Introduction: Expat Tax Missouri Planning for British Families in St Louis and Kansas City
The expat tax Missouri position changed dramatically in 2025, and it now favours wealthy British families in a way no other income-tax state does. Missouri became the first state to exempt every capital gain an individual reports federally, so a UK share portfolio, a London flat or a stake in a British company can now be sold with no Missouri tax at all. However, the same state still charges 4.7% on UK pensions, UK rent and UK dividends, gives no credit for tax paid to HMRC, and lets St Louis and Kansas City add a 1% earnings tax on salaries. Consequently, the right answer depends entirely on what kind of British income you hold.
At TaxYork, we prepare federal, state and UK returns for British executives, physicians, aerospace and agribusiness professionals, founders and retirees across St Louis, Clayton, Ladue, Chesterfield, Kansas City and the Country Club Plaza. In our experience, most families arrive knowing nothing about the capital gains exemption and far too much about the older, higher rates. Therefore this expat tax Missouri guide explains what the exemption covers, where it stops, and how to time your UK disposals around it.
Expat Tax Missouri Basics: Three Layers, One Big Exemption
A British family in Missouri deals with three income tax layers, and in two cities a fourth. First, federal tax reaches worldwide income, relieved by the foreign tax credit on IRS Form 1116. Second, HMRC keeps taxing UK property income and UK land gains. Third, Missouri taxes residents on federal adjusted gross income, less the new capital gains deduction, at up to 4.7%. Finally, St Louis and Kansas City charge 1% on earned income. Between Missouri and Britain, however, there is no bridge, because Missouri's credit covers other US states only.
Who This Guide Is Written For
This guide addresses high-net-worth British nationals, dual national US UK families and accidental Americans who live in Missouri or keep Missouri ties while working in London. Specifically, it suits senior executives, investment professionals, company owners, medical consultants and retirees who still hold UK property, pensions, ISAs or companies. If that describes your household, the expat tax Missouri rules below can save you tens of thousands of dollars, but only if you plan around them.
How Missouri Compares With Our Other State Guides
On capital gains, Missouri now beats every income-tax state in our series. Utah charges 4.45% on UK gains, and New Jersey charges up to 10.75% with no loss carryforward. Across the Mississippi, Illinois taxes the same gains at a flat 4.95%. For the federal rules underneath every state, see our complete 2026 guide to UK expat tax in the USA.
How Missouri Taxes High Earners in 2026
Missouri's structure is simple once you strip away the headlines. Nevertheless, three recent changes shape every British family's bill.
The Expat Tax Missouri Rate Schedule
The expat tax Missouri brackets are graduated, but they are tiny. The top rate of 4.7% starts at a little over $9,000 of taxable income in 2026, so a high earner effectively pays a flat 4.7%. The state's revenue trigger can cut the top rate towards 4.5%, yet it did not fire for 2026. Importantly, Missouri starts from federal adjusted gross income, so the expat tax Missouri calculation inherits most federal rules on what counts as income.
The 100% Capital Gains Deduction
In 2025 Missouri enacted House Bill 594, and the Missouri Department of Revenue confirmed that Missouri is the first state to fully exempt capital gains. From tax years beginning on or after 1 January 2025, individuals deduct 100% of income reported as a capital gain for federal purposes. The deduction does not distinguish short-term from long-term gains, and it applies to shares, bonds, real estate and cryptocurrency. As a result, a Missouri resident pays federal capital gains tax and the 3.8% net investment income tax, but no Missouri tax on the same gain.
Amendment 5 Failed, So the Income Tax Stays
Missouri voters were asked on 4 August 2026 whether to phase out the individual income tax and expand sales tax instead. They rejected Amendment 5 by roughly 82% to 18%, according to local reporting on the vote. Therefore the expat tax Missouri rate on pensions, rent, dividends and salary remains 4.7% for the foreseeable future, and we plan on that basis.
Deductions That High Earners Lose
The expat tax Missouri rules once let residents deduct part of their federal income tax. However, that deduction phases out completely above $250,000 of Missouri adjusted gross income. Similarly, the private pension exemption of up to $6,000 disappears at modest income levels. For a wealthy family, therefore, very little stands between UK income and the full 4.7% rate.
What the Capital Gains Exemption Covers, and What It Misses
This is where the real expat tax Missouri planning happens. The exemption follows federal character exactly, so anything the IRS does not call a capital gain stays taxable.
UK Shares, Property and Company Stakes
Gains on UK listed shares, UK private company shares and UK property are capital gains federally, so the expat tax Missouri exemption covers them. Similarly, the unrecaptured section 1250 gain on a London buy-to-let remains a capital gain federally, so the deduction reaches it too. Consequently, a Missouri resident selling a London flat pays HMRC's non-resident capital gains tax, claims a federal credit for it, and pays nothing to Missouri. That combination is unique among income-tax states.
UK Funds Caught by the PFIC Rules
Most UK unit trusts, OEICs and investment trusts are passive foreign investment companies for American taxpayers. Gains on them are usually taxed as ordinary income under the excess distribution regime or a mark-to-market election, reported through Form 8621. Because the IRS does not treat that income as a capital gain, the expat tax Missouri exemption does not apply. In practice, therefore, a British family's ISA funds and pension-style fund holdings can still produce Missouri tax at 4.7%, while their directly held shares produce none.
Currency Gains and Other Ordinary Income
Foreign currency gains on sterling bank balances and sterling mortgages are ordinary income under section 988. Likewise, depreciation recapture on equipment and gains recharacterised as dividends remain ordinary. None of these qualify for the expat tax Missouri deduction. Our FBAR and FATCA reporting service identifies these items when it reviews your UK accounts each year.
Temporary Non-Residence Can Reopen UK Tax
If you left Britain within the last five years and return within five full years, HMRC can tax gains on assets you owned when you left. The rule sits within the statutory residence test guidance. Therefore, a gain that is free of Missouri tax during a short posting can later attract UK tax, so we test your return plans before any large sale.
Why Missouri Gives No Credit for UK Tax
Outside capital gains, the ordinary expat tax Missouri rules apply, and they give nothing back for UK tax.
The Credit Covers Other States Only
Missouri's credit for income tax paid elsewhere, claimed on form MO-CR, is limited to tax paid to other US states. The Department of Revenue's guidance for residents with other state income sets out the rules. It covers neither foreign countries nor local taxes. Consequently, UK income tax on rent, UK tax on a pension paid before an NT code arrives, and non-resident landlord tax all count for nothing in the expat tax Missouri calculation.
Why the Federal Credit Does Not Flow Through
Missouri starts from federal adjusted gross income, while the foreign tax credit reduces federal tax after income is calculated. In other words, UK rent that the federal credit shelters completely still arrives on your Missouri return in full. The US-UK tax treaty binds only the federal government, so it cannot fix the gap.
The Foreign Earned Income Exclusion Does Flow Through
By contrast, income excluded under the foreign earned income exclusion never enters federal adjusted gross income, so Missouri cannot tax it. For a Missouri-domiciled American working in London, that makes the exclusion worth an extra 4.7% on up to $132,900 of 2026 salary. Our tax treaty optimisation service models the exclusion against the credit across both returns before you elect.
UK Pensions and Rent in Missouri
Every expat tax Missouri review we carry out works through the family's UK income one item at a time. Pensions and rent are where the 4.7% bites hardest.
SIPP and Workplace Pension Drawdowns
Under Article 17 of the treaty, a UK pension paid to a US resident is usually taxable only in the United States, so HMRC can issue an NT code and pay you gross. Federally, the drawdown is then taxed under the IRS rules on foreign pension distributions, and the expat tax Missouri charge adds 4.7%. The 25% tax-free lump sum is not tax-free for a US resident, because the treaty's saving clause preserves US tax on residents. As a result, a £200,000 lump sum can add about $12,400 to your Missouri bill at an illustrative $1.32 exchange rate.
The UK State Pension Is Not Social Security
Missouri stopped taxing US Social Security benefits from 2024. However, the UK State Pension is not US Social Security; the IRS treats it as fully taxable pension income. Consequently, the Missouri exemption does not reach it, and your whole UK State Pension falls into the expat tax Missouri charge at 4.7%.
UK Rental Income
Britain keeps first right to tax UK rent, and HMRC explains the rules for UK rental income when you live abroad. Federally, the UK tax is credited against US tax on the same rent. The expat tax Missouri charge, however, hits the full net rent again at 4.7%, with no credit. Furthermore, US depreciation often produces a different net figure from the UK computation, so the two returns rarely match.
St Louis and Kansas City Earnings Taxes
The two largest cities add a layer that surprises many newcomers. The expat tax Missouri bill for a city resident or city worker includes it.
The 1% Earnings Tax
St Louis and Kansas City each charge 1% on the earned income of residents and of non-residents who work in the city. Residents pay on salary and self-employment profits wherever they are earned, while non-residents pay only on work done in the city. Importantly, the tax does not reach investment income, pensions or capital gains. St Louis voters renewed their earnings tax in April 2026 by about 85%, so it will stay until at least the next statutory vote in 2031.
Choosing Where to Live
Many British families choose Clayton, Ladue or Chesterfield in St Louis County, which sit outside the city and its residents' earnings tax. However, if you work downtown, you still pay 1% on that salary as a non-resident. Around Kansas City, the choice is sharper, because the Kansas suburbs of Overland Park and Leawood sit in a different state. Kansas taxes capital gains at up to 5.58%, so a family selling UK shares pays far more on the Kansas side of State Line Road.
No Credit Anywhere for the City Tax
The earnings tax is a local tax, so neither Missouri's credit nor HMRC's relief applies to it. Federally, it counts towards the SALT deduction, but the 2026 cap of $40,400 shrinks by 30% of income above $505,000 to a $10,000 floor. For most of our clients, therefore, the city tax is a pure cost.
Missouri Residency and Domicile
Missouri's residency rules decide who pays expat tax Missouri on worldwide income. They matter both for Britons arriving and for Missouri Americans leaving for London.
The Two Resident Tests
Under section 143.101 of the Missouri statutes, you are a resident if Missouri is your domicile. You are also a resident if you keep a permanent place of abode in Missouri and spend more than 183 days in the state. Domicile means the place you intend as your permanent home and return to after absences.
The 30-Day Exception for Americans Abroad
A Missouri domiciliary is treated as a non-resident if they keep no permanent place of abode in Missouri, maintain one elsewhere, and spend no more than 30 days in the state during the year. However, a family home kept available in Ladue, or a long summer back in Kansas City, can defeat the exception. Consequently, we plan the housing arrangements and the travel calendar before a client relocates.
Arrival and Departure Years
In your first and last years, you file as a part-year resident. Federally, however, a British national usually becomes a resident alien under the substantial presence test from the first day of presence. If you plan to move on from Missouri to a higher-tax state, realise large gains before the move, while the expat tax Missouri exemption still covers you.
Case Study: The Harcourts in Clayton
This illustrative case study shows how the expat tax Missouri rules combine for a real-world family. The names are invented, but the numbers reflect the patterns we see every season.
The Facts
James Harcourt is a British executive who moved to Clayton, in St Louis County, in 2024 with his wife Clare. In 2026 James earns $650,000 of salary at an office in downtown St Louis. The couple still own a London flat, which produces net rent of £30,000. In addition, James sells his UK share portfolio for a gain of £400,000, and a UK equity fund held under a mark-to-market election produces an ordinary gain of £45,455. We use an illustrative rate of $1.32 to the pound, so the figures are $39,600 of rent, $528,000 of share gains and $60,000 of fund income.
The Missouri Bill
Their federal adjusted gross income is $1,277,600. The capital gains deduction removes the $528,000 share gain, leaving Missouri adjusted gross income of $749,600. After the standard deduction, their expat tax Missouri charge is about $33,600. Of that sum, about $4,700 relates to the UK rent and the UK fund, and Missouri gives no credit for the £3,486 of UK tax on the rent. In addition, St Louis charges James $6,500 of earnings tax on his downtown salary.
The Federal and UK Position
Federally, the share gain pays 20% plus the 3.8% net investment income tax, which is $125,664, or about £95,200. The UK rent tax is credited on Form 1116. You can model the federal element with our US capital gains tax calculator. Had James sold before leaving Britain, UK capital gains tax at 24% on the gain above the £3,000 annual exempt amount would have been £95,280, almost exactly the same.
What the Exemption Saved
Without the 2025 deduction, Missouri would have taxed the share gain at 4.7%, which is $24,816. In Utah the same gain would have cost about $23,500, and in New Jersey more than $56,000. However, the fund gain was taxable because the PFIC rules made it ordinary income. Therefore, the lesson is twofold: sell directly held UK shares while resident in Missouri, and restructure UK fund holdings before they grow further.
Compliance That Comes With Missouri Residency
Living in Missouri adds state deadlines to an already heavy federal and UK reporting load. The expat tax Missouri calendar is simple, but missing it is still costly.
FBAR and Form 8938
Missouri has no foreign account report of its own. However, as a US tax resident you must file an FBAR through FinCEN's BSA E-Filing system if your UK accounts, including ISAs and many pensions, exceed $10,000 combined at any time in the year. Married couples living in Missouri must also file Form 8938 once foreign assets pass $100,000 at year end or $150,000 at any time. Missed FBAR filings are among the most common problems we fix for newly arrived British families.
Deadlines and Estimated Tax
Expat tax Missouri returns are due on 15 April, and a federal extension also extends the Missouri filing date. However, an extension never extends the time to pay. Missouri also expects estimated payments once you owe $100 or more. Consequently, a large pension lump sum or a PFIC gain without matching estimates will attract interest.
Missed Missouri Returns
If you have lived in Missouri, or stayed domiciled there from London, without filing, the state can assess every open year with interest. The same facts usually mean missed US tax returns and missed FBAR filings federally. We prepare the missing Missouri, federal and UK returns together, so the figures agree and the exposure is closed in one exercise.
How TaxYork Can Help
TaxYork provides comprehensive US tax return preparation for expats and US UK tax returns preparation for families who live across both countries. We handle the expat tax Missouri layer as part of one joined-up compliance process.
Joined-Up Returns
We prepare your federal return, Missouri MO-1040, city earnings tax filings and UK self assessment together, using the same exchange rates and dates throughout. As a result, the capital gains deduction, the foreign tax credit and HMRC's figures reconcile, and nothing is taxed twice by accident.
Before the Sale, Not After
The largest savings come before a disposal or a move. Therefore, our cross-border planning and compliance team reviews portfolios, fund structures, pension drawdowns and residency dates while there is still time to change the outcome.
Conclusion
Missouri is now the most favourable income-tax state in America for a British family selling UK shares or property, because it exempts every federal capital gain. However, the 4.7% rate still reaches UK pensions, UK rent, UK dividends and PFIC fund income, with no credit for UK tax. Moreover, St Louis and Kansas City add 1% on salaries, and the Kansas suburbs tax gains in full. In short, the expat tax Missouri bill rewards families who plan which income they realise, where they live and when they move.
Contact Us
If you are moving to St Louis or Kansas City, already live in Missouri with UK assets, or are working in London with Missouri ties, our team can prepare your federal, Missouri and UK returns together. Please book a consultation with our US-UK tax team, email hello@taxyork.com or call 020 3488 8606.
Disclaimer
This article provides general information about US federal, Missouri, city and UK tax rules as they stood in September 2026. It is not tax or legal advice for your specific circumstances, and the case study is illustrative only. Tax rules, rates, thresholds and exchange rates change, and the outcome for your family depends on your full facts. Please take professional advice before acting. TaxYork provides US and UK tax return preparation and compliance services; contact us for help applying these rules to your own situation.