Form 1120-F instructions for foreign corporations in the US

Form 1120-F is the US income tax return for a foreign corporation with specified US activity or income. For a 2025 calendar-year filer, the main 2026 deadline is April 15 with a US office or June 15 without one. Missing a timely return can cost ECI deductions.

File Form 1120-F when a foreign corporation has a US trade or business, certain US-source income, a refund claim, or a required treaty position. A protective return can preserve deductions if US business status is uncertain.

IRS statistics track active Form 1120-F corporations by industry, but those figures do not determine whether one company must file. The IRS SOI Table 10 records historical Form 1120-F return data.

Foreign-company structures can also create owner-level reporting. See TFX’s guide to offshore corporation benefits and disadvantages and its overview of business structures for expats before treating entity-level Form 1120-F as the only US filing question.

The IRS forms and instructions library is the controlling place to check the current form revision before filing.

The following 3 groups are the main readers for this guide:

• Foreign corporations selling goods or services into the United States.
• Foreign corporations with US employees, offices, property, partnerships, or withholding.
• Advisers and owners reviewing treaty, refund, protective-return, or branch-tax exposure.

What is Form 1120-F?

Form 1120 F is the IRS return for a foreign corporation’s US income-tax position. For 2025, it can report US-source income, ECI, deductions, credits, refunds, treaty disclosures, and Section 884 branch taxes. The IRS uses the return to determine US tax or refund.

For broader entity-level reporting, TFX’s foreign company tax reporting guide explains how Form 1120-F differs from owner information returns.

Entity classification can also change the analysis, so review the Form 8832 entity classification election when classification is uncertain.

The following 4 reporting buckets capture the form’s main purposes:

• Income, including non-ECI US-source amounts and ECI.
• Gains and losses, including items treated as effectively connected.
• Deductions and credits allowed against ECI when filing rules are met.
• Tax, refund, treaty-disclosure, and branch-tax amounts.

Form 1120-F separates income categories because ECI and non-ECI US-source income can face different tax rules.

 

IRS purpose: Form 1120-F reports income, gains, losses, deductions, credits, US income-tax liability, refunds, treaty disclosures, and Section 884 taxes when applicable.

A French software company that sends employees to perform implementation work in New York can have a US trade-or-business question even though it was incorporated in France.

Its filing analysis turns on the US activities, income classification, and any treaty protection.

What is a foreign corporation for US tax purposes?

For US federal tax purposes, a corporation is foreign if it is not created or organized in the United States or under US or state law. Form 1120-F can still apply when that foreign entity has a US trade or business, US-source income, or another filing trigger.

The IRS corporation forms and instructions provide current corporate filing materials.

TFX’s guide to US tax rules for resident and nonresident aliens covers individuals, which is a separate classification question from whether a legal entity is a foreign corporation.

The following 4 entity examples can be foreign corporations if their US tax classification is corporate:

• A UK private limited company.
• A German Aktiengesellschaft.
• A French société anonyme.
• A Canadian corporation organized under provincial or federal law.

Foreign incorporation does not mean “no US filing.” A Canadian corporation with no US owners can still need Form 1120-F if its own US business activities or income trigger the filing rules.

Who must file Form 1120-F under US rules?

A foreign corporation generally files Form 1120-F if it was engaged in a US trade or business during 2025, even without ECI. Filing can also be required for certain US-source income, refund claims, treaty positions, or qualified derivatives dealer status under the IRS instructions.

The IRS SOI Table 11 shows historical Form 1120-F returns with net income, but filing is not limited to profitable companies.

TFX explains the wider non-US-person framework in whether foreigners pay US taxes.

A dormant company can still have separate owner-reporting issues. TFX’s dormant foreign corporation guide addresses that distinction.

The following 7 conditions should be checked before deciding that no Form 1120-F is required:

• The entity is a foreign corporation for US tax purposes.
• It was engaged in a US trade or business during the year.
• It had income, gain, or loss treated as ECI.
• It had US-source income not fully satisfied by withholding.
• It is claiming a refund of overwithheld or overpaid US tax.
• It takes a treaty position that requires Form 8833 disclosure.
• It was, or had a branch that was, a qualified derivatives dealer.

A single US trade-or-business finding can create a filing duty even when the corporation reports no taxable ECI.

 

Mini flowchart: Foreign corporation → US trade or business? If yes, file. If no → refund, treaty disclosure, QDD, or underwithheld US-source income? If yes, file. If no → test the specific IRS exception before treating the return as unnecessary.

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How effectively connected income (ECI) determines your tax responsibility

ECI is generally taxed to a foreign corporation on a net basis at the 21% corporate rate for 2025, after permitted deductions. Non-ECI US-source FDAP income is generally taxed at 30% gross unless an exemption or treaty rate applies. The classification changes both tax and reporting.

TFX’s ECI tax guide explains the connected-income rules in more depth.

For passive US-source amounts, its FDAP income guide covers the separate withholding framework.

For 2025, ECI is generally subject to 21% corporate tax after deductions, while non-ECI FDAP is generally subject to 30% gross withholding absent treaty relief.

 

The following 2 tests commonly determine whether US-source income becomes ECI under Section 864(c):

• Asset-use test: US assets materially contribute to producing the income.
• Business-activities test: US business activities are a material factor in producing the income.

US employees performing revenue-producing services can support a US trade-or-business finding.

Inventory sales can also create ECI depending on sourcing and activities, while FIRPTA rules generally treat gain from US real property interests as ECI.

For tax years beginning after December 31, 2024, Section 174A allows a current deduction for domestic research expenditures.

A corporation can instead elect capitalization and amortization over at least 60 months, subject to the 2025 transition rules.

 

Filing deadlines with submission options

For a 2025 calendar-year foreign corporation, the regular Form 1120-F deadline is April 15, 2026 with a US office or June 15, 2026, without one. A qualifying corporation with a US office can use the separate Regulations Section 1.6081-5 extension to June 15.

TFX’s estimated tax payment due-date guide helps with separate payment timing.

Its filing extension guide explains general extension concepts, but Form 1120-F uses corporate rules rather than the individual Form 4868 process.

Deadline summary: US office – April 15, 2026 regular due date. No US office – June 15, 2026 regular due date. Extensions depend on the corporation’s facts and do not all follow the same payment rule.

The following 4 dates or actions belong on the filing calendar:

1. Original due date: 15th day of the 4th month with a US office, except certain June 30 year-ends.
2. No-US-office due date: 15th day of the 6th month after year-end.
3. Extension action: Use Form 7004 when required; certain corporations first use Regulations Section 1.6081-5.
4. Refund claim: An amended refund claim generally follows the later of 3 years after filing or 2 years after payment.

Electronic filing is available for most Form 1120-F returns.

Paper returns go to Ogden, Utah, and a private delivery service cannot deliver to an IRS P.O. box.

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Can you e-file Form 1120-F?

Yes. Corporations can generally e-file Form 1120-F, related schedules, and Form 7004. For returns filed on or after January 1, 2024, a corporation filing 10 or more returns of any type during the calendar year generally must e-file unless the IRS grants a hardship waiver.

TFX’s guide on how to pay US taxes online covers payment methods separately from return transmission.

E-filing the return does not erase a payment deadline.

For 2026 filings, the 10-return threshold is the key mandatory e-file trigger for Form 1120-F.

 

The IRS can waive mandatory e-filing when the corporation shows that e-filing would cause hardship.

Waiver requests follow the procedure in the current Form 1120-F instructions.

 

Requesting an extension for Form 1120-F

Form 7004 is the main corporate extension form, but 2025 Form 1120-F filers must also check Regulations Section 1.6081-5. A qualifying foreign corporation with a US office receives an automatic file-and-pay extension to the 15th day of the 6th month without filing Form 7004.

The IRS Form 7004 page provides the current form and instructions.

TFX handles non-personal extension requests through the client’s TFX account, rather than through the personal expat-extension service.

The following 4 extension checks prevent the most common timing errors:

• Confirm whether the corporation has a US office or place of business.
• Calculate the tax due using a proper estimate before the applicable deadline.
• File Form 7004 by the required date if Form 7004 is needed.
• Keep electronic acceptance or mailing proof with the corporate records.

Form 7004 itself does not extend payment time.

The separate Regulations Section 1.6081-5 rule can extend both filing and payment to the 15th day of the 6th month for qualifying entities, after which any additional Form 7004 extension is filing-only.

Form 7004 does not require a signature.

The Form 1120-F return itself must be signed by an authorized corporate officer when filed.

Need a non-personal extension? Submit the Form 7004 request through your TFX account.

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When Form 1120-F is due

The Form 1120-F due date depends on whether the foreign corporation has a US office. For calendar-year 2025, the regular deadline is April 15, 2026, with a US office and June 15, 2026 without one. Fiscal-year corporations use the corresponding month-after-year-end rule.

A corporation with a US office generally files by the 15th day of the 4th month after year-end.

A June 30 year-end is special: the return is generally due by the 15th day of the 3rd month.

A foreign corporation without a US office generally files by the 15th day of the 6th month after year-end.

If a due date falls on a weekend or legal holiday, the deadline moves to the next business day.

The following 3 deadline examples show how the rules work:

• Calendar-year 2025, US office: April 15, 2026 regular due date.
• Calendar-year 2025, no US office: June 15, 2026 regular due date.
• June 30 fiscal year, US office: September 15 regular due date.

Warning: A filing extension does not automatically mean the tax-payment date moves. Check Form 7004 and Regulations Section 1.6081-5 separately before delaying payment.

Where to file

A paper Form 1120-F for 2025 is filed with the IRS Service Center in Ogden, Utah, at the P.O. Box 409101 address in the current instructions. Corporations subject to the 10-return electronic-filing rule generally must e-file unless an IRS waiver or exclusion applies.

TFX’s IRS mailing addresses guide explains why the correct destination and delivery method matter.

Private delivery services cannot deliver to an IRS P.O. box, so use the IRS-designated street address when an approved private carrier is used.

Paper filers using the US Postal Service should use the Ogden P.O. box shown in the current Form 1120-F instructions.

 

The following 4 pre-mail checks reduce avoidable processing problems:

• Confirm an authorized officer signed and dated the return.
• Attach required forms, schedules, statements, and withholding documents.
• Verify the current IRS destination before mailing.
• Retain proof of timely mailing or approved private delivery.

Quick reference: 2026 filing deadlines

Calendar-year Form 1120-F deadlines differ by US-office status in 2026. A 2025 filer with a US office generally starts at April 15, while one without a US office starts at June 15. Regulations Section 1.6081-5 also creates a special extension route for qualifying corporations.

TFX’s estimated tax payments guide covers payment installments, which are separate from the filing table below.

For a 2025 calendar-year return, US-office status can move the regular filing deadline by 2 months, from April 15 to June 15, 2026.

 

This table is a planning aid, not a substitute for checking the corporation’s year-end, US-office status, legal holidays, and any special return facts.

How to file Form 1120-F step by step

A reliable Form 1120-F filing process for 2025 has 8 steps: confirm the filing duty, gather records, classify income, compute ECI, complete applicable form parts, attach required statements, sign and file, then pay. Schedules H, I, P, and others apply only when their own triggers are met.

Use the 1120 F instructions for the exact line and schedule rules that apply to the corporation’s facts.

The following 8 steps turn the filing rules into a reviewable workpaper:

1. Confirm the filing requirement. Document foreign-corporation status, US activities, income, withholding, refund claims, and treaty positions.
2. Gather records. Collect books, invoices, contracts, payroll, Forms 1042-S or 8805, US property records, and prior returns.
3. Classify income. Separate ECI from non-ECI US-source income and identify treaty effects.
4. Compute ECI. Allocate allowable expenses and calculate effectively connected taxable income.
5. Complete applicable parts. Prepare Sections I, II, III, Schedule J, and only the schedules triggered by the facts.
6. Attach statements. Add Form 8833, withholding forms, elections, and supporting statements when required.
7. Sign and file. Use an authorized officer and e-file if required or otherwise appropriate.
8. Pay and retain proof. Make required payments and keep acceptance, mailing, and supporting records.

A current expat IRS form checklist can help identify related individual forms, but it is not a substitute for the corporate schedule instructions.

Use the corporate preparation process when the filing itself is a foreign-corporation return.

The following 6 document groups should be ready before preparation begins:

• Corporate formation and entity-classification records.
• 2025 general ledger, trial balance, and financial statements.
• US contracts, employee, office, property, and inventory records.
• Withholding forms such as Forms 1042-S, 8805, or 8288-A.
• Prior Form 1120-F returns, elections, and treaty disclosures.
• Partnership, related-party, and branch records when applicable.

Want a second look at your Form 1120-F before filing? Check your return for reporting gaps

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Key components of Form 1120-F

The 2025 Form 1120-F has 3 core income-tax sections plus supporting schedules that apply by fact pattern. Section I covers certain non-ECI US-source income, Section II covers ECI, and Section III covers branch profits tax and excess interest. The form also handles refunds and treaty disclosures.

The current Form 1120-F instructions belong in the preparation file because the 2025 revision changed items that affect 2026 filing.

TFX’s Form 1118 guide covers corporate foreign tax credits, while its Form 5472 guide covers reportable related-party transactions.

The following 5 form areas deserve a separate review:

• Page 1 and identifying items: entity details, status boxes, tax, payments, refund choices.
• Section I: certain US-source income not effectively connected with a US trade or business.
• Section II: ECI, deductions, taxable income, and regular corporate tax.
• Section III: branch profits tax and tax on excess interest under Section 884.
• Schedules and attachments: apply only when the specific schedule trigger is met.

The 2025 Form 1120-F adds filing-season details that can change preparation even when the corporation’s business facts are unchanged.

 

The following 4 2026 filing-season updates are material to the 2025 form:

• The minimum failure-to-file penalty after more than 60 days is now the lesser of tax due or $525 for returns required in 2026.
• New direct-deposit fields appear on Form 1120-F lines 9c through 9e for eligible US accounts.
• Section 174A permits a current deduction for qualifying domestic research costs for tax years beginning after December 31, 2024.
• 2025 CAMT estimated-tax relief continues under Notice 2025-27 for the covered Section 6655 underpayment amount.

Section 1062 farmland installment reporting is a 2025 form change only for tax years beginning after July 4, 2025.

It does not apply to a calendar-year 2025 corporation whose tax year began January 1, 2025.

Comparing Form 1120 and Form 1120-F

Form 1120 and Form 1120-F serve different corporations. For 2025, a domestic corporation generally files Form 1120, while a foreign corporation with a US filing trigger uses Form 1120-F. The entity’s place of organization drives that distinction under US federal tax rules.

The IRS SOI Table 16 contains historical Form 1120 corporation data and helps distinguish the domestic-return population from Form 1120-F statistics.

The decision starts with where the corporation is organized: US-organized corporations generally use Form 1120; foreign corporations with US filing triggers use Form 1120-F.

 

Use Form 1120-F because the entity is foreign and has a US filing trigger, not because it merely has foreign shareholders.

A US-incorporated company stays a domestic corporation even when every shareholder lives abroad.

US corporations vs foreign corporations

A US corporation is domestic if organized in the United States or under US or state law; one organized elsewhere is foreign. For 2025, that distinction directs the return form, income scope, treaty analysis, and related reporting tied to US activity.

Place of organization determines the corporation’s domestic or foreign status for US federal tax purposes.

 

A German GmbH selling through a staffed US office remains a foreign corporation and can have Form 1120-F obligations.

A Delaware corporation owned entirely by German shareholders remains domestic and generally files Form 1120.

Form 1120-F late filing penalties

For returns required in 2026, Form 1120-F’s minimum failure-to-file penalty after more than 60 days is the lesser of unpaid tax or $525. The general failure-to-file rate is 5% of unpaid tax per month or part of a month, up to 25%.

TFX explains the general late-tax penalty rules and options when a taxpayer cannot pay on time.

Form 1120-F also has a separate filing-timeliness consequence: deductions and credits against ECI can be lost even when that loss is not itself a penalty.

The following 4 delay costs should be separated rather than labeled as one penalty:

• Failure to file: generally 5% of unpaid tax per month or part of a month, up to 25%.
• Failure to pay: generally 0.5% of unpaid tax per month or part of a month, up to 25%.
• Interest: accrues on unpaid tax under the federal underpayment rate rules.
• Estimated-tax additions: can apply under Section 6655 when required corporate installments are missed.

Based on our client scenario at TFX: a corporation has $20,000 of unpaid tax and files 2 full months late while both failure-to-file and failure-to-pay charges apply.

For the same 2 months, the failure-to-file rate is reduced by the concurrent 0.5% failure-to-pay rate.

That produces $1,800 of failure-to-file penalty plus $200 of failure-to-pay penalty, or $2,000 before interest, assuming no relief applies.

NOTE! A late Form 1120-F can also jeopardize ECI deductions and credits. That is a substantive tax consequence, not a separate statutory “late-filing penalty.”

Exemptions from filing Form 1120-F

A foreign corporation can skip Form 1120-F only when a filing exception applies. For 2025, tax-exempt income does not automatically mean no return. Treaty positions, Section 883 claims, QDD status, refunds, and US trade-or-business facts can still require filing under separate IRS rules.

TFX’s US tax treaty guide explains why treaty results vary by country and article.

When disclosure is required, its current Form 8833 guide explains the treaty-based return position form.

The IRS income tax treaties A to Z page is the authoritative starting point for the current treaty text and related documents.

The following 4 categories can support a no-filing result only after all other triggers are tested:

• No US trade or business and US tax fully satisfied by withholding.
• Certain US-source income excluded from gross income under the Code.
• Certain income exempt under a treaty, subject to any required return or disclosure.
• No refund, deduction, QDD, Section 883, or other special filing trigger.

The following 3 questions should be answered before treating an exemption as final:

• Does the corporation have a US trade or business even if ECI is zero?
• Does the treaty or Code exemption still require Form 1120-F, Form 8833, or Schedule S?
• Was withholding complete, and is any refund being claimed?

Forward-looking 2026 note: On August 11, 2026, the IRS said foreign-flagged vessels using the 2026 Jones Act waiver do not qualify for Section 883 or related treaty benefits for that waived transportation.

This concerns 2026 activity, not a standard 2025 calendar-year return.

Refunds and deductions

A foreign corporation can use Form 1120-F to claim a refund of overwithheld or overpaid US tax and to claim deductions against ECI. For 2025, deductions generally depend on timely filing, while refund claims need supporting records such as Forms 1042-S, 8805, or 8288-A when applicable.

TFX’s tax refund guide gives broader refund context.

Its tax and financial records guide explains why supporting documents should be retained after filing.

A refund claim needs proof of the payment or withholding, while ECI deductions need both substantive support and a return filed within the applicable timing rules.

 

The 2025 form adds direct-deposit fields on lines 9c through 9e.

Direct deposit is not available to a foreign bank or foreign branch of a US bank, and some withholding-based refunds can take up to 6 months to process.

An amended refund claim generally must be filed within 3 years after the original return was filed or 2 years after the tax was paid, whichever period ends later.

Protective filing made simple

A protective Form 1120-F return can preserve ECI deductions and credits when a foreign corporation believes no US tax is due, but the IRS could later disagree. The 18-month deduction-preservation period is measured from the return’s due date, not the filing date.

TFX’s discussion of whether to file when the obligation is uncertain provides broader decision context.

A protective return does not create treaty benefits; it preserves specified filing rights while the underlying US trade-or-business or treaty conclusion remains uncertain.

The following 5 steps create a basic protective-return file:

1. Check the “Protective return” box on Form 1120-F.
2. Enter the corporation’s name, address, EIN, and required identifying information.
3. Complete the required page 2 questions and any other applicable items.
4. Attach Form 8833 if the protective position is based on a treaty and disclosure is required.
5. Have an authorized corporate officer sign and date the return.

A protective return preserves specified deduction and credit rights; it does not replace the underlying ECI, treaty, withholding, or information-return analysis.

 

Common mistakes and how to avoid them

High-risk Form 1120-F errors for 2025 include classification and process mistakes. A corporation can misclassify income, miss a treaty attachment, use the wrong address, assume every schedule applies, or overlook the 10-return e-file threshold before submitting its 2026 corporate return.

The following 7 mistakes each have a direct fix:

1. Skipping the USTB analysis. Fix: document US people, offices, services, property, inventory, and partnership activity.
2. Mixing ECI and FDAP. Fix: prepare a sourcing and character workpaper before completing Sections I and II.
3. Using the wrong paper address. Fix: confirm Ogden and the delivery method in current IRS instructions.
4. Missing supporting statements. Fix: test Form 8833, withholding documents, elections, and schedule-specific attachments.
5. Filing every schedule. Fix: apply each Schedule H, I, P, S, and M-3 trigger separately.
6. Confusing filing and payment extensions. Fix: test Form 7004 and Regulations Section 1.6081-5 independently.
7. Ignoring mandatory e-file rules. Fix: count all return types against the 10-return threshold.

The following 6 self-audit checks should be completed before submission:

• Filing trigger documented.
• US-office status documented.
• ECI and FDAP reconciled to books.
• Treaty and withholding support attached.
• E-file or mailing method confirmed.
• Payment and extension dates documented.

A zero tax balance does not make every late filing harmless. Some penalties depend on unpaid tax, while separate information-return penalties and lost ECI deductions can arise under different rules.

Get expert help with filing Form 1120-F

Form 1120-F preparation can require 5 reviews: entity classification, US trade-or-business status, ECI and FDAP sourcing, treaty disclosure, and filing mechanics. A preparer should also test deductions, refunds, branch taxes, related reporting, and the 2026 filing deadline before final submission.

TFX’s guide on when to hire an expat tax professional explains what to look for when the return has cross-border issues.

The following 3 items help a preparer scope the filing before work begins:

• Prior US returns, EIN, formation documents, and entity elections.
• 2025 books plus US contracts, payroll, property, partnership, and withholding records.
• Treaty residence evidence, prior Form 8833 disclosures, and refund documents if applicable.

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