Effectively connected income is the U.S. business income of a foreign person, and it’s taxed on a net basis at the same graduated rates that apply to U.S. citizens and residents.1Office of the Law Revision Counsel. 26 USC 871 – Tax on Nonresident Alien Individuals That means business deductions come off before the tax is calculated, which sets it apart from passive U.S. income like interest or dividends. Passive income gets hit with a flat 30% tax on the gross amount, with no deductions allowed.2Internal Revenue Service. Fixed, Determinable, Annual, or Periodical (FDAP) Income
The difference is not small. A foreign person earning $500,000 of U.S. business income with $400,000 in expenses pays tax on $100,000 under the effectively connected income rules. The same $500,000 taxed as passive FDAP would generate a $150,000 tax bill on the full gross amount.
What Makes Income Effectively Connected
Two things have to be true. First, you need a U.S. trade or business. Second, the specific income has to be connected to it under one of the tests below.
The Internal Revenue Code doesn’t define “U.S. trade or business” precisely, but courts and the IRS look for activity that is regular, continuous, and substantial. Actively managing a portfolio of U.S. rental properties, handling leasing, arranging repairs, and dealing with tenants generally qualifies. Owning a single property run by an independent agent, or simply holding shares in a U.S. corporation, does not.
One rule catches many foreign investors off guard. If you’re a partner in a partnership that runs a U.S. trade or business, you’re automatically treated as running one yourself.3Office of the Law Revision Counsel. 26 USC 875 – Partnerships; Beneficiaries of Estates and Trusts The size of your interest doesn’t matter, and neither does how passive your role is. The partnership’s activity flows through to you.
Short-Term Personal Services
Performing services inside the United States normally creates a U.S. trade or business, but a narrow exception exists. A nonresident alien working for a foreign employer avoids that treatment if the stay is 90 days or fewer during the tax year and compensation is $3,000 or less.4Office of the Law Revision Counsel. 26 USC 864 – Definitions and Special Rules Both conditions must be met. Cross the $3,000 line by a dollar and the whole amount becomes U.S. trade or business income, not just the excess.5Internal Revenue Service. Nonresident Aliens – Exclusions From Income
How Investment Income Gets Pulled In
Once a U.S. trade or business exists, investment income that would otherwise be passive FDAP can be reclassified as effectively connected under two statutory tests.
Under the asset-use test, income is effectively connected when the asset generating it is used in, or held for use in, the U.S. business.4Office of the Law Revision Counsel. 26 USC 864 – Definitions and Special Rules Interest on a U.S. bank account used as working capital is the classic example. Gain from selling equipment the business actually used qualifies for the same reason.
Under the business-activities test, income counts as effectively connected when the business’s activities were a material factor in producing it. This one matters most for financial businesses. A foreign bank with a U.S. branch that actively trades securities earns interest and dividends because of that trading operation, so the returns are effectively connected.
Then there is the force of attraction rule. All other U.S.-source income that isn’t the passive FDAP type is automatically treated as effectively connected once you have a U.S. trade or business. The rule prevents foreign taxpayers from carving off parts of their U.S. activity to avoid the treatment.
Income That Is Effectively Connected by Statute
Some categories are effectively connected regardless of whether the general tests are met.
U.S. Real Estate Sales
The Foreign Investment in Real Property Tax Act treats any gain or loss from selling a U.S. real property interest as if you were running a U.S. business and the gain were connected to it.6Office of the Law Revision Counsel. 26 USC 897 – Disposition of Investment in United States Real Property A U.S. real property interest covers direct ownership of land or buildings and indirect ownership through a corporation whose assets are primarily U.S. real estate. Gains are taxed at graduated rates on a net basis instead of the flat 30% FDAP rate.
To secure collection, the buyer generally withholds 15% of the total amount realized at closing.7Office of the Law Revision Counsel. 26 USC 1445 – Withholding of Tax on Dispositions of United States Real Property Interests That’s a prepayment, not a final tax. The foreign seller files a return, computes actual gain after deductions, and applies the withholding as a credit. If it exceeds the tax owed, the difference is refunded. Reduced or zero withholding applies to some residential sales at or below $1,000,000.
The Rental Income Election
Foreign individuals and corporations earning rental income from U.S. real property can elect to treat that income as effectively connected even when the rental activity doesn’t rise to a U.S. trade or business.8Office of the Law Revision Counsel. 26 USC 882 – Tax on Income of Foreign Corporations Connected With United States Business Without the election, gross rents are taxed as FDAP at 30% with no deductions. With it, you subtract depreciation, mortgage interest, repairs, property taxes, and other expenses, then pay tax on net rental profit. The math almost always favors the election.
One catch: the election sticks. Once made, it applies every future year unless the IRS grants permission to revoke.
How the Tax Is Calculated
Start with gross effectively connected income, subtract allowable business deductions, and apply the rate. Ordinary and necessary business expenses come off: wages, rent, utilities, depreciation, insurance, and allocated interest. Foreign corporations face a more complex interest deduction calculation under Treasury regulations designed to prevent excessive debt from being loaded onto U.S. operations.9eCFR. 26 CFR 1.882-5 – Determination of Interest Deduction
Nonresident alien individuals report on Form 1040-NR at the same graduated rates as U.S. residents. For 2026, the top individual rate is 37% on taxable income above $640,600 for single filers.10Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026 Foreign corporations report on Form 1120-F and pay the flat 21% corporate rate.11GovInfo. 26 USC 11 – Tax Imposed
The Branch Profits Tax
Foreign corporations operating in the U.S. through a branch rather than a separately incorporated subsidiary face a second layer of tax. The branch profits tax is a 30% levy on the “dividend equivalent amount,” essentially after-tax effectively connected income not reinvested in U.S. business assets.12Office of the Law Revision Counsel. 26 USC 884 – Branch Profits Tax The logic is symmetry. A foreign-owned U.S. subsidiary pays 21% corporate tax, and dividends to its foreign parent face a 30% withholding. Without the branch profits tax, a foreign corporation could operate through a branch and skip that second layer. An applicable income tax treaty can reduce or eliminate the rate.
Partnership Withholding
Partnerships earning effectively connected income must withhold tax on the share allocable to each foreign partner under Section 1446. The rate is 37% for non-corporate foreign partners and 21% for corporate foreign partners.13Internal Revenue Service. Partnership Withholding Partnerships report the withholding on Form 8804 and issue each foreign partner a Form 8805.14Internal Revenue Service. Instructions for Forms 8804, 8805, and 8813 Installment payments run quarterly on Form 8813.
When a foreign partner sells or transfers a partnership interest, the buyer must withhold 10% of the amount realized.15eCFR. 26 CFR 1.1446(f)-2 – Withholding on the Transfer of a Non-Publicly Traded Partnership Interest Amount realized includes cash, other property, and the reduction in the seller’s share of partnership liabilities. Reporting and payment are due within 20 days of the transfer. As with the real estate withholding, this is a prepayment, not the final bill.
Treaty Relief and Permanent Establishment
Most U.S. tax treaties replace the broad “U.S. trade or business” concept with a narrower “permanent establishment” standard. Business profits of a foreign resident of a treaty country are exempt from U.S. tax unless the business is conducted through a permanent establishment in the United States, which usually requires a fixed place of business like an office, factory, or workshop. A treaty-country resident can have a U.S. trade or business under domestic law and still owe no U.S. tax on business profits if no permanent establishment exists.
Claiming the benefit requires disclosure. Taxpayers file Form 8833 whenever they take a treaty-based position that overrides the Internal Revenue Code.16Internal Revenue Service. About Form 8833, Treaty-Based Return Position Disclosure Under Section 6114 or 7701(b) Skipping it triggers a penalty of $10,000 for corporations and $1,000 for other taxpayers, assessed separately for each undisclosed position.17eCFR. 26 CFR 301.6712-1 – Failure to Disclose Treaty-Based Return Positions The penalty applies even when the underlying treaty claim is correct.
Filing Deadlines and the Cost of Missing Them
The deadline depends on your status and how income is earned:
- Nonresident aliens receiving U.S. wages file Form 1040-NR by April 15 following the close of the tax year.18Internal Revenue Service. Taxation of Nonresident Aliens
- Nonresident aliens without U.S. wages or a U.S. office file Form 1040-NR by June 15.
- Foreign corporations with a U.S. office file Form 1120-F by April 15 for calendar-year filers.
- Foreign corporations without a U.S. office file Form 1120-F by June 15 for calendar-year filers.19Office of the Law Revision Counsel. 26 USC 6072 – Time for Filing Income Tax Returns
An automatic six-month extension is available, but it extends filing only, not payment. Tax owed must still be paid by the original due date to avoid interest. If you expect to owe at least $1,000 after withholding and refundable credits, quarterly estimated payments are required on the same schedule as domestic taxpayers.20Internal Revenue Service. Form 1040-ES(NR) – U.S. Estimated Tax for Nonresident Alien Individuals Missing them draws an underpayment penalty even if you settle the full balance at filing.
The consequence of filing late is where the effectively connected income regime has real teeth. Fail to file a timely return and the IRS can strip away every deduction and credit, taxing gross effectively connected income instead of net.8Office of the Law Revision Counsel. 26 USC 882 – Tax on Income of Foreign Corporations Connected With United States Business For a business with thin margins, that can multiply the tax bill several times over. The IRS grants a limited reprieve: filing within 18 months of the original due date preserves the right to claim deductions.21Internal Revenue Service. Allowance of Deductions and Credits on 1120-F Delinquent Returns After that window closes, gross-basis taxation applies and the damage is often irreversible.