Form 5472 Fax Number and Mailing Address: Where to Submit Your Filing

For a foreign-owned single-member LLC, the IRS publishes one dedicated fax number in the Form 5472 instructions: 855-887-7737. This is a toll-free US number. You send the complete package — a pro forma Form 1120 with Form 5472 (and any supporting Form 5472s for additional related parties) stapled behind it — to that single number. There is no separate fax line for the form versus the cover return; everything goes to 855-887-7737 in one transmission.

The fax route exists precisely because a disregarded entity has no e-file path. The IRS built the fax channel so non-residents abroad could submit on time without relying on international postal mail. The single most important byproduct of faxing is the transmission confirmation pageyour machine or fax service prints: it carries the date, the destination number, and a “success” status. That page is your dated evidence that the return was filed before the deadline.

Confirm the number before you send

Numbers and addresses in IRS guidance can change between revisions. The current Form 5472 instructions (Rev. December 2025) list 855-887-7737. Before faxing, glance at the “Where To File” section of the instructions you downloaded to confirm the number still reads 855-887-7737, then send the full package in one go and retain the confirmation.

If you prefer paper, the IRS assigns one address for a foreign-owned disregarded entity's Form 5472 package: Internal Revenue Service, P.O. Box 149342, Austin, TX 78714-9342. The Austin campus handles these international information returns. Write the address exactly, including the full ZIP+4 of 78714-9342, so the envelope reaches the correct processing unit rather than a general corporate-return queue.

Because this is a P.O. Box, the US Postal Service can deliver to it, but some private couriers cannot deliver to a P.O. Box. If you want a courier with tracking, use USPS Certified Mail (which does reach a P.O. Box) rather than a service that requires a street address. The certified-mail receipt and green card give you the postmark date, which establishes timely filing under the mailbox rule.

This is the single most misunderstood point about filing Form 5472, so it is worth stating plainly: a foreign-owned disregarded entity cannot e-file. A normal C-corporation e-files Form 1120 through the IRS Modernized e-File system, but a disregarded entity is not actually filing a real 1120 — it is filing a pro forma (shell) 1120 whose only job is to carry Form 5472. That shell return is not accepted electronically for this purpose.

Consumer and professional tax software will happily e-file a regular corporate or personal return, which misleads founders into thinking they can transmit the Form 5472 package the same way. They cannot. If you try, the software will either reject the disregarded-entity return or, worse, transmit something the IRS does not associate with the foreign-owned DE filing requirement, leaving you unfiled and exposed to the $25,000 penalty.

The full step-by-step is covered on how to file Form 5472, and the line-by-line completion guidance lives in the Form 5472 instructions.

Form 5472 never travels alone. The regulations require it to be attached to an income-tax return, and the only return available to a disregarded entity is a pro forma Form 1120. So your fax or envelope contains, in order: the pro forma 1120 on top, then Form 5472 behind it. If your LLC had more than one related foreign party — for example, you plus a foreign company you also own — you complete a separate Form 5472 for each party, all attached to the same single pro forma 1120.

You do not complete the income, deduction, or tax lines of the 1120 — those stay blank, because a disregarded entity pays no entity-level federal income tax. See the Form 5472 PDF page for what each printable section looks like, and the pro forma 1120 page for exactly which boxes to fill.

Both fax and mail are equally valid for a foreign-owned disregarded entity, so the choice comes down to speed and what proof you prefer. Faxing is the faster route: the transmission completes in minutes and your machine or online fax service prints a confirmation page with the date and time. That speed and instant timestamp make fax the popular choice when the April 15 deadline is close.

Whichever you pick, send the package only once. Do not fax and mail the same return — duplicate filings can confuse processing. Pick the method, keep the proof, and stop there.

Proof of filing is not optional paperwork — it is your insurance against a $25,000 penalty. If the IRS later claims it never received your Form 5472, the burden is on you to show you filed on time. The two documents that do this are the fax confirmation page (date, destination number 855-887-7737, and a success status) and the USPS certified-mail receipt with its postmark, ideally paired with the signed green card.

Section 6038A also imposes a separate record-keeping obligation, so keep this proof with the LLC's books — bank statements, the operating agreement, and a ledger of owner transactions — for at least six years. If you missed a year entirely, read Form 5472 catch-up filing before sending anything.

Most Form 5472 filers are non-residents living outside the United States, so cross-border submission is the norm. The fax number is the same for everyone: 855-887-7737. From abroad you dial it with the US country code as +1-855-887-7737. Toll-free (855) numbers are reachable from many — though not all — countries, so test the connection or use an alternative if your carrier blocks US toll-free dialing.

The simplest path for an international founder is an online fax service. You upload a PDF of the pro forma 1120 with Form 5472, the service dials 855-887-7737 from a US line, and you receive an emailed confirmation page as your proof. This avoids both international postal delays to the Austin P.O. Box and the need for a physical fax machine.

Country-specific walkthroughs are available for several large filer groups, including Indian owners, Chinese owners, and Turkish owners.

The method does not change the deadline. A foreign-owned single-member LLC's Form 5472 package is due on the 15th day of the fourth month after the tax year ends — April 15 for a calendar-year LLC. The 2025 tax-year form is due April 15, 2026. If you file Form 7004 on or before April 15, you push the deadline to October 15.

When you fax close to the deadline, the timestamp on the confirmation page is what counts — a fax completed before midnight on April 15 is timely. For the full deadline mechanics see the Form 5472 deadline, and to claim the extension read the Form 5472 extension and Form 7004.

The Form 5472 package for a foreign-owned disregarded entity goes to one specific address: P.O. Box 149342, Austin, TX 78714-9342. This is not the same as the address where a normal C-corporation mails its real 1120. If you send the package to a different IRS campus, two things can go wrong: best case, it gets internally rerouted and processing is delayed; worst case, it is never associated with the DE filing requirement and the IRS treats the form as never filed.

Because an unfiled or substantially incomplete Form 5472 triggers the $25,000 penalty under IRC section 6038A, an addressing error can be expensive. The defense is simple: use the exact dedicated address, send by certified mail, and keep the postmarked receipt. If the form is ever questioned, the certified-mail receipt proves you mailed the correct package on time, which supports a reasonable-cause position if a dispute arises.

Form 5472 carries one of the harshest information-return penalties in the US tax code. The base penalty is $25,000 for each form not filed, filed late, or filed substantially incomplete. A package faxed or mailed after the deadline — or never received because it went to the wrong address — can trigger it. Under IRC section 6501(c)(8), there is no statute of limitations on an unfiled information return, so a missed year stays open indefinitely.

The penalty also compounds. If the IRS issues a notice of failure and the form is still not filed within 90 days, an additional $25,000 applies for each 30-day period the failure continues. That is why submitting the correct package to the correct destination with retained proof is the entire game. See the full breakdown on the Form 5472 penalty and estimate exposure with the penalty calculator.

Many founders assume a zero-revenue LLC need not file, then mail or fax nothing — and walk straight into the penalty. The trigger is a transaction, not income. The moment you wire money from your personal account to fund the LLC, pay a state formation fee on its behalf, or lend it money, you have created a reportable transaction that must be reported on Form 5472.

Because forming and funding an LLC always involves moving money from the owner, virtually every foreign-owned single-member LLC has at least one reportable transaction in its first year. So the practical answer is almost always that you must fax or mail the package. Learn what counts on reportable transactions, see how a capital contribution qualifies, and if your LLC truly never moved money, check the dormant LLC rules.

The submission itself is short once the forms are filled. The sequence below is the same whether you fax or mail; only the final send step differs.

If you would rather not handle the fax line, the addressing, and the proof yourself, form5472.tax prepares Form 5472 and the pro forma 1120, has a specialist review them, and files the package the correct way for a flat $299 — compared with $547 at form5472.online.

Form 5472 and its pro forma 1120 both ask for the LLC's Employer Identification Number. Without an EIN, the package is incomplete and cannot be properly filed. A non-resident with no Social Security Number obtains the EIN by submitting Form SS-4 to the IRS — itself a fax or mail process, because foreign applicants cannot use the online EIN tool that requires a US taxpayer ID.

Plan the timing: getting an EIN by fax can take a couple of weeks, so apply well before April 15 so the number is in hand when you complete and submit the Form 5472 package. The reference number that ties your LLC's filings together is explained on the Form 5472 reference ID number, and the broader disregarded-entity background is on the foreign-owned disregarded entity page.

The IRS does not mandate a cover sheet when you fax the Form 5472 package, and your filing is valid without one. In practice a one-page cover sheet reduces the chance of a misrouted or split transmission. Keep it plain: the LLC's legal name and EIN, the words “Form 5472 with pro forma Form 1120”, the tax year being reported, your return fax or email, and the total page count so the receiving unit can confirm it got every page.

Set the page count carefully: if you fax a pro forma 1120, one Form 5472, and a cover sheet, that is three pages. After the transmission, the confirmation page should show that same count went through. A mismatch is your early warning to re-send before the deadline passes.

Catch-up filers often have two, three, or more missed years to submit. The rule is one complete package per tax year: a 2022 pro forma 1120 with the 2022 Form 5472, a separate 2023 package, and so on. Each year stands alone because the $25,000 penalty is assessed per form, per year — combining years onto one return would leave some years effectively unfiled.

Before sending back years, read Form 5472 catch-up filing and what to do if you missed Form 5472, because how you submit late forms affects whether a reasonable-cause statement can reduce the penalty. Estimate exposure first with the penalty calculator.