Estate and Investment Planning Around Receiving a Foreign Windfall
Estate investment planning, receiving a foreign windfall means treating two questions as one decision: what you must report to the IRS, and where the money should sit afterward. A large inheritance or gift from abroad is rarely taxable on arrival, but reinvesting it badly can create a decade of avoidable tax drag.
By the TaxYork Cross-Border Tax Team — reviewed by a US-UK dual-qualified adviser (CPA / Enrolled Agent).
Do I owe US tax on a foreign inheritance or gift?
No. Receiving a foreign inheritance or gift is not income to you under US law, so there is no federal income tax due simply because the money landed in your account. The obligation that follows is reporting, not tax, and missing that distinction is the single most common mistake we see in estate investment planning for those receiving a foreign windfall.
The IRS confirms that gifts and inheritances are excluded from the recipient's gross income, regardless of the source country.
(https://www.irs.gov/faqs/interest-dividends-other-types-of-income/gifts-inheritances/gifts-inheritances). What changes the picture is size. Once a foreign gift or bequest from a nonresident individual or estate exceeds $100,000 in aggregate for the year, Form 3520 becomes mandatory, and each gift over $5,000 must be itemized separately on that form (https://www.irs.gov/businesses/gifts-from-foreign-person).
Why the reporting threshold catches people off guard
Clients often assume that because no tax is owed, no form is needed. That assumption is wrong and expensive. Form 3520 is an information return, not a tax return, but the penalty regime attached to it is severe: 5% of the unreported foreign gift amount per month of delinquency, capped at 25% of the total. A £400,000 inheritance reported six months late could theoretically face a $50,000-plus penalty before any tax question even arises, because there was never any tax due in the first place — only a missed disclosure.
The threshold for gifts received from a foreign corporation or partnership is far lower: $20,116 for 2025 and $20,573 for 2026, as set out in the current Form 3520 instructions (https://www.irs.gov/instructions/i3520). Anyone receiving payouts from a foreign family company, rather than directly from an individual relative's estate, should check which threshold applies before assuming they are below the reporting threshold (https://www.irs.gov/forms-pubs/about-form-3520).
What is estate investment planning, and what is it really about?
At its core, estate investment planning for a foreign windfall is the process of correctly sequencing three tasks: filing the disclosure paperwork on time, understanding the tax basis you inherited, and choosing investment vehicles that don't create a second layer of hidden US tax. Skipping any one of the three tends to undo the benefit of the other two. Get the reporting wrong, and you invite penalties on money you never owed tax on. Get the basic question wrong, and you overpay capital gains tax for years. Get the reinvestment wrong — typically by parking the funds in UK collective investment vehicles — and you trade a one-off compliance headache for an ongoing PFIC filing burden.
The step-up in basis, most people don't realize they received
Under IRC §1014, inherited property generally receives a basis equal to its fair market value on the decedent's date of death (or the alternate valuation date if Form 706 was filed), converted to US dollars at that date's exchange rate (https://www.law.cornell.edu/uscode/text/26/1014). This applies whether the decedent was American, British, or any other nationality, and regardless of whether any US estate tax was ever due on the estate.
That step-up is valuable and easy to waste. If you inherit a London flat that was worth £600,000 at your mother's death and sell it two years later for £650,000, your US taxable gain is roughly £50,000, not the full appreciation since she originally bought it decades earlier. Clients who don't document the date-of-death valuation properly often end up reconstructing it years later from estate agent estimates, which is far weaker evidence than a contemporaneous appraisal.
Where should I actually invest a foreign windfall as a US person?
Cash sitting in a UK current account earning negligible interest is safe from a compliance standpoint but poor for growth. The mistake is jumping straight into UK-domiciled funds, OEICs, unit trusts, or a stocks-and-shares ISA, all of which are typically classified as Passive Foreign Investment Companies for US tax purposes. Careful estate investment planning, receiving a foreign windfall, means choosing US-compliant or US-domiciled investment wrappers from day one.
The PFIC trap in UK investment products
A PFIC triggers Form 8621 filing for every fund holding (https://www.irs.gov/forms-pubs/about-form-8621), and absent a timely QEF or mark-to-market election, the default "excess distribution" regime taxes gains at the highest marginal rate plus an interest charge that can wipe out years of real return. This is exactly the trap that catches windfall recipients who ask a UK financial adviser to "just invest it sensibly" without mentioning their US tax status. UK life insurance bonds carry a related mismatch: they usually fail the US definition of life insurance under §7702 and are treated as PFICs on the underlying funds, while the UK taxes them under the chargeable-event-gain regime with top-slicing relief. The two systems tax the same gain on different timelines, and only the Foreign Tax Credit on Form 1116 bridges the gap — imperfectly.
Comparing common windfall investment routes
Investment route
US tax treatment
UK tax treatment
Filing burden
UK OEIC / unit trust / ISA
PFIC — excess distribution regime unless elected
Tax-free in ISA wrapper; taxable outside it
Form 8621 per fund
UK investment bond
Fails §7702; PFIC on underlying funds
Chargeable event gain, top-slicing relief
Form 8621, Form 1116
US-domiciled brokerage account
Standard capital gains treatment
UK tax on worldwide income if UK resident
Standard Schedule B/D
Direct property (UK or US)
Standard capital gains on disposal
UK CGT/SDLT rules apply as usual
None beyond standard returns
How does the new UK inheritance tax residence rule affect what I do next?
From 6 April 2025, the UK replaced the old domicile-based test with a long-term residence test: anyone who is a UK tax resident for 10 of the previous 20 tax years is now exposed to UK Inheritance Tax on their worldwide assets, not just UK-situated ones (https://www.gov.uk/guidance/inheritance-tax-if-youre-a-long-term-uk-resident). This is a materially lower bar than the previous 15-of-20-year deemed-domicile rule (https://www.gov.uk/guidance/inheritance-tax-deemed-domicile-rules), and it catches long-term American expats who never considered themselves "UK domiciled" in the old sense.
A departure tail of up to ten years' continued IHT exposure applies even after leaving the UK, so anyone who received a windfall while UK resident and later moves away cannot assume the exposure ends the moment they board a flight. This is a key part of estate investment planning for anyone who has spent a decade or more living in Britain, receiving a foreign windfall.
UK nil-rate bands to factor into the plan
The UK nil-rate band remains £325,000 and the residence nil-rate band £175,000, both frozen until 5 April 2030, giving a combined £500,000 per individual or £1 million per married couple before UK IHT bites at 40% (https://www.gov.uk/inheritance-tax). The residence nil-rate band tapers by £1 for every £2 an estate exceeds £2 million, which matters if the windfall itself pushes your eventual estate over that threshold.
What happens if I don't report a foreign windfall to the IRS?
Late or missing Form 3520 filings attract the 5%-per-month penalty described above, and the IRS has been increasingly active in matching foreign wire transfers against filed returns. Recipients who also have unfiled FBARs or Form 8938 obligations from the account that received the windfall face compounding exposure, since FinCEN Form 114 covers any aggregate foreign account balance over $10,000 at any point in the year
(https://www.irs.gov/businesses/small-businesses-self-employed/report-of-foreign-bank-and-financial-accounts-fbar). Form 8938 thresholds run from $50,000 up to $600,000 depending on filing status and residence (https://www.irs.gov/forms-pubs/about-form-8938).
For someone who has fallen behind on filings and then receives a large foreign inheritance, cleaning up unfiled returns before receiving a foreign windfall through the Streamlined Filing Compliance Procedures (https://www.irs.gov/individuals/international-taxpayers/streamlined-filing-compliance-procedures) is usually the sensible first move, since it resolves three years of amended returns and six years of FBARs under a non-wilful certification before the new asset even shows up on a return. Anyone still working through backlogged filings should also consider catching up on FBARs before a large inheritance lands, so the windfall doesn't arrive into an already-exposed filing history.
How do I invest a windfall without triggering PFIC or double-tax problems?
The safest default is a US-domiciled brokerage account holding US-registered funds or individual securities, which avoids PFIC classification entirely and keeps reporting to the standard Schedule B and D. If UK residency requires some UK-based holdings, a Stocks and Shares ISA wrapper at least shelters the income from UK tax even though it remains fully taxable — and PFIC-exposed — on the US side.
SIPPs, pensions, and treaty relief
Unlike investment bonds and OEICs, a UK Self-Invested Personal Pension generally receives favorable treaty pension treatment under Articles 17 and 18 of the US-UK treaty, so windfall recipients who also hold UK pensions don't need to unwind those. The savings clause in that treaty still means that a US citizen is taxed on worldwide income regardless of residence, so treaty relief here works through the Foreign Tax Credit and specific pension articles rather than by exemption.
Sound estate investment planning, including receiving a foreign windfall, also means thinking ahead to what the windfall itself earns. The inheritance is tax-free on receipt, but every pound of interest, dividend, or capital gain it generates afterward is fully taxable income to a US person, and choosing the FEIE, FTC, or a mix of both to shelter that ongoing income is a separate decision from the windfall itself. For clients earning employment income abroad, too, sheltering income earned on your inherited assets alongside salary requires comparing Form 2555 (https://www.irs.gov/forms-pubs/about-form-2555) against Form 1116 (https://www.irs.gov/forms-pubs/about-form-1116) rather than assuming one always wins.
Case study: a windfall handled two different ways
A client we advised — a dual US-UK citizen based in Manchester — inherited £480,000 from her late father's estate in 2025, along with a smaller £22,000 distribution from a family company incorporated in Jersey. She filed Form 3520 on time, itemizing both amounts separately becausese the corporate distributioexceededd the lower foreign-entity threshold. Her solicitor had obtained a professional date-of-death valuation of the London property her father left her, which later saved her roughly £9,000 in US capital gains tax when she sold it eighteen months later, compared with an informal estimate that a cousin in a similar case had relied on.
Where she nearly went wrong was in reinvestment.
Her UK financial adviser recommended a stocks-and-shares ISA holding a spread of OEICs, unaware she held US citizenship. Correcting course before the first tax year-end avoided PFIC filings on a dozen fund holdings, and the funds were instead held in a US-domiciled brokerage account holding index funds, with a modest ISA allocation kept for genuinely UK-only savings. This is precisely the kind of case where estate planning and windfall planning overlap when moving to the UK, since her existing UK residency status shaped which reporting rules applied.
Does the reduced US estate tax exemption affect 2026?
No — and this corrects a persistent misconception. Earlier law would have reverted the federal estate and gift tax exemption to roughly $7 million per person in 2026. The One Big Beautiful Bill Act, signed 4 July 2025, instead permanently sets the exemption at $15 million per person ($30 million per married couple) from 1 January 2026, with inflation indexing from 2027 and the 40% rate above that threshold unchanged. The annual gift tax exclusion is $19,000 per recipient for 2026.
This matters for windfall planning in reverse: American relatives considering a lifetime gift rather than waiting for inheritance now have considerably more room before triggering their own US gift tax exposure, which can shape the timing conversation with a foreign relative planning to pass on assets. Broader cross-border tax planning should factor this permanent exemption level into any multi-generational transfer strategy involving both UK and US family members.
Talk to TaxYork about your foreign windfall.
If you've recently received, or expect to receive, a significant inheritance or gift from overseas, get the Form 3520 filing and the reinvestment strategy sorted together rather than in sequence. TaxYork's cross-border team handles the disclosure paperwork, correctly correctly values the step-up in basis, and structures the reinvestment to avoid PFIC and double-taxation traps from the outset. Contact us at hello@taxyork.com, call 020 3488 8606, or visit taxyork.com to arrange a review before you move any money.