Guide 26 · Federal tax, beyond 5472

Form 1040-NR and ECI: when a foreign founder owes a personal US return

Form 5472 is the return your company files about you. Form 1040-NR is the return you file about yourself — and the two are triggered by different things. Most foreign founders of a single-member LLC never owe a 1040-NR. Some do, from the first year. The dividing line is one phrase: effectively connected income.

On this page

1. Two returns, two different taxpayers
2. ECI: the phrase that decides it
3. FDAP: the other bucket, taxed differently
4. The cases founders actually hit
5. Treaty positions and Form 8833
6. What Sethhost does, and what your CPA does
7. Reading is step one. The paperwork is the rest.

Two returns, two different taxpayers

Start with the separation, because confusing these two returns is the most common tax mistake in this niche. Form 5472, filed with a pro-forma Form 1120, is an information return of the company: a foreign-owned single-member LLC reports its transactions with its owner and related parties. It is due even in a year with no trading at all, and the penalty for missing it starts at $25,000. Form 1040-NR is the individual nonresident alien income tax return. It exists to tax a person, not to inform on a company, and it is only due when that person has US-source income of a kind the code taxes.

So a dormant LLC can owe a 5472 and no 1040-NR in the same year, and a busy founder can owe both. Neither return substitutes for the other, and filing one does not excuse the other. Our Form 5472 guide covers the company side in full; this page is the personal side.

ECI: the phrase that decides it

US tax law splits a nonresident's US income into two buckets. The first is effectively connected income (ECI): income effectively connected with a US trade or business. ECI is taxed on a net basis — deductions allowed — at the same graduated rates as a US person's income, and it is reported on Form 1040-NR. The second bucket, FDAP, is covered in the next section and taxed completely differently.

There is no single statutory checklist for when a foreign founder's LLC is engaged in a US trade or business; the IRS applies facts and circumstances, and for an LLC the analysis looks through to the owner. The practical markers practitioners look for are a US office or other fixed place of business, US-based employees or dependent agents who habitually conclude contracts, and inventory or operations physically in the United States. Selling digital products or services from your desk abroad, to US customers, through your own website, is the classic case that generally does not, by itself, create ECI — which is why so many foreign founders correctly file only the 5472. The moment you add US people, premises or stock, the answer can change, and it changes the return you owe.

FDAP: the other bucket, taxed differently

FDAP — fixed, determinable, annual or periodical income — covers US-source interest, dividends, rents and royalties that are not effectively connected. FDAP is generally taxed at a flat 30% on the gross amount, usually collected by withholding at source, and a treaty may reduce the rate. If withholding was done correctly, a nonresident with only FDAP income often has no 1040-NR filing obligation at all; the withholding is the tax. A 1040-NR enters the picture when withholding was wrong, when a treaty refund is claimed, or when some of the income is ECI after all.

This is why the same founder can receive a Form 1042-S from a US payer showing tax withheld and owe nothing further, while the founder in the next chair — same revenue, but a part-time US-based contractor closing sales — owes a full personal return. The forms follow the facts, not the revenue figure.

The cases founders actually hit

• Services performed from your home country, clients in the US. Generally no ECI where you have no US office, staff or dependent agent; the 5472 still applies. The most common founder posture, and the one our tax-ID guide assumes.
• You travel to the US and work from there for stretches. Services income is sourced where the services are performed. Work physically done in the US can create US-source income and, with enough presence, a US trade or business. Track your days and where the work happened.
• US rental property or a US-based operation. Rents are FDAP by default but can be elected into ECI treatment (the section 871(d) election) so expenses can be deducted — a decision to make with a CPA before the first return, not after.
• You later take a salary from a C corporation. Wages for US-performed services are ECI; the corporation withholds, and a 1040-NR reconciles the year.

Treaty positions and Form 8833

Where a tax treaty applies, it can re-draw the ECI line: most US treaties tax business profits only when there is a permanent establishment in the US, which is a narrower test than the domestic trade-or-business rule. Claiming a treaty position that overrides or reduces US tax generally requires disclosure on Form 8833 attached to the return, and the return itself — a protective 1040-NR — is often filed precisely to start the statute of limitations and preserve deductions if the IRS later disagrees with the position.

Treaties are country-specific and fact-specific; our treaty guide explains what they do and do not do. What no treaty does is cancel Form 5472: it is an information return, not a tax, and treaty relief does not reach it.

What Sethhost does, and what your CPA does

Sethhost is not a tax preparer and does not file 1040-NR. What the membership does is put the obligation on your compliance calendar from day one, keep the company-side 5472 duty in front of you with its April 15 deadline, and record the facts a CPA will ask about — where you worked, who works for the company and where, what the company owns in the US. The determination itself — ECI or not, treaty position or not — is your CPA's call, made on your facts. If your facts include US staff, US premises or US inventory, raise it in your first CPA conversation, not your third.