Introduction: Foreign Currency Gains and Your GBP Account
Foreign currency gains sit quietly inside almost every American bank account in Britain. Notably, most sophisticated filers never see them until a large conversion forces the issue. The mechanism is simple but counter-intuitive. Your functional currency remains the US dollar, even after twenty years in London. Therefore every pound you hold is, to the Internal Revenue Service, an asset with a dollar cost basis rather than money.
When you eventually convert sterling back to dollars, the exchange rate movement produces a measurable gain or loss. Consequently these foreign currency gains crystallise on a wire home, on a share option exercise settled in dollars, or on a simple rebalancing. Notably the resulting taxable event never appears on any statement. Furthermore, and this is the part that stings, Britain usually taxes none of it. No UK tax means no foreign tax credit, so the charge lands uncushioned.
At TaxYork we see this most often among partners, founders and investment professionals moving seven-figure sums across the Atlantic. Notably, the exposure is rarely the result of speculation. Instead it accumulates passively, over years, in ordinary current and deposit accounts.
How Foreign Currency Gains Arise Without a Single Trade
Section 988 of the Internal Revenue Code governs the treatment, and its logic is unforgiving. Under 26 U.S. Code section 988, any gain attributable to a section 988 transaction is computed separately from the underlying economics. In other words, you can lose money in sterling terms and still owe US tax on a dollar gain.
Consider a straightforward example. You receive a bonus of £500,000 when the pound trades at 1.13 dollars, giving a basis of $565,000. Three years later you convert the same £500,000 at 1.32, receiving $660,000. Accordingly you have realised a gain of $95,000 for US purposes, despite having spent nothing and earned nothing beyond the original bonus.
Importantly, this is not an obscure anti-avoidance rule. It is the default treatment for every US person holding a non-dollar balance. Moreover it applies whether or not you consider yourself an investor.
Who This Affects Most
High-net-worth Americans in Britain carry the largest exposure for an obvious reason: the gain scales with the balance. A £40,000 current account rarely produces a material figure. A £2 million deposit account funded during the weak-sterling period of 2022 can produce several hundred thousand dollars of unreported income.
Additionally, business owners and partners face a second layer of complexity. Their accounts often fail the personal-use test that would otherwise offer limited relief. Ultimately the people most likely to owe substantial foreign currency gains are precisely the people least likely to have been told.
How Section 988 Treats Foreign Currency Gains as Income
The statute begins from a single premise. Your functional currency is the US dollar, so anything else is nonfunctional currency and therefore property rather than cash. Consequently the tax system measures every pound against its dollar cost, and foreign currency gains follow automatically from that comparison.
The Dollar Remains Your Measuring Stick
Residence abroad changes nothing here. Whether you left Boston in 2008 or arrived in London last spring, the IRS still measures your income in dollars using published rates. The IRS yearly average currency exchange rates show 0.759 pounds to the dollar for 2025 and 0.783 for 2024. Meanwhile the IRS foreign currency guidance confirms that spot rates apply to individual transactions. For FBAR purposes a different rate applies entirely, drawn from the Treasury reporting rates of exchange.
Ordinary Income, Computed Separately
Where section 988 applies in full, the resulting gain is ordinary income rather than capital gain. Therefore it attracts your marginal rate, which reaches 37% for 2026, instead of preferential long-term capital gains rates. Moreover foreign currency gains are computed separately from the transaction that produced them, which is why so many filers miss them.
Losses receive symmetrical treatment when section 988 governs. Consequently a genuine ordinary loss can offset other ordinary income, which makes accurate tracking valuable in both directions.
What Counts as a Section 988 Transaction
The provision reaches debt instruments, accrued receivables and payables, forward contracts, futures and options denominated in a nonfunctional currency. Notably it also reaches the currency itself. Holding sterling is therefore enough to generate foreign currency gains, and no financial instrument is required.
The Bank Account Rule That Most Guides Get Wrong
Here is where the mainstream commentary fails readers badly. Numerous articles suggest that every movement in your account produces a taxable event each year. That is simply wrong, and the regulation says so explicitly.
Deposits, Withdrawals and Transfers Are Not Disposals
Under 26 CFR section 1.988-2, depositing nonfunctional currency triggers no exchange gain or loss. The deposit must simply be denominated in that same currency. The same treatment covers withdrawals and transfers between such accounts. Accordingly, moving £300,000 from your Barclays current account to an HSBC savings account triggers nothing whatsoever.
This matters enormously in practice. Foreign currency gains do not accrue annually inside the account, and there is no mark-to-market. Instead the tax sits dormant until a genuine disposal occurs.
What Actually Triggers the Gain
Three events crystallise the position. Converting sterling into dollars is the obvious one. Spending the currency on property or another asset is the second. Using the pounds to acquire something outside the deposit mechanism is the third.
Therefore the timing of your conversions, rather than the passage of time, controls your foreign currency gains. Furthermore this gives you genuine planning latitude that an annual mark-to-market regime would deny.
Tracking Basis Across Currency Lots
Because the account is not marked to market, you must track the dollar basis of each tranche of sterling you acquire. Salary in March, a bonus in December and a dividend in June each carry their own basis. Consequently the foreign currency gains on a partial conversion depend on which pounds you are treated as having converted.
In our experience preparing returns for clients with substantial sterling balances, this reconstruction is the single largest piece of work. Nevertheless it is entirely achievable from bank statements and payslips, provided somebody actually does it.
The $200 Exemption and Its Cliff Edge
Congress recognised that taxing holiday money would be absurd. Section 988(e) therefore carves out personal transactions, but the carve-out is far narrower than most readers assume.
How the Personal Transaction Relief Works
Section 988(e)(1) disapplies the rest of section 988 to any transaction entered into by an individual that qualifies as a personal transaction. The following paragraph then provides that no gain is recognised by reason of exchange rate movements. However, the relief evaporates entirely once the foreign currency gains on that transaction exceed $200.
A personal transaction means any individual transaction except one where the related expenses would qualify under section 162 or section 212. Broadly, therefore, spending abroad is personal while business and income-production activity is not.
The All-or-Nothing Trap Above $200
Read the provision carefully, because the threshold behaves unlike almost every other de minimis rule in the code. It is not an allowance against the first $200. Instead, gain of $201 makes the entire $201 taxable, and gain of $95,000 makes the whole $95,000 taxable.
Consequently the exemption protects a fortnight in Provence and nothing else. Foreign currency gains on any meaningful conversion fall outside it completely, and the test applies transaction by transaction rather than annually.
When Your Account Stops Being Personal
This distinction deserves more attention than it receives. A current account used for groceries, school fees and council tax looks personal. An interest-bearing deposit account held alongside a managed portfolio, generating income and attracting management costs, looks like section 212 territory instead.
The characterisation matters because it drives the answer. Where the transaction is personal and the gain exceeds $200, section 988 switches off. Filers then generally report the gain as a capital gain. Where the account is held for the production of income, section 988 governs and the gain is ordinary. Practitioners genuinely differ on borderline cases, so document your reasoning at the time.
Why Britain Gives You No Credit for These Gains
Now for the asymmetry that turns an accounting curiosity into a real bill. The United Kingdom does not tax this gain at all, which sounds like good news and is not.
Section 252 and the 2012 Change
From 6 April 2012, HMRC aligned foreign currency bank accounts with simple debts. The change covers individuals, trustees and personal representatives. As HMRC guidance at CG78320 confirms, such debts give rise to no chargeable gain in the hands of the original creditor. Nor do they produce an allowable loss. The governing provision is section 252 of the Taxation of Chargeable Gains Act 1992. The broader framework appears in HMRC's foreign currency manual at CG78300.
Put plainly, a UK resident pays no capital gains tax on foreign currency gains arising in a bank account. Meanwhile HMRC taxes your worldwide income and gains on the arising basis. Relief requires a claim under the foreign income and gains regime, as the general position on foreign income explains.
An Uncreditable Charge
The consequence follows directly. A foreign tax credit requires foreign tax, and here there is none. Therefore the ordinary treaty mechanics that protect most of your UK income cannot relieve the US charge. Foreign currency gains thus become one of the few genuinely uncushioned items in a cross-border return.
Understanding your credit position across all baskets consequently becomes essential. We cover how Americans in Britain stop wasting UK tax paid in detail elsewhere.
The Sourcing Rule That Can Rescue the Position
Fortunately the statute contains a provision that most commentary omits entirely, and for Americans living in Britain it changes the arithmetic materially.
Section 988(a)(3) and Your UK Tax Home
Section 988(a)(3) sources currency gain by reference to the residence of the taxpayer. For an individual, residence means the country in which the tax home sits, using the definition in section 911(d)(3). A US citizen with no tax home defaults to US residence.
Therefore an American whose tax home is genuinely London has foreign-source foreign currency gains, not US-source income. That single fact opens the door to credit relief that a US-source characterisation would slam shut.
Absorbing Credits in the Right Basket
Character and basket then determine whether the door actually helps. Net currency gain generally falls within passive category income. Section 954(c) treats such foreign currency gains as foreign personal holding company income. Consequently UK tax paid on your UK dividends, interest and other investment income can shelter the gain, subject to the usual limitation.
Importantly, an exception applies where the currency relates directly to business needs, which pushes the item into the general category instead. Accordingly the analysis is fact-specific and worth doing properly.
Why the Paperwork Decides the Outcome
Two preparers can reach opposite answers on identical facts, simply because one documented the tax home and the other did not. Therefore keep evidence of your UK residence position, your account purpose and your basis records. Ultimately the credit is only as good as the file supporting it.
Case Study: £1.5 Million Repatriated From London
A client of ours, an American partner in a London investment firm, received a £1,500,000 partnership distribution in September 2022. Sterling was weak, trading around 1.13 dollars, so his dollar basis was $1,695,000. He held the funds in an interest-bearing GBP deposit account alongside his UK portfolio.
The Conversion
In 2025 he converted the entire balance to dollars to fund a US property purchase, at an effective rate of 1.3175. He therefore received $1,976,250. His previous accountant reported the property purchase and nothing else, because no statement anywhere showed a gain.
The section 988 gain came to $281,250. Furthermore, because the account was held for the production of income rather than personal expenditure, the $200 relief was irrelevant twice over. Ordinary treatment applied at his marginal rate of 37%, producing a charge of $104,063.
The Rescue
Reviewing his position, we established that his tax home had sat in London throughout. That fact changed the sourcing of his foreign currency gains entirely. Consequently the gain was foreign-source under section 988(a)(3) and fell into his passive category. He held $46,000 of passive basket credits from UK tax on his investment income, carried forward and otherwise heading towards expiry.
Applying those credits reduced the bill from $104,063 to $58,063. Additionally, the exercise revealed the same issue in two earlier years, which we corrected before HMRC data reached the IRS.
What He Should Have Done
Timing was his real lever. Had he converted in tranches across two tax years, he would have spread the ordinary income across two credit limitations. Consequently he would have absorbed more of his carryforward. Notably, he would also have avoided pushing a single year into the top bracket.
Reporting, FBAR and Fixing Earlier Years
Getting the number right is only half the exercise. The reporting mechanics matter, and so does the position for years already filed.
Where the Gain Belongs on Your Return
Ordinary section 988 gain is reported as other income on Schedule 1 of Form 1040. Where the transaction is personal and the gain exceeds $200, the gain is generally reported on Schedule D instead. Therefore your characterisation of the foreign currency gains drives the form, and inconsistency across years invites questions.
Remember also that the foreign earned income exclusion does nothing for you here. It stands at $132,900 for 2026, per the IRS inflation adjustments for tax year 2026. Foreign currency gains are not earned income.
FBAR and Form 8938
The account holding the currency carries its own obligations. Aggregate balances above $10,000 at any point trigger the FBAR filing requirement, while higher thresholds apply under FATCA reporting on Form 8938. Our FBAR and FATCA service covers both. Notably the correct rate for each differs, as we explain in which exchange rate to use on your US and UK returns.
Correcting Past Years
Unreported foreign currency gains in closed-looking years are fixable. Where the omission was non-wilful, the IRS Streamlined Filing Compliance Procedures remain the standard route. Our IRS Streamlined Filing service handles the full three-year and six-year package. Alternatively, where returns were otherwise correct, an amended return may suffice.
A related trap deserves mention. Repaying or refinancing a sterling mortgage can produce its own gain, which we cover in the section 988 US tax trap on UK remortgages.
How TaxYork Can Help
We prepare US and UK returns for wealthy Americans in Britain, and currency work sits at the centre of that. Specifically, we reconstruct the dollar basis of every sterling tranche. Additionally we characterise each account correctly and evidence your tax home. Accordingly the resulting foreign currency gains land in the right basket, so available credits actually apply.
Furthermore we model conversion timing before you move the money, rather than explaining the consequences afterwards. Our cross-border planning service and our US tax return preparation work together on exactly this. Accordingly clients repatriating large sums come to us first, not at filing time.
Conclusion
Foreign currency gains are the quietest liability in a cross-border portfolio. They accrue invisibly, produce no statement, attract no UK tax and therefore no automatic credit, and surface only when you finally move serious money home. Nevertheless the rules reward anyone who engages with them early.
Three points carry most of the value. Your account is not marked to market, so timing is yours to control. The $200 relief is an all-or-nothing cliff that protects nothing substantial. Above all, your London tax home makes the gain foreign-source, which is frequently the difference between a full charge and a sheltered one. Ultimately, foreign currency gains reward preparation and punish discovery.
Contact Us
Speak to us before your next large conversion rather than after it. To review your sterling basis position and model the timing, book a consultation with our cross-border team.
Email hello@taxyork.com or call 020 3488 8606. Alternatively, contact us through the website and we will respond within one working day.
Disclaimer
This article provides general information about foreign currency gains for US persons resident in the United Kingdom and does not constitute tax advice. Tax treatment depends on individual circumstances and on legislation current at the date of publication, which may change. You should obtain professional advice before acting. TaxYork accepts no liability for action taken in reliance on this article.