California Residency Exit Moving Abroad Tax & NY Rules

Leaving the United States does not, by itself, end your California or New York tax residency. Both states tax worldwide income for as long as you remain resident or domiciled there, and both audit high-value departures aggressively. Sound California residency exit moving abroad tax planning turns on domicile, day counts and documentary evidence — sequenced well before any liquidity event.

At Jungle Tax we see the same pattern repeatedly: a founder or executive spends eighteen months designing a beautiful federal position — foreign earned income exclusion, treaty positions, foreign tax credit planning, UK arrival timing — and never asks whether Sacramento or Albany agrees that they left. Two years later a residency questionnaire arrives, and the state assesses tax on a nine-figure exit at rates that can exceed the federal long-term capital gains rate on the same dollars.

Why does federal expatriate planning not solve the state problem?

The federal and state systems are legally separate. The United States taxes citizens on worldwide income wherever they live; California and New York tax residents on worldwide income and non-residents on state-source income. Nothing in the US–UK income tax treaty binds a state. States are not parties to US tax treaties and, as a general matter, are not required to give effect to treaty relief, foreign tax credits or the foreign earned income exclusion in the way the Internal Revenue Code does.

The practical consequences are stark:

• A US citizen living in London who is still a California resident for state purposes files a full-year California return reporting worldwide income — UK salary, UK investment income, global capital gains.
• UK tax paid on that income does not automatically produce a California credit. Relief that works cleanly at federal level under the foreign earned income exclusion rules may simply not exist at state level.
• The result is genuine double taxation: UK tax on the income, plus state tax with no offsetting relief.

This is why the state analysis has to sit inside, not after, your cross-border tax planning workstream.

What actually makes you a California resident?

California defines a resident as any individual in the state for other than a temporary or transitory purpose, plus any individual domiciled in California who is outside the state for a temporary or transitory purpose. There is no bright-line day count. The Franchise Tax Board and the Office of Tax Appeals apply a facts-and-circumstances test, weighing the closest connections a taxpayer maintains.

The closest-connection analysis

Auditors examine a broad, non-exhaustive list of contacts. In practice the factors that carry the most weight are:

• Where your spouse and dependent children actually live and attend school.
• The location, size and use pattern of your residences — and whether the California home was sold, let on a genuine arm's-length lease, or simply left available.
• Where you spend your time, measured in days, and whether California days cluster around business or family.
• The state issuing your driver's licence and vehicle registrations, and where you are registered to vote.
• The location of your professional advisers, banks, safe deposit boxes and principal brokerage relationships.
• Memberships — clubs, gyms, places of worship, charitable boards — and where you receive medical and dental care.
• The situs of your business interests, and where you exercise management and control of them.

No single factor is decisive. The test is comparative: California asks whether your connections to California are more substantial than your connections to your new home. A move to London that leaves the Atherton house furnished, the family in place until the school year ends and the founder returning monthly for board meetings will not sever residency, however impeccable the federal filing.

Is there a safe harbour for employment abroad?

California provides a statutory safe harbour for individuals who leave the state under an employment-related contract for an uninterrupted period covering at least 546 consecutive days, subject to limits on California-source intangible income and on the number of days spent back in the state. It is a genuine shelter for a seconded executive, but it is narrow. It does not assist a founder taking a sabbatical, a retired principal, or someone whose income is predominantly investment income. Where the safe harbour is unavailable — which is most of the time for our high-net-worth clients — you are back to the facts-and-circumstances test, and evidence is everything.

How does New York test residency?

New York runs two independent tests. Failing either makes you a resident, and New York City applies a parallel set of rules on top of the State rules for anyone resident in the five boroughs.

The domicile test

New York domicile changes only when you demonstrate, by clear and convincing evidence, both abandonment of the New York domicile and the acquisition of a new one with the intention of making it your permanent home. The Department of Taxation and Finance analyses five primary factors: the use and maintenance of homes, active business involvement, the pattern of time spent, the location of items "near and dear" to the taxpayer, and family connections. Auditors also examine a secondary factor — citizenship and immigration status — where a foreign move is claimed.

The statutory residency test

Even a taxpayer who has genuinely changed domicile can be taxed as a New York resident if they maintain a permanent place of abode in the state for substantially all of the year and spend more than 183 days in New York. This is the trap that catches London-based bankers who keep the Tribeca apartment "for when we visit". Days are counted brutally: any part of a day physically present in New York generally counts as a full day, including a connecting flight where you leave the airport, a funeral, or a Saturday spent moving boxes.

New York also applies a foreign-country day rule that can relieve statutory residency for taxpayers with a permanent place of abode abroad who spend fewer than 30 days in New York in the tax year, and a separate 548-day rule for extended foreign employment. Both are technical and both are policed. Neither should be relied upon without a contemporaneous day log.

California, New York and the UK compared

Feature	California	New York	United Kingdom
Core test	Facts and circumstances: closest connections plus domicile	Domicile test plus separate statutory residency test	Statutory Residence Test — mechanical automatic and sufficient-ties tests
Bright-line day count	None; days are evidence, not a threshold	Yes — more than 183 days with a permanent place of abode	Yes — automatic UK test at 183 days, plus tie-based thresholds
Part-year treatment	Part-year return available on a genuine change of residence	Part-year return available on a genuine change of domicile	Split-year treatment available under specific statutory cases
Relief for foreign tax	Very limited; treaty relief generally not binding on the state	Very limited; treaty relief generally not binding on the state	Double tax relief available under the US–UK treaty
Taxation of capital gains	Taxed as ordinary income at the top marginal state rate	Taxed as ordinary income; New York City tax may also apply	Separate CGT regime with its own rates and reliefs
Post-departure exposure	State-source income; deferred compensation sourcing rules	State-source income; convenience-of-the-employer rule for remote work	Temporary non-residence anti-avoidance rules on return

What evidence does a state auditor actually credit?

Residency audits are won on documents, not narratives. Auditors discount self-serving statements of intention and look for objective, contemporaneous, third-party-generated evidence. In our experience the following carries real weight:

• A closed transaction on the old home. A sale is strongest. A genuine long lease at market rent to an unconnected tenant is next best. Retaining an unlet property, or letting to a family member, invites the inference that you kept it for yourself.
• A comparable or better home abroad. Auditors compare the two residences. Trading a Bel Air estate for a studio in Zone 3 undermines the claim that London is now your permanent home; a substantial London purchase or long-term lease supports it.
• Movement of items "near and dear". Art, family photographs, heirlooms, pets, the wine cellar. Shipping manifests and insurance schedules are precisely the kind of third-party evidence that persuades.
• A defensible day log. Mobile phone location records, credit card and toll data, flight manifests and building entry swipes are what auditors subpoena. A calendar reconstructed after the fact does not survive contact.
• Relocated professional and personal infrastructure. UK GP and dentist, UK bank and brokerage accounts, UK-domiciled advisers, a UK driving licence, resignation from state clubs and boards, and where relevant a new will governed by the new jurisdiction.
• Family alignment. Where the spouse and school-age children live is close to dispositive. Split-family departures are the single most common cause of a failed severance.

Assemble this evidence contemporaneously, in a dated file, at the point of departure. Reconstructing it three years later, under audit, costs multiples of what it costs to build correctly on day one.

How should a liquidity event be sequenced around a state exit?

This is where the money is. A founder selling a business, an executive vesting a large equity position, or a family de-enveloping a structure ahead of a UK move faces materially different outcomes depending on the order of events.

Establish non-residency before the gain is triggered

Gain on the sale of intangible personal property — including private company stock — is generally sourced to the state of residence at the time of sale. Establishing non-residency before signing, not before closing, is the objective. Both states will scrutinise a departure that occurs weeks before a transaction that was negotiated for a year. The defensible position is a real move, made for real reasons, completed well ahead of the letter of intent.

Understand what remains taxable regardless

Some income follows you out of the state no matter how clean the severance:

• Income from real property physically located in the state, including gain on sale and rental income.
• Income from a business, trade or profession carried on within the state, apportioned under state rules.
• Compensation attributable to services performed in the state, including the state-workday portion of non-qualified stock options and restricted stock that vested while you worked there.
• New York's convenience-of-the-employer rule can treat days worked remotely for a New York employer as New York workdays unless the remote location meets a bona fide employer office test.
• Instalment sale proceeds tracing back to a resident-period disposition.

Deal with trusts and entities separately

A state exit does not automatically move a trust. California can tax trust income based on the residence of fiduciaries and non-contingent beneficiaries; New York applies its own resident trust rules and a separate throwback regime. Families relocating to the UK should review trustee residence, situs and beneficiary location as a discrete workstream within their trust and estate planning — ideally in the same review that addresses UK inheritance tax exposure under the long-term residence rules.

What has to happen on the UK side at the same time?

Your UK arrival date is not a matter of feel. The Statutory Residence Test guidance published by HMRC is mechanical: automatic overseas tests, automatic UK tests, and a sufficient ties test that combines UK days with family, accommodation, work, 90-day and country ties. Split-year treatment may apply where you start to have a home in the UK or begin full-time work here, but only under specific statutory cases.

Two UK points matter disproportionately for departing Californians and New Yorkers:

• Arrival timing versus the gain. Realising a gain after you become UK resident can bring it within the UK capital gains net, potentially alongside state tax if the severance failed. Realising it while non-UK-resident, but still state-resident, achieves the opposite. Only a combined model shows the true rate.
• The four-year foreign income and gains regime. Individuals arriving in the UK after a sufficient period of non-residence may access a limited-duration relief for foreign income and gains under the rules that replaced the remittance basis. Eligibility, duration and interaction with US foreign tax credits should be modelled before, not after, arrival.

Do not overlook federal compliance in the transition. Continued US filing obligations, FBAR and FATCA reporting, and PFIC exposure on UK funds all persist. Where past filings are incomplete, the streamlined filing compliance procedures may offer a route back to compliance, and our US tax services team can assess eligibility. HMRC's own overview of UK residence and foreign income is a useful primer, but it does not model the state overlay.

What are the most common ways a state exit fails?

• Keeping the apartment. The single most expensive sentimental decision in cross-border tax. In New York it can create statutory residency independently of domicile.
• Leaving the family behind. A spouse and children remaining through the school year, with the taxpayer commuting, rarely severs anything.
• Moving after the deal is signed. Timing that tracks the transaction rather than the life change reads as tax-motivated and is treated accordingly.
• Sloppy day counting. Partial days, layovers and a single board meeting a month add up faster than clients expect.
• Filing as a non-resident without filing a final part-year return. Simply ceasing to file invites an audit; filing a considered part-year return with a clear residency change date starts the assessment clock.
• Ignoring the entity layer. The individual moves; the LLC, the management company and the trust do not.

A practical pre-departure sequence

• Twelve months out: model state, federal and UK outcomes together. Identify the target residency change date and work backwards.
• Nine months out: resolve the property question — list the home or agree a genuine arm's-length lease. Secure UK accommodation of comparable standing.
• Six months out: relocate professional infrastructure. Change advisers, banking, insurance and registrations. Resign state board and club memberships.
• Three months out: move the family and the personal effects. Ship the items near and dear. Begin the contemporaneous day log.
• Departure: record the residency change date, surrender the state driving licence, register to vote where appropriate, and open the evidence file.
• Post-departure year one: file the part-year state return, keep state days minimal, and review the position before any transaction.

Our library of cross-border guides covers the adjacent federal and UK issues in more depth, but the sequencing above is the part clients most often get wrong.

Speak to us before you move — not after the questionnaire arrives

A clean state exit is achievable, but it is an evidence exercise conducted in advance, not an argument constructed later. If you are leaving California or New York for London and a material liquidity event sits anywhere within the next three years, the state analysis should be running alongside your federal and UK planning from the outset. To review your position confidentially, contact our cross-border team and we will map your domicile, day-count and evidence position before your departure date is fixed.