Why a Section 431 Election Matters More for Americans in Britain
A section 431 election is a joint written agreement between an employer and an employee to tax shares on their unrestricted value at acquisition, and for an American in Britain it carries a second set of consequences that no UK adviser is paid to model. Furthermore, the deadline is fourteen days. Miss it and the door closes permanently, because HM Revenue and Customs has no power to accept a late one.
British executives treat the form as routine paperwork passed round the table on completion day. However, a dual filer faces two tax authorities that measure the same shares differently, on different dates, using different valuation standards. Consequently, the section 431 election either aligns those systems or quietly destroys the foreign tax credit that keeps the total bill reasonable.
At TaxYork we see the damage most often at exit, three or four years later, when a client discovers that the relief they paid for in Britain produced a dry charge in America. Therefore, this guide sets out the UK mechanics in full, then the US overlay that every competing article omits.
What a Section 431 Election Actually Does
A section 431 election disapplies the restricted securities rules in Chapter 2 of Part 7 of the Income Tax (Earnings and Pensions) Act 2003. Specifically, it treats the shares as if no restrictions existed, so income tax bites once on the full unrestricted market value at acquisition.
Without the election, Britain taxes you twice in substance. Initially you pay income tax on the discounted actual market value. Subsequently, every time a restriction lifts or you sell, section 428 ITEPA 2003 claws back a proportion of the growth as employment income at up to 45 per cent, plus National Insurance.
Moreover, the election converts all future growth into a capital gain. Accordingly, the difference between a 45 per cent employment charge and a 24 per cent capital gains rate on several hundred thousand pounds of value makes the section 431 election the single most valuable signature in a UK management equity deal.
Who Needs to Think About This
Private equity portfolio managers, founders taking growth shares, bankers receiving restricted stock in a UK entity and partners converting to corporate structures all sign these forms. Additionally, anyone acquiring employment-related securities carrying leaver provisions, transfer restrictions or compulsory transfer triggers falls squarely inside the regime.
American citizens and green card holders in these roles carry the full burden. Notably, the United States taxes worldwide income regardless of residence, so both systems examine the same share award simultaneously. In our experience preparing US tax returns for expats, the election paperwork is signed months before anyone considers the American position.
How the UK Restricted Securities Rules Work Without an Election
Britain defines restricted securities in sections 423 and 424 ITEPA 2003, and the definition is deliberately wide. Therefore, most private company share awards qualify, even where the commercial parties regard the restrictions as trivial.
What Counts as a Restricted Security
Three categories exist. First, securities subject to forfeiture provisions. Second, securities where a restriction limits freedom to retain, deal in or exercise rights attaching to them. Third, securities where a provision reduces the value on disposal.
Standard articles of association almost always trigger at least one limb. Consequently, a good leaver and bad leaver clause, a drag-along right or a pre-emption provision each pull the shares into Chapter 2 and make a section 431 election relevant.
The Chargeable Event Formula
When restrictions lift, section 426 ITEPA creates a chargeable event and section 428 sets the amount. The formula is unrestricted market value multiplied by the initial uncharged proportion, less the previously charged proportion and the outstanding proportion, reduced by allowable expenses.
In plain terms, Britain remembers the discount it gave you at acquisition and recovers tax on that slice of every subsequent rise in value. Hence a 15 per cent restriction discount on entry means 15 per cent of a tenfold gain returns as employment income. A section 431 election eliminates that memory entirely.
The Five-Year Forfeiture Rule
Where shares carry forfeiture provisions that will lift within five years, section 425(2) ITEPA switches off the acquisition charge altogether. Nevertheless, this apparent kindness is a trap, because the whole eventual gain then arrives as employment income on vesting.
Americans suffer badly here. Specifically, the United States frequently taxes nothing at that moment if an 83(b) election was made years earlier, leaving a large UK charge with no matching US liability to absorb it.
Making the Section 431 Election: Mechanics and the Fourteen-Day Deadline
The rules governing the section 431 election sit in the HMRC Employment Related Securities Manual at ERSM30450. Importantly, the election must be made jointly by employer and employee within fourteen days of acquisition, using a form approved by HMRC.
You do not send it to HMRC. Instead, both parties retain signed copies, and the company confirms the position on its annual employment related securities return.
Full Elections Under Section 431(1)
A section 431(1) election ignores every restriction. Accordingly, income tax and National Insurance apply to the full unrestricted market value at acquisition, and the shares leave Chapter 2 permanently.
Most transactions use this version. Furthermore, institutional investors normally insist on it, because a partial election leaves residual exposure for the company on employer National Insurance at 15 per cent.
Partial Elections Under Section 431(2)
A section 431(2) election disapplies only chosen restrictions. Therefore, parties can tax the forfeiture discount away while leaving a permanent restriction in place, which keeps the acquisition charge lower.
This flexibility rarely helps a British employee. Conversely, it occasionally helps an American, because a smaller UK acquisition charge can be matched more precisely against the US section 83 inclusion in the same year. We model that comparison whenever a section 431 election is signed by a dual filer.
Valuation, Unrestricted Value and Actual Value
Two numbers drive everything. Unrestricted market value ignores the restrictions; actual market value reflects them, and the gap is the discount an independent valuer certifies.
Get the valuation wrong and the election protects nothing, because HMRC can argue the unrestricted value was higher than the price paid. Consequently, contemporaneous valuation evidence matters as much as the signature itself. The Chartered Institute of Taxation and the ICAEW both stress documentation as the first line of defence in an enquiry.
Reporting on the Annual ERS Return
Every company with employment-related securities must file an employment related securities annual return by 6 July following the end of the tax year. The return asks whether a section 431 election was made.
That answer is the audit trail. Therefore, a mismatch between the return and the paperwork in the data room is exactly what surfaces during due diligence on the next transaction.
The United States Side: Section 83 and the 83(b) Election
America approaches the same shares through section 83 of the Internal Revenue Code. Fundamentally, property transferred in connection with services is taxed as compensation when it substantially vests, not when it is granted.
How Section 83 Taxes Restricted Stock
Substantial vesting occurs when the shares are transferable or no longer subject to a substantial risk of forfeiture. At that point, the excess of fair market value over the price you paid becomes ordinary income, taxable at rates reaching 37 per cent.
Crucially, the American test is narrower than the British one. Transfer restrictions and pre-emption rights generally do not create a substantial risk of forfeiture in the United States, whereas they do make shares restricted securities in Britain. Consequently, the two systems can disagree about whether anything has happened at all.
The Thirty-Day Section 83(b) Deadline
A section 83(b) election accelerates the US charge to acquisition, mirroring what a section 431 election achieves in Britain. However, the American deadline is thirty days, it is irrevocable, and the Internal Revenue Service grants no extensions.
The IRS now publishes Form 15620 for section 83(b) elections, although a written statement under the regulations remains valid. Importantly, you must keep proof of timely mailing, because the burden of establishing the filing sits with you.
Why the Two Deadlines Do Not Align
Here lies the trap that no UK share scheme lawyer will flag. The section 431 election runs for fourteen days and needs your employer countersignature, while the 83(b) election runs for thirty days and is yours alone to file.
Treat the fourteen-day clock as the binding constraint, because you do not control how quickly a company secretary returns paperwork. Additionally, agree the US position before completion, since deciding afterwards means one election has already expired.
Foreign Tax Credit Arithmetic When the Elections Mismatch
Making both elections usually aligns the two charges into a single tax year, which is the outcome we recommend. Nevertheless, understanding each mismatch explains why the section 431 election cannot be considered in isolation, and our tax treaty optimisation work begins here.
Electing in Britain Only
File the section 431 election without an 83(b) election and Britain taxes the full unrestricted value now, while America waits for vesting. Subsequently, the US charge arrives in a later year with no UK tax remaining to credit against it.
Section 904(c) permits only a one-year carryback of excess foreign tax credits. Therefore, a UK charge in year one cannot reach a US charge in year four, and both taxes are paid in full on the same economic gain.
Electing in America Only
The reverse mismatch is worse. America taxes the spread at acquisition, then Britain taxes the growth as employment income at up to 45 per cent plus employee National Insurance when restrictions lift.
National Insurance is never a creditable foreign tax for US purposes. Accordingly, a meaningful slice of the British charge has no American relief at all, which is why a section 431 election should accompany every 83(b) election a UK-based American files.
The Net Investment Income Tax Gap
Once the section 431 election converts future growth into a capital gain, the eventual disposal attracts US capital gains tax at 20 per cent plus the 3.8 per cent net investment income tax. Unfortunately, the net investment income tax admits no foreign tax credit.
British capital gains tax at 24 per cent therefore covers the 20 per cent federal charge but never the surtax. Consequently, budget for 3.8 per cent of the gain as an unavoidable American cost, whatever Britain charges.
Sourcing, Forfeiture and Reporting Traps
Three further issues decide whether the planning survives contact with reality. Moreover, each one is invisible in UK-only guidance.
Section 865(g) and the Ten Per Cent Test
American citizens normally source capital gains to the United States, which would strand the credit entirely. However, section 865(g) treats a citizen with a genuine foreign tax home as a non-resident where the gain bears at least 10 per cent foreign tax.
UK capital gains tax at 18 or 24 per cent clears that threshold comfortably. Conversely, sheltering the gain with losses or the annual exempt amount can drag the effective rate below 10 per cent and flip the gain to US source, destroying the credit the section 431 election was designed to protect.
Bad Leaver Forfeiture After an 83(b) Election
If you leave as a bad leaver and forfeit shares at cost, section 83(b) gives no deduction for the amount you already included in income. Meanwhile, Britain generally provides relief through the negative charge provisions.
That asymmetry is real money. Hence an American should weigh personal leaver risk before paying tax upfront on shares that a compulsory transfer clause can remove for a nominal sum.
Internationally Mobile Employees and Workday Apportionment
Few holders of UK shares spend an entire vesting period in one country. However, Chapter 5B of Part 7 ITEPA apportions employment income from securities by reference to the relevant period, which normally runs from acquisition to the date restrictions lift.
A section 431 election collapses that period to a single day. Therefore, an American who signs on arrival in London is taxed by Britain on the whole spread, even though much of the underlying service may later be performed elsewhere. Conversely, an executive who signs nothing and subsequently moves to New York can find Britain taxing a proportion of growth accrued entirely on American soil.
Article 15 of the United States and United Kingdom double taxation treaty allocates employment income by where the duties are performed. Accordingly, the treaty and the election can pull in opposite directions, and the resulting credit position depends on which country charges first. We recommend modelling expected workdays across the full vesting period before the fourteen days expire, not afterwards.
Form 8938 and FBAR Reporting
Shares held directly are specified foreign financial assets reportable on Form 8938 once you cross the threshold, which is 200,000 dollars for a single filer living abroad. Directly held shares are not, however, foreign financial accounts for FBAR purposes.
Completion escrow accounts and nominee arrangements are different, and they routinely trigger a first filing obligation. Our FBAR and FATCA reporting team reviews the whole structure rather than the share certificate alone.
A Worked Case Study: Sweet Equity in a London Buyout
Consider Rachel, an American citizen and UK resident, appointed chief financial officer of a London portfolio company in June 2026. She subscribes for 400,000 ordinary shares at 25 pence, paying 100,000 pounds.
The Numbers at Acquisition
The independent valuation puts unrestricted market value at 40 pence per share, or 160,000 pounds, with a 15 per cent restriction discount giving an actual market value of 34 pence. Without an election, Britain taxes 36,000 pounds now and remembers the discount forever.
Rachel signs a section 431 election within fourteen days. Consequently, Britain taxes the full 60,000 pound spread as employment income, costing 27,000 pounds at 45 per cent, and the shares leave the restricted securities regime.
She also files an 83(b) election within thirty days, reporting roughly 81,000 dollars of compensation. Therefore, the American charge lands in the same tax year, and the UK income tax generates a general basket credit that absorbs it entirely.
The Exit Four Years Later
In 2030 the group sells and the shares realise 1,600,000 pounds. Her UK gain is 1,440,000 pounds, taxed at 24 per cent, producing 345,600 pounds of capital gains tax.
Her US gain is calculated in dollars against a basis built from the price paid plus the amount included under the 83(b) election. Because the UK effective rate exceeds 10 per cent, section 865(g) sources the gain to Britain, the 20 per cent federal charge is fully covered, and only the 3.8 per cent surtax remains payable.
What the Elections Saved
Had Rachel signed nothing, the restriction discount would have returned 15 per cent of her 1,440,000 pound gain as employment income. That is 216,000 pounds taxed at 45 per cent plus 2 per cent National Insurance, costing roughly 101,520 pounds instead of 51,840 pounds at capital gains rates.
The paired elections therefore saved close to 50,000 pounds of UK tax and removed an uncreditable National Insurance charge. Above all, they kept both charges in one tax year, which preserved the foreign tax credit that a section 431 election alone would have wasted.
How TaxYork Can Help With Your Section 431 Election
We advise American executives, founders and fund principals who acquire UK company shares, and we work to the fourteen-day clock rather than around it. Specifically, we review the articles, the valuation report and the election form before completion, then model both the British and American outcomes on the same numbers.
Our team prepares the US return, the Form 8938 disclosure and the foreign tax credit computation that turns a section 431 election into an actual saving. Furthermore, where elections were missed in earlier years, we quantify the exposure and set out the realistic remediation routes through offshore disclosure and catch-up filing.
Many clients reach us after signing. Even then, a correctly structured 83(b) election and a disciplined credit strategy recover a substantial part of the value, so early contact matters more than perfect history.
Conclusion
A section 431 election is the most consequential fourteen days in a UK equity award, and for an American it is only half the exercise. Britain and America measure restricted shares differently, tax them on different dates and recognise each other elections not at all.
File both elections, align them in one tax year, and the foreign tax credit works as intended. File one alone, and you fund two tax authorities on a single economic gain. Ultimately, the arithmetic of a section 431 election is decided in the fortnight after completion, not at exit.
Contact Us
Speak to a specialist before you sign. To review your section 431 election and the matching US filing, book a consultation with our cross-border team today.
Email hello@taxyork.com or call 020 3488 8606.
Disclaimer
This article provides general information about the UK and United States tax treatment of restricted securities and does not constitute tax advice. Tax rules change and individual circumstances differ significantly. You should obtain professional advice tailored to your own position before acting. Useful background reading is available from HM Revenue and Customs, the Internal Revenue Service, the American Institute of CPAs and MoneyHelper.