If you are a non-resident with income from US sources, the IRS sorts that income into two categories: ECI (effectively connected income) and FDAP (fixed, determinable, annual, periodical). Two frameworks apply depending on the nature of the income and your level of US business activity. The ECI vs FDAP classification matters because the difference is not just a label.
Quick Answer
ECI is taxed on net income at graduated rates after deductions, the same way a US resident is taxed on business income. FDAP is taxed at a flat 30% on the gross amount with no deductions allowed. Treaty reductions can lower the FDAP rate. Both categories appear on Form 1040-NR but in different sections with different rules.
1. The Threshold Question
The whole ECI vs FDAP analysis comes down to one question: are you engaged in a US trade or business?
If yes, income connected to that business is ECI. If no, or if you have passive US-source income that is not connected to a business, that income is FDAP. Some non-residents have both, and each category is reported and taxed separately on Form 1040-NR.
Whether your activity rises to the level of a US trade or business is fact-specific and interpreted broadly by the IRS and courts. A physical office is not required. Regular and continuous business activity in the US is sufficient. Sending employees or agents to conduct negotiations, executing contracts in the US, providing services from within the US: all have been found to constitute a US trade or business in various circumstances. A single transaction is generally not enough on its own, though specific service or agent arrangements can rise to the level even with limited activity.
2. Effectively Connected Income (ECI)
ECI is income that is effectively connected with the conduct of a trade or business in the United States. The IRS applies two tests to determine the connection: the asset use test (was the income derived from assets used in the US business) and the business activities test (were US business activities a material factor in producing the income).
ECI is taxed at the same graduated rates that apply to US citizens and residents. You report gross ECI, deduct ordinary and necessary business expenses, and pay tax on the net amount. Effective rates can be substantially lower than the headline FDAP rate when there are meaningful business expenses to offset.
ECI is reported on the income section of Form 1040-NR. There is generally no fixed 30% withholding regime, but specific withholding rules apply, most commonly under IRC Section 1446 for partnerships, which are required to withhold on ECI allocated to foreign partners. FIRPTA withholding under Section 1445 applies separately to dispositions of US real property interests.
3. FDAP Income
FDAP is the catch-all category for US-source income that is not ECI. The name describes the income's character: fixed when known in advance, determinable when there is a basis for calculating the amount, and annual or periodical when paid at regular intervals.
Common FDAP types:
- Dividends from US corporations
- Interest from US bank accounts or bonds
- Rent from US real property (unless an election is made to treat as ECI)
- Royalties from US intellectual property licenses
- Certain annuity payments
Compensation for services performed in the US is generally treated as ECI rather than FDAP, even where the work is short-term or limited in scope.
FDAP is generally subject to 30% withholding on the gross amount, applied at the source by the US payer before payment reaches you. No deductions are allowed against FDAP income. The 30% applies to the full payment, not the net.
4. The Worked Example That Shows the Difference
To make the difference concrete:
A non-resident owns shares in a US company and receives a $50,000 dividend. The company withholds $15,000 (30%) before payment. No deductions apply. No return is required unless a treaty reduction is being claimed.
If the same person instead operates a US consulting business earning $50,000 with $30,000 in legitimate business expenses, only $20,000 is subject to tax under ECI rules at graduated rates. At a 22% bracket, the tax owed is roughly $4,400, compared to $15,000 under FDAP on the same gross amount. The structure of the activity, not just the dollar figure, determines the outcome.
This is why getting the classification right matters. The same income can be taxed three to four times higher depending on how it is treated.
The two regimes side by side:
| Aspect | ECI | FDAP |
|---|---|---|
| Type of income | Active US business | Passive US-source |
| Tax basis | Net (after deductions) | Gross |
| Tax rate | Graduated up to 37% | Flat 30% (or treaty rate) |
| Form filed | 1040-NR (income section) | 1040-NR (separate schedule) |
| Deductions allowed | Yes | No |
| Treaty reduction | Limited | Available for many income types |
| Withholding mechanism | Section 1446 partnerships, FIRPTA real property | 30% by US payer at source |
| Examples | Consulting, services, US-based business | Dividends, interest, royalties, rents |
If your withholding does not match what you reported, or if you are not sure whether your activity creates ECI, a compliance review confirms the position before the IRS does.
5. The Section 871(d) Election for Real Estate
Certain types of income that would normally be FDAP can be reclassified as ECI by election. Rental income from US real property is the most common example.
By default, rental income from US real property is FDAP, subject to 30% withholding on gross rents. A non-resident can elect under IRC Section 871(d) to treat that rental income as ECI, paying tax at graduated rates on net rental income after expenses.
For a property with mortgage interest, depreciation, property tax, and operating costs, the ECI election typically produces a substantially lower tax bill than the default FDAP treatment. The election applies to all US real property income for that taxpayer, not on a property-by-property basis. It is made on a timely-filed return.
This is one of the most underused planning tools available to foreign owners of US real estate. Defaulting to FDAP because no election was made means leaving the deduction value on the table.
6. Tax Treaties and Withholding
If your country of residence has an income tax treaty with the United States, the treaty may reduce the 30% FDAP withholding rate on specific income types.
- Dividends: often reduced to 15% or lower
- Interest: often reduced to 10% or eliminated entirely
- Royalties: rates vary by treaty and income type
The reduced rate does not apply automatically. You claim it by providing the US payer with a completed Form W-8BEN (individuals) or W-8BEN-E (entities) before the payment is made. Without the form on file, the payer withholds at the default 30%.
If documentation is not provided before payment, the default 30% is withheld. To recover the difference, you file a Form 1040-NR after year-end claiming the treaty position, and request a refund of the over-withholding. The refund process can take six months or longer.
7. Form 1040-NR Mechanics
ECI and FDAP are reported in separate sections of Form 1040-NR. They are not interchangeable, and combining them produces an incorrect return.
- ECI is reported in the income section, reduced by allowable deductions, and taxed at graduated rates
- FDAP is reported in a separate schedule on the face of the return, taxed at the flat rate, and not combined with ECI for deduction purposes
Most consumer tax software does not support Form 1040-NR at all. The software that does often does not handle the ECI and FDAP distinction correctly for complex situations. Misclassification on the return produces incorrect tax in either direction and is one of the most common triggers for IRS notices.
If you have not yet confirmed your residency status, that question comes before the income classification question. Our post on US tax residency vs non-residency covers the green card and substantial presence tests.
8. Common Mistakes
- Assuming no US business activity means no ECI: the standard for a US trade or business is fact-specific and interpreted broadly. Services performed in the US, regular business visits, and US-based agents acting on your behalf can all create ECI exposure without a fixed office.
- Not providing W-8BEN before payment: the default withholding is 30%. If you are entitled to a treaty reduction and do not provide the form before payment, the full 30% is withheld and recovery requires filing a return.
- Treating all rental income as passive FDAP: the Section 871(d) election exists because the default treatment is often worse for properties with significant expenses. Not evaluating the election before the filing deadline means losing it for that year.
- Mixing ECI and FDAP on Form 1040-NR: the categories are reported in separate sections. Combining them produces an incorrect return that needs to be amended.
If you own a US LLC or corporation as a non-resident, the income classification feeds directly into your overall US tax exposure. Our post on whether foreign-owned US entities pay US tax covers the entity-level picture.
This post is for general informational purposes only and does not constitute professional tax, legal, or accounting advice for your specific situation. Reading this post does not create a CPA-client relationship. Tax laws are complex and subject to change. If you would like advice tailored to your situation, consult a qualified tax professional, including through the services offered on this site.