State Tax Residency for US Expats: The Domicile Trap

Most US expats understand the federal picture: worldwide income, FEIE, FBAR, Form 8621 for PFICs. What catches people off guard is state taxes. Moving to London or Singapore doesn't automatically terminate your state tax relationship. California, New York, and several other aggressive states will continue taxing your worldwide income — sometimes for years after you've left — unless you've taken specific steps to prove you've gone for good.

Two Ways You Stay Liable to a State

1. Domicile

Your legal domicile is your permanent home — the place you intend to return to. It doesn't change automatically when you leave. An expat who has lived in Singapore for three years is still a California domiciliary if she hasn't taken steps to establish a new permanent home elsewhere. Domicile persists until you satisfy three things simultaneously:

1. Physically leave the prior domicile state
2. Establish a new domicile somewhere else (US state or foreign country)
3. Intend to remain at the new location permanently (not just "for now")

All three must be present. Intent is the hardest element to demonstrate — and the easiest for a state to challenge.

2. Statutory Residency

Several states have a second-tier rule: even if you've abandoned domicile, you're taxed as a full resident if you spend enough days in-state AND maintain a permanent place of abode. This catches expats who've "left" but still own a home or apartment back home and spend several months a year visiting.

New York is the most prominent example: 184+ days in-state plus a maintained permanent place of abode triggers full resident taxation on worldwide income — regardless of where you're domiciled.³ If you still own your Manhattan apartment and visit for summers plus holidays, you may be a New York statutory resident.

California: The Most Aggressive State

California has the broadest residency rules in the country and actively audits expats. Three things to know:

California doesn't recognize FEIE

Income you exclude on Form 2555 at the federal level is not excluded in California. A US expat earning $150,000 in the UK may owe zero federal income tax on the first $132,900 (2026 FEIE limit) — but if they remain a California domiciliary, California taxes that entire amount at up to 13.3%.¹ Similarly, California does not allow a foreign tax credit the way the federal return does; California has its own limited credit that may not fully offset UK taxes.

The nine-factor domicile test

The California Franchise Tax Board evaluates domicile using nine factors laid out in FTB Publication 1031:²

• Location of principal residence
• Location of spouse and children
• Location of employment and business ties
• Location of social, civic, and fraternal memberships
• Where driver's license is maintained
• Where voter registration is held
• Location of bank and investment accounts
• Location of medical providers and advisors
• Location of a place of abode (owned or rented)

No single factor controls, but the more of these that point back to California, the stronger the FTB's argument. The FTB can audit several years after the fact — and the burden of proof is on you, not the state.

The 546-day safe harbor (employees only)

California offers a narrow safe harbor for employed workers: if you leave California under an employment contract for 546+ consecutive days, limit California return visits to 45 days or fewer per year, and keep intangible income (dividends, interest, capital gains) below $200,000 per year, the FTB presumes you're a nonresident for that period.⁵

Important caveats: the safe harbor applies only to employees with a foreign employment contract — not the self-employed, not retirees, not investors. Two sequential contracts with a California stay in between don't qualify; the 546 days must be consecutive. And even within the safe harbor, California can still challenge if other evidence of domicile is strong.

New York: The "Clear and Convincing Evidence" Standard

New York uses a high legal standard for domicile changes: you must demonstrate with clear and convincing evidence that you have abandoned your New York domicile and established a new one outside New York.³ Courts have found that going abroad for a long-term employer assignment doesn't meet this standard on its own — especially if you've left furniture in a New York apartment, maintained New York bank accounts, and kept children in New York schools.

The statutory residency trap

New York's second-tier rule is particularly dangerous for expats who visit home frequently: spend 184 or more days in New York during the year AND maintain a permanent place of abode (owned or leased) and you're taxed as a full New York resident on your worldwide income — even if you're clearly domiciled in another country.⁴ A day in New York counts from the moment you enter the state; partial days count as full days in many audits.

The practical implication: if you still own or lease a New York apartment, be meticulous about counting days. 183 days in New York is safe. 184 days is not.

Other Aggressive States

The no-income-tax states matter for planning purposes. Expats who have flexibility about where they're "from" domestically — those with addresses in multiple states or who move domestically shortly before an international relocation — sometimes deliberately establish domicile in Florida or Texas before departing. Once you're a Florida domiciliary, there's nothing to sever.

Steps to Properly Sever Domicile Before You Leave

These steps should happen before or in the tax year of departure, not after the fact:

1. Establish a new domicile. Get a foreign address, foreign driving license if available, open local bank accounts at your destination. The new domicile can be in a foreign country — you don't need a US domicile as an intermediate step.
2. File a final part-year resident return. In your departure year, file as a part-year resident of your old state, reporting the date you left. For New York, attach Form IT-203. For California, attach Schedule CA and mark the residency change boxes. Keep a copy permanently.
3. Sever the ties systematically.
   • Close or transfer financial accounts to non-state institutions
   • Change mailing address on all accounts and subscriptions
   • Surrender driver's license or let it lapse; don't renew a California license while abroad
   • Update or cancel voter registration
   • Resign from state-based professional organizations and social clubs
   • Cancel safe deposit boxes
4. Sell or lease out the home. A vacant owned home is one of the strongest ties the FTB and NYDTF can point to. If you're not selling, at minimum lease it to an unrelated tenant at fair market value so it's clearly not maintained as your personal abode.
5. Document everything. Keep dated records of your location for each day of the year. Calendar apps, travel itineraries, passport stamps, and credit card statements have all been used in state residency audits.

Common Mistakes

• Assuming FEIE handles everything. Your federal exclusion does not flow through to California. If you excluded $132,900 of income on your 1040, that same income is still fully California-taxable if you're a California domiciliary.
• Spending too many days back. California's 546-day safe harbor allows 45 return days per year. New York's statutory residency threshold is 184 days. Many expats underestimate how quickly "summer visits + holidays + work trips" add up.
• Ignoring state after filing federal. Your expat CPA handles your federal return (Form 2555, FTC, FBAR) but may not coordinate on state. State residency is a separate analysis with different rules — explicitly confirm who is handling your state return and residency position.
• Children enrolled in a state university. Not determinative on its own, but children enrolled at a California or New York university, a family home still in the state, and summer visits create a picture the FTB is happy to use.
• Ignoring the year you return. State tax exposure doesn't only apply to the years abroad. If you repatriate and re-establish domicile before year-end, that year's worldwide income may be partially taxed by the state for the re-entry period.

How This Interacts With the Rest of Expat Planning

State residency planning doesn't exist in isolation. Several federal elections interact with state treatment:

• If you make the FEIE election (Form 2555), California taxes that excluded income anyway. This can tip the FEIE vs. FTC decision — in some scenarios, the Foreign Tax Credit leaves you in a better state-tax position depending on the foreign tax rate.
• If your spouse is a non-US citizen, the state may not recognize the same §6013(g) joint filing election that applies federally. California and New York analyze state returns separately.
• FBAR and FATCA filings are federal obligations only — state taxes have no direct interaction — but the accounts disclosed there are the same ones the state may use as evidence of ongoing ties (e.g., a California bank account you forgot to close).

The advisor who coordinates your overall expat financial plan — covering FEIE vs. FTC, portfolio construction to avoid PFIC, and retirement account integration — should also be coordinating with your expat CPA on state residency. These decisions interconnect.

Sources

1. California Franchise Tax Board — California does not conform to IRC § 911 (FEIE); see FTB Publication 1031 (2024): Guidelines for Determining Resident Status. Values current as of 2026 tax year.
2. FTB Publication 1031 — nine-factor domicile test, safe harbor requirements, and part-year resident rules.
3. N.Y. Comp. Codes R. & Regs. Tit. 20 § 105.20 — New York resident individual definition, domicile rules, statutory residency threshold.
4. New York State Department of Taxation & Finance — Nonresident FAQs — 183-day rule, permanent place of abode, and expat domicile guidance.
5. EisnerAmper/KROST: The California Safe Harbor for Residents Working Abroad — 546-day rule requirements, intangible income limit, and self-employed exclusion from safe harbor.