Tie-breaker: Dual Tax Residency and Its Resolution

One and the same person can simultaneously be considered a tax resident of two countries: each has its own domestic criteria—number of days, permanent home, centre of interests, sometimes citizenship. When two states claim the same resident, dual residency arises and the risk of taxing worldwide income twice. For such situations, tax treaties provide a tie-breaker—a sequence of rules that assigns residency to one country for treaty purposes.

Where Dual Residency Comes From

Each country determines residency under its own law, and these definitions overlap. The British Statutory Residence Test can recognize a person as resident based on number of days and ties, while another country simultaneously considers them resident based on permanent home or centre of vital interests. Domestic rules are not coordinated with each other, so conflict is a common occurrence when relocating or living between two countries.

Tie-breaker Under OECD Model Convention Article 4

When a double taxation agreement is in force between countries, it is built on the OECD Model Convention. Article 4(2) resolves the conflict for individuals through a strict hierarchy: each subsequent criterion is applied only if the previous one did not give a definitive answer.

• Permanent home: residency is assigned to the country where the person has housing permanently available for their use. If there is a home in both countries or in neither—move to the next criterion.
• Centre of vital interests: where personal and economic ties are closer—family, home, business, sources of income.
• Habitual abode: where the person is physically present more often and more regularly.
• Nationality: applied if the previous steps did not produce a result.
• Mutual agreement procedure: the competent authorities of the two countries negotiate directly.

Companies: Place of Effective Management

For legal entities, many older treaties resolve the conflict in favour of the place of effective management. Article 4(3) of the 2017 Model Convention moved to agreement between the competent authorities, with the place of management left as one factor alongside incorporation and other circumstances. Article 4 of the MLI carries that approach into a particular Covered Tax Agreement only where the notifications of both sides match and neither has reserved against it — paragraph 3(a) lets a Party keep the entire article out of its treaties — so the result is checked in the Matching Database. Until agreement is reached, the company's entitlement is governed by the exact text of the applicable treaty, and a dual-resident company risks not receiving treaty benefits at all.

Important Caveats

The tie-breaker only works when a tax treaty is in force. Without it, double taxation is relieved only by unilateral mechanisms like foreign tax credit—and even then not always completely. For Russians, the picture is more nuanced than it seems. Decree No. 585 of August 8, 2023 suspended in agreements with 38 "unfriendly" countries the distributive articles—dividends, interest, royalties, employment income and independent services (essentially Articles 5–22). However, general provisions, including Article 4 on residency with its tie-breaker, the mutual agreement procedure and exchange of information, remained in force on the Russian side: the tie-breaker itself still determines which country you are considered a resident of under the treaty—what fell away were precisely the reduced rates and exemptions for specific types of income. An important caveat: a number of countries responded with mirror suspensions, and some suspended the convention in its entirety—and then even Article 4 ceases to apply. The United Kingdom is the example: having notified Russia on 4 February 2025, it suspended the convention from 1 April 2025 for corporation tax and from 6 April 2025 for income tax and capital gains tax. Therefore, the outcome depends on the specific pair of countries: what happens on the exit side and on the entry side is laid out for twelve jurisdictions in the relocation matrix.

Assignment of treaty residency to one country does not erase residency under the domestic law of the other. Therefore, the tie-breaker distributes taxing rights between states but does not cancel the domestic obligations of the "losing" side: reporting, automatic exchange of account data under CRS and rules on controlled foreign companies may continue to apply based on its domestic status.

USA and Green Card: Citizenship Saving Clause

The USA taxes citizens and green card holders on worldwide income regardless of where they live, and most US treaties contain a saving clause—a provision preserving the US right to tax "its own" as if the treaty did not exist. Therefore, a US citizen cannot "exit" US taxation through the tie-breaker. A foreigner with dual residency has the right to invoke the treaty tie-breaker and file as a non-resident (Form 8833 together with 1040-NR). But for a green card holder, the tax authority may consider such a step as termination of residency—with all the consequences of exit tax for long-term residents. Before playing the tie-breaker card, an American should calculate the consequences in advance for both citizenship and income tax.

When the Knot Cannot Be Untied

Sometimes the four-step ladder does not provide an answer: housing and interests are distributed equally, and the person is a citizen of both countries at once or of neither. Then the case goes to the mutual agreement procedure, where competent authorities negotiate directly. Calling this step “deadline-free” is wrong: Article 25(1) of the Model Convention allows three years from the first notification of the action resulting in taxation not in accordance with the Convention, and that period is preclusive. Whether the outcome is guaranteed depends on the pair of states, and arbitration is not automatic. Part VI of the MLI reaches a Covered Tax Agreement only where both jurisdictions have opted into it under Article 18 and their notifications, reservations and scope match. Article 19 then sets a baseline two-year period running from a defined start date and requires the taxpayer to ask in writing — but it also lets the competent authorities agree a different period for the case, lets a Party reserve to replace the two years with three, and stops the clock while a court or administrative tribunal case is pending or the procedure is suspended by agreement. Inside the EU, Directive 2017/1852 sets its own timetable. The procedure, the deadlines and the forks are set out in the analysis of treaty tax disputes. For companies after 2017 there is no single default rule: the 2017 Model refers corporate dual residence straight to competent-authority agreement, but whether a given treaty carries that rule depends on its own text and on both sides' MLI positions. Where the applicable text does require mutual agreement and none is reached, the firm may be left without treaty residency and benefits. Hence the practical conclusion: residency is more reliably established in advance—through a permanent home and real centre of interests—than proven after the fact.

How This Is Applied in Practice

A classic situation—an entrepreneur keeps a home and family in one country, but conducts main activities in another and spends a lot of time there. There is a permanent home in both, so the dispute shifts to centre of vital interests: tax authorities weigh where family, property and sources of income are concentrated. A well-assembled dossier—rental agreements, children's school, banking ties, memberships—often determines the outcome.