About Taxbordr: founder-led social security advisory for international residents
Taxbordr is a Lisbon-based cross-border tax advisory founded by Telmo Ramos, member of the Ordem dos Economistas, Cédula nº 16379. Telmo trained at KPMG Luxembourg and EY Lisbon, where Segurança Social mechanics across EU coordination and the US-PT Totalization Agreement were daily work. He founded Taxbordr in 2022. Every NISS registration, A1 application, USA/PT 1 reconciliation, and quarterly base calculation goes out under his name. The firm has handled 250+ cross-border cases, including social-security and IRS positions.
2026 contribution rates at a glance
| Category | Employee share | Employer share | Self-employed | |---|---|---|---| | Standard employee | 11% | 23.75% | | | Self-employed services | | , | 21.4% on 70% of declared quarterly income | | Self-employed goods | | , | 21.4% on 20% of declared quarterly income | | Board members (managers) | 11% | 23.75% | | | Board members (no executive function) | 9.3% | 20.3% | |
Rates are set by Código Contributivo (Lei 110/2009, as amended). The 21.4% self-employed rate is fixed; the variable is the contribution base (the 70% rule for service providers vs the 20% rule for goods sellers, applied to declared quarterly turnover). A first-registration 12-month exemption applies to first-time self-employed registrants meeting the prescribed conditions; the exemption is claimed at registration, not retroactively.
US-PT Totalization Agreement (1988)
The Acordo sobre Segurança Social entre os Estados Unidos da América e a República Portuguesa, signed 1988 and in force from 1989, prevents double Social Security taxation between the two systems.
Detached-worker rule: US workers temporarily assigned to Portugal can stay on US Social Security for up to 5 years (extendable by 1 year on case-by-case approval), using a Certificate of Coverage Form USA/PT 1 issued by the US Social Security Administration.
Reverse case: Portuguese workers in the US use a Portuguese-issued Certificate of Coverage from Segurança Social.
Self-employment coverage: independent contractors are covered under specific provisions of the agreement; the analysis depends on which country the activity is genuinely organised from, not where the client is.
Totalization for benefits: prevents loss of qualifying credits when retirement spans both systems; SSA and Segurança Social will combine quarters for entitlement calculation, with each system paying a proportionate benefit.
EU Social Security Coordination (Regulation 883/2004)
EU Regulation (EC) 883/2004 coordinates Social Security across EU/EEA Member States plus Switzerland. The default rule is contributions in the country of work. Cross-border posting allows up to 24 months on the home-country system with an A1 certificate issued by the home authority. Multi-state activity (working in two or more Member States) is allocated under Article 13 of the Regulation, typically to the country of residence if 25%+ of the activity is performed there. The UK is no longer in the system post-Brexit; the UK-EU Trade and Cooperation Agreement (Title XII) provides a similar but narrower framework with limited equivalence and case-by-case A1 issuance.
Quarterly declarations for self-employed (Janeiro / Abril / Julho / Outubro)
Self-employed taxpayers file an Income Declaration (Declaração Trimestral) on Segurança Social Direta in the relevant month per quarter:
January: declares Q4 of the prior year (Oct-Dec)
April: declares Q1 (Jan-Mar)
July: declares Q2 (Apr-Jun)
October: declares Q3 (Jul-Sep)
The declared turnover sets the contribution base for the next quarter (70% for services, 20% for goods). Monthly contributions due the 10th to 20th of the following month. Late declaration triggers an automatic estimated base from the prior period and a coima under Código dos Regimes Contributivos.
Certificate of Coverage and A1 documentation
US side: Form USA/PT 1, requested via SSA Office of International Programs. Lead time is typically 4-8 weeks.
EU side: A1 certificate from the home-country competent authority. Lead time varies by country.
Portuguese side: Segurança Social-issued residency or coverage certificate when needed for reverse cases.
Without a current certificate at the start of the cross-border period, the host-country system can claim contributions even where a totalization agreement applies, and recovery of overpaid contributions is procedurally slow. Document early. Refusals at the host side without an A1 are common despite the regulation; the document is the cure.
Board-member status: what to confirm before you accept
Portuguese SS treats board members under Código Contributivo as either standard non-executive (9.3% / 20.3%) or executive/manager (11% / 23.75%). The classification is fact-based: actual management responsibility, day-to-day decision authority, and remuneration structure. Mis-classified board members of family or holding companies are a common audit point at AT and Segurança Social. Confirm the classification in writing before the first payroll runs.
Common mistakes
Self-registering as self-employed in Portugal without claiming the first-year SS exemption (it is not automatic)
Operating without an A1 certificate or USA/PT 1 and absorbing double SS contributions
Misclassifying board-member status (manager rate vs standard rate) at incorporation
Underestimating quarterly base (70% vs 20% rule for services vs goods)
Missing the 24-month posting limit under EU Reg 883/2004 and continuing on home-country SS
Frequently Asked Questions
What are the Portugal social security contribution rates in 2026?
Employees pay 11% and employers pay 23.75% on gross salary. Self-employed taxpayers pay 21.4% on a contribution base equal to 70% of declared quarterly turnover (services) or 20% (goods). Non-executive board members pay 9.3% / 20.3%; executive board members pay 11% / 23.75%. Rates are set by Código Contributivo (Lei 110/2009).
Is there a first-year social security exemption for self-employed in Portugal?
Yes. A 12-month exemption from Segurança Social applies to first-registration as self-employed in Portugal under specific conditions (no prior registration in the same activity, registration completed at the start of activity). The exemption must be claimed at registration; it is not granted retroactively.
How does the US-PT Totalization Agreement work?
The 1988 US-PT Totalization Agreement (in force 1989) prevents double Social Security taxation. US workers temporarily in Portugal can stay on US Social Security for up to 5 years (plus 1-year extension) using Form USA/PT 1 from the SSA Office of International Programs. Self-employed and benefit-totalization provisions also apply.
Do I need an A1 certificate for cross-border work in Europe?
Yes if you are working in another EU/EEA Member State (or Switzerland) while remaining on Portuguese SS. The A1 certificate, issued by Segurança Social, evidences home-country coverage under EU Regulation 883/2004. Without a current A1, the host country can claim contributions despite the regulation.
When are Portuguese self-employed quarterly declarations due?
In January (Q4 prior year), April (Q1), July (Q2), and October (Q3) on Segurança Social Direta. The declaration sets the contribution base for the following quarter (70% of declared services turnover; 20% of declared goods turnover). Monthly contributions are paid the 10th to 20th of the following month.
Are board members in Portugal subject to social security?
Yes. Portuguese SS classifies board members as either non-executive (9.3% employee / 20.3% employer) or executive/manager (11% / 23.75%) depending on actual management responsibility and remuneration structure. The classification is fact-based; confirm it in writing before the first payroll.
What is NISS and how do I get one?
NISS is the Número de Identificação de Segurança Social, the Portuguese SS identification number. New residents register at a Loja de Cidadão or the local Centro de Segurança Social with passport, NIF, residence proof, and (for employees) an employment contract. Self-employed register before starting activity at the same offices or via Segurança Social Direta.