Technical article
United States: How Many Forms a Trust Like This Files, and What a Missed One Costs
Over the life of that trust, what paperwork does it generate, and what does it cost if something is missed?
Imagine a family with a US$15 million trust run by a US trustee. Two grandchildren live abroad, and the trust holds an account at a bank in another country. These are example facts. Over the life of that trust, what paperwork does it generate, and what does it cost if something is missed?
The forms, by moment in the trust's life
| Form | What it reports | When |
|---|---|---|
| 709 | The gift that funds the trust, and the allocation of the skipping-tax allowance | When the gift is made |
| 1041 | The trust's yearly income tax return | April 15; extension of 5.5 months on Form 7004 |
| K-1 | Each beneficiary's share of the trust's income | With the 1041 |
| 8960 | The 3.8% investment tax | With the 1041 |
| 1042 and 1042-S | Tax held back on payments to heirs abroad | 1042 by March 15 |
| Foreign bank account report | Foreign accounts above US$10,000 in total | April 15, with automatic extension to October 15 |
| 8938 | Foreign financial assets of certain trusts above US$50,000 at year end or US$75,000 at any time | Tested at year end and during the year |
| 706 | The estate return at death, for estates over the US$15,000,000 allowance | After death, by the executor |
| 3520 and 3520-A | A foreign trust, its owner, payouts and yearly return | 3520 on the 15th of the fourth month, 3520-A on the 15th of the third |
| 8854 | An heir who gives up US citizenship | When citizenship is given up |
Not all apply to every trust. A domestic trust with no foreign accounts and no heirs abroad would file fewer. Forms 3520 and 3520-A come into play only if the trust is foreign for US tax. The Form 1041 instructions call for a return where the trust has any taxable income, gross income of US$600 or more, or a nonresident alien beneficiary.
What a missed one costs
Penalties differ by form.
| Missed item | Penalty in the sources |
|---|---|
| Form 1042 filed late | 5% a month, up to 25%, plus 0.5% a month for late payment, up to 25% |
| Tax not held back | The payer is liable for it |
| Foreign trust reports (3520) | The greater of US$10,000 or 35% of the gross amount reported |
| Foreign trust annual return (3520-A) | The greater of US$10,000 or 5% of the trust assets treated as owned |
| Foreign gifts reporting | 5% a month, up to 25% |
| Added after 90 days' notice | US$10,000 for each 30 days |
On the accuracy side, an underpayment penalty can rise from 20% to 40% in some cases. The 35% penalty is on the amount transferred or paid out, not on the tax, so it can be large compared with the tax itself.
Who files what
The trustee files most of these. The person who makes the gift files the gift return. The executor files the estate return. A US citizen heir abroad files the foreign bank account report and Form 8938 on the heir's own foreign accounts if the thresholds apply. Those are US$10,000 in total for the report, and US$200,000 at year end for Form 8938 for a single person living abroad.
You could
You could ask a trustee to give you a calendar of the forms the trust would file in a year, with the person responsible for each. You could ask which of the foreign-trust forms would apply under your plan, because those carry the largest penalties.
Which of these forms would your family find hardest to track? Share what has helped you. Someone else in the same position may find it useful.
Figures are estimates for planning, based on public data. Date read: October 2026.
Sources
- IRS Instructions for Form 1041 (A)
- IRS Instructions for Form 1042 (A)
- IRS Instructions for Form 3520 (A)
- Cornell LII 26 USC 6677 (A)
- IRS comparison of Form 8938 and the foreign bank account report (A)
- IRS expatriation tax page (A)
- IRS What's New estate and gift tax (A)
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