FDAP vs ECI: Which One Applies to Your US Income? (2026)

Read the table top to bottom and a pattern emerges. FDAP is built for collection without cooperation: the US cannot easily make a foreign investor file a return, so it takes a slice of the gross at the point of payment and calls it done. ECI is built for someone who is already here: a foreign person running a US business is treated much like a US business, taxed on profit, allowed deductions, and expected to file.

The rate column is where people stop reading, and it is misleading on its own. A 30% flat rate can be far heavier than a 37% top rate, because 30% of gross revenue on a low-margin activity can exceed 100% of the profit. The worked example below shows how quickly that happens.

The Code does not define a “US trade or business” precisely. Courts and the IRS look for activity in the US that is considerable, continuous and regular— carried on by you, your employees, or a dependent agent who habitually concludes contracts for you. Owning a US company, holding a US bank account, or selling to US customers from abroad does not, by itself, put you in a US trade or business.

• Step 1 — Is the income US-source? If not, it is neither FDAP nor ECI for most foreign persons. Services performed abroad are foreign-source and stop here.
• Step 2 — Are you engaged in a US trade or business? If no, US-source passive income is FDAP. Business-type income without a US business is generally not taxed at all.
• Step 3 — Is the income connected to that business? Under IRC section 864(c)(2), interest, dividends, rents and royalties are ECI if they come from assets held for use in the business (the asset-use test) or the business activities were a material factor in producing them (the business-activities test).
• Step 4 — Is there an election? Rental income from US real property can be treated as ECI by election, even without a business.

Personal services: the special rule

Performing personal services in the United States is a US trade or business in its own right, with a narrow exception under section 864(b)(1) for short visits: under 90 days in the year, no more than $3,000 of pay, and work for a foreign employer. Outside that exception, pay for work done physically in the US is ECI. Pay for work done outside the US is foreign-source — not ECI, not FDAP, not US-taxable.

For most foreign founders the left-hand column is the relevant one. Running an e-commerce store or a consultancy from outside the US, through a US LLC, does not create a US trade or business by itself, so any passive US income that business receives is usually FDAP. The general rules on FDAP, including treaty rates by country, are on the FDAP income page.

Take a foreign individual who owns a US rental property earning $40,000 of rent a year, with $30,000 of mortgage interest, property tax, insurance, repairs and depreciation.

The gap is dramatic because rent is high-gross, low-net income. The picture flips for a royalty with no costs attached: if a UK resident earns $10,000 of copyright royalties, the treaty rate is 0% as FDAP, and there is no reason to want ECI treatment and the annual return that comes with it.

So the practical rule is to look at margins before rates. Where income arrives with real costs attached — property, staff, inventory — the net basis of ECI almost always produces the lower bill, and the rental election exists precisely so that passive landlords can reach it. Where income arrives with no costs at all, the gross basis costs nothing extra, and a treaty rate on a W-8 is the simplest and cheapest outcome available.

The branch profits tax

A foreign corporation with ECI pays the 21% corporate rate on net profit and, under section 884, a further 30% branch profits taxon profits it does not reinvest in the US business — the equivalent of a dividend withholding tax. Many treaties reduce it. Foreign individuals are not subject to it.

Giving a payer a W-8ECI is a promise, not a shortcut. It switches off the 30% withholding because you are telling the IRS you will report and pay tax on that income yourself. A W-8ECI with no matching US return is a mismatch the IRS can see. Choosing between the W-8BEN and W-8BEN-E for FDAP is covered at W-8BEN vs W-8BEN-E.

Multi-member LLCs and partnerships

A US LLC with two or more members is a partnership by default. If it has ECI, it must withhold under section 1446on each foreign partner’s share of that income, at the highest individual or corporate rate, whether or not it distributes the cash. Foreign partners receive a Schedule K-1 and the related withholding statements, and file their own US returns.

The two categories meet treaties in different articles. FDAP is handled by the interest, dividend and royalty articles, which cap the withholding rate — for example 15% on portfolio dividends for UK and Canadian residents, or 10% across the board for Chinese residents. ECI is handled by the business profits article, which typically says a resident of the treaty country is taxed in the US only on profits attributable to a permanent establishment — a fixed place of business such as an office or branch, or a dependent agent.

That makes the permanent-establishment test the treaty equivalent of the trade-or-business test, but stricter. A treaty resident can be engaged in a US trade or business and still owe no US tax on the profits if there is no US permanent establishment. Claiming that position generally means filing a return and disclosing it on Form 8833. Residents of countries with no US treaty — including the UAE and Nigeria — get neither benefit.

Most of these mistakes come from the same root: treating FDAP and ECI as labels you pick rather than conclusions that follow from facts. The type of payment, where the work happened, and whether there is real US business activity decide the category. The form you send the payer should record that conclusion, not try to create it.

The last row is the one with the largest price tag and the least connection to the FDAP-or-ECI question. Neither category changes whether a foreign-owned LLC files Form 5472. A founder who has carefully established that the LLC owes no income tax at all still owes the information return, every year, on time. Getting the tax analysis right and missing the filing is the most expensive combination on this page.

This is the conclusion that surprises founders most. An LLC formed in Wyoming or Delaware, owned by one non-resident, selling online or invoicing clients for work done abroad, typically owes no US income tax. Its income is not ECI because it has no US trade or business, and it is not FDAP because it is not passive US-source income. The full analysis is in how a foreign-owned LLC is taxed.

Zero tax does not mean zero filings. A foreign-owned single-member LLC is a reporting entity for Form 5472, and virtually every one has at least one reportable transaction — even the capital contribution that funded it. Missing the filing carries a $25,000 penalty per form, per year, whether or not any tax is owed. The FDAP guide for LLC owners covers the cases where an LLC does receive passive US income.