Form 1120-F: Foreign Corporation Return (IRS)

Form 1120-F is the U.S. income tax return for a foreign corporation. A foreign corporation uses it to report income, gains, losses, deductions, and credits that relate to a U.S. trade or business, and to figure its U.S. tax.

This post is general information from the 2025 Form 1120-F and its instructions, dated January 21, 2026. It does not say whether a corporation has U.S. tax duties. That depends on its facts and on any tax treaty that applies.

Who must file

The instructions say a foreign corporation must file Form 1120-F if, during the tax year, it:

was engaged in a trade or business in the United States, whether or not it had U.S. source income from that business, and whether or not that income is exempt under a tax treaty;
had income, gains, or losses treated as effectively connected with the conduct of a U.S. trade or business;
was not engaged in a U.S. trade or business but had U.S. source income, and its tax was not fully satisfied by withholding at source; or
was, or had a branch that was, a qualified derivatives dealer.

The instructions also list cases where the form is required even if an exception applies. One example is a foreign corporation that claims a deduction or credit. Another is a corporation that takes a treaty position that must be disclosed on Form 8833.

Exceptions from filing

The instructions say a foreign corporation does not have to file if any of these apply:

It did not engage in a U.S. trade or business during the year, and its full U.S. tax was withheld at source.
Its only U.S. source income is exempt from U.S. tax under section 881(c) or (d).
It is a beneficiary of an estate or trust engaged in a U.S. trade or business, and would not otherwise need to file.

A corporation with no gross income because it claims a treaty or Code exemption must still file to show that the income was exempt. In that case, it completes the identifying information at the top of page 1 and attaches a statement describing the income and the amount excluded.

Special returns

Some foreign organizations file a different form instead. The instructions list Form 1120-L for a foreign life insurance company, Form 1120-PC for a foreign nonlife insurance company, and Form 1120-FSC for a foreign sales corporation that still has its election in effect.

Due date and extension

The instructions say a corporation generally files by the 15th day of the fourth month after the end of its tax year. For a calendar year 2025 return, that date is April 15, 2026. The instructions also cover the case where a due date falls on a Saturday, Sunday, or legal holiday.

To request an extension of time to file, the corporation files Form 7004 by the due date. The instructions say to see the Form 7004 instructions for details.

Electronic filing

For returns filed on or after January 1, 2024, the instructions say a corporation must e-file Form 1120-F if it files 10 or more returns of any type during the calendar year. That count includes income tax, employment tax, excise tax, and information returns. A corporation may ask the IRS for a waiver if e-filing would cause a hardship.

Parts of the return

Section I covers U.S. source income that is not effectively connected with a U.S. trade or business. The form says the rate on these items is 30% or a lower treaty rate.
Section II covers income effectively connected with a U.S. trade or business, with deductions and taxable income.
Section III covers the branch profits tax under section 884. The form says the branch profits tax is 30% of the amount on line 5, or a lower treaty rate.
Schedule S (Form 1120-F) is attached when the corporation claims the section 883 exclusion for income from the international operation of ships or aircraft.
Schedule M-3 (Form 1120-F) has its own rules for corporations with reportable assets of $10 million or more.

A foreign eligible entity that elected to be taxed as a corporation on Form 8832 attaches a copy of that form to its Form 1120-F for the election year.

Estimated tax

A corporation can owe a penalty when it does not make estimated tax payments when due. The instructions say the penalty generally applies when the tax liability is $500 or more and the corporation did not timely pay at least the smaller of its current year tax or its prior year tax. No estimated payments are required for the branch profits tax.

A domestic corporation's return is covered in Form 1120: The Corporate Income Tax Return and Who Must File It. Owners of foreign corporations often read about Form 5471: Reporting Interests in Foreign Corporations. A treaty position may require Form 8833: Treaty-Based Return Position Disclosure. For a foreign tax credit against U.S. tax, see Form 1118: The Foreign Tax Credit for Corporations.

Sources: Sources: IRS, Form 1120-F, U.S. Income Tax Return of a Foreign Corporation (2025) (https://www.irs.gov/pub/irs-pdf/f1120f.pdf); Instructions for Form 1120-F (2025) (https://www.irs.gov/pub/irs-pdf/i1120f.pdf) This is general information, not advice about your specific return.

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