Dual citizenship provides global mobility and investment freedom while creating an invisible financial risk for many individuals: the possibility of paying taxes in two countries on the same income. Moreover, the issue is not limited to salaries; types of income such as dividends, interest, rental income, royalties, and pension payments can also be subject to claims of “taxation rights” by both countries simultaneously. At this point, Double Taxation Agreements (DTAs) come into play.
In this article, we discuss how DTAs work in dual citizenship, how they reduce the tax burden through various mechanisms, why they have become more critical in countries like the USA that employ citizenship-based taxation, and what mistakes on the compliance side can lead to significant financial costs.
Why does the issue of “double taxation” arise in dual citizenship?
Double taxation occurs when two different countries claim the right to tax the same income item. There are two main reasons for this:
- Residence-based taxation: Many countries tax residents on their “worldwide income”.
- Citizenship-based taxation: Some countries (the most well-known example is the USA) continue to tax individuals based on their citizenship, regardless of where they live.
Dual citizens find themselves at the intersection of these two systems. For example, if someone lives in one country (is considered a resident there) and has a tax declaration obligation as a citizen of another country, their salary, investment income, or pension payment can be subject to two separate tax regimes simultaneously.
What is a Double Taxation Agreement (DTA)?
Double Taxation Agreements (DTAs) are treaties made between two countries aimed at preventing the same income from being taxed twice. These agreements:
- Determine which country has the primary right to tax based on types of income,
- Can reduce withholding tax rates applied in the source country,
- Provide a mechanism for offsetting through exemptions or tax credits in the other country,
- Offer solutions through tie-breaker rules in gray areas like dual residency.
In the case of the USA, it is important to note that while the USA has tax treaties with many countries, the “saving clause” included in these treaties significantly preserves the right of the USA to tax its citizens; however, the treaties help reduce the burden through credits/offsets. For a framework and guidance on the USA’s tax treaties, the IRS Tax Treaties page can be referenced.
Why are DTAs critical for dual citizens?
For dual citizens, the value of DTAs is not just “lower taxes.” The main critical benefit is the opportunity for predictability and proper planning. Thanks to the agreements:
- It becomes clear where each type of income will be taxed,
- Withholding deductions can be reduced (especially for dividends/interest/royalties),
- The declaration strategy (credit or exemption) can be structured more rationally,
- Binding criteria come into play in high-risk situations like dual residency.
Which incomes are most often affected by the agreements? (Practical scenarios)
DTAs often define types of income separately. The most common items that create conflicts in practice are:
Salary and wage income
In a typical agreement approach, salary is taxed in the residence country; however, if the work occurs briefly in the source country or if employer/workplace criteria are met, taxation may also arise in the source country. This distinction becomes particularly important in short-term assignments, “posted worker” scenarios, and multi-location work models.
Dividend and interest income
Many agreements reduce the withholding tax on dividends and interest in the source country to certain rates (in practice, a range of 0%–15% is often seen). Subsequently, the residence country can offset the tax paid on the same income as a tax credit.
Royalty income
In royalties, agreements often prioritize the residence country; the source country may foresee limited taxation at a low withholding rate. This item becomes critical for dual citizens with digital content, software licenses, brand/know-how contracts.
Pension and social security payments
The approach to pension income can vary from agreement to agreement. Some agreements may prioritize the residence country, while others may prioritize the source; some may establish a hybrid model. Here, not only income tax but also obligations related to the social security system may come into play.
How do DTAs prevent double taxation? (Two main methods)
1) Exemption method
In this method, income is taxed in the country determined by the agreement; the other country may exempt the same income from tax. The exemption method simplifies certain types of income; however, it may not be applied uniformly in every country/income.
2) Credit method
This is the most common approach. The tax paid in one country is offset dollar-for-dollar (or unit-for-unit) against the tax calculated in the other country. This way, even if the same income is taxed twice, the effect of the second taxation is reduced or eliminated.
This credit method yields effective results, especially for dual citizens working in high-tax rate countries while having additional declaration obligations in a country with a lower tax rate.
Dual residency and “tie-breaker” rules
In some cases, an individual may be considered a tax resident in two countries. This scenario is quite common in dual citizenship: there may be homes, jobs, families, long-term stays, and economic ties in both countries. DTAs use “tie-breaker” rules to unlock this situation. The typical order is as follows:
- Permanent home
- Center of vital interests (intensity of personal and economic ties)
- Habitual abode (actual presence during the year)
- Nationality
- Mutual agreement procedure (resolution by competent authorities)
This assessment requires evidence on a case-by-case basis: rental/residential documents, family residency, employment contracts, company partnership structure, bank/spending trails, travel day counts, etc. Misconfiguring the tie-breaker can exacerbate the “residency” debate during audits.
Why does the game change in countries like the USA that employ citizenship-based taxation?
In most countries, the focus of tax liability is residency. However, in the USA, the citizenship link maintains the declaration obligation regardless of where one lives in the world. Therefore, a significant portion of dual citizens, even if they do not actually pay additional taxes with proper planning, must fulfill their declaration and form obligations.
Key tools highlighted by the USA include:
- Foreign Earned Income Exclusion (FEIE): Exemption of foreign earned income up to a certain amount. According to research data, the limit is USD 130,000 for 2025 and USD 132,900 for 2026. (Under suitable conditions, it can double for spouses.)
- Foreign Tax Credit (FTC): A credit mechanism that offsets taxes paid abroad against US taxes. It is generally more advantageous in high-tax rate countries.
- Housing exclusion/deduction: An exemption/deduction mechanism covering certain foreign housing expenses.
Example scenario: Consider a US-Canada dual citizen living in Canada with a salary of USD 95,000 and USD 25,000 in investment income. If structured correctly, using FEIE for salary and FTC for investment income can lead to structures that reduce the effective tax burden in the USA to near zero after taxes paid in Canada. The critical point is not “one tool” but to correctly establish the balance between FEIE + FTC according to income composition.
A structure preventing double deductions in social security: Totalization agreements
DTAs focus on income tax; however, one of the main cost items for employees is social security contributions. At this point, especially the totalization agreements between the USA and many countries come into play. These agreements:
- Reduce social security/medicare-like deductions in both countries during the same period,
- Facilitate access to retirement rights by combining work periods,
- Clarify which country’s contribution system will apply.
When structuring cross-border employment, it is essential to consider the “tax + social security” duo together; otherwise, you may optimize only income tax and face unexpected burdens in contribution costs.
Compliance side: What should you do correctly to benefit from DTAs?
DTAs do not work automatically; in most cases, they require correct declarations and proper documentation. Key risk areas for dual citizens include:
- Different classification of income in two countries: For example, being classified as “self-employed” in one country and “salary” in another.
- Incorrect establishment of residency status: Especially for those changing countries during the year.
- Failure to disclose the agreement position: Some countries may require additional notifications/forms if you are relying on the agreement clause.
- Late declarations and incomplete information: Rights to deductions/credits may be lost; risks of penalties and interest arise.
In the USA, situations like “dual-status” (being considered a resident for part of the year and a non-resident for another part) require technical calculations and become even more complicated with claims of agreements. For the framework of this concept, the IRS Dual-Status Individuals guide is instructive.
Extra layer for business owners and international employees: Structure and process design
Dual citizenship is not just about individual tax declarations; the issue expands when company partnerships, management locations, payroll, assignments, and permanent establishment (PE) risks come into play. Especially in the following scenarios, reading DTAs should go hand in hand with “operational design”:
- Establishing a company in one country and managing it from another (discussions on management location and resident company)
- Relocating a remote employee to another country (payroll, withholding, social security, residence permit)
- Temporary assignments with a posted worker model (day counts, source country taxation, contributions)
- Optimizing costs when sending personnel abroad (including EOR/payroll structures)
At this point, professional support becomes critical not only for “tax reduction” but also for managing the risks of audits, retroactive assessments, and double taxation that may arise from incorrect structures.
How does Corpenza add value in this process?
Managing tax risks in dual citizenship often requires a multidisciplinary approach: immigration and residency structuring, incorporation, payroll/EOR, international accounting, and employee mobility are all pieces of the same puzzle. Corpenza focuses on bringing these pieces together into a single strategy with its services offered across Europe and globally:
- Incorporation and global structure establishment: Country selection, operational structuring, key compliance headings
- International accounting and payroll/EOR processes: The payroll and reporting aspect of cross-border employment
- Staff leasing/posted worker model: Tax and cost optimization perspective in suitable scenarios
- Golden visa and citizenship by investment: A planning approach that also considers the tax implications of mobility decisions
The important thing is to establish a plan that reads the DTA not as “a standalone agreement text” but in conjunction with personal income composition, residency status, working model, and company structure.
Conclusion: What reduces the tax burden in dual citizenship is as much about implementation as it is about the agreement
Double Taxation Agreements are one of the strongest frameworks preventing dual citizens from paying tax twice on the same income. However, the determining factor in practice is correctly classifying which income will be taxed where, positioning residency correctly, selecting exemption/credit mechanisms accurately, and fulfilling all declaration obligations in a timely manner.
If you are planning for dual citizenship or are already declaring in two countries, investing in the right structure and process design from the outset provides lower costs and less risk in the long run, rather than trying to “correct the tax later.”
Disclaimer
This article has been prepared for general informational purposes; it does not constitute legal, financial, or tax advice. Tax treaties, local regulations, rates, and practices may vary by country and personal circumstances. We recommend checking the publications of relevant official authorities (e.g., IRS) for current and binding information and seeking support from professionals specializing in double taxation/international tax.
