Global mobility

Global mobility is the legal and operational discipline governing when, where, and how employees can work across borders without creating employer exposure.

For global payroll and HR teams, mobility is a four-rail compliance framework that runs alongside the headcount plan: permanent-establishment risk, payroll-tax residency, employment-law nexus, and immigration status. Each rail has its own thresholds, its own audit window, and its own enforcement regime.

The November 2025 OECD Model Tax Convention update introduced the 50 percent / 12-month remote-work benchmark for permanent establishment. The CJEU 2025 ruling in A v. GKV-Spitzenverband shifted EU substantial-activity assessment to a country-by-country basis.

Both changes pushed previously-borderline assignments into compliance scope. Mobility programmes built on pre-2025 rules carry hidden exposure into the next renewal cycle.

The discipline matters because individual rails can trigger independently. A worker may avoid PE exposure but still trigger host-country payroll-tax residency.

The same worker may avoid both but trigger an immigration violation. Mobility is the framework that maps all four against the assignment profile before the offer letter goes out.

What does global mobility mean in payroll?

In payroll and HR, global mobility is the framework that decides what compliance work runs alongside each cross-border assignment. Three operational features matter for the buyer.

The four-rail framework

Mobility splits into four parallel compliance rails. Each has its own threshold, its own authority, and its own remediation cost.

The PE rail looks at corporate-tax exposure under Article 5 of the OECD Model Tax Convention. The payroll-tax rail looks at worker income-tax residency. The employment-law rail looks at host-country labour-code protections. The immigration rail looks at the right to work in the host country.

The OECD 2025 remote-work benchmark

The November 2025 OECD update introduced a 50 percent / 12-month test for home-office working. Below 50 percent of total working time, a home office generally does not create fixed-place PE.

Above 50 percent, the update adds a commercial-reason test. Remote working for retention or cost reasons alone does not satisfy it. India has formally reserved its position; Israel applies additional criteria.

The pre-travel filing requirement

Most jurisdictions require registration or notification before work begins. UK HMRC Short Term Business Visitors Appendix 4 gives a 60-day safe harbour, but only if the PAYE agreement is in place before travel occurs.

French SIPSI lodgement must complete before the worker crosses the border. German DVKA A1 applications need 2-8 weeks. Missing the pre-travel filing removes the safe harbour retroactively and triggers full host-country compliance on the first day of work.

How do mobility thresholds compare across major host countries?

Each rail has its own threshold per country. The matrix below covers the major mobility destinations across all four rails.

The 50 percent threshold measures working days, not calendar days. A full-time worker working 240 days annually can spend up to 119 days abroad before triggering enhanced PE scrutiny under the OECD 2025 benchmark.

Each threshold operates independently. A worker in Berlin three days per week creates different exposure than the same worker relocated to serve German clients. The activity drives the verdict, not just the location. See the shadow payroll entry for the parallel host-country payroll-tax mechanic.

What do the major mobility patterns look like in practice?

Mobility programmes cluster into four standard patterns. Each has its own threshold profile and provider-coverage requirement.

The workation pattern is the most operationally complex because the day-count tracking sits across the worker's calendar, not a single posting. The OECD 2025 50 percent test applies on a rolling 12-month basis, so accumulated time abroad can trigger PE retroactively when a quarter shifts the rolling average.

See the secondment entry for the short-term-posting framework, the A1 certificate entry for the EU social-security coordination route, and the Posted Worker Directive entry for the labour-law layer that overlays EU postings.

What do buyers consistently get wrong on global mobility?

The recurring mistakes cluster into four moves visible across mobility programmes that have rebuilt their compliance posture after a host-country enforcement event.

The first is treating mobility as travel logistics. The four-rail framework runs alongside the worker's calendar regardless of how the trip is booked. A "business travel" trip that includes a contract signing creates dependent-agent PE exposure even if it lasts three days.

The second is missing the pre-travel filing. The UK STBV 60-day safe harbour, the French SIPSI lodgement, the German A1 application, and the Singapore work-pass approval all need to land before the worker crosses the border. Retroactive registration is rejected in most jurisdictions and removes the safe harbour back to day one.

The third is misreading the OECD 2025 benchmark as a vacation from PE. The 50 percent threshold is a presumption test, not a safe harbour. Below 50 percent, fixed-place PE is generally not created. The dependent-agent and service PE routes remain independent and can trigger at any duration above zero days.

The fourth is missing the regulatory hard limits. Germany imposes an 18-month EOR cap forcing entity formation or repatriation. Singapore's 2024 MOM ban on EOR for non-Singaporeans closes the market-test route for expatriate hiring. Both rules force the assignment into a different shape regardless of the underlying mobility plan.

What does an EOR or mobility provider handle?

An employer of record sits at one end of the mobility provider spectrum, mobility-tax firms (Big Four, boutique) at the other. The split depends on whether the worker is on the home payroll (mobility-tax firm) or on the host EOR's books (EOR).

The recurring confusion is treating the EOR as a complete mobility provider. The EOR runs host-country employment for workers on its books. Mobility tax (shadow payroll, tax equalisation, gross-up), day-count tracking, and PE analysis remain separate. See the net-to-gross payroll entry for the tax-equalisation mechanic and the work-permit sponsorship entry for the immigration rail.

Germany's 18-month EOR cap and Singapore's MOM ban on EOR for non-Singaporeans force a structural decision point. Below the threshold the EOR carries the assignment; above it, the buyer needs a local entity or a repatriation plan. Plan both before signing the EOR contract.

Global mobility FAQs

What is the difference between business travel and posting?

Business travel covers short trips for activities like meetings, prospecting, training, and conferences that fall within preparatory or auxiliary exceptions to PE. Posting covers temporary assignment to perform work for the home-country employer in another country.

Most jurisdictions distinguish enforcement priority: business travel attracts lighter scrutiny until the 60-day STBV-equivalent threshold; posting triggers full host-country portal lodgement and equal-pay rules from day one in the EU.

Does the OECD 2025 update simplify mobility compliance?

Partially. The 50 percent over 12 months benchmark provides a clearer fixed-place PE threshold for home-office working. Below 50 percent, the home office generally does not create PE. Above 50 percent, the commercial-reason test applies.

Dependent-agent PE, service PE, and host-country payroll-tax residency remain on their own thresholds and are not simplified by the 2025 update. India has reserved its position; Israel applies additional criteria.

How is day-count tracked across multiple jurisdictions?

Most mobility platforms track days through self-reported travel logs, expense data, or border-crossing API integrations. The HMRC SRT counts midnight presence rules. The OECD 2025 benchmark counts working time over rolling 12-month windows.

Many EU countries aggregate days across connected projects rather than the calendar year. Day-count discipline has to be set up before the assignment begins, not reconstructed at year-end.

Does an EOR cover full mobility compliance?

Partially. The EOR covers host-country employment registration and labour-law compliance for workers on its books. Mobility tax, day-count tracking, PE analysis, and immigration sponsorship are separate scope items.

Workers on temporary posting from parent payroll need a separate mobility-tax firm. The Germany 18-month EOR cap and Singapore 2024 MOM ban on EOR for non-Singaporeans force structural decision points the EOR cannot resolve alone.

What happens at the Germany 18-month EOR cap?

German labour-supply law caps EOR employment at 18 months. After that the worker must either repatriate, transfer to a host-country contract via the buyer's own entity, or end the assignment.

The switch often formalises PE exposure that may already exist rather than creating new exposure. Plan the entity-or-repatriate decision before month 11 so the conversion can complete by month 18. See the EOR explainer for the conversion mechanic.