When Is Form 3520 Due? Deadlines, Extensions, and Penalties

The Form 3520 due date is April 15 for calendar-year individual filers, the same day your Form 1040 is due, even though Form 3520 is a separate paper return mailed to its own IRS address.¹ If you extend your individual return with Form 4868, the Form 3520 deadline shifts automatically to October 15. U.S. citizens and residents living and working abroad get an automatic run to June 15. Miss the deadline entirely and the penalties start at the greater of $10,000 or a percentage of the reportable amount, so the date matters here in a way it doesn’t for most IRS forms.

The Standard April 15 Deadline

Form 3520 is due by the 15th day of the fourth month after the end of your tax year.¹ For anyone on a calendar year, that means April 15. When April 15 falls on a Saturday, Sunday, or legal holiday, the deadline rolls to the next business day.

The form is not attached to your Form 1040. It is a standalone information return, mailed on its own to a designated IRS service center, and the IRS treats the postmark as your filing date. Filing on time therefore depends on getting the envelope into the mail stream by the due date with proof you can produce later.

If You Live Abroad

U.S. citizens and residents whose tax home and abode are outside the United States get an automatic two-month extension, moving the deadline to the 15th day of the sixth month, which is June 15 for calendar-year filers.² You don’t file anything to claim the two extra months. The date simply applies.

How to Extend Form 3520

Form 3520 has no extension form of its own. You extend it by extending your underlying income tax return. Individuals file Form 4868 by April 15 to push Form 3520 to October 15.¹ Partnerships, corporations, and other entities that extend their business returns with Form 7004 receive the same automatic extension for Form 3520.

The extension is only for filing. Form 3520 is a disclosure return, so extending it doesn’t change any tax payment obligations on your underlying return. And it doesn’t stand alone: the extension form has to be postmarked by the original April 15 due date. If Form 4868 or Form 7004 is late, Form 3520 has no extension either.

Where and How to Mail It

Form 3520 still cannot be filed electronically. The complete paper return goes to the IRS service center in Ogden, Utah:³

Internal Revenue Service
P.O. Box 409101
Ogden, UT 84409

Because timeliness depends on the postmark, use a method that gives you dated proof. Certified or registered mail through the U.S. Postal Service works. If you use a private carrier instead, only IRS-designated services count for the timely-mailing rule. The approved carriers are DHL Express, FedEx, and UPS, but only specific service levels within each qualify.⁴ Standard ground shipping from any of them is not on the list.

Completeness also matters. Depending on your situation, Form 3520 may require a Foreign Grantor Trust Owner Statement, a Foreign Trust Beneficiary Statement, or both.² Sending the form without a required statement can be treated the same as not filing at all, and penalties begin accruing from the original due date.

Form 3520-A Has a Different Deadline

If you also have obligations under Form 3520-A, the companion return filed by (or on behalf of) a foreign trust with a U.S. owner, don’t assume the April 15 date carries over. Form 3520-A is due on the 15th day of the third month after the end of the trust’s tax year, meaning March 15 for a calendar-year trust.⁵

Extending your personal return does not extend Form 3520-A. To push its deadline, you must file Form 7004 by March 15 using the foreign trust’s own employer identification number.⁵ Filing Form 4868 for yourself has no effect on the trust’s separate obligation. If the foreign trust doesn’t file at all, the U.S. owner can attach a substitute Form 3520-A to their own Form 3520, which then travels on the Form 3520 deadline.

What a Missed Deadline Costs

Form 3520 penalties are steep, and they apply even when no tax is owed on the underlying transaction. The amount depends on which reporting obligation you missed.

For failing to report a transfer to a foreign trust or a distribution received from one, the penalty is the greater of $10,000 or 35% of the gross reportable amount.⁶ On an unreported $200,000 distribution, that is a $70,000 penalty even if the distribution itself is not taxable.

For the annual owner reporting obligation, the same statute substitutes 5% for 35%, with the $10,000 floor still in place.⁶

For failing to report a large foreign gift, the penalty is 5% of the gift’s value for each month the failure continues, capped at 25%.² A $500,000 foreign gift that goes unreported for five months hits the 25% cap and produces a $125,000 penalty.

There is a second, quieter consequence. Not filing Form 3520 keeps the statute of limitations open. The IRS has at least three years from the date you eventually provide the required information to assess tax connected to the unreported items, and if you never file, the assessment window never closes.⁷

Reasonable Cause

Penalties can be abated if you show reasonable cause. The statement must be in writing, signed under penalties of perjury, and must lay out the specific facts and circumstances that prevented timely filing. One argument the IRS explicitly rejects: that a foreign country would penalize you for disclosing the information.⁸

Options If You’ve Already Missed the Deadline

If you discover you should have filed in a prior year and didn’t, two IRS programs offer a way back into compliance.

Delinquent International Information Return Submission Procedures

DIIRSP is designed for taxpayers who missed an information return but are otherwise in compliance. You can’t use it if you’re under civil examination or criminal investigation, and the IRS must not have already contacted you about the missing return.⁹

For a delinquent Form 3520 or 3520-A, you file it under the form’s normal instructions rather than attaching it to an amended return.⁹ You can include a reasonable cause statement, but the IRS may still assess a penalty initially and require you to defend the reasonable cause claim separately. DIIRSP is a path to compliance, not a guaranteed penalty waiver.

Streamlined Filing Compliance Procedures

If your failure was non-willful and you have broader offshore issues (unreported income, missing FBARs, or other unfiled information returns), the streamlined procedures may fit better. They are available only to individuals, including estates, and require a certification that the failure was due to negligence, inadvertence, mistake, or a good-faith misunderstanding of the law.¹⁰

Under the domestic version, you pay a miscellaneous offshore penalty equal to 5% of the highest aggregate value of your foreign financial assets during the covered period, and in exchange the IRS waives information return penalties, accuracy-related penalties, and FBAR penalties.¹¹ Taxpayers who qualify for the foreign-resident version have even the 5% penalty waived. The streamlined route is closed if you are already under examination or criminal investigation.¹⁰

For a single overlooked Form 3520 with no unpaid tax behind it, DIIRSP is usually the simpler path. For a tangled situation with unreported income, unfiled FBARs, and missing information returns, the streamlined procedures offer a more comprehensive resolution.

1
Internal Revenue Service. Instructions for Form 3520 (12/2025)
2
Internal Revenue Service. Instructions for Form 3520
3
Internal Revenue Service. Where to File – Forms Beginning With the Number 3
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Internal Revenue Service. Private Delivery Services (PDS)
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Internal Revenue Service. Instructions for Form 3520-A (Rev. December 2025)
6
Office of the Law Revision Counsel. 26 USC 6677 – Failure to File Information Returns With Respect to Certain Foreign Trusts
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Office of the Law Revision Counsel. 26 USC 6501 – Limitations on Assessment and Collection
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Internal Revenue Service. Failure to File the Form 3520/3520-A – Penalties
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Internal Revenue Service. Delinquent International Information Return Submission Procedures
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Internal Revenue Service. Streamlined Filing Compliance Procedures
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Internal Revenue Service. U.S. Taxpayers Residing in the United States