You know where you’ve been and where you live. But can you prove tax residency and do it convincingly if the tax authorities ask?
Today, being confident about your residency status is no longer the same as being able to defend it. Many internationally mobile individuals receive excellent tax advice on residency thresholds and day-counting limits. Yet high-net-worth individuals (HNWIs) still often lack a structured system to evidence those days in a way that withstands scrutiny.
At the same time, tax enforcement has entered a new era that is defined by cross-border collaboration. Authorities aren’t just talking to each other more; they’re sharing information. They also use AI tools to collect and cross-reference huge amounts of data.
Key Takeaways
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Tax investigations are on the rise. In the UK alone, HMRC opened around 300,000 compliance investigations during the 2022/23 tax year. And while high-profile evasion makes headlines, the reality is more mundane: many inquiries begin with human error, not malice.
“I didn’t spend 183 days there. I thought I wasn’t resident.”
It’s a familiar refrain and one that is often not a misunderstanding of the rules, but a failure to document them properly. The 183-day rule is widely known but far from the whole story. In some jurisdictions, you can trigger tax residency well before reaching that threshold — or even without spending significant time there — if certain lifestyle or financial ties remain.
Owning a home, having a spouse or dependent in the country, keeping a mobile contract, and maintaining a gym membership can all weigh heavily in the eyes of tax authorities, depending on the jurisdiction.
A move to Dubai doesn’t necessarily break your UK tax residency if accessible accommodation is retained. Claiming Italy’s flat tax regime might invite questions elsewhere if economic or personal ties aren’t carefully managed. A spreadsheet documenting your travel days back to the UK may be insufficient if you can’t provide evidence that you were actually in the country.
While these specifics are carefully advised, the complication comes from the process of day counting and record-keeping, or lack thereof.
Tax agencies apply a multifactorial test to assess where you live. It’s no longer just about where you say you reside, but also what you do there and how much time you spend there. All of these require proof, not just a claim.
Here’s a comparative snapshot of how some countries determine tax residency:
Authorities are looking at where you spend time, where you earn, where you stay, where your family lives, and what your lifestyle suggests.
While tax residency is assessed using a mix of factors, day counting remains the foundation to prove tax residency. It’s the first metric authorities look at and often the most objective. Yet it’s also where many residency positions weaken. The limits are understood and explained, but the records kept are informal, retrospective, or insufficiently corroborated.
The solution? Recognise that day count is your starting line, not the finish. It’s the core of a defensible residency position. Still, it must be backed by clarity, consistency, and corroborating evidence across your broader footprint.
What’s changed in recent years is how this information is gathered.
At the heart of this shift is the Organisation for Economic Co-operation and Development (OECD). In response to growing pressure on governments to reduce tax evasion and improve transparency, the OECD launched the Common Reporting Standard (CRS), a global framework that compels financial institutions to automatically report account information to local tax authorities, who then share that data across borders.
As of 2026, over 120 jurisdictions have signed on, including many that were once considered “low disclosure” destinations. CRS is now regarded as the global standard for information exchange.
Here’s what that means in practice:
These exchanges occur annually and silently. There’s no opt-out and no notification.
But these aren’t the only digital trails that tax authorities are following.
The authorities are:
These are digital breadcrumbs. And they’ve already been used in audits, with authorities building compelling cases based on modern tech.
Let’s take a step back. If your tax residency is challenged, what actually counts as compelling proof? How can you prove tax residency in the era of digital surveillance?
To strengthen your claims, you should prioritise the following strong evidence:
On the other side is the “weak evidence” that often fails to stand up to scrutiny and, in some cases, can even lead to a higher risk of human error:
The real challenge is that memories fade, records get lost, and personal declarations are no longer persuasive without backup. Your documentation must be objective, reliable, and available on demand in this new environment.
The goal is to have a contemporaneous system capable of proving compliance beyond a reasonable doubt.
A failed tax residency claim doesn’t just mean a slight inconvenience and a one-off fine. It can lead to:
For globally mobile HNWIs, these risks extend beyond finances. They affect lifestyle flexibility, asset structuring, and family peace of mind. What’s the point of freedom if it leads to uncertainty?
Rather than living in fear of an audit or scrambling to build a timeline retroactively, the smartest individuals are adopting a proactive stance. This means moving from knowing the rules to operationalising them:
These systems aren’t about bureaucracy. They’re about preserving freedom. Establishing a continuous record ensures that your lifestyle stays aligned with your legal obligations without sacrificing flexibility.
In many ways, tools that automate this process are becoming the new insurance for international living. They not only protect you from audits but also allow you to live with clarity and control.
Yes. In many jurisdictions, tax authorities can open enquiries several years after the relevant tax year, particularly if they suspect careless or deliberate inaccuracies. Retaining structured, long-term residency records is critical to defend historical positions effectively and minimise prolonged disputes.
No. While advisors provide guidance on the residency rules you must follow, maintaining accurate day counting records is up to you. A structured system that captures real-time location data and supporting evidence helps ensure your advisor can rely on defensible documentation if your residency status is ever questioned.
Wealth offers mobility and the ability to follow the opportunities, no matter where they take you. But with that mobility comes complexity. To reduce this complexity, your advisor may have given you clear guidance on residency thresholds, split-year treatment, and day-counting limits.
But knowledge of day counting limits isn’t proof.
If challenged, do you have a contemporaneous, objective system capable of evidencing that advice in practice?
Tax authorities no longer take your word for it. The burden of proof rests squarely on your shoulders. You want to be proactive in understanding your movement patterns and keeping a record of them in real-time. Together with the right digital tools and professional tax advice, you achieve the confidence to state:
‘There’s nothing to see here, everything is in order.”
Protecting Your Tax Residency Position
If you are relocating from the UK, maintaining UK ties, or restructuring your global footprint, clarity around day counting and evidence is essential.
We work alongside leading tax advisors and family offices to help internationally mobile individuals establish robust, defensible residency records to prove tax residency.
If you or your advisor would like to discuss how structured, real-time documentation can support your tax residency strategy, arrange a confidential call with the Daysium team.
Created in partnership with industry experts, tackle the complex challenges of day counting and tax record-keeping.
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