There is a small but expensive corner of the U.S. tax code where the IRS punishes you for what your foreign trustee did or did not do. If you are the U.S. owner of a foreign trust under the grantor trust rules, the trust has to file an annual information return with the IRS — and if it does not, the penalty falls squarely on you. The starting bid is 5% of the trust's gross value, with a continuation penalty that can climb to $50,000 if you let the clock keep running. That is the world of Form 3520-A, and it catches more taxpayers every year as cross-border families, dual citizens, and entrepreneurs with offshore retirement plans discover this filing exists only after a notice arrives.
This guide walks through who has to file, what the form does, the March 15 deadline that surprises almost everyone, the "substitute" filing rule that saves U.S. owners when foreign trustees refuse to cooperate, and the penalty regime under Section 6677 — including how to fight back when a penalty has already been assessed.
What Form 3520-A Actually Is
Form 3520-A is the Annual Information Return of Foreign Trust With a U.S. Owner. It is filed by the trust itself, not by the U.S. person. The form provides the IRS with a full picture of one specific kind of arrangement: a foreign trust that has at least one U.S. owner under the grantor trust rules of Sections 671 through 679.
In plain terms, a grantor trust is a trust where, for U.S. tax purposes, the income and deductions flow through to a particular person rather than the trust itself. Section 679 sweeps a wide net for foreign trusts: if a U.S. person transfers property to a foreign trust that has, or may have, a U.S. beneficiary, that U.S. person is treated as the owner of the portion of the trust attributable to the transferred property. That ownership status is the trigger for Form 3520-A.
The form contains three parts that the U.S. owner cares about most:
- The trust's income statement and balance sheet for the tax year, prepared under U.S. tax principles.
- The Foreign Grantor Trust Owner Statement, which the trust gives to each U.S. owner. This statement reports how much of the trust's income, gain, deduction, and credit the U.S. owner has to pick up on their own return.
- The Foreign Grantor Trust Beneficiary Statement, which the trust gives to any U.S. beneficiary who received a distribution during the year. Without this statement, distributions are presumed to come from accumulated income and may be subject to the throwback tax and the punitive interest charge under Section 668.
Form 3520 and Form 3520-A often get talked about as if they were the same return, but they have different purposes. Form 3520 is filed by the U.S. person who creates a foreign trust, owns one, receives a distribution from one, or receives a large foreign gift or bequest. Form 3520-A is filed by the trust to back up what the U.S. owner is reporting. Most U.S. owners of a foreign grantor trust will end up filing both — Form 3520-A through the trust, and Form 3520 on their own.
Who Has to File
The duty to file Form 3520-A sits with the foreign trust. In practice that means the trustee. But the IRS does not chase foreign trustees, especially trustees who sit in jurisdictions outside U.S. enforcement reach. Instead, it puts the consequence on the U.S. owner.
Under Section 6048(b), every U.S. person who is treated as the owner of any portion of a foreign trust is required to ensure that the trust files Form 3520-A and furnishes statements to U.S. owners and U.S. beneficiaries. If the trust does not file, the U.S. owner is personally liable for the penalty.
You can be a U.S. owner without realizing it. Common situations include:
- A U.S. resident or citizen who set up an offshore family trust before or after moving to the United States.
- A green card holder who is the grantor of a trust in their home country and is now subject to U.S. worldwide taxation.
- An entrepreneur who transferred startup equity, intellectual property, or rental real estate into a foreign holding trust to support estate planning back home.
- A beneficiary of certain foreign retirement or savings plans that the IRS classifies as trusts rather than pensions. Some Canadian RRSPs and many foreign retirement vehicles outside the U.S. tax treaty network can fall into Form 3520-A territory.
- A founder who is treated as the owner of a foreign employee benefit trust under Section 679 because of contributions tied to U.S. employees or beneficiaries.
If you are in any of these patterns and you have not heard the words "Form 3520-A" before, it is worth a careful review.
The March 15 Deadline That Trips Everyone Up
Most U.S. tax deadlines run on the April 15 calendar. Form 3520-A does not. It is due on the 15th day of the third month after the end of the trust's tax year — March 15 for a foreign trust with a calendar-year tax year. That is the same date that S corporations and partnerships file their returns, and it is one of the most common reasons U.S. owners miss it: they wait for their personal return to come together, then realize the trust filing was already late by a month.
There is a built-in safety valve. The trust can request an automatic six-month extension by filing Form 7004 by the original March 15 due date, which pushes the filing to September 15. Form 7004 must include the foreign trust's Employer Identification Number. Many foreign trusts do not have an EIN, and getting one as a non-U.S. entity takes longer than people expect, so this is a step to start early — ideally before the first filing year, not the week of the deadline.
The Form 3520 the U.S. owner files for themselves is due on a different date — April 15, with extensions matching the owner's personal extension. Mismatched deadlines are part of why these two forms slip through so often.
When the Foreign Trustee Will Not Cooperate: Substitute Form 3520-A
Foreign trustees are often unwilling, sometimes unable, and occasionally unaware that they should be filing a U.S. tax form. They may view U.S. reporting as a breach of duty to other beneficiaries, a privacy violation, or simply outside their fee scope. None of those reasons protect the U.S. owner.
The IRS gives the U.S. owner an escape hatch: the substitute Form 3520-A. Here is how it works in practice:
- The U.S. owner prepares a Form 3520-A as best they can, using whatever financial records they can obtain from the trust — bank statements, trustee accountings, custodial reports, or their own contribution records.
- The substitute Form 3520-A is attached to the U.S. owner's Form 3520, not filed separately.
- The substitute is due when the U.S. owner's Form 3520 is due — generally April 15, or the extended due date, not the trust's March 15.
- The U.S. owner completes and attaches the Foreign Grantor Trust Owner Statement and, if relevant, the Foreign Grantor Trust Beneficiary Statement for any U.S. beneficiaries who received distributions.
Done correctly, the substitute filing fully satisfies the Section 6048(b) reporting duty even though the trustee has not filed anything. Done incompletely or late, it does not, and the penalty regime kicks in. A common mistake is to file Form 3520 by the personal return deadline but forget to attach the substitute 3520-A — that omission re-opens the door for a Section 6677 penalty even though the rest of the package was on time.
If you do file a substitute Form 3520-A with your Form 3520, do not also send a separate Form 3520-A. The IRS is explicit: a duplicate filing is unnecessary and can introduce mismatches in the case file.
Section 6677 Penalties: How the Math Works
This is where the form earns its reputation. Section 6677 creates a layered penalty for failures connected to Form 3520-A:
- Initial penalty: 5% of the gross value of the portion of the trust assets treated as owned by the U.S. owner at the end of the year, if Form 3520-A is not filed on time, or is filed without the required information, or contains incorrect information.
- Continuation penalty: $10,000 per 30-day period (or fraction of a period) after the IRS mails a notice of failure to comply, capped so total penalties do not exceed the gross reportable amount.
- Cap on aggregate penalty: not more than the gross reportable amount. If the IRS cannot determine the gross reportable amount, the penalty floor is $10,000.
A small example makes this concrete. Suppose a U.S. owner is treated as the owner of $400,000 worth of trust assets and forgets to file Form 3520-A for one tax year. The 5% initial penalty is $20,000. If the IRS later sends a notice and the owner does not respond within 90 days, the continuation penalty starts running at $10,000 per 30-day period — up to the $400,000 ceiling. Multi-year non-compliance compounds quickly and is a common feature of disclosure cases.
The penalty is not automatic. Section 6677(d) provides that no penalty applies if the failure is due to reasonable cause and not willful neglect. The Internal Revenue Manual instructs examiners to consider the facts and circumstances, including the taxpayer's experience with U.S. tax matters, reliance on a qualified tax professional, the trustee's refusal to cooperate, and the steps the taxpayer took to come into compliance once they learned of the issue. Reasonable cause is established case by case; saying "I did not know" is rarely enough on its own, but a paper trail showing genuine effort to obtain records, professional advice, and prompt action when the issue surfaced is often persuasive.
Cleaning Up Past Non-Compliance
Many people first learn about Form 3520-A while reviewing prior returns with a new accountant, after a financial institution sends an FBAR-related letter, or after a divorce or inheritance forces a closer look at offshore structures. There are three main paths to come back into compliance:
- Delinquent international information return submission procedures. If you have a reasonable-cause explanation, no unreported income, and are not under examination, you can file the missing forms with a reasonable-cause statement and ask the IRS not to assess a penalty. This is the lightest path and is the right tool for many ordinary cases.
- Streamlined filing compliance procedures. For taxpayers whose non-compliance was non-willful and who also have unreported foreign income, the streamlined procedures provide a structured way to file three years of returns and six years of FBARs with a five-percent miscellaneous offshore penalty for domestic filers (and no penalty for qualifying expat filers).
- IRS Criminal Investigation Voluntary Disclosure Practice (Form 14457). Reserved for taxpayers whose conduct may be willful. This path is significantly more expensive and slower, but it preserves protection from criminal prosecution that the other paths do not provide.
The wrong path can be as damaging as no action at all. Submitting through streamlined procedures when conduct was actually willful can convert a closeable case into a criminal one. Filing under the delinquent procedures without a sound reasonable-cause story can lead to automatically assessed penalties that are harder to fight after the fact. This is one of the areas where investing in a one-hour consult with an international tax attorney before filing pays back many times over.
Practical Documentation That Saves You Later
The IRS expects a U.S. owner to be able to defend the numbers on Form 3520-A even if the trustee never participates. A handful of habits make this defensible:
- Keep U.S.-format books for the trust. Translate balances into U.S. dollars at year-end rates, classify income under U.S. tax principles (rather than the local tax code of the trust's situs), and reconcile to bank statements.
- Document trustee correspondence. Save every request you made for trust accountings, every response or refusal, and every legal opinion you received. This file is the backbone of any reasonable-cause argument.
- Track contributions and distributions in real time. A simple ledger that records each contribution, each distribution, the recipient, the date, and the U.S. dollar value at the spot rate is enough. Do not wait for year-end to assemble this from memory.
- Coordinate Form 3520-A with Form 3520 and FBAR. A U.S. owner of a foreign trust often has signature authority over the trust's foreign accounts, which triggers an FBAR (FinCEN Form 114). The three filings should tell the same story. Mismatched numbers between them is one of the top triggers for follow-up correspondence.
Plain-text accounting is a good fit for this kind of bookkeeping. A complete year of trust activity can live in a single human-readable file, every transaction is timestamped and version-controlled, and currency conversions are explicit. When the IRS asks "how did you arrive at that number?", a plain-text ledger answers the question without anyone having to reconstruct a spreadsheet from scratch.
Keep Your Cross-Border Records Audit-Ready
Form 3520-A is one of those filings where the cost of being slightly disorganized is wildly disproportionate to the cost of being slightly more careful. The taxpayers who handle it well are the ones who treat the foreign trust like a small business that happens to live abroad — separate books, separate ledger, separate paper trail — rather than as a vague offshore arrangement that they revisit each spring.
If you are working through the substitute filing path, building a multi-year compliance package, or just trying to set up a clean process going forward, your records are the entire game. Beancount.io gives you plain-text accounting that is transparent, version-controlled, and AI-ready — exactly what you want when you have to defend a foreign trust filing two or five years after the fact. Get started for free and see why developers, finance professionals, and cross-border families are switching to plain-text accounting.