Three countries have a plausible claim on the same salary. Two of them will not get it, one will take considerably more than the person expected, and the arrangement creates a risk for the employer that nobody in the chain has thought about.
The facts, which we will keep fixed throughout: a Brazilian citizen holds a Portuguese residence permit and lives in Lisbon. He works remotely, full time, for a company incorporated in the United States. He is not a US citizen and does not hold a green card. He has no US clients of his own, and he has not set foot in the United States during the tax year.
Almost everyone gets this case wrong in the same direction: they assume that because the employer is American and the money originates in America, some part of the tax belongs to America. It does not. But the correct answer is not the comfortable one either.
Everything follows from tax residence, and tax residence has nothing to do with citizenship. His Brazilian passport is irrelevant to the analysis. What matters is where he physically is and where his life is centred.
Portugal treats an individual as tax resident on more than 183 days in any twelve-month period, or where they maintain a dwelling in circumstances suggesting an intention to keep it as a habitual residence. Living in Lisbon on a residence permit satisfies this comfortably. He is a Portuguese tax resident, and Portuguese residents are taxed on worldwide income.
The governing principle for employment income in essentially every treaty, including the Portugal–US convention, is that salary is taxable where the work is physically performed. Not where the employer is registered, not where payroll runs, not where the bank account sits. Where the person's body is when they do the work.
He performs the work in Lisbon. The salary is Portuguese-source employment income, and the fact that it arrives from a Delaware corporation changes nothing about that characterisation.
The US taxes non-resident aliens on income from US sources, and compensation for personal services is sourced to the place where the services are performed. Services performed entirely in Portugal are foreign-source income from the US perspective, and foreign-source income of a non-resident alien is outside US taxing jurisdiction.
Practically this means the employer should not be withholding US federal income tax, and the individual should have a valid Form W-8BEN on file. Where things go wrong is administrative rather than legal: a payroll department that treats him as domestic, withholds, and issues a W-2. The money is recoverable, but recovering it means filing a US non-resident return to claim back tax that was never owed.
One qualifier changes the entire analysis: if he were a US citizen or green card holder, the United States would tax him on worldwide income regardless of where he lives. He is not — but it is the first question worth asking of anyone presenting this fact pattern, because people volunteer their current passport and forget to mention a second one.
Brazil taxes its residents on worldwide income, and Brazilian tax residence does not end because you bought a plane ticket. It ends when you formally declare it ended, through the Declaração de Saída Definitiva do País.
Not filed — and this is the single most common defect we see in Brazilian client files — and Brazil continues to regard him as resident. He is then simultaneously resident in two countries, with both taxing the same salary. The treaty contains tie-breakers that will eventually resolve it, usually in Portugal's favour on these facts. But "eventually" involves invoking a treaty and possibly a mutual agreement procedure between two administrations. It is an expensive way to fix a filing that would have cost an afternoon.
Portuguese personal income tax is progressive, reaching roughly 48% at the top bracket with an additional solidarity surcharge on very high incomes. For a well-paid remote engineer on a US salary, a substantial part lands in the upper brackets.
Portugal's non-habitual resident regime closed to new entrants and was replaced by IFICI, which offers a flat 20% on qualifying employment income for ten years. On the surface, a highly-qualified tech professional moving to Lisbon looks like the intended beneficiary.
He almost certainly does not qualify, and the reason is structural. IFICI attaches not only to what you do but to who employs you: eligible employment must be with a qualifying Portuguese entity — a certified startup, a recognised technology or innovation centre, an entity benefiting from certain investment incentives, or a company deriving a defined share of turnover from exports. A US corporation with no Portuguese establishment is none of these.
The regime was designed to attract talent into the Portuguese economy, not to subsidise foreign employers. Whether that is good policy is a separate argument; it is what the rules say.
Social security is a separate system with separate rules, and it is where remote arrangements most often turn out to be structured wrongly. The threshold question is whether he is genuinely an employee or a contractor. Many US companies "hire" internationally by paying an invoice, which makes the individual self-employed in Portugal, registering and paying contributions personally.
If the relationship has the substance of employment — fixed hours, direction and control, exclusivity, integration into a team — labelling it a contract does not make it one. Portugal looks at substance, and a misclassified relationship can be recharacterised with contributions and penalties attaching to the employer.
Where he is properly an employee of the US entity, the Portugal–United States totalisation agreement governs which system applies and prevents contributions being owed twice.
Everything above concerns the individual. There is a second exposure sitting entirely with the American company, and it is usually the reason a US employer eventually says no.
An employee working habitually from Portugal can create a permanent establishment for the employer — a taxable presence in Portugal. The risk is low for a purely internal role with no customer-facing authority. It rises sharply where the individual negotiates contracts or concludes sales. A remote salesperson in Lisbon is a considerably more dangerous proposition for a US employer than a remote back-end developer.
Change one variable. Same citizen, same employer, same work — living in Madrid instead of Lisbon. The first half of the analysis is identical: Spain has the taxing right, the United States still has none, and ordinary Spanish rates run to roughly 47%.
The difference is what Spain offers on top. The special regime for inbound workers — the "Beckham Law" — was extended by the Startups Law to cover exactly this profile: people who move to Spain to work remotely for a foreign employer. Qualifying individuals are taxed at a flat 24% on employment income up to €600,000, for the year of arrival plus five.
The conditions are real: no Spanish tax residence in the preceding five years, a move connected to the work, a limited share of income from Spanish clients, and the election filed on Modelo 149 within six months of registering with Spanish social security. That deadline is absolute.
The comparison is uncomfortable for Portugal on this specific fact pattern. Portugal's incentive requires a qualifying Portuguese employer, which a remote worker for a US company by definition does not have. Spain's requires a foreign employer, which is precisely what he has. If the Spanish route is worth examining, our Spanish practice handles it at voixa.es.
The employer's location is nearly irrelevant. People organise their thinking around where the money comes from; tax authorities organise theirs around where the person is.
Special regimes are drafted narrowly and on purpose. The gap between "Portugal has a 20% flat regime" and "this person can use it" is the entire substance of the analysis.
The exit is as important as the entry. The most expensive defect in this file has nothing to do with Portugal or any incentive regime. It is an unfiled Brazilian exit declaration — administration that costs nothing at the time and produces a dual-residence conflict that costs a great deal later.
Most of these situations resolve cleanly once the facts are set out in order. The ones that do not are usually missing an exit declaration.