A pro forma Form 1120 is a stripped-down version of the corporate income tax return that foreign-owned single-member LLCs must attach to Form 5472. It carries no income or expense entries. It exists only to give Form 5472 a valid form to attach to.
If you own a US LLC through a foreign entity or as a non-US person, and that LLC is treated as a disregarded entity, this filing is likely part of your annual compliance picture. It applies even in years with no income, and even for a single loan or capital contribution between you and the LLC.
The rules can feel counterintuitive since you are filing a corporate return for an entity that is not a corporation and owes no corporate tax.
Key Summary: Pro Forma 1120
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A pro forma Form 1120 is not a real tax return. It is a required attachment for Form 5472.
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All financial lines on the pro forma 1120 stay blank or at $0.
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The form must be labeled “Foreign-owned US DE” and cannot be e-filed.
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Missing the pro forma 1120 carries the same $25,000 penalty as missing Form 5472 entirely.
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The filing requirement applies even if the LLC had no income, as long as a reportable transaction occurred.
Pro Forma 1120 Filing Snapshot
| Item | Detail |
| Who files it | Foreign-owned US disregarded entities (single-member LLCs) |
| Attached to | Form 5472 |
| Financial lines | Left blank or entered as $0 |
| Required label | “Foreign-owned U.S. DE” written across the top |
| Filing method | Fax or mail only, no e-file |
| Deadline | April 15, 2026 for calendar-year entities |
| Penalty for missing it | $25,000, same as failing to file Form 5472 |
What is a Pro Forma Form 1120?
Form 1120 is normally the US Corporation Income Tax Return. Real corporations use it to report income, deductions, and tax owed.
A foreign-owned single-member LLC is not a corporation. The IRS treats it as a disregarded entity for income tax purposes. That means the LLC itself does not owe corporate income tax and does not have its own tax liability to report.
So why does the LLC need a Form 1120 at all?
Because Form 5472 cannot be filed on its own. The IRS requires it to be attached to a Form 1120. Since the LLC has no income tax return to file, it attaches a pro forma version instead: a Form 1120 filled out only with identifying information, not financial data.
Think of the pro forma 1120 as a cover sheet. It exists to satisfy a filing mechanism, not to report tax.
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Our team prepares Form 5472 and the pro forma 1120 together, so nothing gets filed incomplete. Get your compliance handled before the deadline.
Form 5472 and Pro Forma 1120: Why the IRS Requires This Combination
Form 5472 reports transactions between a US entity and its foreign owner. Historically, Form 5472 was designed to attach to an actual corporate return.
When Treasury Regulation 1.6038A-1 extended these reporting rules to foreign-owned disregarded entities in 2017, the IRS did not create a new standalone form. It simply required these LLCs to file the same two documents: Form 5472, carrying the actual transaction data, and Form 1120, serving only as the vehicle that carries it to the IRS.
The result is a combined 5472/pro forma 1120 filing that looks unusual compared to a normal corporate return, but it is the standard and required format for foreign-owned disregarded entities.
Who Needs to File a Pro Forma 1120?
You need a pro forma Form 1120 if both of the following apply:
- Your LLC is a single-member entity treated as a disregarded entity for federal tax purposes
- A non-US person or entity owns 25% or more of the LLC
If your LLC also had a reportable transaction with its foreign owner during the year, such as a capital contribution, loan, or payment, you must file both Form 5472 and the pro forma 1120 together.
This applies even if your LLC earned no income. The filing requirement is based on transactions, not profit. Moving even a small amount of money into or out of the LLC can trigger the requirement.
What Goes on a Pro Forma Form 1120
A pro forma 1120 is deliberately incomplete. You are not reporting income, expenses, or tax owed. You are only providing identifying information.
Here is what belongs on the form:
- The LLC’s legal name and address
- The LLC’s Employer Identification Number (EIN)
- Boxes B and E checked to identify the return as a pro forma filing tied to Form 5472
- The words “Foreign-owned US DE” written across the top of page 1
All financial lines, including income, deductions, and tax liability, are left blank or entered as $0. Do not attempt to calculate a tax liability or report business revenue on this form. Doing so can create confusion with the IRS about whether the LLC is filing as an actual corporation, which it is not.
Common Mistakes With the Pro Forma 1120
Foreign-owned LLC owners run into a handful of predictable problems with this filing.
- Filing Form 5472 without the pro forma 1120. Form 5472 cannot stand alone. Submitting it without an attached pro forma 1120 is treated by the IRS as an incomplete filing, which carries the same $25,000 penalty as not filing at all.
- Filling in financial data. Some filers assume they need to report the LLC’s income and expenses on the 1120 portion. They do not. A disregarded entity does not have its own tax return, and entering numbers here can create an unnecessary compliance headache.
- Forgetting the “Foreign-owned US DE” label. This label tells the IRS how to process the return. Without it, the filing can be misrouted or flagged as incomplete.
- Trying to e-file. Foreign-owned disregarded entities filing a pro forma 1120 with Form 5472 cannot e-file. The combined filing must go by fax or mail.
Don't Risk a $25,000 Penalty
A missing or incomplete pro forma 1120 costs as much as not filing at all. Talk to a specialist who handles these filings correctly the first time.
How to File the Pro Forma 1120
The pro forma 1120 is filed together with Form 5472, not separately. The basic steps:
- Confirm your LLC meets the 25% foreign ownership threshold and had a reportable transaction during the year.
- Complete Form 5472 for each foreign related party involved in a reportable transaction.
- Prepare the pro forma Form 1120, filling in only identifying information and leaving financial lines blank.
- Write “Foreign-owned US DE” across the top of page 1 and check boxes B and E.
- Attach the pro forma 1120 to Form 5472.
- Submit by fax to 855-887-7737 or by mail to the IRS in Ogden, UT, by April 15 for calendar-year entities.
