Do I have to report the sale of my London home under the Streamlined Foreign Offshore Procedures?

Only if the sale year falls inside the three-year return window, meaning the three most recent tax years whose US due date has passed. In that case the gain, any Section 121 exclusion, depreciation recapture and mortgage exchange gain go on that streamlined return. If the sale was earlier, the procedure does not require that return, but the proceeds still appear on FBARs within the six-year window.

Is my London flat itself reported on Form 8938 or the FBAR?

No. The IRS comparison of Form 8938 and FBAR requirements confirms that foreign real property held directly is not reported on either form. The cash proceeds are different: once they reach a UK bank or investment account, that account is reportable on the FBAR if aggregate balances exceed $10,000, and counts towards Form 8938 thresholds for that year.

Does the Section 121 exclusion apply to a home in the UK?

IRS Publication 523 does not restrict the exclusion to US homes. A London main residence can qualify if you owned and used it as your main home for at least 24 months in the five years before sale. Up to $250,000 of gain is excludable for a single filer, or $500,000 for a married couple filing jointly, but depreciation from any letting period cannot be excluded.

Do I need a UK 60-day return if private residence relief covers my gain?

GOV.UK says you must report and pay any Capital Gains Tax due on UK residential property within 60 days of completion, and that a UK resident need not report gains online if total gains are below the tax-free allowance. Where private residence relief removes the whole gain there is usually no tax due, but a partly let home often leaves a chargeable portion that does need the return.

Is there a penalty for using the Streamlined Foreign Offshore Procedures after a property sale?

No. Eligible filers pay the tax shown on the streamlined returns plus statutory interest, and the IRS states they are not subject to failure-to-file, failure-to-pay, accuracy-related, information return or FBAR penalties. The 5% miscellaneous offshore penalty applies only to the Streamlined Domestic Offshore Procedures for US residents, not to UK-resident filers who meet the foreign residency test.

Can UK Capital Gains Tax paid on the sale reduce my US tax?

Usually, yes. UK Capital Gains Tax paid on the same gain is generally available as a foreign tax credit against the US tax on that gain, subject to the foreign tax credit limits. Keep the 60-day return, the HMRC computation and proof of payment. Because the US gain is measured in dollars and differs from the UK gain, the credit rarely matches the US liability exactly.

Streamlined Foreign Offshore: London Flat Sale Gain

Streamlined Foreign Offshore filers who sold a London flat during their unreported years must report that sale to the IRS only if it falls inside the three-year return window, but the cash proceeds will appear on every FBAR and Form 8938 in the six-year window regardless. That is the short answer. The IRS Streamlined Foreign Offshore Procedure (SFOP) lets a non-wilful American living in the UK catch up with three years of returns, six years of FBARs and a signed certification, paying any tax and interest due but no penalty. A home sale tests every part of that package at once: the gain itself, the Section 121 exclusion, any depreciation if the flat was let, a sterling mortgage redemption, and a sudden spike in account balances.

In the returns we prepare for UK-resident bankers, investors and business owners, the sale of a London home is one of the most common triggers for coming forward. This guide explains how the timing of the sale shapes the streamlined submission, what the information returns show, how the certification narrative should handle a large one-off gain, and where filers go wrong. We keep the gain computation itself deliberately short, because our separate guide comparing UK private residence relief with Section 121 and the Section 988 mortgage issue covers that in depth.

What is the Streamlined Foreign Offshore Procedure and who can use it?

The Streamlined Foreign Offshore Procedure is an IRS compliance route for US citizens, green card holders and other individual taxpayers who live outside the United States and whose failure to file returns, report income and file FBARs was non-wilful. The IRS describes non-wilful conduct as negligence, inadvertence, mistake, or conduct resulting from a good faith misunderstanding of the law.

The residency test for a US citizen or lawful permanent resident is specific. According to https://www.irs.gov/individuals/international-taxpayers/us-taxpayers-residing-outside-the-united-states, in any one or more of the most recent three years for which the US return due date (or properly applied for extended due date) has passed, the individual must not have had a US abode and must have been physically outside the United States for at least 330 full days. A banker who commuted heavily to New York needs to check day counts year by year.

The package itself has four parts:

Complete and accurate Form 1040 returns (or Form 1040-X amended returns) for the three most recent years whose due date has passed, with every required information return attached.
Delinquent FBARs for the six most recent years whose FBAR due date has passed, filed electronically through FinCEN's BSA E-Filing System.
A signed Form 14653 certification, including a narrative explaining why the failures were non-wilful.
Payment of all tax shown on the returns plus statutory interest. The IRS states that eligible filers are not subject to failure-to-file, failure-to-pay, accuracy-related, information return or FBAR penalties.

Each return is marked Streamlined Foreign Offshore in red at the top and submitted on paper. One point is worth stating plainly because it is often confused: the 5% miscellaneous offshore penalty belongs to the Streamlined Domestic Offshore Procedures, not the foreign version. A UK resident who qualifies for the Streamlined Foreign Offshore route pays tax and interest only.

Is the London flat sale inside the Streamlined Foreign Offshore three-year window?

This is the first question we answer on any file involving a property sale, because the answer changes the whole shape of the submission. The return window and the FBAR window are different lengths and are measured from different due dates.

The three-year return window covers the three most recent tax years whose return due date has passed. For a US person living abroad, the regular return due date is 15 April, with an automatic two-month extension to 15 June, and a further extension to 15 October if Form 4868 was properly filed. That matters right now. A submission made in early October 2026 by someone who did not extend their 2025 return would typically cover 2023, 2024 and 2025. Someone who properly extended 2025 to 15 October 2026 would, until that date passes, be looking at 2022, 2023 and 2024. Pin down the window before anyone computes a gain.

The six-year FBAR window covers the six most recent calendar years whose FBAR due date has passed. FBARs are due 15 April with an automatic extension to 15 October, according to https://www.irs.gov/businesses/small-businesses-self-employed/report-of-foreign-bank-and-financial-accounts-fbar. In practical terms, a submission this autumn reaches back roughly to 2019 or 2020.

That produces three distinct situations for a London home sale:

Sale inside the three-year return window: the gain, any exclusion, any depreciation recapture and any mortgage exchange gain must all be reported on the streamlined return for that year, and tax plus interest is paid with the package.
Sale inside the six-year FBAR window but before the three-year return window: the procedure does not require a return for the sale year, so the gain is not computed or paid under the streamlined submission. The proceeds still appear on the FBARs for the sale year and any later year in which they sat in UK accounts.
Sale before both windows: neither the return nor the FBARs for the sale year are part of the submission, although any proceeds still held in UK accounts show up in the later FBARs and Forms 8938.

The middle case deserves caution. The procedure asks for three years of returns, but under US law the assessment period for a year in which no return was filed does not begin to run. The procedure does not request the earlier years, but it is a framework, not a statutory closing agreement. Where a sale year sits just outside the window and the gain was large and clearly taxable, that is a factor to weigh, not to ignore.

How is the US gain computed in short?

We cover the comparison with UK relief in detail elsewhere, so this section is a compact reminder of the US mechanics that feed the streamlined return.

The US gain is measured in dollars. The purchase price is translated at the exchange rate when the flat was bought, and the sale proceeds at the rate when it was sold. That is why the US gain and the UK gain can differ sharply: a flat that rose in sterling can show a smaller dollar gain if the pound weakened, or a larger one if it strengthened.

The Section 121 exclusion then applies. IRS Publication 523 at https://www.irs.gov/publications/p523 allows a single filer to exclude up to $250,000 of gain, and a married couple filing jointly up to $500,000, where the owner both owned and used the home as a main residence for at least 24 months in the five years before the sale. The 24 months do not have to be a single block. The exclusion can be used only once in any two-year period. Publication 523 does not limit the exclusion to US homes, and in practice a London main residence qualifies on the same tests.

Two restrictions bite on homes that were let. First, any period after 2008 when the property was not used as a main residence is nonqualified use and reduces the excludable gain, except that a period after the last date the property was used as a main home is not treated as nonqualified use. A flat that was a home first and let afterwards, then sold within the five-year window, often escapes proration entirely. Second, the exclusion never covers depreciation.

What happens to depreciation recapture if the flat was let?

A US person who lets a London flat is required to depreciate it for US purposes, whether or not a return was ever filed. Publication 523 states that you cannot exclude the part of the gain equal to depreciation adjustments allowed or allowable after 6 May 1997. The word allowable is the trap. Unreported years do not erase the depreciation; the IRS treats it as taken whether or not it was claimed, and it reduces basis on sale.

That recaptured amount is taxed as unrecaptured section 1250 gain, at a maximum rate of 25%, as described in IRS Topic 409 at https://www.irs.gov/taxtopics/tc409. Residential property used predominantly outside the United States is depreciated under the alternative depreciation system rather than the standard system. If the letting years fall inside the three-year window, the streamlined returns also need the rental schedules for those years, with UK letting income, expenses and depreciation, which in turn feed the foreign tax credit.

Does a sterling mortgage redemption create a currency gain?

Often, yes. When a US person borrows in sterling and repays the loan after the pound has weakened against the dollar, the dollar value of what was repaid is lower than the dollar value of what was borrowed. The IRS treats the borrowing and repayment as a separate transaction from the purchase and sale of the home, so that difference can be a taxable exchange gain in the sale year, while an exchange loss on a personal home loan is generally not deductible. The character of the gain can turn on whether the property was a personal home or a let property at redemption. If the redemption falls in a return year, the gain belongs on that return. Our dedicated guide on the Section 988 mortgage issue walks through the computation.

How do the sale proceeds affect FBAR and Form 8938?

This is the part filers underestimate. The flat itself is not on either form. The IRS comparison table at https://www.irs.gov/businesses/comparison-of-form-8938-and-fbar-requirements confirms that foreign real property held directly is not reported on Form 8938 and is not reported on the FBAR. Property held through a foreign company is different, because the company interest becomes the reportable asset.

The moment completion money arrives in a UK bank account, however, it is cash in a foreign financial account, and both forms see it. FBAR maximum value is the highest balance during the calendar year, converted to dollars using the Treasury reporting rate for the last day of that calendar year, according to the FinCEN filing instructions. A completion account that held net proceeds for only three days still reports that peak.

Form 8938 has its own thresholds. Under the instructions at https://www.irs.gov/instructions/i8938, a single taxpayer living abroad files if specified foreign financial assets exceed $200,000 on the last day of the year or $300,000 at any time during the year; for married couples filing jointly the figures are $400,000 and $600,000. Many London homeowners were below these levels in ordinary years and crossed them only in the sale year. If that year sits inside the three-year return window, Form 8938 must be attached to the streamlined return, and filing it does not replace the FBAR.

List every account the proceeds passed through: the conveyancer's client account does not belong on your FBAR, but your receiving current account, savings accounts and any investment platform do.
Record each account's maximum value and the Treasury year-end rate published at https://fiscaldata.treasury.gov/datasets/treasury-reporting-rates-exchange/.
Check joint accounts with a non-US spouse: the American spouse reports the full account value on the FBAR.
Follow the money forward: if proceeds were invested in UK funds, the later years may raise separate reporting on those holdings.

What does a worked Streamlined Foreign Offshore scenario look like?

The following is an illustration only. The names, figures and exchange rates are assumed for teaching purposes and do not reflect any real client or actual historical rates.

Daniel is a US citizen working in investment banking in London. He has never filed a US return since moving to the UK. In June 2015 he bought a flat for £700,000 with a £400,000 sterling mortgage. He lived in it as his main home until December 2020, then let the whole flat until he sold it in September 2023 for £1,300,000, with £20,000 of selling costs. He is single and plans to submit in October 2026 without having extended his 2025 return, so his return window is 2023, 2024 and 2025, and his FBAR window reaches back to 2020.

US gain, at assumed rates of $1.55 to the pound on purchase and $1.25 on sale: cost $1,085,000; net proceeds £1,280,000, or $1,600,000. Assume depreciation allowed or allowable for the letting period of $75,000, giving an adjusted basis of $1,010,000 and a total gain of $590,000. The $75,000 depreciation portion cannot be excluded. Daniel used the flat as his main home for 27 of the 60 months before sale, so he passes the 24-month test, and the letting period came after his last use as a main home, so there is no nonqualified-use proration. He excludes $250,000, leaving $265,000 of long-term gain plus $75,000 of unrecaptured section 1250 gain on his 2023 return.

Mortgage, on the same assumed rates: borrowed £400,000, worth $620,000 in 2015; repaid £400,000, worth $500,000 in 2023. That is roughly a $120,000 exchange gain that must be analysed and reported on the 2023 return.

UK side, for comparison: Daniel owned the flat for 99 months, lived in it for 66, and the final 9 months always qualify for private residence relief, so 75 of 99 months are relieved. On a £580,000 UK gain, the chargeable portion is roughly £140,606. Letting relief does not help because he let the whole flat, as HMRC's helpsheet HS283 confirms. His UK accountant filed the 60-day return and paid the CGT. That UK tax is available as a foreign tax credit against the US tax on the same gain, subject to the usual limits.

Information returns: after redeeming the mortgage, about £880,000 arrived in Daniel's UK current account. At an assumed year-end Treasury rate of $1.27, the 2023 FBAR shows a maximum value of around $1,117,600 for that account, and his 2023 Form 8938 is required because his assets exceeded $300,000 during the year. His 2024 and 2025 returns carry the rental schedules up to sale only, investment income on the proceeds, and Form 8938 again if the balances stayed above the thresholds. Tax and interest for 2023 are paid with the package.

Change one fact. If Daniel had sold in 2021 instead, the sale year would fall outside his return window but inside the FBAR window. The gain would not be computed under the procedure, but the 2021 FBAR would still show the proceeds, and his narrative would need to describe the account history honestly.

How should the Form 14653 narrative treat a large one-off gain?

Form 14653 is the certification by a US person residing outside the United States for the Streamlined Foreign Offshore Procedures. The narrative is where the IRS decides whether the story is non-wilful, and a large property gain draws attention. In the narratives we prepare, three principles hold up best.

First, explain the facts, not the tax result. State when the taxpayer moved to the UK, what they understood about US filing, how the home was bought, financed, occupied and sold, and how the taxpayer learned of the obligation. Second, address the sale directly. A narrative that is silent about a seven-figure completion when the FBARs show a seven-figure balance looks evasive. A single factual paragraph acknowledging the sale, the UK reporting already made and the belief, if genuine, that a UK home sale fully taxed in the UK was a UK matter, is far stronger. Third, show conduct consistent with good faith: the UK 60-day return was filed, UK tax was paid, accounts were held in the taxpayer's own name and nothing was moved to conceal it.

What the narrative must not do is minimise. Phrases such as the gain was small or I had no reason to think it mattered contradict the numbers on the attached forms. If the facts suggest the taxpayer knew of the US obligation and chose not to file, the Streamlined Foreign Offshore route is the wrong route, and the certification should not be signed.

How are tax and interest paid with the streamlined package?

The IRS requires payment of all tax due on the streamlined returns plus statutory interest. For a US person abroad, interest runs from the original 15 April due date even though the filing date is automatically extended to 15 June. The IRS sets underpayment rates quarterly, published at https://www.irs.gov/payments/quarterly-interest-rates, and interest compounds daily. On a sale year two or three years back, interest is a meaningful line, and on a large gain it can be substantial.

Two points reduce surprises. Compute the foreign tax credit carefully, because UK CGT paid through the 60-day return is often the single biggest offset against the US tax on the gain, and the timing and currency of that credit must be right. Then pay in full with the submission. The IRS states that streamlined returns are processed like any other return and may be selected for examination under normal selection processes, as noted at https://www.irs.gov/individuals/international-taxpayers/streamlined-filing-compliance-procedures. A tidy, fully paid package is the best protection.

What does the UK side require for a UK resident selling a home?

For a UK resident, the UK disposal is usually already dealt with by the time the US question comes up. GOV.UK states at https://www.gov.uk/report-and-pay-your-capital-gains-tax/if-you-sold-a-property-in-the-uk-on-or-after-6-april-2020 that you must report and pay any Capital Gains Tax due on UK residential property within 60 days of completing the sale. The same page says that a UK resident does not need to report gains online if total gains are less than the tax-free allowance.

Private residence relief usually removes most or all of the UK gain on a main home. GOV.UK at https://www.gov.uk/tax-sell-home explains that there is no tax to pay where you have one home that you have lived in as your main home for all the time you owned it, have not let part of it out apart from to a lodger, have not used part of it exclusively for business, and the grounds are under 5,000 square metres. HMRC's helpsheet HS283 at https://www.gov.uk/government/publications/private-residence-relief-hs283-self-assessment-helpsheet confirms that the final 9 months of ownership always qualify where the property was your only or main residence at some point.

For the streamlined file, the UK paperwork is evidence as much as tax. The 60-day return, the payment reference and the completion statement prove the UK gain, support the foreign tax credit and show the good-faith conduct the narrative relies on.

Streamlined Foreign Offshore checklist for a London flat sale

Confirm SFOP eligibility: 330 full days outside the US and no US abode in at least one year of the window, and genuinely non-wilful conduct.
Fix the three-year return window and the six-year FBAR window on the actual submission date, taking any properly filed extension into account.
Place the sale year in one of the three situations: return window, FBAR window only, or neither.
Collect the purchase completion statement, sale completion statement, mortgage offer and redemption statement, and letting records.
Compute the dollar gain, Section 121 exclusion, depreciation allowed or allowable, and any mortgage exchange gain for a sale year inside the return window.
Gather the UK 60-day return, UK CGT computation and payment evidence for the foreign tax credit.
Trace the proceeds through every UK account and record year-end-rate maximum values for each FBAR.
Test Form 8938 thresholds for every return year, remembering that the flat is excluded but the cash is not.
Draft a factual Form 14653 narrative that addresses the sale directly.
Calculate tax and statutory interest and include payment with the paper package marked Streamlined Foreign Offshore.

Which failure modes do we see most often?

Assuming the UK private residence relief result carries across. It does not; the dollar gain, the 24-month test and depreciation all work differently.
Ignoring allowable depreciation because no US return was ever filed for the letting years.
Forgetting the mortgage. The redemption appears on the completion statement, and a currency gain can be larger than expected.
Leaving the completion account off the FBAR because the money moved on within days.
Missing Form 8938 in the sale year when ordinary years were below the threshold.
Miscounting the windows, especially when an extension was filed, so the wrong three years are prepared.
Writing a narrative that never mentions the sale while the attached FBARs show a seven-figure balance.
Treating the withdrawn Delinquent FBAR Submission Procedures as an alternative. The IRS removed that page around 1 July 2026; late FBARs now go through the BSA E-Filing System with a reason for late filing, or through the Streamlined procedures.