Part IV · Tax Regimes · No. 07

State residency and domicile

The state that claims a taxpayer as resident gets the first call on income tax — and, in twelve states, on estate tax. The line between resident and non-resident runs through two tests: domicile and statutory residency. The high-tax states police it aggressively.

The rule

A U.S. state may tax the worldwide income of its residents, and may tax non-residents on income sourced to the state. Residency is determined by two largely independent tests:

• Domicile. The single place a person treats as a true, fixed, and permanent home, with intent to return after any absence. A taxpayer has one domicile at a time, and it persists until a new domicile is acquired through the combination of physical presence and intent to remain.
• Statutory residency. A second, parallel test under which a person who maintains a permanent place of abode in the state and spends more than 183 days there is treated as a resident, regardless of domicile.
• The two tests are independent. A taxpayer can lose domicile and still be a statutory resident; can change domicile and avoid statutory residency; or can be subject to both. A taxpayer can also be a resident of two states simultaneously — and pay tax to both. Resident credits generally cover only income sourced to the other state (wages, business income, real property there), so intangible investment income of a dual resident can be fully taxed twice.

The statutory basis

Residency is creature of state law. The principal high-tax-state statutes:

• New York Tax Law §605(b). Defines "resident individual" as one who is domiciled in New York or who maintains a permanent place of abode and spends more than 183 days in New York.
• California Revenue and Taxation Code §17014. Defines resident as one who is in California for other than temporary or transitory purpose, or domiciled but outside on temporary basis. California uses a "closest connection" test rather than a strict day count for domicile.
• Massachusetts General Laws ch. 62, §1(f). Domicile-or-183-days test similar to New York.
• Illinois 35 ILCS 5/1501(a)(20). Defines "resident" as an individual in Illinois for other than a temporary or transitory purpose, or domiciled in Illinois but absent for a temporary or transitory purpose.

Federal law does not preempt or harmonize state residency rules. Comptroller of the Treasury of Maryland v. Wynne, 575 U.S. 542 (2015), held that Maryland's personal income tax, which denied residents a full credit against the county portion for income taxes paid to other states on income earned there, violated the dormant Commerce Clause — a rule about sourced income, not the definition of residency. It does not prevent two states from each taxing a dual resident's investment income; the New York Court of Appeals upheld exactly that result in Matter of Tamagni v. Tax Appeals Tribunal, 91 N.Y.2d 530 (1998).

Domicile — the factor test

Domicile is a question of intent, demonstrated through objective facts. Courts and revenue agents weigh factors. New York's Department of Taxation and Finance applies five "primary factors" set out in its Nonresident Audit Guidelines:

1. Home. The size, character, and use of the homes in each state. A primary home with personal effects and family use is heavily weighted.
2. Active business involvement. Where the taxpayer's principal business or profession is conducted.
3. Time. Where the taxpayer spends days; not dispositive but a factor.
4. Near and dear items. Where the taxpayer keeps personal property of sentimental or intrinsic value — family photographs, heirlooms, art, jewelry, the dog, the wine collection.
5. Family connections. Where the spouse and minor children reside.

Secondary factors include voter registration, vehicle registration, driver's license, club memberships, religious affiliations, professional licensure, and the address used on federal tax returns. None is dispositive; the totality is weighed.

The five-factor framework is the operative tool for change-of-domicile audits. A taxpayer who claims to have changed domicile from New York to Florida is examined on each factor. The case turns on whether the new domicile has been established and the old one abandoned — both requirements, both judged on facts.

Statutory residency — the 183-day trap

Statutory residency is a separate and simpler test. Two elements:

1. Permanent place of abode. A dwelling permanently maintained by the taxpayer, suitable for year-round use. New York's Matter of Gaied, 22 N.Y.3d 592 (2014), narrowed the test to require that the taxpayer use the dwelling as a residence, not merely own or maintain it.
2. More than 183 days. Any part of a day in the state counts as a day, with limited exceptions for travel through the state. Day counts are reconstructed in audit from cell tower records, credit card receipts, e-ZPass logs, calendar entries, and air travel records.

A statutory resident pays tax on worldwide income to the statutory-resident state, even if domiciled elsewhere. The same income is also taxed by the domicile state. Credits for tax paid to the other state generally reach only income sourced there, so investment income of a domiciliary of one state who is a statutory resident of another can be taxed in full by both.

The stakes

For a high-income taxpayer the rate differential between high-tax and no-tax states is material. California's top marginal rate is 13.3% (including the 1% mental-health-services surcharge on income above $1 million), New York's top combined state-and-city rate is approximately 14.776% for New York City residents earning above the highest threshold, and New Jersey's top rate is 10.75%. Florida, Texas, Tennessee, Nevada, Wyoming, South Dakota, Washington (which taxes long-term capital gains above an annual standard deduction at 7%, plus 2.9% on gains above $1 million from 2025), Alaska, and New Hampshire (whose interest-and-dividends tax was repealed from 2025) impose no broad-based state income tax on wages. A change of residency from California to Florida can save up to 13.3% of top-bracket income each year.

The stakes extend beyond income. State estate tax exists in twelve states plus the District of Columbia, with exemptions far below the federal level (Oregon at $1 million, Massachusetts at $2 million). A New York domiciliary dying with a $20 million taxable estate is far past New York's exclusion "cliff" and owes roughly $2.7 million of New York estate tax at rates up to 16%; the federal deduction for state death taxes (§2058) offsets part of that cost. The same decedent domiciled in Florida pays no state estate tax.

For sales-tax purposes — see sales and use tax — the residency state is often where use tax attaches on a mobile asset (yacht, aircraft, vehicle) brought into the state.

Common planning approaches

• Establish the new domicile. Acquire a primary residence in the new state with at least the character of the prior primary residence. Spend more time in the new state than in any other. File federal returns with the new state's address. Register to vote, register vehicles, change driver's license. Move "near and dear" items to the new state.
• Sever the old. Sell or significantly downsize the prior primary residence. Resign club memberships. Move spouse and minor children if applicable. Close professional offices in the old state.
• Mind the 183-day count. Even after domicile change, a taxpayer who maintains a New York apartment and spends 184 days in New York is a statutory resident. Keep a documented day log.
• Florida homestead. Filing for the Florida homestead exemption is a powerful objective signal of intent to make Florida the permanent home and triggers Florida's homestead asset protection. See Florida.
• Trailing-year audit defense. Change-of-domicile audits typically focus on the first one to three years after the asserted move. Documentation captured during that period (cell-tower data, calendar entries, receipts) is the principal defense.
• Trust situs. Trusts have their own residency tests under state law, distinct from individual residency. New York and California in particular tax trusts on a connection-based test that may sweep in trusts settled or administered with state contacts. Sourcing investments through a non-grantor trust administered elsewhere (in South Dakota or Delaware) can move investment income outside the state, but New York (since 2014) and California (since 2023) tax incomplete-gift non-grantor ("ING") trusts as grantor trusts, and New York applies a throwback tax on accumulation distributions to resident beneficiaries.

Recent developments

State enforcement of change-of-domicile claims has intensified. New York's Department of Taxation and Finance has published detailed audit guidance; California Franchise Tax Board has pursued domicile audits aggressively against departing taxpayers. The wave of departures from California and New York beginning in 2020 has produced a corresponding wave of residency audits.

The Gaied decision in 2014 narrowed New York's permanent-place-of-abode prong, reducing the audit risk for taxpayers who maintain a New York pied-à-terre used only by a child or other relative, but the agency continues to scrutinize the use pattern carefully.

The 2017 federal cap on the state-and-local-tax deduction at $10,000 raised the after-tax cost of high state income tax. The One Big Beautiful Bill Act raised the cap to $40,000 for 2025 and $40,400 for 2026 (rising 1% a year through 2029), but phases it down by 30% of modified AGI above $500,000 for 2025 ($505,000 for 2026) to a $10,000 floor, so top earners remain effectively capped at $10,000; the cap reverts to $10,000 for everyone in 2030. Pass-through-entity tax elections remain the principal workaround for business owners.

Several states have considered "exit taxes" on departing high-net-worth taxpayers; none has been enacted as of the review date. California voters will decide Proposition 40, the 2026 Billionaire Tax Act initiative, on 3 November 2026: a one-time tax of up to 5% on residents with net worth above $1.1 billion, with residency tested as of 1 January 2026. Competing measures on the same ballot would nullify it if they receive more votes. Outcome pending as of this review.

Reviewed October 2026