Form 3520 Foreign Inheritance Reporting: 25% Penalty Risk
Form 3520 foreign inheritance reporting explained: how US heirs of UK estates and family trusts avoid penalties of up to 25%. Book a confidential review.
The gift that files itself late
A UK inheritance or family gift received by a US citizen is, in almost every case, not taxable income in the United States. What is taxable is silence. If the amount received from a non-US individual or estate exceeds the reporting threshold and Form 3520 is not filed on time, the IRS can assess a penalty of 5% of the gift for each month it goes unreported, capped at 25% of the entire amount.
Why a tax-free gift becomes a 25% problem
The United States does not tax the recipient of a gift or inheritance. The donor's estate may be taxed, the assets may generate taxable income once received, but the act of receiving is not an income event. Section 102 of the Internal Revenue Code puts it plainly: gross income does not include property acquired by gift, bequest, devise or inheritance.
That principle is what lulls otherwise careful people into a very expensive mistake. A US citizen living in London inherits £1.8 million from a British grandmother. Her accountant confirms, correctly, that there is no US income tax to pay. Nobody mentions that a separate information return was due, and that the penalty for missing it is calculated as a percentage of the inheritance itself rather than of any tax owed.
Congress created that regime in section 6039F of the Code, which requires a US person who receives large gifts or bequests from foreign persons to report them, and imposes a penalty where they do not. The mechanics are unforgiving: 5% of the gross reportable amount for each month the failure continues, to a maximum of 25%. On a £1.8 million inheritance, a filing that is never made can theoretically expose the recipient to a penalty measured in the hundreds of thousands of pounds on money that carried no tax liability whatsoever.
This is one of the most common and most avoidable failures we see in transatlantic families. It is also, importantly, one of the most fixable — provided it is addressed before the IRS raises it.
What Form 3520 actually reports
Form 3520, the Annual Return To Report Transactions With Foreign Trusts and Receipt of Certain Foreign Gifts, is not one form. It is four separate reporting regimes bolted onto a single document, and a wealthy cross-border family can easily trigger three of them in the same year.
- Part I — transfers by a US person to a foreign trust, including funding a UK settlement or a Jersey or Guernsey structure.
- Part II — a US person treated as the owner of any part of a foreign trust under the grantor trust rules, which pairs with Form 3520-A.
- Part III — distributions received by a US person from a foreign trust, including a UK family discretionary trust or a will trust created by a British parent.
- Part IV — receipt of large gifts or bequests from foreign persons: the inheritance from a non-US grandmother, the deposit from an overseas parent toward a London house purchase.
Only Part IV is the classic inheritance filing. The others are where the numbers escalate, because the penalty regime that applies to foreign trust transactions is harsher still.
What are the Form 3520 reporting thresholds?
Two thresholds matter, and they are structured very differently depending on who the donor is.
| Source of the gift or bequest | Reporting threshold | Aggregation rule |
|---|---|---|
| Non-resident alien individual or foreign estate (a British parent, grandparent, or the estate of a deceased UK relative) | More than $100,000 in the tax year | Aggregate all gifts from that person and from related foreign persons; once over the threshold, itemise each gift above $5,000 |
| Foreign corporations or foreign partnerships, including certain entities used by family offices | Approximately $20,000, indexed annually for inflation | Aggregate all such gifts in the year; each must be separately identified |
| Distributions from a foreign trust | No de minimis threshold — any distribution is reportable | Reported in Part III regardless of size |
The $100,000 figure is not indexed for inflation and has not moved in decades, which means it now captures a very large number of ordinary UK estates. A modest London flat left to an American child will exceed it comfortably.
Note also the aggregation trap. A UK father who gives $60,000 and a UK mother who gives $60,000 in the same year have jointly triggered the threshold, because gifts from related parties are combined. Families who split gifts between spouses to stay under the limit are frequently in exactly the position they were trying to avoid.
How the penalty is actually calculated
The penalty structures differ sharply by part of the form, and understanding which one applies to your facts is the difference between a manageable problem and a catastrophic one.
| Failure | Statutory penalty | Practical exposure |
|---|---|---|
| Failure to report a foreign gift or bequest (Part IV) | 5% of the gross reportable amount per month, capped at 25% | Up to 25% of the inheritance itself, not of any tax |
| Failure to report a transfer to, or distribution from, a foreign trust (Parts I and III) | Generally the greater of $10,000 or 35% of the gross reportable amount | 35% of the distribution received |
| Failure to file Form 3520-A for a foreign trust with a US owner | Generally the greater of $10,000 or 5% of the gross value of trust assets treated as owned by the US person | Assessed against the US owner, annually |
| Continued failure after IRS notice | Additional monthly penalties may accrue | Compounds an already large figure |
Two features make this regime unusually dangerous for high-net-worth clients. First, the penalty base is the amount received rather than the tax avoided — and there is usually no tax avoided at all. Second, under section 6501(c)(8), the failure to file a required international information return can hold the statute of limitations open on the recipient's entire tax return, not merely the unreported item, until the information is supplied. A missed Form 3520 in a prior year can therefore leave every line of that year's Form 1040 open to examination indefinitely.
Has the IRS changed its approach to automatic penalties?
Yes, and it matters. The IRS historically issued systemic, automatically generated penalty notices the moment a late Form 3520 was processed, before any human being read the taxpayer's reasonable cause statement. That practice drew sustained criticism from the National Taxpayer Advocate, who documented very high abatement rates on appeal — which is another way of saying most of those penalties should never have been assessed in the first place.
The IRS has announced that it would stop automatically assessing penalties on late-filed Form 3520 Part IV foreign gift filings, and would instead review reasonable cause statements before assessment. This is a meaningful procedural improvement, but it is not an amnesty. The penalty statute is unchanged, trust-related failures under Parts I to III have been treated differently, and a taxpayer who files late without a properly constructed reasonable cause position remains exposed.
There has also been significant litigation over whether certain international information return penalties are assessable — that is, whether the IRS may simply post them to your account, or must instead bring a civil action to collect. The law in this area has moved in both directions in recent years and remains unsettled. It is a defence to be argued by counsel, not a filing strategy to be relied upon.
The UK side: why HMRC is not the problem, and where it is
UK inheritance tax operates on the opposite principle to the US information regime. IHT is charged on the estate of the deceased, not on the beneficiary. A UK beneficiary receiving a legacy has no filing obligation and no personal tax to pay; the executors settle IHT before distribution. There is no UK equivalent of Form 3520 for an ordinary inheritance.
That asymmetry is precisely why the trap catches people. A British family's advisers do everything correctly under UK law, the estate pays what it owes, and the American beneficiary receives a clean distribution — with nobody in the chain having any reason to mention a US information return.
| Issue | United States (IRS) | United Kingdom (HMRC) |
|---|---|---|
| Who is taxed on an inheritance | Nobody on receipt; the estate is taxed if the decedent was US-connected | The estate, before distribution |
| Beneficiary filing obligation | Form 3520 where the threshold is exceeded; information only | None for a straightforward legacy |
| Penalty for beneficiary non-filing | Up to 25% of the amount received for gifts and bequests | Not applicable |
| Lifetime gifts | Reportable by the US recipient above the threshold; no US tax on receipt | Potentially exempt transfers, generally falling out of the estate after seven years |
| Family trusts | Foreign trust regime: Forms 3520 and 3520-A, throwback rules on accumulated income | Relevant property regime: ten-year anniversary charges and exit charges |
| Base cost on death | Step-up to fair market value generally available under section 1014, including for foreign assets | Uplift to probate value for capital gains tax purposes |
Where HMRC does become relevant is in the UK's shift from domicile to a long-term residence test for inheritance tax from April 2025. Families who assumed a British relative's non-UK assets sat outside the IHT net need that assumption re-tested, particularly where the deceased had been resident in the UK for a substantial part of the preceding two decades. Our trusts and estate planning team reviews these positions alongside the US reporting analysis, because the two questions are almost never separable in practice.
Why UK family trust distributions are the real exposure
A one-off inheritance is a single reporting event with a known number. A UK family trust is a recurring obligation with compounding consequences, and it is where we see the most serious damage.
The classic fact pattern: a British family established a discretionary settlement decades ago for the benefit of children and grandchildren. One grandchild is a US citizen — perhaps by birth in the United States, perhaps through an American parent, sometimes without ever having lived there. The trustees, in Jersey or in London, make an annual distribution. From a UK perspective this is entirely orthodox. From a US perspective, three distinct problems arise simultaneously.
1. The distribution must be reported, with no de minimis threshold
Every distribution from a foreign trust to a US beneficiary is reportable in Part III of Form 3520, however small. There is no $100,000 shelter here. A £5,000 school-fees payment made directly by trustees to a school on a US grandchild's behalf is a reportable distribution, and so is the rent-free use of trust-owned property.
2. Accumulated income triggers the throwback rules
Where a foreign non-grantor trust has accumulated income in prior years, distributions to a US beneficiary can be recharacterised as an accumulation distribution of undistributed net income. The throwback rules then tax that income by reference to the beneficiary's historic rates and add a non-deductible interest charge for the period of deferral. Long-established UK family trusts frequently hold decades of accumulated income, and the interest charge on a large distribution can approach or in extreme cases exceed the distribution itself.
3. Without proper trustee statements, the default method applies
If the trustees do not provide a Foreign Grantor Trust Beneficiary Statement or a Foreign Nongrantor Trust Beneficiary Statement, the beneficiary must generally apply a punitive default calculation that treats a substantial portion of the distribution as an accumulation distribution regardless of the trust's actual income history. Persuading offshore trustees to produce US-format statements is often the single highest-value piece of work in these engagements, and it needs to happen before the distribution is made, not after.
Add the underlying investments — UK unit trusts, OEICs and investment companies are typically passive foreign investment companies for US purposes — and a single trust distribution can generate Form 3520, Form 8621, Form 8938 and an FBAR obligation in the same year. Our cross-border tax planning practice models the combined effect before anything is paid out.
How do you fix a Form 3520 that was never filed?
The remediation route depends on whether income was also unreported, and this distinction drives everything that follows.
- Information return missed, income correctly reported. Where the only failure is the missing Form 3520 — the classic inheritance case, since the inheritance itself is not income — the usual route is a delinquent information return filing with a robust reasonable cause statement attached, explaining why the failure was due to reasonable cause and not to wilful neglect.
- Information return and income both missed. Where the inherited assets generated unreported income, or where trust distributions carried taxable amounts, the Streamlined Foreign Offshore Procedures may be available to qualifying non-resident US taxpayers, submitting amended or delinquent returns together with the missing forms.
- Wilfulness in issue. Where the facts suggest the failure was not innocent, neither route is appropriate and the matter should move to counsel before anything at all is filed.
The quality of the reasonable cause narrative is not a formality. It is the entire case. A statement that says the taxpayer did not know is materially weaker than one documenting reliance on a qualified UK adviser, the absence of any US tax due, the taxpayer's broader compliance history, and the promptness of the corrective filing once the obligation was discovered. We build these as evidenced submissions, and our private client tax team treats them accordingly.
When is Form 3520 due?
Form 3520 is generally due on the date of the recipient's income tax return, including extensions — so an individual on extension to 15 October has until 15 October. Critically, it is filed separately from the Form 1040 and posted to the IRS service centre in Ogden, Utah. It does not travel with your tax return, and filing your 1040 on time does nothing to protect a Form 3520 that was sent late or to the wrong address. Form 3520-A, filed by or on behalf of the foreign trust, carries an earlier deadline in March.
Planning ahead: what wealthy transatlantic families should be doing now
Nearly every Form 3520 disaster we remediate was preventable with a conversation that never happened. The practical steps are straightforward.
- Tell the family early. British parents and grandparents planning gifts to an American child or grandchild should understand the reporting consequence before the money moves, not after.
- Time gifts deliberately. Because the threshold is applied per tax year and per related-donor group, the sequencing of large lifetime gifts is a genuine planning variable.
- Audit the trust deed for US beneficiaries. A US-connected beneficiary changes the analysis for the whole structure, and in some cases exclusion or restructuring is the cleaner answer.
- Secure trustee statements in advance. Agree with trustees, in writing, that US-format beneficiary statements will be produced for every distribution.
- Document the source and character of every receipt. Distinguish a bequest from a trust distribution from a loan; the reporting consequences diverge sharply, and contemporaneous paperwork is what proves the distinction years later.
For families holding assets on both sides of the Atlantic, this sits within a wider structuring conversation covering estate tax treaty relief, situs planning and the interaction between UK inheritance tax and US estate tax. Our high-net-worth advisory practice addresses these together rather than in isolation, and further technical material is available in our guides library.
The point to hold on to
Form 3520 is an information return. It raises no tax, produces no liability and, filed on time, costs nothing but attention. Filed late, or not at all, it converts a tax-free inheritance into a penalty assessed on the inheritance itself. The asymmetry between the cost of compliance and the cost of failure is as extreme as anything in the US tax code, and it falls hardest on people who did nothing wrong except receive money from a family that was not American.
If you have received a UK inheritance, a substantial family gift, or any distribution from a British or offshore family trust — whether last month or ten years ago — we will review your position in confidence and tell you plainly what needs to be filed and what, if anything, is genuinely at risk. Speak to our US-UK cross-border tax team for a discreet, no-obligation consultation before the IRS raises the question for you.
