Owning assets in more than one country can be a sign of success, mobility, and family opportunity. It can also create one of the most complicated estate planning situations a family will ever face.

A cross-border estate may involve real estate in one country, investment accounts in another, a family business in a third, and heirs who live somewhere else entirely. Different countries may tax the same transfer, apply different inheritance rules, require different court procedures, and recognize different estate planning documents. The result can be costly if the planning is not coordinated before death or incapacity.

Inheritance, estate, and gift taxes vary widely across countries. Inheritance and estate taxes are imposed in 24 OECD countries, but the design of those taxes differs significantly, including whether the tax applies to the estate as a whole or to each recipient, and how much wealth can pass tax-free. That variation is exactly why families with international assets should avoid “one-country” estate planning.

Mistake 1: Assuming One Will Covers Everything

A will prepared in one country does not always work smoothly in another. Even when it is legally valid, it may not be practical.

A U.S. will, for example, may be accepted by a foreign court only after translation, legalization, apostille, or a local recognition process. Some countries require local probate or succession proceedings before real estate, bank accounts, or company shares can be transferred. Other countries have forced heirship rules that limit how much property can pass freely under a will.

The better approach is usually coordinated planning. Families often need either:

• One carefully drafted international will designed to be used across jurisdictions
• Separate wills for separate countries, drafted so that one does not revoke the other
• Local estate documents for real estate or business interests
• Trust, entity, or beneficiary designation planning that avoids probate where appropriate

Do not make this mistake of assuming the domestic estate plan will automatically operate abroad without delay, expense, or conflict.

Mistake 2: Confusing Citizenship, Residence, and Domicile

Cross-border estate planning often turns on a person’s legal status. Citizenship, tax residence, immigration residence, and domicile are not always the same thing.

For U.S. federal estate tax purposes, the rules distinguish between citizens or residents and nonresidents who are not U.S. citizens. A U.S. “resident” decedent for estate tax purposes is someone domiciled in the United States at death; a “nonresident” decedent is someone domiciled outside the United States. Domicile generally depends on where a person lives and intends to remain, not simply where the person has a visa, passport, bank account, or vacation home.

This distinction matters because the U.S. estate tax base changes dramatically depending on status:

Decedent’s U.S. Estate Tax Status	General U.S. Estate Tax Exposure
U.S. citizen or U.S.-domiciled resident	U.S. estate tax can apply to the worldwide estate.
Nonresident who is not a U.S. citizen	U.S. estate tax generally applies only to U.S.-situated assets.

The U.S. gross estate rules for citizens and residents are part of the federal estate tax system under Chapter 11 of the Internal Revenue Code. For nonresident noncitizens, only the portion of the estate situated in the United States is generally included for U.S. estate tax purposes, unless special rules such as certain expatriation rules apply.

A family that gets domicile wrong can miss a filing requirement, understate estate tax exposure, or fail to plan for assets that a tax authority treats as part of the taxable estate.

Mistake 3: Ignoring U.S.-Situated Assets Owned By Non-U.S. Persons

Many non-U.S. families are surprised to learn that relatively modest U.S. holdings can trigger U.S. estate tax filing requirements.

For a nonresident who is not a U.S. citizen, U.S.-situated property includes U.S. real estate, tangible personal property located in the United States, stock issued by a U.S. corporation, and certain debt obligations or bank deposits, depending on the applicable rules and exceptions.

The filing threshold is low. Under IRC § 6018(a)(2), the executor of a nonresident noncitizen’s estate must file a U.S. estate tax return if the U.S.-situated gross estate exceeds $60,000. Form 706-NA is used to compute U.S. estate and generation-skipping transfer tax for nonresident noncitizen decedents, and the instructions state that the executor must file Form 706-NA if the date-of-death value of U.S.-situated assets, together with the gift tax specific exemption and adjusted taxable gifts, exceeds the $60,000 filing threshold.

This is one of the biggest traps in cross-border estate planning. A non-U.S. person may own a U.S. brokerage account with U.S. stocks, a condominium in Florida, shares of a U.S. private company, or tangible property located in the United States and assume no U.S. estate filing is needed simply because the person was not American. That assumption can be wrong.

Mistake 4: Assuming The U.S. Estate Tax Exemption Applies The Same Way To Everyone

For U.S. citizens and U.S.-domiciled residents, the federal estate tax exemption is large. Estates of decedents dying during 2026 have a basic exclusion amount of $15,000,000, up from $13,990,000 for estates of decedents who died in 2025. Under IRC § 6018(a)(1), an estate tax return is required for a U.S. citizen or resident when the gross estate exceeds the basic exclusion amount in effect for the calendar year of death.

Nonresident noncitizens do not simply receive the same practical filing threshold. Their U.S. estate tax return requirement can arise when U.S.-situated assets exceed $60,000.

That difference can produce surprising results. A U.S. citizen with a worldwide estate under the 2026 exclusion amount may have no federal estate tax return filing obligation, while a nonresident noncitizen with more than $60,000 of U.S.-situated assets may have a Form 706-NA filing requirement. Planning should identify the owner’s status before deciding whether U.S. estate tax exposure is material.

Mistake 5: Failing To Plan For Double Taxation

Cross-border estates can be taxed by more than one country. One country may tax based on the decedent’s domicile or residence. Another may tax based on the location of real estate. A third may tax the beneficiary. Some countries tax the estate; others tax the recipient.

The United States provides a foreign death tax credit in certain cases. Under IRC § 2014(a), U.S. estate tax is credited with estate, inheritance, legacy, or succession taxes actually paid to a foreign country with respect to property situated in that foreign country and included in the gross estate. The credit is subject to limitations, including limits tied to the foreign tax attributable to the property and the U.S. estate tax attributable to the property. Treasury regulations also state that no credit is allowed for interest or penalties paid in connection with foreign death taxes.

The foreign death tax credit is not automatic. The estate must prove the amount paid, the date of payment, the property taxed, and other information needed to verify and compute the credit. The credit generally applies only to taxes actually paid and claimed within four years after the federal estate tax return is filed, subject to specific exceptions.

For U.S. estate tax reporting, Schedule P to Form 706 is used to claim the credit for certain foreign taxes, and Form 706-CE is used to certify payment of foreign death tax. If more than one foreign country imposes death tax, the Form 706 instructions require a separate computation for each foreign country.

The planning point is straightforward: families should identify possible tax claims country by country before death. Waiting until the estate is already in probate can make it harder to claim credits, gather proof, and avoid unnecessary double taxation.

Mistake 6: Overlooking Estate And Gift Tax Treaties

Tax treaties can change the result in a cross-border estate. Some treaties may affect domicile, situs, marital deductions, credits, or taxing rights. But treaty coverage is limited, and not every country has an estate or gift tax treaty with the United States.

Where a treaty applies, it must be reviewed alongside domestic law. The Form 706 instructions state that the foreign death tax credit may be authorized by statute or treaty, and if a treaty authorizes a credit, the estate may use the most beneficial of the treaty credit, the statutory credit, or a combination described in the instructions for certain taxes not creditable under the treaty.

A common mistake is assuming that an income tax treaty also solves estate tax problems. Income tax treaties and estate tax treaties are not the same. A family with assets in multiple countries should confirm whether the relevant treaty covers estate, inheritance, succession, or gift taxes.

Mistake 7: Leaving Assets Outright To A Noncitizen Spouse Without Reviewing The Marital Deduction Rules

U.S. estate plans often assume that assets passing to a surviving spouse qualify for the marital deduction. That assumption can fail when the surviving spouse is not a U.S. citizen.

Under IRC § 2056(d)(1), if the surviving spouse is not a U.S. citizen, the marital deduction is generally not allowed for property passing to that spouse. The key exception is property passing to a qualified domestic trust, often called a QDOT. IRC § 2056(d)(2) allows the marital deduction for certain transfers in a QDOT, including property transferred or irrevocably assigned to the QDOT by the required time.

There is also a special rule if the surviving spouse becomes a U.S. citizen before the estate tax return is filed and was a U.S. resident at all times after the decedent’s death and before becoming a citizen. In that case, the general disallowance rule does not apply.

QDOT planning is technical, and it applies only when the surviving spouse is not a U.S. citizen. Form 706-QDT is used by the trustee or designated filer to report estate tax due on certain QDOT events, and that person may be responsible for filing and paying the tax.

Families with a noncitizen spouse should address this during the estate planning process, not after the first spouse dies.

Mistake 8: Missing U.S. Reporting For Foreign Gifts, Bequests, And Trusts

A U.S. beneficiary who receives money or property from abroad may not owe U.S. income tax merely because the transfer is a gift or inheritance, but reporting can still be required.

Form 3520 is one of the most commonly missed forms. A U.S. person must file Form 3520 if, during the year, the person receives more than $100,000 from a nonresident alien individual or foreign estate and treats the amount as gifts or bequests. Reporting is also required for gifts from foreign corporations or foreign partnerships above the applicable threshold amount.

Foreign trusts create additional reporting obligations. Reportable events include the creation of a foreign trust by a U.S. person, the transfer of money or property to a foreign trust by a U.S. person (including by reason of death), and the death of a U.S. citizen or resident if the decedent was treated as owning part of a foreign trust or if part of a foreign trust was included in the gross estate. U.S. beneficiaries receiving distributions from a foreign trust must also report information such as the trust name and aggregate distributions.

The deadlines matter. In general, Form 3520 is due on the 15th day of the 4th month after the end of the U.S. person’s tax year, which is usually the same day as the income tax return due date for a calendar-year individual. If the U.S. person receives an income tax return extension, Form 3520 is due no later than the 15th day of the 10th month after year-end. Certain U.S. citizens or residents living abroad, or serving in the military outside the United States and Puerto Rico, may have the due date extended to the 15th day of the 6th month after year-end if the required statement is included.

The penalties can be severe. For failure to report certain foreign trust transactions, the initial penalty can be the greater of $10,000 or 35% of the gross value of property transferred to a foreign trust, 35% of foreign trust distributions received, or 5% of the gross value of the portion of foreign trust assets treated as owned by a U.S. person, depending on the reporting failure. For failure to report foreign gifts, the penalty is 5% of the foreign gift for each month the failure continues, up to 25%, unless the taxpayer shows reasonable cause and not willful neglect.

The biggest mistake is assuming “inheritance” means “nothing to report.”

Mistake 9: Forgetting That Legal Title Controls More Than The Will

Estate planning documents do not automatically override how assets are titled. Joint ownership, beneficiary designations, company registers, nominee arrangements, local land records, and trust ownership can all determine who controls or receives an asset at death.

Cross-border families should review:

• How each real estate parcel is titled
• Whether accounts have transfer-on-death or beneficiary designations
• Whether jointly owned property passes automatically or through the estate
• Whether shares of private companies require director, shareholder, or court approval before transfer
• Whether local law recognizes trusts
• Whether marital property or community property rules apply
• Whether a nominee or holding company structure creates tax or disclosure issues
• Whether powers of attorney are recognized in the country where the asset is located

A well-drafted will cannot fix every title problem. Asset ownership should be reviewed country by country.

Mistake 10: Ignoring Local Succession Rules And Forced Heirship

Some countries give children, spouses, or other family members mandatory inheritance rights. These rules can override a will or limit the ability to leave assets freely.

This is especially important for families that include:

• Children from prior marriages
• Unmarried partners
• Second spouses
• Estranged family members
• Beneficiaries living in different countries
• Religious or civil-law inheritance systems
• Real estate located in forced-heirship jurisdictions
• Family businesses where control is intended to pass to one child but economic value is intended to be shared

If the estate plan assumes U.S.-style testamentary freedom, but the foreign jurisdiction applies forced heirship or reserved share rules, the result can be litigation, delay, and family conflict.

Mistake 11: Creating Liquidity Problems

Cross-border estates often need cash quickly. Taxes, legal fees, translations, appraisals, court deposits, and local administration costs may be due before assets can be sold or transferred.

A family may be asset-rich but cash-poor. Estate liquidity planning should identify which country will need cash, in what currency, by what deadline, and from which source.

Mistake 12: Not Coordinating Advisors Across Countries

A domestic estate lawyer may not know foreign inheritance rules. A foreign lawyer may not know U.S. estate tax rules. An investment advisor may not know that a U.S. brokerage account holding U.S. stocks can create estate tax exposure for a nonresident noncitizen. A trustee may not know that a U.S. beneficiary of a foreign trust distribution has Form 3520 reporting obligations.

Cross-border estates require coordination among advisors. The planning team may include:

• Estate planning counsel in the country of domicile
• Local counsel where real estate is located
• U.S. tax counsel or a U.S. international tax advisor
• Foreign tax counsel
• Fiduciary or trust counsel
• Corporate counsel for business interests
• Investment advisors familiar with cross-border restrictions
• Insurance advisors
• Valuation experts
• Accountants who can manage foreign reporting deadlines

The advisors should work from the same asset schedule. Without coordination, one document can unintentionally undo another.

Mistake 13: Waiting Until Illness Or Death

Cross-border planning takes time. Documents may need translations, notarization, apostilles, legal opinions, local filings, entity approvals, beneficiary updates, or court-recognized formalities. Some planning techniques also work better during life than after death.

Incapacity planning is as important as death planning. If the asset owner becomes incapacitated while assets are spread across multiple countries, family members may need separate court authority in each jurisdiction.

Mistake 14: Treating Lifetime Gifts As Simple

Lifetime gifts can reduce probate complexity, but they can create tax, reporting, and control issues. Gift tax rules differ across countries, and the tax treatment of gifts varies significantly by country, even though lifetime giving often receives preferential treatment compared with transfers at death.

For U.S. purposes, foreign gift reporting can apply to U.S. recipients even when the transfer is treated as a gift or bequest. Transfers involving foreign trusts can also trigger reporting.

Mistake 15: Not Maintaining A Cross-Border Asset Inventory

The simplest planning failure is often the most damaging: no one knows what exists, where it is, or who to contact.

A useful cross-border estate inventory should include:

Asset Category	Information To Collect
Real estate	Country, address, title holder, purchase documents, mortgage details, local counsel, estimated value
Bank and investment accounts	Institution, country, account owner, beneficiaries, account type, reporting history
Business interests	Entity name, jurisdiction, ownership percentage, shareholder agreements, directors, buy-sell provisions
Trusts and foundations	Governing law, trustee or council, beneficiaries, tax classification, reporting obligations
Insurance	Issuer, country, owner, insured, beneficiary, currency, policy number
Retirement accounts	Country, custodian, beneficiary, tax treatment, distribution rules
Personal property	Location of jewelry, art, vehicles, boats, aircraft, collectibles, storage records
Digital assets	Custodians, access procedures, legal authority, password management, private keys if applicable
Liabilities	Country, lender, collateral, guarantees, currency, maturity dates
Advisors	Lawyer, accountant, banker, trustee, investment advisor, insurance advisor in each country

This inventory should be updated regularly and stored securely. The right plan cannot be built around incomplete information.

Cross-Border Estate Planning Is About Coordination

The largest cross-border estate mistakes usually come from treating international assets as an afterthought. A family may have excellent planning in one country and no practical plan in another. That gap can lead to double taxation, frozen accounts, probate delays, family disputes, and missed reporting deadlines.

The goal is not to create a complicated plan. The goal is to create a coordinated plan. Each country’s tax rules, inheritance rules, asset transfer procedures, and reporting obligations should be reviewed together so the family knows what will happen before incapacity or death occurs.