Common UK and US Tax Reporting Mistakes Made by Dual Citizens

Holding both British and American citizenship can provide significant personal and professional opportunities, but it can also create unusually complex tax-reporting obligations.

The United Kingdom generally taxes individuals according to residence and the source of their income. The United States, by contrast, generally requires its citizens to report worldwide income regardless of where they live. A dual UK-US citizen living in Britain may therefore need to consider both countries’ rules every year.

The UK-US Double Taxation Convention and foreign tax credit systems can help prevent the same income from being taxed twice. They do not, however, eliminate filing obligations or automatically coordinate the two returns.

Many problems arise not from deliberate non-compliance but from assuming that the rules in one country will be recognised in exactly the same way by the other.

Assuming You Can Choose Which Country Taxes You

Dual citizenship does not normally allow an individual to select the more favourable tax system.

A British-American citizen who is resident in the UK will normally be subject to UK tax on worldwide income, unless a specific exemption or relief applies. At the same time, US citizens remain subject to American worldwide income-reporting rules while living abroad.

The fact that income has been reported in one country does not remove the requirement to consider it in the other.

The correct approach is to determine how each country classifies the income, which country has the primary taxing right and whether a foreign tax credit or treaty provision can reduce double taxation.

Failing to Establish UK Tax Residence Correctly

UK residence is determined under the Statutory Residence Test rather than citizenship, nationality or immigration status.

The test includes automatic overseas tests, automatic UK tests and a sufficient-ties test. Factors can include days spent in Britain, UK accommodation, family connections, working patterns and previous residence.

A dual citizen may incorrectly assume that they are UK resident simply because they own a British home, or non-resident because they spend substantial time in the United States.

Residence must be assessed for each UK tax year. Travel records should show arrival and departure dates, locations, working days and the availability of homes in both countries.

An incorrect residence conclusion can affect the reporting of employment income, investments, property income and capital gains.

Leaving American Income Off a UK Tax Return

A UK-resident dual citizen may assume that income earned or received in America only needs to be reported to the Internal Revenue Service.

UK residents normally pay UK tax on income from both UK and overseas sources. This can include US interest, dividends, pensions, employment income, business profits and rental income. Foreign income may need to be reported through Self Assessment even when US tax has already been deducted.

Tax already paid in America should not normally be dealt with by omitting the income from the UK return. The gross income is generally reported, with Foreign Tax Credit Relief claimed separately where available.

The amount of relief may be limited to the lower of the admissible foreign tax and the UK tax attributable to the same income.

Assuming UK Residence Ends US Filing

Some dual citizens stop filing US tax returns after moving permanently to Britain.

US citizens and resident aliens are generally subject to American tax-reporting rules on worldwide income regardless of where they live. The normal filing requirement can therefore continue even where the person has no US home, employment or day-to-day financial activity.

Foreign tax credits, exclusions and treaty provisions may reduce or eliminate the final US tax liability, but these benefits often have to be claimed through a properly filed return.

Having no American tax to pay is not necessarily the same as having no American return to file.

Confusing Tax Reporting with Tax Payment

A common misconception is that income does not need to be reported if foreign tax credits will ultimately eliminate the liability.

A tax return generally begins by reporting the relevant income. Relief is then calculated and claimed according to the applicable rules.

For example, a US citizen may report a UK salary on a US return and then claim a foreign tax credit or, where eligible, the Foreign Earned Income Exclusion.

Similarly, a UK resident may report US investment income through Self Assessment and claim relief for eligible US tax already paid.

Leaving the income off the return can produce an incomplete filing even where the final additional tax would have been nil.

Treating the FBAR as Part of the US Tax Return

The Report of Foreign Bank and Financial Accounts, commonly known as the FBAR, is separate from the individual’s federal income tax return.

A US person generally has an FBAR filing obligation where the aggregate value of relevant foreign financial accounts exceeds $10,000 at any point during the calendar year. The threshold applies to the combined value of the accounts rather than to each account individually.

A person with four UK accounts each holding less than $10,000 may still need to file if the combined maximum balance exceeded the threshold.

The FBAR is filed electronically with the US Financial Crimes Enforcement Network rather than being attached to Form 1040.

Confusing the FBAR with Form 8938

The FBAR and Form 8938 are different reporting requirements.

Form 8938 is filed with the federal income tax return where the total value of specified foreign financial assets exceeds the threshold applying to the taxpayer’s residence and filing status. The FBAR uses different definitions, thresholds and filing procedures.

An account or asset may need to be disclosed on both forms.

Filing an FBAR does not automatically satisfy Form 8938, and including an account on Form 8938 does not automatically satisfy the FBAR requirement.

Dual citizens should assess the two forms independently rather than assuming one replaces the other.

Forgetting Joint Accounts and Signature Authority

FBAR reporting is not limited to accounts held solely in the taxpayer’s name.

A US person may need to consider jointly held accounts and accounts over which they have signature or other authority. This can include certain business, charity or family accounts even where the money does not personally belong to them.

A dual citizen who acts as a company director, trustee, treasurer or authorised banking signatory should review whether that role creates a reporting obligation.

The relevant account values may also contribute to the aggregate FBAR threshold.

Overlooking UK Pensions on US Reporting Forms

A UK pension is not automatically outside the American reporting system merely because it is intended for retirement.

An interest in a foreign pension or deferred-compensation arrangement may need to be included on Form 8938 where the individual exceeds the applicable reporting threshold.

The income tax treatment of contributions, growth and distributions must be considered separately from information reporting.

Workplace pensions, personal pensions and self-invested personal pensions may not all receive identical treatment. Employer contributions, employee contributions and pension distributions can also require different analysis.

A pension appearing to be tax-deferred or tax-free in the UK should not be assumed to receive precisely the same treatment in the United States.

Assuming an ISA Is Tax-Free in Both Countries

Income and gains within an Individual Savings Account may receive favourable treatment in the UK.

That UK treatment does not by itself exempt the income from US reporting or taxation. US citizens generally remain subject to American worldwide income rules, including while living in Britain.

The investments held inside the ISA must also be reviewed.

Certain non-US collective investment companies may be classified as Passive Foreign Investment Companies for US tax purposes. A US person who is a direct or indirect shareholder in a PFIC may have to file Form 8621 and can face a more complicated tax calculation.

The UK tax efficiency of an investment should therefore be considered alongside its US classification before it is purchased.

Choosing Investments Without Checking US Classification

Dual citizens can encounter similar issues outside an ISA.

British investment funds, investment trusts, offshore funds and insurance-based investments may be treated differently under US tax law from how they are treated in Britain.

A product described as simple or tax-efficient by a UK provider may create additional US forms, annual calculations or unfavourable treatment.

The problem is often discovered only when the taxpayer sells the investment or engages an adviser to correct previous returns.

Investments should be reviewed before purchase, with particular attention paid to the underlying legal entity rather than only the product’s commercial name.

Assuming the FIG Regime Removes US Tax Obligations

Qualifying new UK residents may be able to claim relief under the four-year Foreign Income and Gains regime.

The regime can provide UK relief on eligible foreign income and gains during the first four years of UK residence following at least ten consecutive tax years of non-UK residence. A claim is made through Self Assessment and can result in the loss of certain UK allowances.

A British-American dual citizen may still have to report the same income and gains in the United States.

UK relief does not suspend US citizenship-based taxation. The interaction with US tax, foreign tax credits and investment reporting should therefore be calculated before making a FIG claim.

Foreign Tax Credit Relief cannot also be claimed in the UK on income covered by a FIG claim.

Claiming Foreign Tax Credits Against the Wrong Income

Foreign tax credits are intended to reduce double taxation, but they do not operate as a general credit against any tax owed.

The US foreign tax credit can normally reduce US tax relating to qualifying foreign-source income. It cannot simply be applied without considering the source and category of the income.

The UK similarly restricts credit to eligible foreign tax connected with the same income or gain, subject to treaty and statutory limitations.

Problems may arise where one country treats income as US-source while the other treats it as UK-source, or where tax is paid in a different year from the year in which the income was reported.

Unused foreign tax is not necessarily refundable by the other country. Accurate sourcing and timing are therefore essential.

Automatically Claiming the Foreign Earned Income Exclusion

Some US citizens living in Britain automatically claim the Foreign Earned Income Exclusion without comparing it with the foreign tax credit.

The exclusion applies only to qualifying foreign earned income and requires the taxpayer to satisfy the relevant tax-home and residence or physical-presence conditions. The physical-presence route generally requires presence in foreign countries for at least 330 full days during a qualifying 12-month period.

The exclusion does not apply to every type of income. Interest, dividends, pensions and capital gains are not foreign earned income merely because the recipient lives abroad.

Income excluded under the provision may also affect the foreign tax credit calculation. A person cannot normally claim a credit for foreign tax attributable to income excluded from US tax.

For many UK residents, where Income Tax rates can be higher than US federal rates, the foreign tax credit may be more useful. The better method depends on the taxpayer’s income, family circumstances and longer-term plans.

Using the Wrong Currency Conversion

British income must be converted into US dollars for American reporting, while American income and gains generally need to be converted into pounds sterling for UK reporting.

Using the year-end rate for every transaction can produce incorrect figures.

The appropriate method may depend on whether the amount is recurring income, a specific payment, tax withheld or the purchase or sale of an asset. The IRS requires amounts on the US return to be expressed in dollars and recognises the use of appropriate exchange rates according to the facts.

Foreign tax withheld may need to be converted using the rate applying when the tax was paid or withheld.

The same consistent methodology should be retained in the supporting records for each return.

Ignoring the Difference Between the UK and US Tax Years

The UK tax year runs from 6 April to the following 5 April. The US individual tax year normally follows the calendar year.

Income received between 1 January and 5 April may therefore fall into different reporting years in the two countries.

This can create timing differences for employment income, bonuses, dividends, property income and tax payments.

A UK tax payment made after the end of the corresponding US year may not be available for the US foreign tax credit calculation at the time originally expected.

Records should be organised so transactions can be reconciled by both UK tax year and US calendar year.

Reporting Only the Net Amount Received

Income should not automatically be reported as the amount left after foreign tax, management fees or withholding.

A US dividend received after withholding, for example, may need to be reported at its gross value, with the foreign tax considered separately.

The same principle can apply to property income, pensions and employment compensation.

Reporting only the net bank receipt can understate income and prevent the foreign tax credit from being matched correctly.

Statements should therefore identify gross income, tax deducted, fees and the net amount paid.

Applying One Country’s Capital Gains Calculation to the Other

The UK and US may calculate the gain on the same asset differently.

Differences can arise from acquisition costs, allowable expenses, share-identification rules, exchange rates and the treatment of a former main residence.

A gain calculated in US dollars should not simply be converted into sterling and copied onto the UK return. Each country’s gain should normally be calculated under its own rules.

Currency movements can also create an unexpected UK gain. The purchase price and sale proceeds may need to be converted using rates from different dates.

A property or investment showing only a modest dollar gain could produce a different sterling result.

Assuming a UK Tax-Free Gain Is Also US Tax-Free

UK allowances and exemptions do not automatically apply in the United States.

An asset disposal that falls within a UK exemption or annual exempt amount may still need to be reported on the US return.

The reverse can also occur. A transaction receiving favourable American treatment may remain taxable in Britain.

Examples can include the sale of a main residence, investments held through a UK tax wrapper and pension-related transactions.

The gain should be reviewed separately under each system before relief or treaty protection is applied.

Failing to Report American Property Income in Britain

A UK-resident dual citizen who rents out a property in the United States may have filing obligations in both countries.

The UK normally taxes foreign rental income received by UK residents unless a relevant exemption or FIG claim applies.

The expenses allowed by the UK may not match those deducted on the US return.

Mortgage interest, depreciation, repairs, management costs and capital improvements can be treated differently. Copying the net rental profit directly from the American return may therefore produce an incorrect UK figure.

The property records should retain the original purchase price, improvement costs, income, expenditure, foreign tax and exchange rates.

Missing UK Self Assessment Deadlines

Dual citizens who receive foreign income may need to register for and file Self Assessment even where most of their UK employment income is taxed through PAYE.

A person who needs to complete a return generally must notify HMRC by 5 October following the end of the relevant tax year. The standard deadline for filing an online return and paying the Self Assessment liability is 31 January following the tax year.

Waiting for HMRC to issue a return is not always sufficient. The taxpayer may have a responsibility to notify HMRC that taxable foreign income exists.

Late notification, filing or payment can lead to penalties and interest.

Misunderstanding the US Extension for Taxpayers Abroad

Qualifying US taxpayers living abroad can receive an automatic two-month extension to file their federal income tax return.

This extension does not necessarily extend the date from which interest is charged on unpaid tax. Interest can run from the normal payment deadline even where the later filing date applies.

A further extension to file may be available, but an extension to file is not automatically an extension to pay.

The FBAR also has its own filing process and deadlines and should not be assumed to follow the same procedure as Form 1040.

Assuming Banks Will Complete the Reporting

UK financial institutions may collect US citizenship and tax-identification information under international reporting arrangements.

That does not mean the bank files the individual’s US tax return, FBAR or Form 8938.

Financial institutions report information under their own obligations. The taxpayer remains responsible for determining which personal forms must be filed and whether the figures are complete.

Information supplied by a bank may also differ from the values required on a tax form because the reporting periods, currency conversions and asset definitions are not necessarily identical.

Failing to Coordinate Two Separate Tax Advisers

Some dual citizens use a UK accountant and a US preparer who work independently.

Each adviser may prepare a technically reasonable return based only on the information and figures they receive, but the two filings may not coordinate correctly.

Income descriptions, tax payments, exchange rates, entity classifications and foreign tax credits should be reconciled between the returns.

The US adviser may need the final UK tax computation, while the UK adviser may need details of US withholding and the treaty treatment being claimed.

Cross-border advice is most effective when one adviser understands both systems or when the two professionals communicate directly.

Delaying the Correction of Previous Errors

Taxpayers sometimes avoid reviewing older filings because they are concerned that correcting the position will automatically lead to severe penalties.

The appropriate response depends on the nature of the error, the years involved and whether income or accounts were omitted.

HMRC provides procedures for disclosing undeclared overseas income, and approaching the authority voluntarily may be treated more favourably than waiting for HMRC to identify the problem.

The United States also has different procedures for amending returns and addressing certain international filing failures.

A correction should be made using the procedure appropriate to the facts rather than simply adding an old amount to the current year’s return.

Creating a Coordinated Reporting Process

Dual citizens can reduce errors by maintaining one set of records capable of supporting both returns.

This should include:

• complete UK and US bank statements;

• gross income and tax deducted;

• original costs and sale proceeds for investments;

• pension contribution and distribution records;

• property income and expenditure;

• the highest annual value of foreign accounts;

• travel and residence records;

• consistent currency-conversion evidence; and

• copies of all UK and US returns and international information forms.

The records should be updated throughout the year rather than assembled shortly before the filing deadlines.

UK-US tax compliance is not simply a matter of filing two separate returns. The income, tax credits, currencies, reporting periods and financial assets must be coordinated across both systems.

Identifying the potential differences before filing can help dual citizens avoid duplicate taxation, incomplete disclosures and the cost of correcting preventable cross-border reporting mistakes.