Moving to the United States can change your tax position before you feel fully settled. You may still have a home, investments, a business or family obligations abroad, yet the United States may already treat you as a resident for federal tax purposes.
The date matters because U.S. tax residents are generally taxed on worldwide income. It can also affect foreign account reporting, investment treatment, company reporting and the way a part-year return is prepared.
Your visa label, Green Card date, arrival date and U.S. tax residency date may be connected, but they are not always identical.
Start with the two main federal residency tests
A non-U.S. citizen is generally treated as a resident alien for federal tax purposes if the person meets either the green card test or the substantial presence test. Special rules, treaty positions and exceptions can change the result, which is why day counting alone is not always enough.
The green card test
You generally meet the green card test if you are a lawful permanent resident of the United States at any time during the calendar year. The residency starting date may depend on when you were first present in the United States as a lawful permanent resident and whether another residency test also applies.
Receiving a Green Card late in the year does not automatically mean every day of that year is treated the same. A first-year return can be a dual-status return, with a nonresident period and a resident period.
The substantial presence test
The substantial presence test uses a weighted three-year calculation. You generally need to be physically present in the United States for at least 31 days in the current year and reach 183 weighted days across the current year and the preceding two years.
- Count all qualifying days in the current year.
- Count one-third of qualifying days in the previous year.
- Count one-sixth of qualifying days in the second preceding year.
Some days may be excluded, including certain days for exempt individuals or specific medical and transit circumstances. “Exempt” in this context usually means exempt from counting days for this test, not exempt from all U.S. tax.
Use the current IRS substantial presence test guidance and keep a travel calendar supported by passport records, airline confirmations and immigration history.
Why the residency start date deserves attention
The first year is often the hardest because income, assets and transactions may straddle two tax systems. The residency start date can influence when foreign investment income enters the U.S. return and when specialist reporting becomes relevant.
A person who changes from nonresident to resident during the year may be a dual-status individual. The return has special limitations and presentation rules. In some cases a qualifying person can make a first-year choice, while married couples may have separate elections available. These choices can affect worldwide income, deductions, filing status and treaty analysis, so they should be modeled before a return is filed.
The IRS Publication 519 explains residency starting dates, dual-status years and first-year choices. It is detailed, but it gives your tax adviser a reliable framework for the questions that need answers.
Do not confuse tax residency with these other tests
| Question | What it decides | Why it is different |
|---|---|---|
| Immigration status | Whether you may enter, remain or work in the United States | Immigration classifications do not always determine federal tax residency |
| Federal income tax residency | Whether you are generally taxed as a resident or nonresident alien | Usually driven by the green card or substantial presence test, subject to special rules |
| State tax residency | Whether a state treats you as a resident or domiciliary | Each state has its own rules and may look at domicile, days and connections |
| Treaty residency | How a tax treaty may resolve dual residence for treaty purposes | A treaty claim can require careful analysis and disclosure |
Changing your immigration status does not automatically end tax residence in another country. You may have filing obligations in both places while the domestic rules and treaty position are resolved.
When a treaty or closer connection may matter
Some people meet a U.S. domestic residency test while also being resident under another country’s law. A relevant income tax treaty may contain tie-breaker rules. Claiming a treaty position can affect the form filed and may require Form 8833.
A separate closer-connection exception may be available to some people who spend fewer than 183 days in the United States during the current year, maintain a foreign tax home and satisfy the detailed requirements. Form 8840 and its filing deadline matter. This is not a general option for anyone who prefers to remain a nonresident.
Do not rely on a treaty or exception based on a short description online. The facts, dates, home, family, business activity and permanent residence application can all affect the analysis.
What changes once you are a U.S. tax resident?
- Worldwide income: Foreign salary, business income, rent, interest, dividends and capital gains may need to be reported.
- Foreign accounts: FBAR and Form 8938 may apply under different rules and thresholds. Read the practical guide to FBAR and FATCA reporting.
- Foreign investments: Non-U.S. funds can create PFIC reporting and punitive default tax treatment. Review PFICs before changing or selling investments.
- Foreign companies: Ownership, management or directorship of a non-U.S. company can trigger Form 5471 and possible current income inclusions. See the guide to controlled foreign corporations.
- Foreign trusts and pensions: Classification and reporting may differ significantly from the home country treatment.
- State tax: Your U.S. state may have its own residency and income tax rules.
A practical timeline for your first U.S. tax year
Before the move
- Map every financial account, investment, company, trust, pension and property interest.
- Record purchase dates, original cost, contributions, distributions and current values.
- Download statements while foreign banking access is easy.
- Identify investments that may be PFICs and companies that may require U.S. reporting.
- Ask a cross-border tax adviser to model the likely residency start date and first-year choices.
During the year
- Maintain a day-by-day travel record.
- Keep foreign and U.S. income documents together.
- Record the highest annual balance of each foreign financial account for FBAR work.
- Notify the adviser before selling a foreign fund, restructuring a company or receiving a trust distribution.
- Set aside cash for estimated taxes where withholding may be insufficient.
Before filing
- Confirm whether the return is resident, nonresident or dual status.
- Reconcile worldwide income to source documents.
- Complete an international information return checklist.
- Confirm whether state returns are required.
- Ask the preparer which assumptions were made and which elections were considered.
Questions to take to a cross-border tax adviser
- What is my likely federal residency starting date?
- Could I be dual status, and what filing choices are available?
- Am I still tax resident in another country under its domestic law?
- Does a treaty apply, and would a treaty position require disclosure?
- Which foreign accounts, investments, businesses, trusts and pensions create U.S. reporting?
- Are there transactions that should be completed or avoided before residency begins?
- How will state tax residency be determined?
- What records and valuations should I preserve now?
The practical takeaway
Do not wait until the first tax return is due to work out when U.S. tax residency began. By then, investment sales, distributions and company decisions may already have created consequences that are difficult to unwind.
Start with the dates, then map the assets and entities. The America Financial Readiness service helps international families organize the questions and records that need specialist review, while the Finance and Tax resource hub connects the related planning topics.
