How to File Form 1042-S: IRIS, Deadlines, and Penalties

To file Form 1042-S, a withholding agent collects a valid W-8 from each foreign recipient, prepares one form per recipient per income type using the correct income code, tax rate, and exemption code, and submits the return to the IRS with a recipient copy by March 15 of the year after the income was paid. Agents with 10 or more information returns of any kind must file electronically; starting with tax year 2026 forms due in 2027, the IRS’s Information Returns Intake System (IRIS) is the only electronic portal, as the legacy FIRE system shuts down at the end of December 2026.¹

Who Has to File and When

A withholding agent is any person or entity that controls, receives, or has custody of an amount subject to withholding and can make the payment. Employers paying wages to foreign workers, banks and brokerages paying interest or dividends, universities disbursing scholarships or fellowships, and any business paying rent, royalties, or compensation to a non-U.S. person all qualify.¹

The obligation applies even when no tax was actually withheld because of a treaty exemption or a Code exception. If the income was U.S. source and the recipient was a foreign person, the form is required. File a separate 1042-S for each type of income paid to the same recipient: paying a foreign contractor both royalties and consulting fees calls for two forms, not one.¹

Both the IRS filing and the recipient copy are due March 15 of the year following the calendar year the income was paid. If March 15 falls on a weekend or legal holiday, the due date shifts to the next business day.²

What to Gather Before You Start

Accurate reporting depends on getting recipient data in hand well before March. You need the recipient’s legal name, permanent residence address, and a valid taxpayer identification number (a Social Security Number, Individual Taxpayer Identification Number, or Employer Identification Number). Without a TIN, applying treaty-based reductions or exemptions becomes far harder, and the IRS may challenge the withholding rate you used.

This information should come from the recipient’s W-8 form. A foreign individual claiming treaty benefits submits a W-8BEN. A foreign entity uses the W-8BEN-E. A foreign person whose income is effectively connected with a U.S. trade or business provides a W-8ECI.³ Have the correct W-8 on file before making any payment, because it determines both the withholding rate and the exemption codes you’ll enter on the 1042-S.

Check the W-8 Is Still Valid

A W-8BEN is generally valid from the date it is signed through the last day of the third succeeding calendar year. A form signed in June 2024, for example, expires on December 31, 2027.⁴ If any information on the form becomes incorrect before it expires, the recipient must notify you within 30 days and submit a new one. Moving to the United States, becoming a U.S. citizen or resident alien, or relocating outside the treaty country all invalidate the form. Filing a 1042-S based on an expired or inaccurate W-8 can expose you to liability for underwithholding.

Income Codes, Tax Rates, and Exemption Codes

Box 1 requires a two-digit income code identifying the payment type. Common codes include 01 for interest, 06 for dividends, and 12 for royalties. The IRS instructions list dozens of codes, and picking the most specific one matters because it ties directly to the expected withholding rate.¹ A mismatch between the income code and the rate reported will draw IRS attention.

The tax rate must be one of the IRS-approved rates, ranging from 0% to 37%. The default statutory rate on most U.S. source income paid to foreign persons is 30%, but treaties frequently reduce it. Rates below 10% take a leading zero on the form (for example, “04.00” for 4%).¹

When a payment is exempt or subject to a reduced rate, you also enter an exemption code. Code 04, for instance, signals a treaty-based exemption or reduction. Box 3a handles Chapter 3 exemptions (general withholding on foreign persons); Box 4a handles Chapter 4 exemptions (FATCA-related withholding on payments to certain foreign financial institutions and entities).¹ The exemption code has to match the documentation in your files.

Filing Electronically Through IRIS

Any withholding agent required to file 10 or more information returns during a calendar year must file them electronically. That threshold is an aggregate count across nearly all return types, including Forms 1042-S, 1099, W-2G, and others.⁵ Agents below the threshold often choose electronic filing anyway because it’s faster and produces an immediate confirmation.

For tax year 2025 forms due March 15, 2026, either IRIS or FIRE will work. For tax year 2026 forms due March 15, 2027, IRIS is the only option; FIRE permanently shuts down at the end of December 2026.¹ Agents who have been filing through FIRE need to plan the switch now.

Getting onto IRIS takes four steps. You need an Employer Identification Number. Each user must create an account and verify identity through the IRS’s online registration process. You then apply for an IRIS Transmitter Control Code, which is a separate credential from any FIRE TCC you may already hold. Once the TCC is assigned, you can sign in and file.⁶ IRIS accepts returns two ways: manual data entry through the portal or CSV upload for larger volumes. Both methods handle corrections and extension requests too.

Filing on Paper

Withholding agents who file fewer than 10 information returns across all form types may submit paper 1042-S forms by mail.⁷ Every paper submission must include Form 1042-T, the Annual Summary and Transmittal of Forms 1042-S, which acts as a cover sheet reporting the total number of forms, total income, and total tax withheld across all attached documents.⁸ File a separate 1042-T for each type of 1042-S you’re transmitting. Skipping the transmittal can cause the IRS to reject the whole package.

The IRS processes paper forms through optical scanning, so formatting matters. Avoid staples, paper clips, and adhesives that could jam the equipment. Mail the completed package to:

Internal Revenue Service
P.O. Box 409101
Ogden, UT 84201-0007⁹

Certified mail with return receipt gives you legal proof of both the mailing date and delivery, which matters if the IRS later questions whether you met the March 15 deadline. Keep a complete copy of everything you send.

Recipient Copies and Form 1042

You must provide Copies B, C, and D to the recipient so they can report their U.S. source income on their own return or claim a refund of over-withheld tax. The recipient’s TIN may be truncated on those copies for security.¹

Filing Form 1042-S is only half the obligation. You also file Form 1042, the Annual Withholding Tax Return for U.S. Source Income of Foreign Persons, by the same March 15 deadline. Form 1042 summarizes the withholding you reported across every 1042-S you filed and is how you remit or reconcile the withheld tax with the IRS.² The IRS specifically directs agents to reconcile the amounts on Form 1042 with all filed 1042-S forms, including those filed electronically, to avoid follow-up correspondence.¹⁰ If the numbers don’t match, expect a letter.

Electronic filers receive a confirmation number through whichever system they use. Paper filers rely on certified mail receipts. Keep filing records for at least three years.

If You Need More Time

If you can’t meet the March 15 deadline, submit Form 8809, Application for Extension of Time to File Information Returns. Filing it through the electronic system grants an automatic 30-day extension.¹¹ That buys time for the IRS filing only, not for delivering recipient copies.

To request extra time for the recipient statements, fax Form 15397, Application for Extension of Time to Furnish Recipient Statements, to the IRS Technical Services Operation at 877-477-0572 (or 304-579-4105 for international faxes). Do not mail it. The IRS must receive the request no later than the date the statements are due to recipients, and if approved, the extension is typically capped at 30 additional days.¹²

Fixing Mistakes After You File

Corrections happen on an amended 1042-S, not through a phone call to the IRS. Check the “Amended” box at the top of the form, enter all the correct information (not just the fields that changed), and include an amendment number: “1” for the first correction, “2” for the second, and so on. The amended form must carry the same unique form identifier that appeared on the original.¹

If you filed the original electronically, the correction must be filed electronically too. Paper corrections travel with a Form 1042-T like any other paper submission. When corrections change amounts you already reported on Form 1042, file an amended Form 1042 as well.¹ Catching errors quickly matters because the penalty for an incorrect return escalates the longer it stays uncorrected.

Penalties and Personal Liability

The IRS imposes separate penalties for failing to file Form 1042-S with the IRS (under IRC 6721) and for failing to furnish correct copies to recipients (under IRC 6722). Both are tiered by how quickly you correct the problem. For returns due in 2026, the per-return amounts are:¹³

Corrected within 30 days of the due date: $60 per return.
Corrected after 30 days but on or before August 1: $130 per return.
Corrected after August 1 or never filed: $340 per return.
Intentional disregard: $680 per return, or 10% of the total amount required to be reported, whichever is greater, with no annual cap.

Annual maximums apply at each tier and vary by business size, and intentional disregard has no cap.¹⁴

Filing penalties are not the biggest exposure. Under federal law, every person required to withhold tax on payments to foreign persons is personally liable for that tax, whether or not they actually withheld it.¹⁵ Pay a foreign contractor $100,000 and forget to withhold the required 30%, and you owe the IRS $30,000 out of your own funds. The statute does indemnify you against claims from the payee for amounts properly withheld, but it offers no protection when you fail to withhold in the first place. The 1042-S is the paper trail proving you handled the withholding correctly.

1
Internal Revenue Service. Instructions for Form 1042-S
2
Internal Revenue Service. Discussion of Form 1042, Form 1042-S and Form 1042-T
3
Internal Revenue Service. Instructions for Form 1042-S
4
Internal Revenue Service. Instructions for Form W-8BEN
5
Internal Revenue Service. Topic No. 801, Who Must File Information Returns Electronically
6
Internal Revenue Service. IRIS Working Group Meeting
7
Internal Revenue Service. Filing Information Returns Electronically
8
Internal Revenue Service. About Form 1042-T, Annual Summary and Transmittal of Forms 1042-S
9
Internal Revenue Service. Where to File – Forms Beginning With the Number 1
10
Internal Revenue Service. Instructions for Form 1042
11
Internal Revenue Service. About Form 8809, Application for Extension of Time to File Information Returns
12
Internal Revenue Service. Extension of Time to Furnish Statements to Recipients
13
Internal Revenue Service. Information Return Penalties
14
Internal Revenue Service. 20.1.7 Information Return Penalties
15
Office of the Law Revision Counsel. 26 USC 1461 – Liability for Withheld Tax