Pre-Immigration Tax Planning: Why the US Residency Starting Date Decides Everything

Pre-immigration tax planning is the body of decisions a foreign national resolves before becoming a US tax resident. The planning window exists because the two tax regimes rest on different premises. The IRS states the resident side plainly: "Resident aliens are generally taxed on their worldwide income, the same as U.S. citizens."^[1] The nonresident side is the mirror: foreign nationals who do not meet either residency test pay US tax only on US-source income and on income connected with a US trade or business.^[1]

That shift happens on one specific calendar day, the residency starting date. Everything you owned, earned, or deferred before that day belongs to a foreign tax life governed by foreign rules. Everything that happens on or after that day sits on a US return. A built-in gain on a foreign business interest, a distribution from a non-US pension plan, an unrealized gain on a holiday home abroad, all look identical to the IRS once the switch flips. The planning window is therefore not about avoiding US tax after residency, it is about taking an honest inventory of what sits on the foreign side of the line while there is still time to resolve it. Our advisory solutions work is almost always built around that inventory first.

The IRS does not ask about intent or visa label. It applies two mechanical tests. Under the green card test, the IRS states: "You are a resident for tax purposes if you are a lawful permanent resident of the United States at any time during calendar year 2025."^[2] Under the substantial presence test, the agency requires physical presence in the country "on at least: 31 days during 2025; and 183 days during the 3-year period that includes 2025, 2024, and 2023, counting: All the days you were present in 2025, 1/3 of the days you were present in 2024, and 1/6 of the days you were present in 2023."^[3]

The mechanical nature of the second test is where many planning problems originate. The 183-day result is cumulative across three years, so a pattern of long business visits can push a future immigrant over the line without any single stay feeling consequential. Passing either test turns the IRS into the authority that reaches your worldwide income for the year.^[1] For investors arriving through a Florida LLC, our foreign-owned U.S. entity tax services page frames the entity-level questions that pair with this residency question.

The residency starting date is the dividing line between the two tax lives. For a substantial-presence resident, the IRS puts the line like this: "If you meet the substantial presence test for a calendar year, your residency starting date is generally the first day you are present in the United States during that calendar year."^[4] For a green-card resident who did not also meet the presence test, the rule changes: "If you meet the green card test at any time during a calendar year, but do not meet the substantial presence test for that year, your residency starting date is the first day in the calendar year on which you are present in the United States as a lawful permanent resident."^[5]

One narrow softener is built into the first-day rule. The IRS allows up to 10 days of actual US presence to drop out of the starting-date calculation when, on those days, a closer connection to a foreign country and a foreign tax home are both proven.^[4] Those 10 days still count toward the day-count for the presence test itself, so the exclusion only moves the starting date, not residency status. For a family that arrives in two trips, a short January scouting visit followed by a March move, that softener is often the difference between two months of worldwide tax exposure and none.

Before residency, only US source income and income connected with a US trade or business reach the US return.^[1] After residency, income from every country is on the US return at the same graduated rates a citizen pays, and the reporting regimes that attach to foreign holdings activate at the same moment.^[1] A foreign mutual fund that produced an efficient result at home becomes a passive foreign investment company inside a US return, with its own punitive excess-distribution math. A family trust that was transparent abroad can trip the US grantor-trust rules on day one of residency.

That change is why the planning conversation is really about the inventory, not the move. Appreciated foreign securities carry a built-in gain that will be measured against a basis set long before you reached the United States. Pension plans and deferred compensation sit outside tax-favored US treatment unless a treaty says otherwise. A foreign brokerage account triggers an FBAR, as our guide on FBAR vs Form 8938 foreign account reporting explains, and the thresholds for the US international information returns start running the moment residency starts. A sale completed before residency sets a cost basis the US will later recognize, which is why practitioners talk about a de facto step-up: the realized gain is a foreign problem, and the US basis is the proceeds.

Yes, inside a narrow box. The IRS allows a day-count resident to file as a nonresident when three facts hold at once, in its own words: "Even if you meet the substantial presence test, you can be treated as a nonresident alien if you: Are present in the United States for less than 183 days during the year, Maintain a tax home in a foreign country during the year, and Have a closer connection during the year to one foreign country in which you have a tax home than to the United States".^[6] The sub-183-day ceiling is hard: a day over it drops the exception for the year, no matter how strong the foreign ties look.

Making the claim is itself a formal step. The IRS says that "You must attach a fully completed Form 8840 to your income tax return to claim you have a closer connection to a foreign country or countries."^[7] The exception also closes the moment immigration intent appears on paper: an applicant who has filed for permanent residence, or whose adjustment-of-status application is pending during the year, cannot claim it. In practice, the exception is a one-year or two-year bridge for a cross-border executive or investor whose life still runs out of a foreign home, not a long-term strategy for a family and business that have already moved.

The First-Year Choice is the mirror image of the closer connection exception. The IRS defines it directly: "If you do not meet either the green card test or the substantial presence test for 2024 or 2025 and you did not choose to be treated as a resident for part of 2024, but you meet the substantial presence test for 2026, you can choose to be treated as a U.S. resident for part of 2025."^[8] The two conditions attached to the choice are also quoted from the publication: "Be present in the United States for at least 31 days in a row in 2025" and "Be present in the United States for at least 75% of the number of days beginning with the first day of the 31-day period and ending with the last day of 2025. For purposes of this 75% requirement, you can treat up to 5 days of absence from the United States as days of presence in the United States."^[8]

The choice is irrevocable without IRS approval, and it is almost never the right answer for someone with substantial foreign-source income the US would then tax at graduated rates. It is useful when a late-year arrival wants to use US deductions, a joint return with a US-citizen spouse, or treaty credits for the partial year. The decision is a tax calculation first, not a filing preference. For the mechanics of the return itself our guide on who must file a nonresident return is a useful companion once residency starts, and individual tax return preparation handles both halves of a dual-status year.

Real estate carries two of the biggest planning items on the foreign side of the line. Appreciated foreign real estate owned on the first day of residency carries a built-in gain that the US will measure against the original foreign basis, not the market value on the day of arrival, so the gain between purchase and residency becomes a US capital gain if the property is sold later. Inherited property is the usually welcome exception, because US rules allow inherited property to be measured against its fair market value at the date of death, and our note on inherited real estate step-up basis for Latin American heirs explains how that basis step works for a Latin American inheritance received after residency begins.

US real estate held by a nonresident is a separate layer. Even before residency, a sale of US real property by a foreign owner triggers FIRPTA withholding at closing, which our note on FIRPTA foreign seller withholding on Form 8288 covers in detail. For a family that is about to immigrate and also owns a Florida condominium through a foreign holding structure, the planning question is which legs of the structure survive residency and which collapse into a single US owner.

The entrance decision and the exit decision are linked by one statute. If a long-term resident later terminates lawful permanent residence, the section 877A expatriation rules can apply. The IRS writes the covered-expatriate test as three alternative conditions on the expatriation date: "Your average annual net income tax for the 5 years ending before the date of expatriation or termination of residency is more than $206,000 if you expatriated or terminated residency in 2025. Your net worth is $2 million or more on the date of your expatriation or termination of residency. You fail to certify on Form 8854 that you have complied with all U.S. federal tax obligations for the 5 years preceding the date of your expatriation or termination of residency."^[9]

Covered-expatriate status activates a mark-to-market calculation. In the IRS wording, "In the year you expatriate, you are subject to income tax on the net unrealized gain (or loss) in your property as if the property had been sold for its fair market value on the day before your expatriation date" (a treatment the agency itself labels the mark-to-market tax).^[10] The exit calculation measures gain against the US basis, which is why the pre-immigration basis conversation and the post-residency reporting conversation are both really about one future number. New arrivals who have any realistic chance of leaving later should treat the exit test as part of the entry plan, not as a problem for a future year.

Pre-immigration planning is one decision taken many times: for each item of value, do you want it on the foreign tax side of the line or the US side? Realized gains, closed trusts, settled compensation and dissolved foreign structures sit on the foreign side with their original tax treatment. Everything else moves across and lives under US rules from the residency starting date forward. The reader who understands that trade knows why the professional conversation starts well before any plane ticket is booked, not after.

What you need to bring to that conversation is honest: the full asset list including private company interests, the holding structure that owns each piece, every foreign trust or settlor arrangement in the family, deferred compensation and pensions in each country, prior gift or inheritance tax paid at home, and a realistic residency timetable (first day of expected US presence, visa path, expected first filing year). That inventory is what our advisory solutions builds the plan around, and the ITIN that most new residents need in order to file is handled inside ITIN application help.