Spain and the United States may share strong diplomatic and business ties, but their tax systems are fundamentally different. For Spanish citizens preparing to move to the U.S., or Spanish citizens who will transfer assets to U.S. children, early and thoughtful tax planning is essential to avoid unintended consequences.

Here are key cross-border issues that arise:

1. Worldwide Income Taxation: Once a Spanish citizen becomes a U.S. tax resident — generally by meeting the substantial presence test or acquiring a green card — they are subject to U.S. tax on their worldwide income. This includes rental income from Spanish properties, dividends from foreign (non-U.S.) investments, and earnings from Spanish pensions. And even if no income is earned, reporting of all types of foreign assets is nonetheless required. S. taxation and reporting occurs regardless of where the income is earned or whether it is repatriated to the U.S.

For Spanish individuals used to Spain’s territorial and residency-based tax system, this can be a major shift. Without pre-immigration planning, individuals may face double taxation or fail to take advantage of available foreign tax credits or treaty benefits.

2. Entity Classification Elections: One of the most overlooked but powerful tools in pre-immigration tax planning is the ability to make entity classification elections for foreign business entities under the U.S. “check-the-box” regulations. These elections determine how the U.S. tax system treats a foreign entity — as a corporation, partnership, or disregarded entity — and can significantly affect the individual’s future tax obligations.

Foreign entities are not automatically classified the same way under U.S. tax rules as they are in their home country. For instance, a Spanish sociedad limitada (S.L.) is typically treated as a corporation for U.S. tax purposes unless an election is made to treat it otherwise. Without proper planning, this can lead to unexpected exposure to Subpart F or GILTI income, complex Form 5471 filings, or limitations on using foreign tax credits.

By proactively implementing a cross-border tax structure before becoming a U.S. tax resident, an individual can often achieve more favorable tax treatment, such as disregarded entity status (if wholly owned) or partnership treatment (if jointly owned). This can help streamline income reporting, reduce double taxation, and minimize the administrative burden of international tax compliance.

However, the timing of the election is critical. Elections made too early or too late can result in deemed taxable transactions or missed opportunities. For clients with active businesses, intellectual property, or investment holding structures abroad, it is essential to evaluate these options as part of their overall pre-immigration strategy.

3. Asset Reporting: The U.S. imposes broad asset and account disclosure requirements on its tax residents. Spanish citizens newly resident in the U.S. may be unfamiliar with rules related to the reporting of foreign bank and financial accounts, foreign investment accounts, foreign entities, foreign pensions, foreign trusts, and foreign gifts.

The FBAR (FinCEN Form 114)  is required if the aggregate value of all foreign accounts exceeds $10,000 at any point during the year. Form 8938 has higher thresholds but applies to a broader range of foreign assets, including shares in foreign companies, partnership interests, and life insurance policies with cash value. These forms must be filed annually and are separate from tax returns.

In addition to these, U.S. persons with interests in foreign corporations or partnerships may also be required to file:

• Form 5471: For U.S. persons who are officers, directors, or shareholders in certain foreign corporations.
• Form 5472: For U.S. corporations with reportable transactions involving related foreign persons.
• Form 8865: For U.S. persons with an interest in foreign partnerships.

These forms are highly complex and time-consuming to complete, often requiring detailed financial statements and intercompany transaction data. Failure to file can result in severe penalties, starting at $10,000 per violation, and potentially rising to 50% of the account balance for willful noncompliance. This makes early planning and asset review critical. Spanish clients should work with professionals to organize records, understand account ownership, and determine which entities or trusts may fall within the scope of U.S. reporting rules.

For those who move to the U.S. and discover they have missed required filings, there are limited amnesty programs available. The Streamlined Filing Compliance Procedures offer reduced penalties for taxpayers whose noncompliance was non-willful. The Delinquent International Information Return Submission Procedures may be used in some circumstances, provided the taxpayer has reasonable cause. For taxpayers whose noncompliance was willful, the IRS’s Voluntary Disclosure Practice (VDP) provides a pathway to come into compliance. The VDP requires a comprehensive disclosure process and may involve significant penalties. However, it offers the possibility of avoiding criminal prosecution for those who proactively address their tax obligations.  Understanding which program may be available — and whether the facts support eligibility — requires careful legal and strategic analysis.

4. Gift and Estate Tax Planning: The U.S. estate and gift tax system is based on domicile and citizenship, which differs from Spain’s succession rules. U.S. persons are subject to gift and estate tax on their worldwide assets. The lifetime exemption is currently over $13 million per person or double for married U.S. Persons, creating urgency for those looking to pass on wealth.

In contrast, Spain’s succession tax system is based on the heir’s relationship to the decedent and includes regional variations. A lack of coordination between the two systems can result in double taxation or unplanned liabilities.

Spanish citizens planning to immigrate or transfer assets to U.S. children may benefit from pre-domicile gifting, trust formation, or corporate restructuring to shield assets from the U.S. transfer tax system. Moreover, U.S. rules for noncitizen spouses limit the marital deduction, unless a Qualified Domestic Trust (QDOT) is used. These nuances highlight the need for cross-border estate plans that align Spanish civil law frameworks with U.S. transfer tax goals.

5. Exit from Spanish Tax Residency: Spain has its own complex residency rules that can result in overlapping tax obligations. In addition, Spain imposes an exit tax (Impuesto de Salida) on certain individuals who give up tax residency, particularly if they hold significant ownership in companies. For individuals who have lived in Spain for at least ten of the prior fifteen years, there may be capital gains taxes imposed on unrealized gains upon departure.

This means that before taking up U.S. residence, it is essential to analyze whether any deemed disposals or valuation requirements will apply. Coordinating with a Spanish tax advisor ensures that the exit from Spanish residency is clean, well-documented, and strategically timed.

6. Trust Mismatch: The United States has a well-developed body of trust law and uses trusts extensively as part of sophisticated wealth planning strategies. U.S. tax rules distinguish among grantor, nongrantor, foreign, and domestic trusts, each with its own compliance and tax implications. Trusts can be highly effective tools for asset protection, privacy, and tax optimization, particularly in pre-immigration planning.

However, Spain does not recognize trusts in the same way. As a civil law jurisdiction, Spanish tax law may disregard the separate legal identity of a trust and treat the trust’s assets as belonging directly to the grantor or beneficiaries. This difference creates a potential for tax mismatches, double taxation, or loss of intended benefits.

Trust structures can be beneficial before establishing U.S. residency. But if a U.S. tax resident later becomes a Spanish tax resident — for instance, by returning to Spain — the trust structure may need to be re-evaluated or even unwound to align with Spanish tax treatment and avoid unintended consequences.

Proper planning requires coordination between U.S. and Spanish tax professionals to ensure that the structure is robust under both systems and remains flexible as residency changes over time.

7. S.-Spain Tax Treaty: While the U.S.-Spain tax treaty provides relief from double taxation and establishes tie-breaker rules for residency, it doesn’t eliminate all potential conflicts. Spanish pensions, for instance, may be taxed differently in the U.S. depending on the type of plan, whether it’s public or private, contributory or non-contributory. Conversely, certain U.S. retirement accounts may be taxable in Spain while they otherwise would not be in the U.S.

Additionally, dividend and interest income, capital gains, and business profits may be subject to different rates under the treaty. Understanding how the treaty applies in practice — not just in theory — is crucial for effective pre-immigration structuring.

If you have any questions regarding pre-immigration tax panning or cross-border planning, please reach out to Christine Alexis Concepcion at caconcepcion@concepcionlaw.com.