Family Mobility: Schools, Spouses, and Dependents as Tax Anchors

The calendar said “non-resident.” The school record said “home.”

Elena and Marc did everything the modern mobility playbook tells you to do, at least the version people share at dinners.

They kept travel logs. They watched day counts. They rotated between countries so no single jurisdiction crossed the magic threshold. They assumed residency would be decided by arithmetic.

Then their child started school.

It was a practical decision: stability, friends, routine. They chose a strong international program in a country they liked, signed a year-long lease near campus, and built their calendar around term dates. The result was a life that looked coherent, even if the travel spreadsheet looked scattered.

When a tax authority asked where their “habitual residence” was, Elena brought the flight log.

The authority asked for something else: enrollment records, proof of where the child slept most nights, healthcare registration, and evidence of where the parents were during term time. The question was not “How many days?” It was “Where is your family actually living?”

This is the part of mobility that trips up otherwise diligent people: family footprint creates a narrative that is hard to argue against, because it is documented by third parties and reinforced by routine.

The UK’s Statutory Residence Test makes “family tie” a defined concept in its ties framework, focusing on whether a spouse or partner and under-18 children are UK resident. Spain’s tax agency similarly treats residency as more than a day count, including the well-known 183-day test and also the “main core or base” of activities or economic interests test, and it counts “sporadic absences” unless you prove tax residence elsewhere.

Different systems, same direction: family, housing, and routine matter.

MARKET & CAPITAL REALITY CHECK

Why family evidence beats travel spreadsheets in disputes

1) Family ties are a formal input in major residency tests

In the UK, the sufficient ties test explicitly includes a family tie as one of the relevant ties. That alone does not make you resident, but it changes how many days you can spend without tipping into residence, and it changes how authorities read your story.

The UK manual guidance is direct: a person has a family tie if they have a spouse, civil partner, partner, or under-18 child who is UK resident for that tax year (subject to detailed conditions).

2) Schools create a “term-time gravity well”

School calendars generate patterns: where parents are during term, where a family maintains accommodation, where healthcare providers are used, and where social life consolidates.

Even in places where the statutory test is different, the evidence logic is similar. A school file usually includes the address used for enrollment, emergency contacts, parent IDs, and attendance. Those are clean, durable data points.

3) Housing availability and “normal life” are hard to unsee

Spain’s guidance counts “sporadic absences” within the 183-day test unless the taxpayer proves residence elsewhere, and it allows the tax authority to request proof in certain cases. That structure incentivizes authorities to look beyond the travel log and ask where life is anchored.

4) Tier 2/3 enforcement often relies on simple, high-signal anchors

In many smaller administrations, authorities may have fewer tools than a major revenue service, but they do not need sophisticated tools to build claimability if the family story is clear: a long lease near school, healthcare registration, and consistent presence during term.

5) Dual residency happens when the family story and the work story point different ways

This is where people get surprised. You might have business reasons to spend time in one place, but your family life points to another. If two countries can credibly claim you, treaty tie-breakers can matter, but tie-breakers are evidence-driven and fact-specific.

The practical takeaway is not “avoid countries.” It is “avoid contradictions.”

THE PLAYBOOK

A family-first residency posture is consistency plus documentation

Who this playbook is for:

• couples with kids, especially school-age
• families using international schools across borders
• founders with spouse employment in a different country
• families with elderly dependents and medical ties

Conditions that need to be true:

• you will plan around the family reality you want, not the one you wish you had
• you will keep documents aligned across banks, schools, leases, and tax filings
• you will treat residency as a lived story, not a travel hack

The Family Mobility Planning Sheet (how to build it)

Create one 12-month calendar that overlays:

1. School term dates and required presence windows
2. Lease start and end dates, and whether housing is “available” to you
3. Primary healthcare usage and registrations
4. Work travel that is truly necessary, and where decision-making happens
5. Bank and compliance events: CRS recertifications, address refreshes, visa renewals

This sheet does two things: it shows where your life is really anchored, and it lets you design consistency instead of discovering inconsistency later.

The Family Anchor Evidence File (what to collect)

This is not advice to conceal. It is guidance to document truthfully and consistently.

A) School evidence

• enrollment confirmations
• term calendars and attendance summaries where available
• parent IDs used for school systems
• school fee invoices and payment records
• address and contact details on file

B) Spouse and partner location evidence

• employment or business activity documents
• residence permits and registrations
• housing usage evidence (leases, utility bills, insurance)
• travel patterns during term time

C) Dependent healthcare and care ties

• registrations with clinics and providers
• appointment confirmations where relevant
• insurance coverage and claims summaries
• care contracts if elderly dependents are involved

D) Housing and availability

• leases, property ownership, and access arrangements
• evidence of occupancy patterns
• utilities, internet, local insurance
• a clear explanation of which home is “primary” in practice

Seven common failure modes in family mobility

1. Treating school as a neutral detail
2. Keeping a “non-resident” travel log while living full-time near campus
3. Maintaining a long lease that looks like permanence, while claiming no anchor
4. Declaring different residencies to different banks
5. Spouse living in one place, while the other spouse claims residence elsewhere
6. Medical and care routines that anchor a household
7. Multiple homes with no coherent “primary home” narrative

“Clean” mitigation that stays truthful

• Align school choices with where you can credibly maintain a primary home
• If you genuinely split time, document it, and accept that residency may still be asserted depending on the facts
• Keep bank address, school address, and your primary housing story consistent
• Do not assume that avoiding 183 days solves residency everywhere, Spain’s guidance shows other tests can apply.
• If you are in the UK orbit, learn the tie framework, family tie is formal and defined.

Risks and frictions (do not skip):

• dual residency and double filing complexity
• banking friction when family documents contradict declared residence
• retroactive disputes that require reconstructing years of family routine
• stress and cost that hits the household, not just the balance sheet

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DEAL & PRODUCT LENS

Family mobility is governance, not just logistics

Families that move well treat household decisions like governance:

• a single source-of-truth calendar
• a documented plan for where the household is anchored
• clear, consistent documentation across school, housing, banking, and permits
• an annual review after major changes (new school, new lease, new country, new role)

This is how mobility becomes durable instead of fragile.

ACCESS & NEXT MOVES

Build the plan before enrollment, not after the audit letter

Types of actors to speak to first:

• cross-border tax advisor experienced in residency disputes
• immigration counsel (to separate visa status from tax status)
• school administrators (to understand what records exist and what addresses are captured)

Recommended sequence:

1. Decide where you want the family anchor, realistically.
2. Build the 12-month planning sheet.
3. Align housing, healthcare, and schooling to the chosen anchor.
4. Refresh bank files and self-certifications to match the reality.

“Your child’s school record is often a stronger residency signal than your boarding passes.”

Key datapoints box:

• UK SRT includes a defined “family tie” as part of the ties framework.
• HMRC guidance defines family tie by reference to spouse or partner and under-18 children who are UK resident.
• Spain’s tax agency lists the 183-day test, includes sporadic absences, and also uses an “economic interests” test.

SOURCES & DISCLOSURE

Key sources used: HMRC Residence and FIG Manual family tie guidance, UK Statutory Residence Test legislation PDF, LITRG SRT overview, Spain Agencia Tributaria residency guidance and OECD AEOI residency summary for Spain.

Standard I-Invest disclosure: This article is informational and not legal, tax, or migration advice. Seek independent professional advice.