U.S. Trade or Business Trigger

A foreign corporation engaged in a trade or business in the United States at any time during the tax year must file Form 1120-F. The definition of “trade or business” is broad and fact-dependent. It generally requires a level of activity that is regular, continuous, and considerable — though a single significant transaction can sometimes qualify. Having employees or dependent agents in the U.S. who regularly negotiate and conclude contracts on the corporation’s behalf almost always creates a trade or business presence.

Services performed within the United States are a primary trigger. When a foreign corporation’s employees or subcontractors perform work in the U.S., the income attributable to those services is effectively connected income. This applies to consulting firms, production companies, technology companies with U.S. operations, and any entity performing services on U.S. soil regardless of where the contract was signed or where the client is located.

Effectively Connected Income

Income that is effectively connected with a U.S. trade or business is taxed at graduated corporate rates, similar to domestic corporations. This includes revenue from services performed in the U.S., gains from the sale of U.S. real property interests under FIRPTA, and certain income from assets used in or held for use in the U.S. business. The foreign corporation may deduct expenses allocable to effectively connected income, making the actual tax calculation more nuanced than the flat withholding rate applied to non-connected income.

Protective Returns

Even when a foreign corporation believes it has no filing obligation, filing a protective return is strongly recommended. If the IRS later determines that the corporation did have effectively connected income, the ability to claim deductions and credits against that income depends on having filed a timely return. Without a protective filing, the IRS can assess tax on gross income with no deductions allowed. This protective strategy is particularly important for corporations with borderline trade or business activity or those relying on treaty positions to reduce their obligations.

Treaty Considerations

Tax treaties between the United States and the foreign corporation’s home country can modify filing obligations. Many treaties provide that a foreign corporation is not taxable in the U.S. unless it has a permanent establishment here. However, the corporation must still file Form 1120-F and attach Form 8833 to claim the treaty-based position. Failure to disclose the treaty position can result in penalties even if the underlying tax liability is zero.