run through these before the assignment starts:
Check the totalization agreement. Look up whether the destination country has one with the US, and get the Certificate of Coverage if you'll keep FICA running.
Assess permanent establishment risk. Brief legal counsel in the host country on what the employee will be doing and for how long.
Clarify withholding. Ask the employee whether they intend to claim the FEIE and update your payroll accordingly — don't assume.
Review the employment contract. Confirm which country's employment law governs termination, benefits, and working conditions. In some countries, local mandatory minimums override a US contract automatically.
Set a review date. A two-week business trip has different implications than a six-month relocation. Build in a checkpoint so that a temporary stay doesn't drift into a compliance problem.
For companies managing employees across multiple countries, how Mellow runs payroll across six countries on one platform gives a practical overview of how to centralize that complexity without setting up separate legal entities in each location.
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