Introduction: Signing Bonus Sourcing Across Two Tax Systems
A signing bonus paid around a transatlantic move is one of the most mishandled payments in cross-border tax. Furthermore, the sums involved are rarely small. Six and seven-figure inducements are routine for the bankers, fund partners and executives we act for.
The danger is straightforward. Both countries can tax the same payment, and the relief that should prevent duplication depends entirely on getting one technical question right. Specifically, where were the services performed? At TaxYork we have seen a single mis-sourced payroll entry turn a manageable charge into an effective rate above 80%.
This guide explains how each system sources the payment, why the two tax years refuse to align, and what happens when the bonus is later clawed back. Moreover, it sets out the records that protect your position.
Why a Signing Bonus Behaves Differently From Salary
Salary is easy to source because it tracks the days you work. However, an inducement payment often arrives before you have performed a single day of the new role. Consequently, there is no natural workday pattern to point at.
Therefore, a signing bonus must be attributed to the services it relates to rather than the moment it lands. Additionally, the two revenue authorities reach that attribution by different statutory routes, which is precisely where the problems begin.
What Is Actually at Stake
Get the signing bonus sourcing right and the foreign tax credit usually absorbs the duplication. Get it wrong and you pay both charges in full. Notably, the difference on a $500,000 payment routinely exceeds $180,000.
Furthermore, the error is rarely the client's. Instead, a US payroll department issues a Form W-2 showing domestic wages, nobody questions it, and the return follows the payroll rather than the law.
How the United States Sources a Signing Bonus
The American analysis is mechanical once you accept its premise.
Services Sourcing Under Sections 861 and 862
Compensation for personal services is sourced where the services are performed. Specifically, section 861 of the Internal Revenue Code treats services performed in the United States as domestic source, and section 862 treats services performed abroad as foreign source. Consequently, the location of the work governs, not the location of the payer or the bank account.
Importantly, citizenship is irrelevant when sourcing a signing bonus. Therefore, an American remains taxable on worldwide income, yet the source of that income still determines whether foreign tax credits can shelter it.
The Time Basis Formula in Practice
The IRS applies a formula rather than a judgement call. Under Treasury Regulation 1.861-4, compensation for services performed by an employee partly inside and partly outside the United States is determined on a time basis.
The IRS sets out the mechanics in its practice unit on sourcing salary and compensation, last revised in February 2025. Helpfully, its own worked example uses Britain. An employee with $80,000 of compensation who performed services in the United States for 60 days and in the United Kingdom for 180 days sources $60,000 to the UK, calculated as $80,000 multiplied by 180 over 240.
Notably, that same practice unit makes bonus sourcing an explicit audit step. Consequently, examiners are instructed to test whether the taxpayer has correctly sourced any bonus received in the year.
Multi-Year Arrangements and Deferred Awards
Many inducements straddle several years, and the regulations address that directly. Specifically, the practice unit confirms that multi-year compensation arrangement rules may determine the source of bonuses where services are performed in more than one year.
Therefore, a signing bonus relating to a three-year commitment is apportioned across the workdays of that whole period. Moreover, the same principle governs deferred awards and retention payments. Accordingly, the day count must be maintained across years rather than reconstructed later.
How Britain Taxes the Same Payment
The UK reaches a similar destination by an entirely different road.
Golden Hellos Are Earnings Under Section 62
HMRC treats inducement payments as ordinary employment income. Its Employment Income Manual at EIM00700 states that a payment to induce someone to take up an office or employment is taxable as earnings within section 62 of ITEPA 2003 if it is a payment from the employment.
Critically, third parties are caught too. HMRC confirms that payments made by others, including a former employer, are taxable as earnings where they induce someone to become an employee. That principle comes from Shilton v Wilmshurst, in which the House of Lords held it was enough that the payments were made in return for the taxpayer becoming an employee.
Consequently, a signing bonus routed through a former employer or a group company does not escape. Furthermore, the £30,000 exemption that applies to termination payments does not apply here.
Earnings Are Taxed For the Year They Are Earned
HMRC looks through the payment date. Its guidance on globally mobile employees states that it is the period the employment income was earned that determines whether the earnings are chargeable to UK income tax, rather than the employee's circumstances in the year of receipt.
Therefore, a signing bonus received after departure can still be UK taxable if it relates to earlier UK duties. Similarly, a payment received before arrival can relate to duties yet to be performed in Britain. Accordingly, the direction of travel does not change the principle.
Non-Residents, Split Years and UK Duties
Residence status shapes the charge without eliminating it. Specifically, HMRC confirms that earnings for a year of non-residence remain subject to UK income tax where they relate to employment duties carried out in the UK in that year.
Furthermore, split-year treatment excludes earnings from the overseas part, provided they do not relate to UK duties. Nevertheless, split-year treatment is not elective, so the statutory residence test must be worked through carefully before any planning is built on it.
The Tax-Year Mismatch That Strands the Credit
Here the two systems agree in principle and still collide in practice.
Two Calendars That Never Align
Both countries source by reference to the duties rather than the payment date. However, the American tax year ends on 31 December and the British year ends on 5 April. Consequently, a single signing bonus can sit in one US calendar year while the UK tax on it falls across two.
Therefore, the income and the creditable tax can land in different periods. Moreover, that separation is structural rather than avoidable.
Where the Foreign Tax Credit Fails
The credit works on a cash basis by default. Specifically, foreign tax counts when paid, so PAYE deducted in February and March 2027 relieves a UK year that overlaps two American ones. Additionally, any Self Assessment balancing payment falls due on the following 31 January, which can be a full two years after the income arose.
Consequently, the credit arrives after the American tax has already been assessed. The remedy is the accrual election under section 905(a), which matches foreign tax to the year it relates to. Nevertheless, that election is irrevocable once made, so it deserves proper analysis rather than a reflex.
Treaty Re-Sourcing Where Days Fall Both Sides
Some assignments genuinely involve American workdays after the move. Consequently, part of the signing bonus stays US source and the credit cannot reach it. In those cases the relief article of the US-UK treaty can re-source income for credit purposes, and the IRS practice unit expressly flags that mechanism.
However, re-sourcing requires its own computation and its own basket. Therefore, treat it as a deliberate claim rather than an automatic outcome. HMRC explains the reciprocal position in its guidance on income taxed twice.
Overseas Workday Relief and the Four-Year Window
Many new arrivals assume this relief solves the problem. Usually, it does not.
Who Qualifies as a New Resident
The relief was reformed alongside the foreign income and gains regime from 6 April 2025. Consequently, it now applies to qualifying new residents who were not UK resident for the ten tax years before arrival. Furthermore, the relief runs for a maximum of four consecutive years and the window cannot be paused.
Notably, the old offshore banking requirement has gone. Therefore, the administrative burden is lighter than it once was.
The Cap That Limits the Benefit
Relief is no longer unlimited. Specifically, it is capped at the lower of £300,000 or 30% of qualifying employment income for each year. Consequently, a very large package exhausts the cap quickly.
Additionally, the relief only shelters earnings that relate to duties performed outside the United Kingdom. Therefore, the cap and the duties test both have to be satisfied.
Why It Rarely Shelters a Signing Bonus
An inducement to join a London role almost always relates to UK duties. Consequently, a signing bonus falls outside the relief by definition, however generous the cap. Moreover, most Americans arriving from the United States have been US resident recently, though that does not itself break the ten-year UK test.
Therefore, treat Overseas Workday Relief as protection for genuine overseas workdays rather than for the joining payment. Our cross-border tax planning reviews test both separately.
When You Have to Repay the Signing Bonus
Clawbacks are standard on large inducements, and the tax consequences are asymmetric.
Section 1341 Claim of Right in the United States
Repaying a signing bonus does not simply cancel the original charge. Instead, section 1341 applies where you reported income under an apparent unrestricted right and later repaid it. Specifically, the provision applies where the repayment exceeds $3,000.
You then choose between deducting the repayment in the year of repayment or taking a refundable credit for the extra tax the original inclusion caused. Furthermore, you must compute both and use whichever produces the lower tax. Consequently, the credit route usually wins where rates have fallen or income has dropped.
Negative Earnings Under ITEPA in Britain
Britain reached the same destination through litigation. Following HMRC v Julian Martin, a clawed-back bonus is treated as negative taxable earnings under section 11 of ITEPA 2003. The Upper Tribunal decision confirms the analysis.
Consequently, the employee repays the gross signing bonus and claims relief, rather than repaying net and absorbing the tax. Additionally, negative earnings are set against positive earnings for the year, with any excess available as loss relief.
The Mismatch on the Way Back Out
Both reliefs work, yet they rarely work together. Specifically, UK negative earnings need positive UK earnings to absorb them, and a departing employee often has none. Meanwhile, the American credit restores tax at the original year's rate.
Therefore, repaying a signing bonus can produce full relief on one side and stranded relief on the other. Accordingly, negotiate the clawback mechanics before signing, not afterwards.
A Worked Case Study With Real Numbers
Consider Daniel, a 39-year-old US citizen who moved from New York to London on 1 July 2026. He joined a British bank and received a signing bonus of $500,000 on commencement, subject to a two-year clawback. All his duties for the new employment are performed in London.
The Two Computations
Britain treats the signing bonus as a golden hello, taxable as earnings from the UK employment in 2026 to 2027. Converting at an illustrative $1.32, the bonus equals £378,788. At the 45% additional rate, UK tax comes to roughly £170,455, or about $225,000.
America taxes Daniel on worldwide income as a citizen. However, every workday for that employment in 2026 falls in the United Kingdom. Consequently, the time basis sources the entire payment to foreign sources. At 37%, the US charge is approximately $185,000, and the foreign tax credit covers it in full with around $40,000 of excess carried forward.
What Goes Wrong in Practice
Now assume the payment ran through a US payroll and appeared on a Form W-2 as domestic wages. Consequently, the return would treat the signing bonus as US source, and no foreign tax credit would be available against it.
Daniel would then pay roughly $185,000 to the IRS on top of about $225,000 to HMRC. Therefore, the combined charge reaches around $410,000 on a $500,000 payment, an effective rate above 80%. Notably, nothing in the underlying facts changed. Only the sourcing entry did.
The Timing Point and the Clawback
Even with correct sourcing, timing needs attention. Specifically, PAYE on the July payment lands inside US calendar 2026, yet any Self Assessment balancing payment falls due on 31 January 2028. Consequently, part of the creditable tax could arrive two American tax years late, which is where the accrual election earns its keep.
Furthermore, Daniel leaves after fourteen months and repays $250,000 gross. He claims section 1341 relief in the United States, restoring roughly $92,500. Meanwhile, his UK negative earnings relief depends on having positive UK earnings that year, so the two reliefs land unevenly.
Getting the Filings and Records Right
Documentation decides these cases far more often than argument does.
The Day Count That Decides Everything
Keep a contemporaneous workday record showing the country of each working day. Furthermore, retain travel evidence, because the IRS practice unit lists passports, calendars and itineraries as supporting material. Consequently, a reconstructed diary three years later is worth very little.
Additionally, record which employment each day relates to where you hold more than one. Consequently, a signing bonus can be apportioned on evidence rather than estimate. Therefore, the apportionment can be defended rather than asserted.
Withholding and Payroll Coordination
Speak to both payrolls before the payment is made. Specifically, confirm which entity will report the signing bonus and on what basis. Moreover, ask whether a Form W-2 will be issued and, if so, whether the wages are correctly characterised.
Consequently, most sourcing errors can be prevented at source rather than corrected on the return. Additionally, coordinate the position with your US tax return preparation well before the filing season.
Catching Up If It Went Wrong
Past years remain correctable. Generally, an amended return can recover tax paid on a wrongly sourced signing bonus within the normal windows. Furthermore, where wider non-compliance exists, the IRS Streamlined Filing Compliance Procedures may be the appropriate route, and our IRS Streamlined Filing service handles the catch-up.
Additionally, undisclosed accounts often surface alongside relocation issues, so FBAR and FATCA reporting needs reviewing at the same time. Professional guidance from the ICAEW, the AICPA and the Chartered Institute of Taxation reinforces the value of contemporaneous records.
Furthermore, Investopedia's overview of signing bonuses offers a plain-English primer, and MoneyHelper explains the UK income tax framework. Meanwhile, the IRS guidance on the Foreign Earned Income Exclusion confirms that the exclusion rarely helps at these income levels.
How TaxYork Can Help
We prepare US and UK returns for high-net-worth Americans across Britain, including bankers, fund partners, founders and senior executives. Furthermore, we analyse signing bonus sourcing before the payment is made rather than after the W-2 arrives.
Specifically, we establish which duties the signing bonus relates to and build the supporting day count. Additionally, we test whether the accrual election improves the credit position, model Overseas Workday Relief against the cap, and reconcile both filings so they tell the same story. We also review clawback drafting so the relief works on both sides.
Moreover, our clients typically hold layered remuneration alongside the joining payment: deferred cash, restricted stock and carried interest. Therefore, we model the whole package across the move rather than one line of it.
Conclusion
A signing bonus is not a simple payment once a border is involved. Above all, its treatment turns on where the related duties are performed, and both revenue authorities accept that principle. Consequently, the technical answer is usually available, and usually favourable.
Nevertheless, the practical outcome for a signing bonus depends on payroll reporting, day counts and timing. Britain taxes the payment as earnings from the new employment, America sources it to the workdays it relates to, and the two tax years refuse to line up. Therefore, the credit needs deliberate management rather than optimism.
Ultimately, an $180,000 swing on a single payment rewards attention paid before completion. In summary, fix the sourcing at source, keep the day count, and the signing bonus stops being a trap.
Contact Us
Speak to our cross-border team before you accept or repay any joining payment. To review how your signing bonus will be taxed in both countries, book a consultation with our specialists today.
Email hello@taxyork.com or call 020 3488 8606. Alternatively, contact us through our website and we will respond within one working day.
Disclaimer
This article provides general information only and does not constitute tax or legal advice. Tax rules change frequently, and the correct treatment depends entirely on your individual circumstances. Exchange rates and tax rates used in the illustration are indicative only. Therefore, you should obtain professional advice before acting on anything set out here. TaxYork accepts no liability for any action taken in reliance on this content.