A foreign company can create meaningful U.S. tax exposure well before it opens a formal U.S. branch or subsidiary. Under U.S. domestic law, the key threshold is whether the foreign corporation is engaged in a trade or business within the United States. If it is, the corporation is taxed on income that is effectively connected with that U.S. trade or business under IRC section 882(a)(1). In treaty cases, the analysis may narrow to whether the foreign enterprise has a permanent establishment in the United States, but the domestic-law trade-or-business standard is generally broader than the treaty PE standard.
General rule
For foreign corporations, U.S. tax exposure usually begins with two linked questions:
- Is the foreign corporation engaged in a trade or business within the United States?
- If so, what income is effectively connected with that U.S. trade or business?
IRC section 864(b) provides an important starting point. It states that a trade or business within the United States includes the performance of personal services within the United States during the taxable year, subject to narrow exceptions. That rule matters because many foreign businesses first enter the U.S. market through people rather than property: sales personnel, service providers, executives, secondees, or contractors.
Once a foreign corporation is engaged in a U.S. trade or business, IRC section 882(a)(1) taxes its taxable income that is effectively connected with that business. IRC section 864(c) then determines which items of income, gain, or loss are treated as effectively connected.
When U.S. contacts become a U.S. trade or business
The Code does not give a single comprehensive definition of a U.S. trade or business, so the inquiry is heavily factual. Authorities commonly describe the test as whether the U.S. activities are considerable, continuous, and regular.
Common fact patterns that can create a U.S. trade or business include:
- employees or agents performing services in the United States
- a U.S. sales office soliciting, negotiating, or executing contracts
- technicians or service personnel performing after-sale support in the United States
- U.S.-based executives or personnel doing more than mere stewardship or oversight for the foreign parent
By contrast, some activities are specifically carved out. IRC section 864(b)(2) excludes certain trading in stocks, securities, and commodities through independent agents or for the taxpayer’s own account, subject to limitations and dealer exceptions. There is also a narrow personal-services exception in IRC section 864(b)(1), but it applies only to certain services performed by a nonresident alien individual temporarily present in the United States for no more than 90 days and earning no more than $3,000, and it does not provide a general corporate safe harbor.
A practical point is that using a contractor or agent instead of a direct employee does not automatically solve the problem. The activities of agents can be relevant in determining whether the foreign corporation itself is engaged in a U.S. trade or business.
Why source and ECI matter
Not all U.S. contacts produce the same tax result. After a U.S. trade or business exists, the next issue is whether the income is effectively connected income.
IRC section 864(c)(3) provides a broad residual rule: all U.S.-source income of a foreign person, other than the categories governed by section 864(c)(2), is treated as effectively connected with the conduct of a U.S. trade or business. For U.S.-source FDAP income and capital gains, section 864(c)(2) applies the asset-use test and business-activities test. Those tests ask whether the income is derived from assets used in or held for use in the U.S. business, or whether the U.S. business activities were a material factor in realizing the income.
Foreign-source income is generally not ECI, but IRC section 864(c)(4)(B) creates important exceptions. Foreign-source rents, royalties, certain dividends and interest, guarantee fees, and certain inventory sales can be treated as effectively connected if the foreign corporation has a U.S. office or other fixed place of business to which the income is attributable and the statutory conditions are met. The office-attribution rule is limited by section 864(c)(5), which disregards many agent offices unless the agent has and regularly exercises contract authority or regularly fills orders and is not an independent agent.
For services income, source generally follows where the services are performed. U.S.-source income includes compensation for labor or personal services performed in the United States, and foreign-source income includes compensation for services performed outside the United States. Where services are performed partly inside and partly outside the United States, the regulations use the method that best reflects the facts and circumstances, often time-based apportionment.
Permanent establishment: narrower than U.S. trade or business, but still risky
If an income tax treaty applies, the foreign corporation may avoid U.S. tax on business profits unless it has a permanent establishment in the United States. The treaty PE threshold is generally narrower than the domestic-law U.S. trade-or-business threshold.
Two recurring PE theories are especially important.
First, a fixed place of business PE may arise if the foreign enterprise carries on its business through a fixed place in the United States. A U.S. subsidiary’s office does not automatically become the parent’s PE, but if space at the subsidiary is at the disposal of the foreign parent and the parent’s own business is carried on there, a PE may exist.
Second, a dependent-agent PE may arise if a person in the United States acts on behalf of the foreign enterprise and habitually exercises authority to conclude contracts binding on the enterprise.
The treaty materials emphasize several points:
- the contracts must relate to the foreign enterprise’s essential business operations, not merely internal or ancillary matters
- the authority must be exercised habitually, not only in isolated or unusual cases
- the contracts must be binding on the foreign enterprise, even if final signature is elsewhere and the U.S. person effectively negotiates all material terms
- an independent agent acting in the ordinary course of its business generally does not create a PE
This is why “mere lead generation” is often treated differently from active negotiation or contract conclusion. A U.S. person limited to identifying prospects and passing them to non-U.S. personnel presents a materially lower PE risk than a U.S. person who negotiates pricing, commits the foreign principal, or effectively closes deals.
Common traps for foreign groups
Several recurring issues cause foreign groups to underestimate U.S. exposure.
One is assuming that a U.S. subsidiary fully shields the foreign parent. It does not. A foreign parent can still have its own U.S. trade or business or PE if U.S.-based personnel act for the parent rather than solely for the subsidiary.
Another is assuming that management oversight is always safe. The authorities suggest that stewardship and oversight of investments in subsidiaries may not, by themselves, create a U.S. trade or business for the foreign parent. But the line becomes much less favorable when U.S.-based executives negotiate revenue-generating contracts or otherwise act as sales agents for the foreign parent.
A third is overlooking foreign-source income that can become ECI through a U.S. office. Foreign corporations sometimes focus only on U.S.-source receipts, but section 864(c)(4)(B) can pull certain foreign-source items into ECI if they are attributable to a U.S. office or fixed place of business.
A fourth is assuming that remote or digital activity avoids source issues. The traditional rule for services looks to where the service is performed, not where the customer is located. For cloud transactions, recent regulations classify cloud transactions as services, and proposed sourcing rules would use a multifactor formula based on intangible property, personnel, and tangible property rather than customer location. That area remains technically complex, but the broader point is that digital business models do not eliminate U.S. nexus analysis.
Filing consequences
If a foreign corporation is engaged in a U.S. trade or business, filing obligations become critical. IRC section 882(c)(2) provides that a foreign corporation receives the benefit of deductions and credits only by filing a true and accurate return with the required information. In practice, that means Form 1120-F is often essential even where the taxpayer believes little or no net tax is due.
This rule is especially important because failure to file can leave the foreign corporation unable to claim deductions connected with effectively connected income. IRS practice materials also emphasize early factual development around U.S. offices, personnel, contract activity, and service performance locations because those facts drive both the U.S.-trade-or-business determination and the ECI analysis.
State tax is a separate problem
Even where a treaty protects a foreign company from federal income tax absent a PE, that treaty protection generally does not extend to state income taxes. State rules vary widely. Some states start from federal taxable income and may effectively follow treaty-exempt treatment, while others impose tax based on their own nexus and income-computation rules. So a foreign company can have limited or no federal income tax exposure and still face state filing or tax issues.
Conclusion
For foreign companies, U.S. tax exposure often begins with people, not entities. A foreign corporation can create a U.S. trade or business through regular U.S. services, sales activity, or other profit-oriented contacts, and once that threshold is crossed, IRC sections 864 and 882 determine whether the resulting income is effectively connected and taxable on a net basis. If a treaty applies, the permanent-establishment standard may narrow the exposure, but fixed-place and dependent-agent theories remain significant risks where U.S. personnel do more than preparatory or auxiliary work. The practical lesson is that foreign groups should analyze U.S. contacts early, document who is acting for whom, and distinguish carefully between support activity, stewardship, and revenue-generating conduct.