Cross-Border Wealth Planning: Dubai, Portugal, Switzerland

This guide to cross-border wealth planning is for a family whose wealth sits in Dubai, Portugal and Switzerland. Its conclusion: every question needs one named owner, and the whole needs one coordinator who holds the map but not the money. Take a composite family, not a client. The founder sold a company and kept the holding entity in Dubai, where the family lives most of the year. One spouse moved to Lisbon with the children for school and is now a Portuguese tax resident. The liquid wealth, tens of millions, is booked at a private bank in Geneva. Their planning runs through a Portuguese tax advisor, a UAE tax agent, a Swiss private banker and a lawyer in each country. Each is competent. Each sees one country. Below: a matrix of who owns which question, the treaty, reporting and succession questions that cross all three countries, and how to coordinate the advisors without one of them taking over.

Our family’s wealth is spread across Dubai, Portugal and Switzerland: who should own which question, and how do we coordinate the advisors in three countries without one of them taking over?

Each question has one owner: residence and filings go to the tax advisor in each country, structures and succession to the lawyers, custody and execution to the bank, and decisions stay with the family. Coordination belongs to someone paid only by the family, who holds the map, the calendar and the reporting, not the money.

In practice, that is rarely how it works. The default coordinator is the Swiss private banker, for a simple reason: the bank is the only advisor that sees money move. It sees the dividend arrive from the Dubai holding, the transfer to the Lisbon account, the capital call from a fund. The Portuguese tax advisor sees the IRS return once a year. The UAE tax agent sees the corporate tax file. The lawyers see documents when someone asks for one. So the family starts asking the banker the questions that sit between the countries, and the banker starts answering them.

That is a conflict, not a failing of the banker. The bank is paid on assets booked and products placed. Its view of the family’s tax residence is the self-certification in its file. Its view of the structure is the entity that opened the account. It has no mandate to tell the family that a Portuguese filing is missing or that a Dubai will conflicts with an EU choice of law, and no incentive to recommend moving money elsewhere. When the bank coordinates by default, the questions it cannot see go unasked.

The cross-border wealth planning matrix: five questions, three countries, one owner each

International wealth structuring is usually described as a set of entities. For a family across three countries it is better described as a set of questions, each with a decision, an owner and a document. The matrix below is the one we would draw for the composite family above. Every cell is a question to put to someone, not an answer; the facts behind each cell are sourced in the sections that follow.

Two things about the matrix matter more than its contents. First, the owner column never says “the bank” for a tax or legal question. Second, the last column never says “advice”. The coordinator holds the record; the owners hold the answers.

Tax residence across three countries: the question each tax advisor must answer

Tax residence is decided per person, per country, per year. A family across three countries can have members resident in different places at once, and one person can meet two sets of domestic tests (dual tax residence). The tax residence question therefore has three owners, and the coordinator’s job is to make sure all three are asked the same question about the same person in the same year.

UAE. Cabinet Decision No. 85 of 2022, effective 1 March 2023, sets the UAE’s residence tests for individuals, including a 183-day test and a narrower 90-day test. We cover how those tests work in Portugal vs Dubai; for this piece, the point is that the UAE tests are domestic. They decide whether the Federal Tax Authority issues a Tax Residency Certificate. They do not decide how Portugal or Switzerland reads that certificate, and the Decision’s own Article 6 says that where an international agreement sets conditions for tax residence, those conditions apply for that agreement.

Portugal. Here the treaty matters. The convention between Portugal and the United Arab Emirates was signed in Abu Dhabi on 17 January 2011 and approved by Resolução da Assembleia da República n.º 47/2012 (Diário da República, 13 April 2012). Its Article 4(1)(b) defines a resident of the UAE, for individuals, as “an individual who has his domicile in the United Arab Emirates and is a national of the United Arab Emirates”. A Portuguese, British or other European national living in Dubai is not an Emirati national. The question to put to your Portuguese tax advisor is direct: under Article 4, can the UAE side of my life count at all, and if not, what does my UAE certificate do for me in Portugal? Do not let anyone file on the assumption that the certificate settles it.

Switzerland. A Swiss bank account is a banking relationship, not a residence test. Swiss residence turns on domicile and presence in Switzerland, which only becomes a live question if someone in the family keeps a Swiss home or spends long periods there. If anyone does, that is a question for a Swiss tax advisor, not for the relationship manager.

Double tax treaty Switzerland–Portugal, and the UAE–Switzerland treaty

Switzerland levies anticipatory tax (Verrechnungssteuer) of 35% on investment income, in particular dividends and interest. The Federal Tax Administration (ESTV) states that for recipients domiciled abroad the tax generally constitutes a final charge, unless a double taxation agreement entitles them to a full or partial refund. The refund is a claim, not an automatic adjustment: it must be filed within three years after the end of the calendar year in which the income fell due.

Switzerland–Portugal. The two countries’ convention, signed in Berne on 26 September 1974, was amended by a protocol signed in Lisbon on 25 June 2012 and approved in Portugal by Resolução da Assembleia da República n.º 87/2013 (Diário da República, 27 June 2013). The ESTV publishes a dedicated refund form for Portuguese residents (Form 94). The questions for the Portuguese tax advisor: what rate does the amended dividend article leave Switzerland on a dividend paid to me as a Portuguese resident, has the bank withheld the full 35% anyway, and which residence certificate will the refund claim rest on? Note who files. If the bank thinks the advisor files and the advisor thinks the bank does, nobody does, and the three-year window closes.

UAE–Switzerland. The Switzerland–UAE agreement has been in force since 2012. A protocol signed on 5 November 2022 entered into force on 5 May 2025, and most of its changes apply from 1 January 2026. It implements the minimum standards for double taxation agreements, including an abuse clause that refers to “the main purpose of an arrangement or transaction”. The ESTV lists no country-specific refund form for the UAE; claims use its general Form 60. The questions, this time for the UAE tax agent and a Swiss tax advisor together: does the agreement’s residence article treat a non-Emirati living in Dubai as a UAE resident, and does the 2026 main-purpose clause change anything for our UAE holding company receiving Swiss income?

The third treaty in the triangle, Portugal–UAE, is the subject of a separate case study on the Portugal UAE double tax treaty. Here it matters only for its Article 4.

Swiss bank account for non-residents: what the bank needs from the family and what it reports

A Swiss bank account for non-residents works on documents. For a family across three countries, the bank’s file needs proof of residence for each account holder, source-of-wealth evidence (for a founder, usually the sale documents of the company), the constitutional documents of every entity that holds an account, and a self-certification of tax residence for each account holder and controlling person. Each of these goes stale when the family’s life changes, and the bank asks for refreshes on its own calendar, not the family’s.

The self-certification is the document that matters most, because it drives reporting. Under the OECD Common Reporting Standard (CRS), the bank reports each account to the tax authority of the residence it holds on file for the account holder or, for entities, for the controlling persons. Switzerland and all EU member states have collected account data since 2017 and exchanged it since 2018. The flows for our composite family run like this:

• The spouse in Lisbon is reported to Portugal, if the bank’s file says Portugal.
• The founder in Dubai is reported to the UAE, if the file says UAE.
• The Dubai holding company’s accounts are reported through its controlling persons, to wherever each of them is recorded as resident.

The rules are moving. The Swiss Federal Council set 1 January 2026 for Switzerland’s amended CRS, provided no referendum was called against it. The UAE Ministry of Finance announced, on 8 November 2025, that it will apply the updated standard (CRS 2.0) from 1 January 2027, with first exchanges under it in 2028. Switzerland has written the Crypto-Asset Reporting Framework into law but, per the Federal Council on 26 November 2025, will implement it in 2027 at the earliest. Which version Portugal applies to which year is a question for the Portuguese tax advisor.

The failure mode is quiet. One spouse becomes Portuguese resident in year one. The bank’s file still says “UAE” in year three, because nobody told it. The bank reports to the wrong country, Portugal receives nothing, and the gap surfaces only when the Portuguese return and the CRS data disagree. The bank is the custodian of the account, not of the family’s residence history; someone else has to tell it.

The Portuguese side runs in parallel. A Portuguese tax resident who is the holder, beneficiary or authorised signatory of a deposit or securities account at a financial institution outside Portugal must identify it, by IBAN and BIC, in Quadro 11 of Anexo J of the IRS Modelo 3 return, under article 63.º-A of the Lei Geral Tributária. The Portal das Finanças states that this applies even to accounts that produced no income, and that the listing does not change the tax due. Confirm with your contabilista certificado which accounts go on Anexo J, including accounts held through an entity where you count as beneficiary. Our moving to Portugal checklist covers the first IRS filing after a move.

Structures: UAE entities, a Portuguese holding company and a Swiss booking centre

The structure question is where three countries’ rules overlap most and where the entity map most often exists only in the corporate service provider’s files. Our wealth planning and structuring work starts by drawing that map, because no single advisor holds it.

UAE corporate tax. Federal Decree-Law No. 47 of 2022 applies corporate tax at 9% on taxable income above AED 375,000, for financial years beginning on or after 1 June 2023. For individuals, Cabinet Decision No. 49 of 2023 (effective 1 June 2023) brings a natural person’s business into corporate tax only where its turnover exceeds AED 1,000,000 in a calendar year, and does not treat wages, personal investment income or unlicensed real estate investment income as business, whatever the amount. The questions for the UAE tax agent: is our holding company inside corporate tax, is any family member’s activity a business, and is any property income licensed and therefore not “real estate investment”?

UAE corporate tax and the family foundation

A family foundation in the DIFC or ADGM is a common Gulf structure, which we describe in our guide to family foundations in the UAE. For corporate tax, the Federal Tax Authority opened an application on 10 March 2025 through which an eligible family foundation can apply to be treated as an unincorporated partnership. Once approved, the foundation no longer files corporate tax returns, and each beneficiary must determine their own registration and filing position. The question for the UAE tax agent: does our foundation meet the conditions, has it applied, and has anyone told the beneficiaries in Lisbon what that changes for them?

Portugal. Two questions belong to the Portuguese tax advisor. Where is each company effectively managed, given that one director now lives in Lisbon? The Portugal–UAE convention makes that a treaty question too: its Article 4(1)(b) counts a company as a UAE resident only if it “is incorporated and has its place of effective management in the United Arab Emirates”. And does any entity in the structure sit in a jurisdiction or regime that Portugal treats as privileged, which can change how its income is taxed in Portugal? We cover Portugal’s list in Portugal vs Dubai; the coordinator’s role is to make sure the question is asked about every entity on the map, not only the one the advisor happens to know.

Switzerland. The booking centre does not create the structure, but it records it. Each entity account names controlling persons, and those names drive CRS reporting. When the structure changes, the bank’s records must change with it.

Cross-border succession planning: three legal systems, one family

Cross-border succession planning, also searched as cross-border estate planning, is where three competent lawyers can produce three valid documents that contradict each other. Succession planning for this family has to answer which law governs which asset, and the answer may differ by country.

Portugal and the EU. Regulation (EU) No 650/2012 applies to the succession of persons who die on or after 17 August 2015. Under Article 21, the law of the State where the deceased had habitual residence at death governs the succession as a whole, with a narrow exception for a manifestly closer connection elsewhere. Article 22 allows a person to choose instead the law of a State whose nationality they hold, made in a disposition of property upon death, such as a will. The questions for the Portuguese lawyer: where would each of us be habitually resident if we died this year, and should either of us choose a nationality law?

Switzerland. The Federal Council set 1 January 2025 as the entry into force of the revised succession chapter of the Federal Act on Private International Law, with the stated aim of reducing conflicts of jurisdiction between Swiss and foreign authorities. Swiss succession rules are also political: on 30 November 2025, voters rejected the JUSO initiative for a 50% federal tax on estates and gifts above CHF 50 million, with 78.3% voting no. The question for the Swiss lawyer: how do the revised rules treat assets booked in Switzerland by a family domiciled elsewhere, and does any family member’s nationality change that?

UAE. Federal Decree-Law No. 41 of 2022 on Civil Personal Status, in force since 1 February 2023, applies to non-Muslim UAE nationals and non-Muslim foreigners resident in the UAE, unless they hold to their own law. Under its Article 11, without a will, half of the estate goes to the surviving spouse and the other half is divided equally among the children, sons and daughters alike; a foreigner’s heirs may instead ask for the law that the UAE’s conflict rules point to, unless a registered will says otherwise. Non-Muslims with assets or minor children in the UAE can also register a will with the DIFC Courts Wills Service. The question for the UAE lawyer: which regime governs our wills here, and does a Dubai will conflict with the choice we make, or do not make, under the EU Regulation?

Each of these is a question for the lawyers in each country, and they are best answered in one meeting, with one summary afterwards of which document chooses which law.

Failure modes when each advisor only sees their country

These are the six we would look for first. Each has a symptom and an owner who should have caught it.

1. Stale CRS self-certification. Symptom: a family member’s Portuguese return and the CRS data Portugal receives disagree. Owner: the private banker, prompted by the family when residence changes.
2. A residence certificate the treaty does not recognise. Symptom: a UAE certificate is relied on in Portugal for a non-Emirati national. Owner: the Portuguese tax advisor, reading Article 4.
3. Swiss withholding tax never reclaimed. Symptom: Swiss dividends net of 35% for years, no refund claim filed, the three-year window closing. Owner: whoever the family has named in writing; usually nobody has been.
4. A Dubai will that conflicts with the EU or Swiss choice of law. Symptom: two valid wills pointing to different laws for the same assets. Owner: the lawyers, together.
5. A UAE company managed in practice from Lisbon. Symptom: board decisions taken by a director who now lives in Portugal. Owner: the Portuguese tax advisor, with the UAE corporate service provider.
6. Three advisors each assuming another filed. Symptom: Anexo J incomplete, a UAE corporate tax registration missed, a Swiss refund never claimed. Owner: the coordinator’s calendar.

None of these needs a new advisor. Each needs one sentence on the owner map and one line on the calendar.

How to coordinate advisors in three countries without one taking over

Coordination is not a meeting. It is five documents and a habit.

• A one-page owner map. The matrix above, filled in with names: who owns each question in each country, and who is the backup. Each advisor confirms their row in writing.
• One filings calendar. Portugal’s IRS return and Anexo J, each UAE entity’s corporate tax registration and return, the three-year Swiss refund windows, bank KYC refresh dates, and the date each self-certification was last signed.
• One consolidated report across banks. The Geneva bank’s statement, the Dubai accounts and the Lisbon accounts in one view, so the family sees one balance sheet rather than three. We explain why in consolidated reporting across multiple banks, and what consolidated reporting should contain.
• A quarterly three-advisor call with written minutes. Thirty minutes, the same agenda each time: residence changes, structure changes, filings due, open questions. The minutes go to the family and to every advisor.
• Decision rights kept with the family. Advisors recommend; the family decides; the coordinator records the decision and who acts on it.

The coordinator is paid by the family, and only by the family, and gives no advice. That is the role our administration and back office work fills. Our case study on a founder with four banks shows what the absence of that role looks like in one country; across three it compounds.

Where a written second opinion fits

If the family above recognises itself, the fastest first step is a Wealth Operations Review. The Review maps the matrix for the family’s actual set-up: who owns each question today, which cells are empty, which documents are stale, and which question to put to which advisor first. It names the questions; the tax advisors and lawyers in each country answer them. PWA does not manage money, hold mandates, take commissions or give regulated investment, tax or legal advice.

Questions we hear

Who should coordinate advisors when a family’s wealth is in several countries?

Someone paid by the family, and only by the family, who holds the owner map, the filings calendar and the consolidated reporting but not the money. The bank sees the flows but has a product interest; each tax advisor sees one country. Ask each advisor to confirm in writing which questions they own.

Does the Portugal–Switzerland tax treaty reduce Swiss withholding tax on dividends?

Switzerland withholds 35% on Swiss dividends, and for recipients abroad that is final unless a treaty allows a refund. The 1974 convention, amended by a 2012 protocol, sets the rate Switzerland may keep from a Portuguese resident. Ask your Portuguese tax advisor which rate applies and who files the claim within three years.

Is a European national living in Dubai a UAE resident under the Portugal–UAE treaty?

Article 4 of the Portugal–UAE convention, signed in Abu Dhabi on 17 January 2011, defines a UAE resident individual as someone domiciled in the UAE who is also a UAE national. Ask your Portuguese tax advisor whether a non-Emirati living in Dubai can rely on the treaty at all, and what that means for your filings.

Do I have to declare a Swiss bank account in Portugal?

A Portuguese tax resident who holds, benefits from or can operate a deposit or securities account abroad must identify it, by IBAN and BIC, in Quadro 11 of Anexo J of the IRS return, even if it produced no income. Confirm with your contabilista certificado which accounts belong on the list.

Will my Swiss bank report my account to Portugal or to the UAE?

Under the Common Reporting Standard, a Swiss bank reports each account holder and controlling person to the country of residence on its file, which rests on their self-certification. If one spouse became Portuguese resident and the file still says UAE, the report goes to the wrong place. Ask your private banker for the current self-certifications.

Which country’s law governs the succession of a family split between Dubai, Portugal and Switzerland?

Possibly more than one. Portugal applies the EU Succession Regulation, which defaults to the law of habitual residence at death but allows a choice of nationality law in a will. Switzerland revised its own rules from 1 January 2025, and the UAE has a civil law for non-Muslims. Ask your lawyers in all three countries together.

Sources

Accessed 20 October 2026. Primary legal texts first.

• Diário da República, 1.ª série, n.º 74, 13 April 2012: Resolução da Assembleia da República n.º 47/2012 and the Portugal–UAE convention in Portuguese, Arabic and English, as reproduced by the Autoridade Tributária e Aduaneira. Supports: signature in Abu Dhabi on 17 January 2011; approval by Resolution 47/2012; Article 4(1)(b) definition of a UAE resident individual and company. info.portaldasfinancas.gov.pt; record: diariodarepublica.pt
• Diário da República, 1.ª série, n.º 122, 27 June 2013: Resolução da Assembleia da República n.º 87/2013 and Decreto do Presidente da República n.º 70/2013. Supports: protocol signed in Lisbon on 25 June 2012 amending the Portugal–Switzerland convention signed in Berne on 26 September 1974. files.diariodarepublica.pt
• Swiss Federal Council, “Switzerland and Portugal sign revised double taxation agreement”, 25 June 2012. Supports: protocol signed in Lisbon on 25 June 2012. admin.ch
• Swiss Federal Council, “Double taxation agreement between Switzerland and the United Arab Emirates enters into force”, 8 November 2012. Supports: agreement in force since 2012. admin.ch
• State Secretariat for International Finance (SIF), “Entry into force of the amending protocol to DTA with the United Arab Emirates”, 28 November 2025. Supports: protocol of 5 November 2022 in force on 5 May 2025; most changes apply from 1 January 2026; minimum standards and main-purpose abuse clause. sif.admin.ch
• Swiss Federal Tax Administration (ESTV), “Anticipatory Tax (Swiss Withholding Tax) AT”, updated 22 September 2026. Supports: 35% on investment income; final charge for recipients domiciled abroad unless a DTA allows a full or partial refund. estv.admin.ch
• ESTV, “Claim to refund of Swiss anticipatory tax”, updated 22 September 2026. Supports: refund right expires if not claimed within three years. estv.admin.ch
• ESTV, country pages “Portugal” (7 September 2026) and “United Arab Emirates” (22 September 2026). Supports: Form 94 for residents of Portugal; Form 60 for countries without their own form, including the UAE. estv.admin.ch (Portugal); estv.admin.ch (UAE)
• Swiss Federal Department of Foreign Affairs, “Automatic Exchange of Information in Tax Matters”. Supports: Switzerland and all EU member states collecting account data since 2017 and exchanging it since 2018. europa.eda.admin.ch
• Swiss Federal Council, “Federal Council approves amendment to the automatic exchange of information in tax matters”, 26 November 2025. Supports: amended CRS set for 1 January 2026, subject to the referendum period; CARF implemented in 2027 at the earliest. admin.ch
• UAE Ministry of Finance, “Ministry of Finance announces the UAE’s commitment to implement the updated Common Reporting Standard (CRS 2.0)”, 8 November 2025. Supports: CRS 2.0 effective 1 January 2027; first exchanges in 2028. mof.gov.ae
• Portal das Finanças, Lei Geral Tributária, article 63.º-A, n.os 8 and 9. Supports: duty to identify foreign deposit or securities accounts held as holder, beneficiary or authorised signatory. info.portaldasfinancas.gov.pt
• Portal das Finanças, FAQs 3806 and 3808 (IRS, Rendimentos no Estrangeiro). Supports: Anexo J, Quadro 11; IBAN and BIC; accounts without income included; no effect on tax due. info.portaldasfinancas.gov.pt
• Federal Tax Authority (UAE), Cabinet Decision No. 85 of 2022 on the Determination of Tax Residency, issued 2 September 2022 (unofficial translation). Supports: individual residence tests, including 183 and 90 days (Article 4); treaty conditions apply for treaty purposes (Article 6); effective 1 March 2023 (Article 9). tax.gov.ae
• UAE Government portal, “Corporate tax (CT)”. Supports: 0% up to AED 375,000 and 9% above; Federal Decree-Law No. 47 of 2022 applies to financial years beginning on or after 1 June 2023. u.ae
• Federal Tax Authority (UAE), Cabinet Decision No. 49 of 2023, issued 8 May 2023. Supports: natural persons in corporate tax only above AED 1,000,000 turnover in a calendar year; wages, personal investment income and unlicensed real estate investment income excluded whatever the amount; effective 1 June 2023. tax.gov.ae
• Federal Tax Authority (UAE), “Federal Tax Authority launches ‘Family Foundations as an Unincorporated Partnership’ application via EmaraTax”, 10 March 2025. Supports: application route; no corporate tax returns once approved; beneficiaries determine their own position. tax.gov.ae
• Official Journal of the European Union, L 201, 27 July 2012: Regulation (EU) No 650/2012 of 4 July 2012 (Succession Regulation). Supports: Article 21 habitual residence and its exception; Article 22 choice of nationality law in a disposition of property upon death; Article 83(1) deaths on or after 17 August 2015. eur-lex.europa.eu
• Swiss Federal Council, “Droit des successions internationales : de nouvelles règles en 2025”, 26 June 2024. Supports: revised succession chapter of the Federal Act on Private International Law in force 1 January 2025; aim of reducing conflicts of jurisdiction. admin.ch
• Swiss Federal Department of Finance, “Erbschafts- und Schenkungssteuer” (JUSO initiative), and Swiss Federal Administration, “Initiative for a Future”. Supports: vote of 30 November 2025; rejected with 78.3% no; 50% federal tax on estates and gifts above CHF 50 million. efd.admin.ch; admin.ch
• UAE Ministry of Justice, Federal Decree-Law No. (41) of 2022 on Civil Personal Status, official Arabic text, issued 3 October 2022. Supports: application to non-Muslim nationals and resident foreigners unless they hold to their own law (Article 1); without a will, half to the spouse and half equally among the children, and a foreigner’s heirs’ right to request the applicable law unless a registered will says otherwise (Article 11); in force 1 February 2023 (Article 18). moj.gov.ae; Ministry of Justice news, 9 February 2023: moj.gov.ae
• DIFC Courts, “Wills FAQ”. Supports: DIFC Courts Wills Service; non-Muslims with assets or minor children in the UAE may register a will. difccourts.ae

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Pedro Souto is the founder of PWA — Private Wealth Advisory. He works with UHNW founders, families, and single-family offices to build an independent operating layer around complex wealth — combining markets, analytics, technology, and governance to turn fragmented advice into one coherent picture, and to make someone, finally, responsible for the whole of it.