US-UK · Journal
Section 6013(g): Treating an NRA Spouse as US Resident
Married filing separately, head of household or the election: what each does to a British spouse's worldwide income, and why revoking is permanent.
Married filing separately, head of household or the election: what each does to a British spouse's worldwide income, and why revoking is permanent.
If you are a US citizen living in the UK and married to a British spouse who holds no US status, your default filing status is married filing separately. You can instead elect under Internal Revenue Code section 6013(g) to treat your spouse as a US resident and file jointly, which buys the joint standard deduction and the wider joint brackets — but makes your spouse a US taxpayer on their worldwide income for every year the election runs. And once the election ends, neither of you can ever make it again — it is one of the few elections in the US code that is genuinely one-way.
Do nothing and you file MFS. Your British spouse stays outside the US system: no US return, no US reporting, their ISA and workplace pension nobody's business but HMRC's.
The price is paid in the rate table. For 2026 the IRS confirms a standard deduction of $16,100 for married filing separately — the same as single — against $32,200 on a joint return. Publication 501 lists the other MFS penalties: a generally higher rate, no education credits or student loan interest deduction, and a capital loss deduction limited to "$1,500 (instead of $3,000 on a joint return)." The Form 1040 instructions also require you to enter your spouse's name, and "NRA" where the spouse has no SSN or ITIN.
Many Americans abroad assume HOH is closed to married people. Publication 501 is explicit: "You are considered unmarried for head of household purposes if your spouse was a nonresident alien" at any time during the year, unless you choose to treat that spouse as a resident.
The catch is the next sentence: "However, your spouse isn't a qualifying person for head of household purposes." You still need the rest of the test — you paid more than half the cost of keeping up a home for the year, and a qualifying person lived with you there for more than half the year. A child normally fills that role; a relative who qualifies only because they lived with you all year does not.
Where it works, HOH is the quiet winner: for 2026 a $24,150 standard deduction, a friendlier rate table than MFS, and your spouse outside the US net entirely. For an American in London with a child and a non-US spouse, it is often the status to model first.
The only route to a joint return where one spouse is a non-resident alien — and the only route to the $32,200 standard deduction.
Section 6013(g)(1) treats the non-resident alien spouse as "a resident of the United States" for the whole taxable year for income tax purposes, and for wage withholding on wages paid that year. The IRS guidance on a non-resident alien spouse states the consequence plainly: both spouses are treated as US residents for every year the choice is in effect, and "each spouse must report their entire worldwide income."
Read that against a typical British spouse's balance sheet and the problem writes itself: salary, UK bank interest, dividends, ISA growth, rental profit and fund gains all now belong on a US return.
Two boundaries. The election is for income tax — Social Security and Medicare withholding may still treat the spouse as a non-resident — and it does nothing for US estate and gift tax, which has its own non-citizen spouse regime.
No election happens without a taxpayer identification number. The IRS requires the spouse to "have either a Social Security Number (SSN) or an Individual Taxpayer Identification Number (ITIN)." A British spouse with no US work history will need an ITIN on Form W-7.
An ITIN is a tax number and nothing more: no work authorisation, no Social Security entitlement, no earned income credit eligibility. ITINs can also expire.
Mechanically it is light; strategically it is heavy. You check the box in the Filing Status section of Form 1040 or 1040-SR, enter the non-resident spouse's name, and attach a statement signed by both spouses to the joint return for the first year. The statement must declare that one spouse was a non-resident alien and the other a US citizen or resident alien on the last day of the year, that both choose to be treated as US residents for the entire year, and give "the name, address, and identification number of each spouse."
You can also elect retrospectively on a joint Form 1040-X, generally within three years of the original filing date or two years from the date the tax was paid, whichever is later, amending any later returns already filed on another basis.
One subtlety people miss: the first year must be a joint return; later years may be joint or separate. Filing separately in year three does not undo the election — your spouse is still a US resident taxpayer, now filing MFS.
It runs forward automatically, stopping only in the ways section 6013(g)(4) allows, as Publication 519 sets them out:
There is also a suspension rule, which is not an ending: the choice does not apply to a year in which neither spouse is a US citizen or resident at any time, and resumes when one of them is again.
Now the part to read twice. Once the election has ended by any of those routes, the IRS calls it "a once-in-a-lifetime choice": "neither spouse can make this choice in any later tax year, even if married to a different individual." The statute says the same. Revocation is not switching off a setting; it is spending something you cannot get back.
One point often decides the argument the other way. The Schedule 8812 instructions for 2025 confirm that "only one spouse is required to have a valid SSN to be eligible for the CTC or ACTC," the other holding an SSN or ITIN issued by the due date. The American parent's SSN carries the credit — no election is needed to claim it. For 2025 the credit is $2,200 per child, up to $1,700 refundable, phasing out above $400,000 of modified AGI jointly and $200,000 otherwise; the 2026 indexed figures need checking before use.
An ISA is tax-free in the UK — gov.uk says you "can save tax-free with Individual Savings Accounts (ISAs)," with a £20,000 limit for the 2026 to 2027 tax year. The US has never agreed. Elect, and your spouse's ISA interest, dividends and gains become US taxable income with no UK tax paid against which to claim a credit: a tax rise created purely by a filing choice. The same logic reaches the dividend allowance, the personal savings allowance and the capital gains annual exempt amount of £3,000 for 2026-27. Every UK relief producing zero UK tax produces zero foreign tax credit.
UK funds are the sharpest edge. A UK unit trust, OEIC or investment trust is usually a passive foreign investment company, since a foreign corporation is a PFIC if 75% or more of its gross income is passive or at least 50% of its average assets are held to produce passive income. The Form 8621 instructions give a de minimis break — Part I is generally not required where aggregate PFIC stock is $25,000 or less, "a combined threshold of $50,000" on a joint return — but it falls away on an excess distribution or a disposal at a gain. A spouse with a modest stocks-and-shares ISA and two index funds can acquire a multi-form problem the day the election is signed; our guide to PFIC rules sets out what each regime costs.
The Form 8938 instructions list as a specified individual "a nonresident alien who makes an election to be treated as a resident alien for purposes of filing a joint income tax return," so the election pulls your spouse's foreign assets inside FATCA reporting. Living abroad, the joint thresholds are more than $400,000 on the last day of the year or more than $600,000 at any time, against $200,000 and $300,000 for MFS.
The FBAR goes the other way. The IRS international practice unit on FinCEN Form 114 cautions that "the determination of whether an individual is a U.S. resident for FBAR purposes should be made without regard to elections under Internal Revenue Code (IRC) 6013(g) or 6013(h)," citing 31 CFR 1010.350(b)(2), and gives the example that an NRA who made a 6013(g) election "is generally not subject to FBAR filing requirements." The American spouse's own position is unchanged and still turns on the $10,000 aggregate test, including signature authority over joint accounts.
Section 6013(d)(3) provides that where a joint return is made "the liability with respect to the tax shall be joint and several." A British spouse who signs is personally liable for the whole US tax on that return, including tax on the American's income, with penalties and interest.
The IRS adds a caution that matters enormously for pensions: generally neither spouse can claim treaty benefits as a resident of a foreign country for years the choice is in effect, although a savings-clause exception may apply to certain income. Where a British spouse holds a UK pension whose treatment depends on treaty articles, the election can disturb the analysis. That is case-by-case treaty work, not a rule of thumb.
Both reliefs survive. The electing spouse is treated as a resident alien, and the IRS foreign earned income exclusion page allows a resident alien to use the bona fide residence test where they are "a citizen or national of a country with which the United States has an income tax treaty in effect" — which a UK national in the UK satisfies. The physical presence test, "at least 330 full days during any period of 12 consecutive months," is open to citizens and resident aliens alike. The exclusion is $132,900 for 2026, claimed per person on separate Forms 2555.
But the exclusion is not free. The Schedule 8812 instructions warn that "if you file Form 2555, you cannot claim the additional child tax credit," and excluded income cannot also generate a foreign tax credit, so UK tax attached to excluded salary is wasted. For UK-resident Americans the credit often outperforms the exclusion, because UK rates on higher earnings generally exceed US rates — the comparison is in FEIE versus the foreign tax credit.
That credit is the real engine: a joint return brings the spouse's UK tax into the same Form 1116 computation as their UK income, which is why many elections prove close to neutral on employment income. The leakage is everywhere else — income the UK does not tax, PFIC gains the credit baskets handle badly, and the mismatch between a UK tax year ending 5 April and a US calendar year.
Section 6013(g) is for a spouse who stays a non-resident alien. Section 6013(h) covers the year a spouse actually becomes a US resident. If they were a non-resident alien at the start of the year, are a resident alien or US citizen at its close, are married to a US citizen or resident at year-end, and you both elect, they are treated as a US resident for the entire year — turning a restricted dual-status year into a clean joint return.
Two cautions. It also pulls the pre-arrival part of the year into US tax on worldwide income, exactly the wrong answer where the spouse sold a UK house or crystallised UK gains in January before a June move. And section 6013(h)(2) imposes the same one-shot rule: the IRS puts it as "neither you nor your spouse can make this choice for any later tax year, even if you are separated, divorced, or remarried."
| Situation | Likely best status | Why |
|---|---|---|
| British spouse has little income and no UK investments | Section 6013(g), file jointly | Joint deduction and brackets on one income; little dragged in |
| Qualifying child in the home; you pay over half the costs | Head of household | 2026 deduction $24,150, better rates, spouse outside the US net |
| Spouse holds an ISA, a share portfolio or UK funds | Married filing separately | PFIC and Form 8938 exposure usually outweighs the joint-return saving |
| Spouse has a significant UK pension or treaty-sensitive income | Married filing separately | Treaty benefits generally unavailable while the election is in effect |
Filing status with a non-resident alien spouse is arithmetically simple and strategically irreversible, and treaty-sensitive income — pensions above all — needs specific analysis rather than a general rule.
This is general information, not advice on your position: the answer turns on your own facts, your spouse's assets and your filing history, and current-year figures should be confirmed against the IRS and gov.uk sources before anything is filed.
The useful work is a five-year model, not a one-year comparison: what MFS costs, whether head of household is genuinely available, and what the election would pull in from your spouse's side of the balance sheet. The background is in our guide to US tax when you are married to a non-American.
We build those models as US-UK tax specialists, prepare the returns and the Form W-7 package, and document the election so a later adviser can see what was chosen and why — with an IRS Enrolled Agent, who is also ACCA-qualified on the UK side, reviewing and signing off the filings. If a filing-status decision is in front of you this season, book a consultation before the return goes in.