US Tax Preparation for American Expats: Employer NIC Elections

An American executive in the UK who signs a joint election bears the employer's secondary Class 1 National Insurance on share award gains. The UK gives an income tax deduction for it; the US gives neither a deduction nor a foreign tax credit. Form 1040 usually reports the full gain while creditable UK tax is computed on a smaller one.

That mismatch is the heart of this guide. It matters to anyone who needs careful US tax preparation for American expats holding options, restricted stock units or other employment-related securities through a UK employer or the UK arm of a US group. At Jungle Tax we prepare both the US and the UK return for these events, and the employer NIC line is one of the items most often handled incorrectly on the US side, usually because the payslip does not make clear what it is.

What follows is a return-preparation explanation: what the election is, how the UK relieves it, how it should be presented to the IRS, where the US position is not settled by published guidance, and how to correct earlier years in which National Insurance was claimed as a foreign tax credit.

What is an employer NIC election on share awards?

When an employee exercises a non-tax-advantaged option, or an RSU vests, over shares that can readily be converted to cash, the gain is employment income subject to PAYE and to Class 1 National Insurance. The employee pays primary contributions; the employer pays secondary contributions, currently at a main rate of 15% with no upper cap. Because the employer cannot predict the share price at exercise, that secondary charge is an open-ended cost.

UK law permits the employer to pass that specific cost to the employee in one of two ways:

• A joint election. Employer and employee jointly elect that the secondary liability is legally transferred to the employee. The employer still calculates, collects and remits the amount, but the liability itself becomes the employee's.
• A NIC agreement. The liability stays with the employer. The employee simply agrees, usually in the award documents, to reimburse the employer for the cost.

US-headquartered groups have traditionally preferred the joint election, which is why American executives in London meet it so frequently: it is often a condition of the grant and is signed electronically along with the award acceptance. The distinction between the two mechanisms is rarely noticed at signing, yet it is relevant to the US analysis later in this guide.

Does the joint election need HMRC approval?

Historically every form of election had to be approved by HMRC before use. HMRC's guidance on transferring employer National Insurance to employees now explains that, from 1 May 2025, an employer may use HMRC's published model documents (a single election for one employee, or a two-part election for many) without submitting them. An employer that drafts its own wording must still obtain approval, which HMRC indicates can take up to 30 days, and must not have it signed first. In either case the election has effect only once both parties have signed and dated it, and the employer must retain the signed copy.

For return preparation, the practical point is evidential. The US and UK treatment both depend on which mechanism applies, so the signed election or the relevant clause of the award agreement belongs on the file alongside the exercise statement.

Which charges can an election cover, and which can it not?

HMRC's Employment Related Securities Manual sets out the scope. An election can cover:

• gains on securities options, including exercise, assignment, release or cash cancellation (many elections are limited to exercise only);
• post-acquisition chargeable events on restricted securities, such as the lifting of restrictions;
• post-acquisition chargeable events on convertible securities, such as conversion.

It may transfer the whole secondary liability, a stated percentage, or only the liability on gains above a set amount. There are limits. HMRC states that an election does not apply to employment income arising under the anti-avoidance provisions in Chapter 3A of Part 7 of ITEPA 2003, where the employer remains responsible. For restricted and convertible securities, the election reaches only events after the award, so any charge on the original acquisition of the shares is outside it. Secondary contributions on ordinary salary and cash bonuses cannot be passed on at all. Where an election is limited to exercise, a cash cancellation on a takeover may fall outside it, which is a common surprise in a transaction year.

How does the UK relieve employer NIC borne by the employee?

Because the employee is paying a cost that would otherwise be the employer's, the UK allows it as a deduction in computing the taxable gain. For securities options the rule is in section 481 of ITEPA 2003, described in HMRC's manual at ERSM110520; section 482 is a companion provision dealing with a separate special contribution regime. Equivalent relief for restricted securities is given under section 428A and is described at ERSM30490.

Four features of the relief matter when the returns are prepared:

• Income tax only. The deduction reduces the amount charged to income tax. It does not reduce the amount on which either employee or employer NIC is calculated; both are computed on the full gain.
• Under a joint election the relief is the secondary NIC for which the employee is liable.
• Under an agreement the relief is limited to the amount the employer actually receives from the employee on or before 5 June in the tax year following the gain. A late reimbursement can therefore lose the deduction.
• If HMRC withdraws approval of an election, relief is restricted to the liability met by that same 5 June date.

How does it appear through PAYE, on the P60 and on the UK return?

Where the shares are readily convertible assets, the employer operates PAYE on the gain. In practice the payroll takes the deduction into account, so the taxable pay figure for the month, and in due course the year-to-date taxable pay on the P60, is the gain net of the transferred employer NIC. The employee NIC figures on the P60 show primary contributions only. The transferred employer NIC is typically not shown there at all; it appears as a separate deduction on the payslip or, more reliably, on the share plan administrator's exercise or vesting statement.

The P11D is generally not where this item sits, since it reports benefits and expenses rather than payrolled securities income. Where the shares are not readily convertible assets, so that no PAYE is operated, the gain and the deduction are instead reported by the individual on the Self Assessment return. The employer separately reports the event to HMRC on its annual employment-related securities return. A complete file for a year of exercise therefore contains the payslip, the P60, the administrator's statement and the election itself, because no single UK document shows every figure.

How is transferred employer NIC treated on Form 1040?

The US analysis has three separate questions: how much compensation is reported, whether the NIC is deductible, and whether it is creditable. The second and third have clear answers. The first does not have a published one.

Does the NIC reduce the section 83 compensation amount?

Under section 83 of the Internal Revenue Code, the compensation on exercise of a non-qualified option is the fair market value of the shares received less the amount paid for them. The question is whether employer NIC borne by the employee is part of the amount paid.

Under a joint election, the legal liability for the contribution has been transferred to the employee. The employee is then discharging a tax liability of their own, and paying one's own tax is not ordinarily a payment for property. The cautious position, and the one we see most widely adopted, is that the full spread is compensation and the NIC is a separate, unrelieved cost.

Under a reimbursement agreement, the liability remains the employer's and the employee makes a payment to the employer as a condition of receiving the shares. There is a reasoned argument that such a payment forms part of the amount paid for the shares and so reduces the compensation element. There is an equally reasoned counter-argument that in substance the employee is bearing a social security charge, or an unreimbursed employment cost, neither of which is deductible.

We should be candid: we are not aware of any published IRS guidance that addresses UK employer NIC elections or agreements directly. Where a US Form W-2 is issued, for example by a US parent, it will normally report the gross spread, and a return that departs from that figure invites a matching enquiry. A return that takes the reduced figure should do so deliberately, with the reasoning documented and disclosure considered, rather than by simply copying the UK taxable pay from the P60. That last error is common and is not a filing position at all; it is a transcription of a UK number into a US box.

Is it deductible or creditable as a foreign tax?

No, on either count. The United States and the United Kingdom have a totalization agreement, and section 317(b)(4) of the Social Security Amendments of 1977 provides that social security taxes paid to a foreign country for employment covered by that country's system under such an agreement are neither deductible nor creditable for US income tax purposes. IRS Publication 514 states the rule in plain terms: no deduction or credit is allowed for social security taxes paid or accrued to a country with which the US has a social security agreement.

Employee NIC is squarely within that rule. Employer NIC that has become the employee's own liability under a joint election is, on the most natural reading, within it as well: it is a contribution paid by an individual to the UK in respect of covered employment. Nor is there a separate route to relief. US law gives employees no deduction for their own social security contributions, and miscellaneous employee expenses are not currently deductible for federal purposes. The IRS explains the certificate of coverage framework on its totalization agreements page.

Why do UK taxable income and US wages differ?

Put the two systems together and the same exercise is measured twice. The UK charges income tax on the gain after deducting the employer NIC. The US, on the cautious view, taxes the whole gain. Only UK income tax is creditable, and it has been computed on the smaller base. The table summarises the position.

Item	UK (HMRC)	US (IRS)
Amount taxed on exercise	Gain less employer NIC borne by the employee	Full spread under section 83 (cautious view)
Employer NIC borne by employee	Deducted for income tax; not for NIC	No deduction; no credit
Employee NIC	Payable on the full gain	No deduction; no credit
UK income tax (PAYE)	Charged on the reduced gain	Creditable on Form 1116, subject to limitation
Reporting document	Payslip, P60, Self Assessment where required	Form 1040 wages, Form 1116, Form 8949
Tax year	6 April to 5 April	Calendar year
Shares sold to cover	Share identification rules; usually little gain	Basis equals market value at exercise; report the sale

What is the effect on the foreign tax credit and Form 1116?

The credit is claimed on Form 1116, with option compensation normally falling in the general category. Several points need attention in a year with a transferred NIC charge.

• Only income tax goes on the form. PAYE income tax on the gain is entered; employee NIC and transferred employer NIC are not. Payslips that show one combined deduction for an exercise need to be split using the administrator's statement.
• The effective creditable rate falls. Because UK income tax is charged on the reduced gain, the creditable tax expressed as a percentage of the US compensation figure is lower than the headline UK rate.
• Sourcing follows workdays. Option and RSU compensation is generally sourced by reference to where the individual worked between grant and vesting. Any portion attributable to US workdays is US-source and attracts no general category limitation, which is where a thinner credit margin starts to produce US tax.
• Timing and currency. The exercise falls in one US calendar year but may straddle two UK tax years' worth of PAYE, and the paid or accrued basis elected for foreign taxes determines when the tax is counted and at what exchange rate.
• Exclusion interaction. If the foreign earned income exclusion has been claimed, UK income tax allocable to excluded income is not creditable, so the allocation must be made before the credit is computed.

A worked illustration

The figures below are hypothetical round numbers. They assume a UK additional rate taxpayer outside Scotland, a 45% income tax rate, a 15% employer NIC rate and a 2% employee NIC rate on the gain, all UK-source, with a joint election transferring the whole secondary liability.

• Option gain on exercise: £200,000
• Employer NIC transferred to the employee (15%): £30,000
• Employee NIC (2%): £4,000
• UK taxable gain after the section 481 deduction: £170,000
• UK income tax at 45%: £76,500
• Total UK cost to the employee: £110,500, or 55.25% of the gain

On the US return, the cautious presentation reports compensation of £200,000, converted to dollars. The only creditable foreign tax is the £76,500 of income tax, which is 38.25% of that compensation. Had there been no transfer, UK income tax would have been £90,000, or 45%. The election has therefore removed £13,500 of creditable tax and replaced it with £30,000 that the US ignores entirely.

In this illustration the creditable tax still exceeds US federal tax at the top ordinary rate, but the margin is narrow rather than comfortable. It can disappear where part of the gain is US-source because of US workdays during the vesting period, where Scottish or other rate differences apply, or where earlier credit carryovers were overstated. The headline figure of 55.25% paid in the UK says very little about the US outcome, because more than a quarter of it is not creditable.

Sell-to-cover share sales and US basis

Most executives do not fund these amounts from cash. The plan administrator sells enough shares at exercise to cover the exercise price, PAYE, employee NIC and the transferred employer NIC. With an election in place, noticeably more shares are sold than the executive may have expected.

For US purposes each of those sales is a reportable disposal. Basis in the shares is the exercise price paid plus the compensation recognised, which together equal the fair market value at exercise. That is so whichever view is taken on the section 83 question, since any amount treated as additional price paid adds to basis by the same amount that it reduces income. A same-day sale therefore normally produces a small short-term gain or loss, driven by dealing costs and intraday price movement.

The sale is reported on Form 8949 and Schedule D, in US dollars at the rate for the transaction date. A non-US administrator may issue no Form 1099-B; where a US broker does issue one, the reported basis frequently reflects only the exercise price, and an adjustment is needed to avoid taxing the compensation twice. On the UK side the share identification rules, including the same-day rule, generally match the sold shares with those just acquired, so the UK gain is usually modest too. Shares retained in a non-US nominee or brokerage account afterwards should also be considered for FBAR and Form 8938 purposes.

Catch-up: earlier returns that claimed NIC as a foreign tax credit

We regularly see prior-year returns, self-prepared or prepared without sight of the exercise statement, in which every UK deduction on the payslip was entered on Form 1116. That brings in employee NIC and, in exercise years, a large employer NIC figure that should never have been there. A related error is the opposite one: US wages taken from the P60 taxable pay, understating compensation by the amount of the section 481 deduction.

Correcting the position is a methodical exercise:

• Rebuild the figures. Obtain payslips, P60s and administrator statements for each exercise or vesting year and separate income tax, employee NIC and transferred employer NIC.
• Recompute Form 1116 for each year. Remove the National Insurance, restate compensation where it was understated, and recalculate the limitation.
• Roll the carryovers forward. Unused credits carry back one year and forward ten, so an overstatement in one year flows into every later year that used the carryover. The schedule needs correcting even where a given year's tax does not change.
• Amend where tax changes. Where the correction alters US tax for a year that remains open, an amended return on Form 1040-X with a revised Form 1116 is the ordinary route, with interest on any additional tax.
• Consider the wider picture. If the review also reveals unreported income or missed international information returns, the appropriate disclosure route may differ, and our streamlined filing team assesses that at the outset rather than after amended returns have been lodged.

In many cases an executive with surplus UK income tax credits will find that removing the NIC changes no year's tax and only reduces a carryover that was never going to be used. That is a reassuring result, but it is one to establish by computation rather than assume.

Preparation checklist for a year with an NIC election

• The signed joint election or the NIC clause in the award agreement, to establish which mechanism applies.
• The administrator's exercise or vesting statement, showing market value, exercise price, shares sold and each deduction.
• Payslips for the month of the event and the P60 for the UK tax year.
• Any Form W-2 issued by a US group company, reconciled to the UK figures.
• A workday record from grant to vesting, for sourcing.
• The prior-year Form 1116 carryover schedule.
• Year-end statements for any account in which retained shares are held.

Our US-UK tax accountants prepare the US return and, where one is required, the UK Self Assessment return from the same reconciled figures, so that the two filings describe one event consistently. Further return-preparation topics for internationally mobile executives are covered in our guides library.

Speak to a cross-border preparer

A transferred employer NIC charge is a large number that the UK relieves and the US disregards, and the documents that record it rarely make that distinction for you. If you have exercised options or had awards vest under a joint election, or suspect that earlier US returns claimed National Insurance as a foreign tax credit, we would be glad to review the position and prepare the filings accurately. To arrange a confidential consultation, contact our cross-border team.