Can I use the IRS yearly average exchange rate for everything in my streamlined filing?

No. The IRS yearly average table is a reasonable proxy for the prevailing rate on income earned evenly through the year, such as salary, but FBAR and Form 8938 values must be converted at the Treasury rate for the last day of the year. Share and property purchases and sales, and repayments of sterling debt, should be translated at the spot rate on each transaction date. Foreign taxes follow the separate rules in section 986.

Which exchange rate do I use to convert my UK account balances on the FBAR?

FinCEN's instructions require you to find each account's maximum value in pounds during the calendar year, then convert it using the Treasury rate for the last day of that calendar year, published by the Bureau of the Fiscal Service. The year-end rate applies even if the balance peaked months earlier. Round up to the next whole dollar, and if no Treasury rate is available, use another verifiable rate and state its source.

How do I turn P60 figures for a UK tax year into US calendar-year income?

The UK tax year runs from 6 April to 5 April, so a P60 covers parts of two US tax years. Rebuild January to December sterling totals from monthly payslips, or use year-to-date figures at 5 April and 31 December, placing bonuses in the month actually paid. Only after calendar-year sterling totals are established should you apply your chosen exchange rate method for the US return.

Is paying off my UK mortgage a taxable event for US purposes?

It can be. Under section 988, a US person owing a sterling-denominated debt has a foreign currency transaction. If the pound weakened between drawdown and repayment of principal, the dollar cost of repaying is lower than the dollar amount borrowed, creating an exchange gain. Where sterling strengthened, the resulting loss on a personal home loan is generally not deductible. The section 988(e) $200 personal exception covers currency dispositions, not mortgage repayments.

Why does my UK share sale show a gain on my US return when HMRC shows a loss?

US gains are computed in dollars. Your basis is the sterling cost converted at the exchange rate on the purchase date, and your proceeds are the sterling price converted at the rate on the sale date. If the pound strengthened against the dollar while you held the shares, the dollar proceeds can exceed the dollar basis even when the sterling price fell, producing a US-only phantom gain that HMRC never sees.

SFOP: Converting UK Pound Figures to US Dollars Correctly

Q: How is UK income tax converted for the US foreign tax credit?

Under section 986 and Publication 514, cash-method taxpayers translate UK tax at the exchange rate on the date it was paid, so PAYE deductions and Self Assessment payments each use their own date. Taxpayers claiming the credit on an accrual basis generally use the average rate for the year to which the tax relates. Pub 514 describes the accrual choice as made on a timely filed original return, which needs review for delinquent streamlined returns.

A Streamlined Foreign Offshore Procedures submission has to be prepared entirely in US dollars, even though almost every source document a US person living in the UK holds is in pounds sterling. The short answer is that different parts of the package use different conversion rules: income on the three delinquent or amended returns is translated at the rate prevailing when you received or paid each item (a consistently applied yearly average rate is widely used for evenly earned income), while FBAR and Form 8938 maximum values are converted at the US Treasury rate for the last day of the year. Get those rules mixed up and a filing that should be clean can contain figures that do not reconcile.

This guide is written for bankers, investors and business owners in London and elsewhere in the UK who are preparing a catch-up of three years of US returns and six years of FBARs. In the returns we prepare, currency translation is rarely the headline issue, but it is the area where the most avoidable inconsistencies appear. Below we set out each rule, the official source for it, a worked illustration with clearly labelled assumed rates, and the documentation trail we recommend keeping behind the Form 14653 certification.

What does the Streamlined Foreign Offshore Procedures submission actually contain?

The IRS page for US taxpayers residing outside the United States, at https://www.irs.gov/individuals/international-taxpayers/us-taxpayers-residing-outside-the-united-states, sets out the core package. For a US citizen or green card holder, eligibility requires, in at least one of the most recent three years, that you did not have a US abode and were physically outside the United States for at least 330 full days. The submission then consists of:

Delinquent or amended US income tax returns for each of the most recent 3 years for which the return due date (or properly extended due date) has passed, with all required information returns such as Form 8938, Form 5471 or Form 8621.
Delinquent FBARs (FinCEN Form 114) for each of the most recent 6 years for which the FBAR due date has passed, filed electronically through the BSA E-Filing System.
Form 14653, the Certification by U.S. Person Residing Outside of the U.S., including a narrative explaining why the failures were non-willful.
Payment of all tax due plus applicable statutory interest.

Every one of those documents carries dollar figures derived from sterling records: P60s, P11Ds, SA302 tax calculations, ISA and brokerage statements, bank statements, mortgage statements and completion statements on property. The IRS notes that taxpayers who comply with the procedure are not subject to failure-to-file, failure-to-pay, accuracy-related, information return or FBAR penalties, which is exactly why the numbers inside the package need to be defensible if the submission is ever reviewed.

Which exchange rate should you use on the US tax returns?

The governing principle sits on the IRS page Foreign currency and currency exchange rates, at https://www.irs.gov/individuals/international-taxpayers/foreign-currency-and-currency-exchange-rates. It tells individuals to use the exchange rate prevailing when you receive, pay or accrue the item, and where more than one rate exists, to use the one that most properly reflects your income. Publication 54, at https://www.irs.gov/publications/p54, confirms that amounts reported on a US return must be expressed in US dollars and that foreign currency income and expenses must be translated.

The IRS also publishes a table of yearly average currency exchange rates at https://www.irs.gov/individuals/international-taxpayers/yearly-average-currency-exchange-rates. Two points on that page matter. First, the IRS states that it has no official exchange rate and generally accepts any posted exchange rate that is used consistently. Second, the table is quoted as units of foreign currency per US dollar, so you divide the sterling amount by the rate to arrive at dollars. Multiplying by mistake is one of the most common errors we correct in self-prepared drafts.

Yearly average rate is best understood as a practical proxy for the prevailing rate when income arrives in roughly equal instalments across the year. A spot rate is the rate on a specific date. In practice we apply them like this:

Monthly salary paid evenly through the year: a consistently applied yearly average rate is a reasonable reflection of the rates prevailing when each payment was received.
Large one-off receipts such as a bonus paid in March, a carried interest distribution or a special dividend: translate at the spot rate on the date received, because an annual average may not properly reflect that income when sterling moved sharply during the year.
Sale proceeds and purchase costs of shares, funds or property: translate each leg at the spot rate on its own trade or completion date.
Interest and ordinary dividends credited periodically: yearly average is usually acceptable if applied the same way in all three years.
Foreign taxes for the foreign tax credit: follow the specific statutory rules in section 986, covered below, rather than defaulting to whatever rate you used for income.

The consistency point matters more in a streamlined filing than in an ordinary year. The IRS will see three years side by side. A method that switches between average and spot rates from year to year without a reason looks like rate shopping, even when the net tax difference is small.

How are FBAR maximum values converted from pounds?

The FBAR follows a different and much more mechanical rule. The FinCEN FBAR line item filing instructions, at https://www.fincen.gov/sites/default/files/shared/FBAR%20Line%20Item%20Filing%20Instructions.pdf, describe a two-step process. Step one is to determine the maximum value of each account in the currency of that account during the calendar year; the maximum value is a reasonable approximation of the greatest value of currency or non-monetary assets in the account, and periodic statements may be relied on if they fairly reflect that maximum. Step two is to convert that sterling maximum into dollars using the Treasury rate for the last day of the calendar year.

Those Treasury Reporting Rates of Exchange are published by the Bureau of the Fiscal Service at https://fiscaldata.treasury.gov. The critical consequence is that the December 31 rate applies even if the account peaked in February when sterling was worth considerably more or less. If no Treasury rate is available, the instructions direct you to use another verifiable exchange rate and provide its source. Dollar amounts are rounded up to the next whole dollar, and if the computed value is negative the maximum account value is entered as zero.

Two practical traps come up repeatedly for UK filers. The first is using the IRS yearly average rate on the FBAR because it was already in the spreadsheet for the returns. The second is converting each monthly balance at its own spot rate and picking the highest dollar figure; the instructions require identifying the maximum in sterling first and only then converting at the year-end rate. Remember too that because the streamlined package covers six FBAR years but only three return years, the first three FBAR years will have no matching return, so the year-end rates for those years need to be sourced and documented separately.

What conversion rules apply to Form 8938 in an SFOP filing?

Form 8938 is attached to each of the three returns where you exceed the filing threshold. The instructions at https://www.irs.gov/instructions/i8938 require the US Treasury Bureau of the Fiscal Service foreign currency exchange rate for purchasing US dollars on the last day of the tax year, and that year-end rate is used even if the asset was sold or disposed of before the last day of the year. If no Treasury rate exists, you must use another publicly available rate and disclose it on the form. There is also an exception allowing you to rely on the conversion rate shown in a financial account statement issued at least annually by the institution maintaining the account.

For taxpayers who meet the presence abroad test, the instructions set the thresholds at more than $200,000 at year end or more than $300,000 at any time during the year for unmarried filers, and more than $400,000 at year end or more than $600,000 at any time for married couples filing jointly. Because thresholds are tested in dollars, a weaker or stronger pound at December 31 can move a UK portfolio across a threshold even when its sterling value barely changed. Filing Form 8938 does not replace the FBAR, and the FBAR does not replace Form 8938, so the same ISA or brokerage account often appears on both, converted under two sets of instructions that happen to point to the same year-end Treasury source.

How do you split UK tax-year figures into US calendar years?

This is the gap we see least well covered anywhere, and it affects almost every UK employee. The UK tax year runs from 6 April to 5 April, as explained on GOV.UK at https://www.gov.uk/self-assessment-tax-returns, while the US tax year for individuals is the calendar year. A P60 for the year ending 5 April therefore straddles two US years, and an SA302 tax calculation does the same.

The correct approach is to rebuild calendar-year sterling totals before any conversion takes place:

Salary and bonus: use monthly payslips for January to December, or take the final payslip of the calendar year and subtract year-to-date figures at 5 April. Do not simply take three quarters of one P60 and one quarter of the next, because bonuses are rarely spread evenly.
Benefits in kind shown on a P11D: allocate by the period in which the benefit was provided where records allow, and document the method where they do not.
UK dividends and interest: use actual payment dates from broker and bank statements, which are already dated and easy to place in the right US year.
Capital gains: use trade dates, not the UK tax year in which the gain was reported to HMRC.
UK income tax: separate PAYE deducted in each calendar month from balancing payments and payments on account made under Self Assessment, because each is paid on a different date.

Only once calendar-year sterling figures exist should the conversion method be applied. Converting P60 totals first and apportioning dollars afterwards blends two different rate periods and makes the workpapers impossible to follow.

How should UK tax paid be converted for the foreign tax credit?

For most UK-resident US persons, the foreign tax credit on Form 1116 is what keeps the US liability low, so the translation of UK tax matters. Section 986(a) of the Internal Revenue Code, at https://www.law.cornell.edu/uscode/text/26/986, draws a line between two methods. For a taxpayer who takes foreign income taxes into account when accrued, the taxes are translated at the average exchange rate for the taxable year to which they relate. For other foreign taxes, including those of a cash-method taxpayer, section 986(a)(2) requires translation at the exchange rate as of the time the taxes were paid.

Publication 514, at https://www.irs.gov/publications/p514, puts this in practical terms. Cash-method taxpayers use the rate in effect on the date the foreign taxes were paid. Taxpayers claiming the credit on an accrual basis generally use the average rate for the year to which the taxes relate, provided the taxes are paid after the start of that year and within 24 months after its close, and are not in an inflationary currency. Pub 514 also explains that accrued foreign tax is generally fixed on the last day of the foreign tax year, which for a UK individual is 5 April, not December 31.

Two streamlined-specific points follow. Publication 514 describes the choice to claim the credit on an accrual basis as made by checking the Accrued box on Form 1116 on a timely filed original return. Delinquent returns in an SFOP package are, by definition, not timely, so whether an accrual choice can be made for those years should be reviewed carefully before building the credit computation around it. Second, if HMRC later refunds or adjusts UK tax that has been credited, Pub 514 treats that as a foreign tax redetermination that generally requires notifying the IRS through an amended return with a revised Form 1116, and section 986(a)(2) specifies that a refund is translated at the rate at the time of the original payment.

Can repaying a UK mortgage create a taxable currency gain?

Yes, and it surprises nearly every client we explain it to. Section 988 of the Code, at https://www.law.cornell.edu/uscode/text/26/988, treats becoming the obligor under a debt instrument denominated in a non-functional currency as a section 988 transaction. For a US person whose functional currency is the dollar, a sterling mortgage on a London home is exactly that. If the pound weakens between the date the loan is drawn and the date principal is repaid, fewer dollars are needed to extinguish the debt than were originally borrowed, and the difference is a foreign currency gain.

The event that realises that gain is repayment of principal, which includes a full redemption when a home is sold and, in our experience, a remortgage that pays off the old lender. Regular monthly repayments also reduce principal and can produce small gains or losses each year. The reverse position is less generous: where sterling has strengthened, the result is an exchange loss on a personal-use loan, and an individual's losses are generally deductible only in the business, profit-seeking and casualty categories set out in section 165(c), so a loss on a home loan is generally not usable.

The personal transactions exception in section 988(e) is often cited as a way out, but it is narrow. It applies to the disposition of foreign currency by an individual in a personal transaction, and it removes gain from exchange rate movements only where the gain on that transaction does not exceed $200. It does not mention losses, and it is framed around disposing of currency rather than repaying debt. We therefore do not assume it shelters a mortgage repayment gain; it is relevant mainly to converting modest amounts of spending money.

Why can a UK share sale produce a phantom US gain?

Because the IRS rule is to translate each item at the rate prevailing when it is paid or received, the dollar cost basis of a UK investment is fixed at the rate on the purchase date, and the dollar proceeds are measured at the rate on the sale date. The US gain or loss is the difference between those two dollar figures. When the pound moves materially between purchase and sale, the US result can differ sharply from the sterling result HMRC sees, and occasionally a sterling loss becomes a US gain. That is what practitioners call a phantom gain: real for US tax purposes, invisible in the UK.

The same mechanism applies to a sale of UK property, UK funds and shares held in an ISA, which has no special status under US rules. For investment fund holdings, the passive foreign investment company rules add their own layer on Form 8621, but each dollar computation still starts from correctly dated exchange rates. Keeping contract notes and completion statements that show exact dates is essential, because a yearly average rate cannot be used to establish a basis that arose on a single day.

Worked illustration: one year of a streamlined catch-up

The following is an illustration only. The client, balances and every exchange rate below are assumptions chosen to show the mechanics; they are not actual IRS or Treasury rates for any year. Rates are expressed, like the IRS and Treasury tables, as pounds per one US dollar.

Assumed facts: a US citizen investment banker in London. Calendar-year salary rebuilt from payslips is 236,000 pounds, paid evenly. The largest ISA balance during the year was 410,000 pounds in June. Shares bought for 50,000 pounds were sold during the year for 48,000 pounds. A sterling mortgage of 400,000 pounds was fully redeemed on a home sale.
Salary: assumed yearly average rate 0.78. 236,000 divided by 0.78 gives about $302,564 of wages for the return.
FBAR: assumed Treasury rate on December 31 of 0.79. The June peak of 410,000 pounds divided by 0.79 is $518,987.34, reported rounded up as $518,988, even though the rate in June was different.
Form 8938: the same ISA year-end value is converted at the same assumed December 31 Treasury rate, and the maximum value uses that year-end rate too.
Share sale: assumed purchase-date spot rate 0.80, so the dollar basis is 50,000 divided by 0.80, or $62,500. Assumed sale-date spot rate 0.70, so proceeds are 48,000 divided by 0.70, or about $68,571. HMRC sees a 2,000 pound loss; the US return shows a gain of about $6,071.
Mortgage: assumed rate on drawdown 0.62, so the loan was worth about $645,161. Assumed rate at redemption 0.75, so repaying 400,000 pounds of principal cost about $533,333. The exchange gain of about $111,828 is a section 988 gain, reported separately from any gain on the house itself, before considering any other provisions that may apply to the property sale.

Three different rate bases appear in one tax year of one client: an annual average for evenly earned wages, a year-end Treasury rate for the FBAR and Form 8938, and transaction-date spot rates for the investment and the debt. None of those is optional, and all of them need a documented source.

How do you keep the conversions consistent across the Form 14653 package?

Form 14653 is a certification signed under penalties of perjury that you are eligible and that your failures were non-willful. The IRS is entitled to test that certification against the returns and FBARs submitted with it. If the same ISA appears at one dollar figure on the FBAR and a very different, unexplained figure on Form 8938, or if investment income is converted three different ways across three years, the package invites questions that have nothing to do with willfulness but can still slow or complicate the review. The failure mode we see most often is not a wrong rate; it is several preparers or spreadsheets each using a different right rate with no record of which one.

Build one reconciliation workbook covering all six FBAR years and three return years, with a rate tab listing every rate used, its date and its source URL.
Record sterling first, then dollars, so any figure can be traced back to a statement.
Tie each FBAR account to its Form 8938 line where it appears on both, and note why values differ if they do, for example a statement-rate exception on Form 8938.
Keep payslips, P60s, SA302s, HMRC statements of account, broker contract notes and mortgage redemption statements together by year.
Write the Form 14653 narrative in plain factual language that matches the figures, and do not describe balances in approximate terms that conflict with the FBARs.
Apply the same translation method to the same type of income in all three years unless a documented change in facts justifies otherwise.

Late FBARs within the package are filed through FinCEN's BSA E-Filing System at https://bsaefiling.fincen.treas.gov with the streamlined reason for late filing selected. The older delinquent FBAR submission page is no longer available on IRS.gov, so do not rely on outdated guides that describe it as a separate live route.

Key takeaways for UK-based filers

A clean Streamlined Foreign Offshore Procedures submission from a sterling life comes down to applying the right rule to the right figure. Income on returns follows the prevailing-rate principle, with yearly averages for evenly earned items and spot rates for lumpy ones. FBAR and Form 8938 values use Treasury year-end rates. Foreign taxes follow section 986. Debt and investments are measured at transaction-date rates, which is where phantom gains and section 988 mortgage gains come from. UK tax-year figures must be rebuilt into calendar years before conversion. Document every rate once, use it everywhere it belongs, and the dollars in your package will tell the same story as the pounds in your records.