Frequently asked questions

Daysium is a tax residence platform with two connected products. Daysium Mobile keeps your day counts current against the rules set for your position and builds the record as you travel. Daysium Portal gives named people permissioned access to the live day-count position and reports where your membership includes it.

Daysium is for individuals and families whose lives cross borders, and for the advisors, family offices and trust companies that support them. Some people use Daysium directly; others are introduced by a professional advisor.

Daysium Portal is the permissioned professional/shared side of the platform. Where your membership includes it, you can invite named people to see your live day-count position and reports. Access belongs to the person you invite and can be withdrawn. Invited users do not currently see your underlying location history or evidence files.

Daysium Mobile uses your phone’s location to build the factual timeline behind the count. If no new location data is available, Daysium records an assumed day based on the previous known location rather than leaving a silent gap. Assumptions and later corrections remain visible. The count is then worked out against the rules set for your position.

Daysium is an annual membership. Professional is £1,200, Private Client £2,500, Platinum £5,000, and Family Office starts from £10,000. Enterprise arrangements for firms are conversation-led. See Pricing for the current inclusions.

Professional is for one person with one jurisdiction, on Daysium Mobile. Private Client adds Daysium Portal, up to three jurisdictions, the ability to invite your advisors, and the Concierge Service. Platinum adds a second licence, up to five jurisdictions, and lets the two of you each see the other's day counts. Family Office covers the whole family, with governance and continuity across it.

Concierge Service is included from Private Client upwards. The Daysium team handles onboarding, configures the rules for the strategy you and your advisor have established, liaises with your advisors where appropriate, and remains available for product support. Concierge does not provide tax advice.

Yes. If your circumstances or the people who need to be involved change, talk to us and we can move you to the appropriate membership.

A 14-day trial is available for Professional, Private Client and Platinum where you would like to try Daysium before committing. Family Office and Enterprise begin with a conversation so we can understand the people, rules and access model involved.

Yes. Daysium records your travel across borders, and rules can be configured for the jurisdictions relevant to the strategy you are working to. The number included in your membership ranges from one at Professional to our library of jurisdictions at Family Office.

Daysium supports 20+ tax jurisdictions, listed on Supported tax jurisdictions with the legal sources behind the rules. New jurisdictions are continually being added. If the one you need is not listed, ask us.

Each Rule Card is built from identified legal sources and reviewed before it goes live. The source, review and sign-off process is recorded, and the legal sources are re-checked as rules change. How we build rules explains the assurance method in full.

You have a dated record built through the year rather than a story assembled only after the event. That record can include location-derived days, visible assumptions and corrections, and supporting evidence you added along the way. Daysium provides the factual record; it does not guarantee a tax or enquiry outcome. Professional advisors are already using Daysium records for clients involved in live tax enquiries.

No. Daysium provides the day counts, factual record and evidence. Which tax tests apply, what they mean for your position and what you should do remain matters for you and your advisor.

Your Daysium data is encrypted and hosted on Google Cloud Platform in the United Kingdom. Daysium is Cyber Essentials certified, with information security controls mapped to ISO 27001:2022 and working towards certification. Access is permission-based and location data is never sold. See Security for the full due-diligence detail.

Access is granted by the person whose data it is to a named individual. Paying for the account, administering it or working for the same firm does not automatically create access. Each grant can be withdrawn separately.

Your advice has a practical process behind it, your client has support through the year, and you can stay connected to the live position without operating the system. Daysium handles onboarding and client support, so the relationship stays advisor-led without creating another administrative job for the firm.

Your client controls their record and decides who sees it. Where their membership includes Daysium Portal, they can invite you to see their live day-count position and reports. You do not currently see their underlying location history or evidence files, and the client can withdraw your access.

No. Daysium produces the factual record and counts against the rules set for the client’s position. Which tests apply and what the position means remain matters for professional judgement and the client relationship.

Each family member keeps their own Daysium record. Named office staff and advisors can be given permissioned access to the live day-count position and reports for the people who have invited them. Family Office membership starts from £10,000 and includes four Daysium Mobile licences, our library of jurisdictions, Concierge, Daysium Portal and governance and continuity.

The starting point is the individual whose residence matters. They build their record in Daysium Mobile and can give named professionals permissioned access to the live day-count position and reports. For trust companies and other TCSPs, the Enterprise conversation is about making that process repeatable across the relationships and structures where personal residence matters.

The individual builds their day-count record as they travel, with assumptions, corrections and supporting evidence retained around it. Where they grant access, named professionals can work from the live day-count position and reports. The tax or fiduciary significance of that residence remains a matter for the firm and its advisors.

No. Account administration, payment and access are separate. Each individual grants access to named people.

No. Daysium provides the day counts, record and evidence. The tax treatment, fiduciary judgement and decisions remain with the firm and its professional advisors.

No. Access is granted by the individual to named people. Paying for, administering or working for the organisation does not automatically confer access to somebody’s Daysium data.

Daysium cannot compel somebody to participate. The firm must decide what alternative information or evidence is sufficient for the circumstances. Offering a consistent process can support the firm’s governance record, but it does not by itself discharge a fiduciary obligation.

That depends on the governing terms, the circumstances and the firm’s professional judgement. Where the cost can properly be treated as an administration expense, the structure may meet it rather than the individual paying personally.

Yes. New business and existing relationships where the need is already clear are natural starting points. The process can expand as it proves itself.

Current access begins with the individual and the named professionals they invite. The enterprise work for TCSPs is extending that model across structures, roles, permissions and organisational oversight.

No. TCSPs administer trusts, companies, foundations and other private-client structures. Wherever an individual’s residence is material to a structure, transaction or decision, the same need for a clear factual record can arise.

No. Each family member decides which named people can see their position and reports.

No. The individual remains part of the process. Daysium reduces the manual work of counting and recording days while keeping assumptions, evidence and corrections visible.

Yes. Each family member can give named family-office staff and external advisors access to the position and reports relevant to them.

Yes. Professional advisors are currently using Daysium records for clients involved in live tax enquiries. Daysium does not claim HMRC endorsement or that a particular outcome resulted from using the platform.

Daysium Vault provides a retention option for preserving the historic Daysium record and day-count summaries after active membership ends.