90-Day Pre-Move Tax Plan for HNW Families Moving to Spain
Relocating a high-net-worth family to Spain from the UK or the US is not just a change of home. It is a full tax event that touches income, capital gains, wealth, succession, and reporting in at least two, and often three, countries. If you leave the planning to the week before the move, you give up many of the best options.
Spain taxes residents on worldwide income and, in many regions, applies wealth tax and other ownership-based rules. The UK and the US have their own exit concepts and long memories when it comes to residence and domicile. A clear 90-day plan helps you line up exit and entry rules, treaty protections, and documentation so that the move feels controlled rather than reactive. At Del Canto Chambers we focus on Anglo-Spanish matters, with Barristers and Lawyers used to cross-border tax, global mobility, and disputes, so we see first-hand how planning ahead protects families later.
Day 90 to 61: Decide Tax Residency on Paper and in Practice
The first step is to decide where, and from when, each family member will be tax resident. This is not just a formality. The tests are different in each country and the facts have to support your position.
Key concepts include:
- Spain's 183-day rule and the idea of your centre of vital interests, such as where your family, home and main economic links are
- The UK Statutory Residence Test, which looks at days, ties, and sometimes past years
- US rules that tax citizens and green card holders regardless of where they live
For many families, you may see patterns like:
- UK-domiciled, leaving the UK but becoming resident in Spain
- A US citizen moving to Spain who stays fully within the US net while also entering the Spanish system
- Dual-resident cases where you technically meet residence tests in both Spain and the UK or the US
In those dual cases, the tax treaty tie-breaker becomes key. That usually looks at where you have a permanent home, where your personal and economic relations are closer, and where you spend more time. It is wise to:
- Track days in each country, including travel days
- Record where each family member lives, works and attends school
- Keep copies of leases, school enrolments and employment or board roles
Families often move between September and December to match school terms. That timing can easily create an extra UK tax year of residence, US filing twists or a Spanish part-year that pulls more income into one side than planned. Mapping the calendar early lets you choose your move-in date rather than drifting into it.
Day 60 to 31: Manage Exit Tax, Unrealised Gains and Legacy Structures
With residency plans sketched out, the next focus is what you are carrying with you. Existing structures that worked well in the UK or the US may be viewed very differently in Spain.
Some of the issues that need review are:
- UK temporary non-residence rules, which can tax certain gains or income when you come back within a set period
- UK and other trust reporting, including how distributions might be taxed later in Spain
- Re-basing opportunities on assets, where available, to lock in past gains
- US expatriation rules if anyone is giving up citizenship or a long-held green card
Family structures often include:
- Family investment companies
- Trusts, foundations or partnerships
- Carried interest or private equity arrangements
- US LLCs or LLPs with flexible profit sharing
Under Spanish rules, these may be recharacterised. For example, an entity treated as transparent in one country may be seen as opaque in Spain, or the other way round. That can lead to phantom taxation if income is taxed before cash is distributed or if Spain looks through a structure to the underlying assets.
In this period, typical planning questions are:
- Should we crystallise gains on certain assets while still UK or US resident?
- Do we need to clean up mixed funds so that capital, income and gains are clearly traced for future Spanish reporting?
- Is the current ownership of real estate, operating companies and IP aligned with the Spain, UK or Spain, US treaty?
Any step taken to reduce tax in one jurisdiction can trigger anti-avoidance rules in another if not coordinated. Joining up advice across the UK, US and Spain avoids conflicts and helps you pick a path that works on all fronts.
Day 30 to 11: Lock in Spain-Focused Structures and Reporting Readiness
As the move gets closer, the focus shifts to making sure your structures and records are ready for Spanish treatment. Spain has its own look-through rules and wealth-based taxes, so the right holding structure can make a real difference.
Key points at this stage include:
- Reviewing holding companies for investments and family businesses, checking how Spanish Controlled Foreign Company rules might apply
- Looking at wealth tax exposure by region and, where available, the rules in your chosen autonomous community
- Testing whether you have substance in any non-Spanish entities, such as real decision-making and local management
Spain also has strict reporting requirements on foreign assets, including:
- Modelo 720 for foreign assets such as bank accounts, securities, life policies and certain real estate over specific thresholds
- Modelo 721 for certain cryptoassets held abroad
To be ready, you should gather:
- Bank and custody statements that clearly show account ownership, balances and currencies
- Valuation reports for portfolio companies, funds and real estate
- Complete details of foreign policies, plans or pensions
Banking and custody arrangements matter more than many people think. Spanish reporting asks for specific data points, usually as of year-end. If your accounts and investment platforms are set up with clear naming, separate accounts per legal owner and easy access to historic statements, filings are simpler and treaty relief claims are easier to support.
Well-documented structures, with clear boards, minutes, and beneficial ownership evidence, can back up treaty-based positions about residence and source of income. This can reduce the risk of later disputes about whether a company is really managed from Spain or whether income belongs to a person or to an entity.
Day 10, Move-In: Audit-Proof Files, Governance, First Filings
In the final ten days, you move from design to proof. You want an audit-proof file that would make sense to an inspector years from now, when memories have faded.
Practical steps include:
- Confirming travel dates and logging entries and exits from each country
- Completing deregistration or notifications in the UK or US where appropriate
- Registering with Spanish authorities so that you have identification numbers and the right tax profile from the start
An audit-proof dossier might contain:
- Detailed residence calendars for each family member
- Advisory notes explaining the chosen treaty tie-breaker position
- Board minutes and resolutions of companies and family entities
- Trust deeds, letters of wishes and distribution records
- Valuations of significant assets at key dates
- Email or written advice showing the reasoning for key steps
This is also the moment to look at family governance under Spanish rules. Topics to cover include:
- Pre-nuptial agreements and how they interact with Spanish marital property regimes
- Succession plans, including how Spanish forced heirship might apply to Spanish assets
- Cross-border probate, especially for families holding property and companies in both Spain and other countries
Finally, you should prepare for your first Spanish tax year. A basic calendar will usually include:
- Income tax filings and payments on account
- Wealth tax filings where relevant
- Reporting forms like Modelo 720 and 721 in the year after you become resident
Early cash-flow planning matters. Spanish tax payment dates may not align with UK or US schedules, and large on-account payments can surprise families who are used to different systems. Managing ongoing interaction between Spain, the UK and the US is not a one-off exercise but a steady, annual process.
Turn Your 90-Day Plan Into a Bespoke Strategy
Treat this 90-day outline as a framework, not a full solution. Every high-net-worth family has its own mix of trusts, companies, carried interest arrangements and business assets, and each of those reacts differently when you cross borders between Spain, the UK and the US. Without joined-up planning, it is easy to fall into dual residence, trigger unexpected exit tax, or face reporting issues that could have been avoided with earlier action.
At Del Canto Chambers, our Barristers and Lawyers work across Anglo-Spanish tax, private wealth and disputes. We focus on designing, implementing and, when needed, defending bespoke relocation strategies for families with Spanish and international interests. Starting the process at least 90 days before your planned move gives you room to make calm, well-documented decisions that match your long-term family and business goals.
Secure Your Cross-Border Relocation With Confidence
If you are considering HNW relocation in Spain, the UK, and the US, we can help you structure your move efficiently, protect your assets and stay compliant in every jurisdiction. At Del Canto Chambers, we bring together legal, tax and immigration expertise to provide a coherent strategy tailored to your family and business interests. Speak with our team today to discuss your situation in confidence and outline next steps, or contact us to arrange a consultation.
