Deciphering Source of Income: How to Determine Domestic Income vs Foreign Source Income?

Welcome to the intricate world of “Source of Income”. In this article tailored to those engaging with contractors, freelancers, sellers, and royalty earners, we explore the factors that determine source of income and shine a light on the IRS rules that differentiate U.S. and foreign source income.

At its core, the source of income is all about geographical origins. It’s a concept that determines whether the money you earn is categorized under U.S. or foreign sources, a distinction with significant tax implications.

This becomes especially pertinent for businesses with international operations and for the expanding segment of the economy engaging workers from around the globe on a contractual basis.

Why is this important? It’s not just a matter of where the money comes from; it’s about understanding the intricate tax rules that govern these payments.

In this comprehensive post, we’ll cover several important topics related to income sources. First, we’ll look at the main factors that determine whether income is considered U.S. or foreign. Next, we’ll explain the rules for categorizing U.S. source income, followed by those for foreign earned income. We’ll also discuss why these rules exist and how they impact financial management. Lastly, we’ll delve into taxation and tax withholding for nonresident aliens, a key area for anyone involved in international payouts or trying to navigate the maze of global taxation around contractors. So, buckle up and join us as we shed light on this critical aspect of financial management and payout compliance!

Key factors in determining source

At a high level, the key factors that point to U.S. vs foreign source income include:

U.S. source income:

  • Location where services are performed
  • Residence of payer
  • Location of assets or property generating the income
  • Place of sale for purchased inventory
  • In the case of streaming royalties, the content (song, podcast, etc) was consumed by someone within the U.S.

Foreign source income:

  • Services performed outside the U.S.
  • Payers located outside the U.S. 
  • Assets or property located outside the U.S.
  • Production of produced inventory happens outside the U.S.
  • In the case of streaming royalties, the content (song, podcast, etc) was consumed by someone outside of the U.S.

However, rules differ significantly depending on the type of income. Let’s take a closer look at how different income categories are sourced.

Rules for categorizing U.S. source income

The Internal Revenue Code sections 861-865 contain detailed rules for determining whether income is U.S. or foreign-sourced. In general, the following types of income are treated as U.S. sources:

Personal services income

Income from personal services, including salaries, wages, and independent contractor fees, is typically sourced based on where the services were performed. If services are performed partly in the U.S. and partly in another country, an allocation is required based on time spent working in each location.

There are some exceptions, such as for foreign vessel crew members and scholarship income for activities conducted outside the U.S.

Salary and wages

With respect to salary and wages, their source is typically based on where the services are performed. Allocation of income in this category also follows a ‘time basis’ method. This means if the service is conducted both within and outside the USA, remuneration needs to be allocated accordingly.

Some fringe benefits like housing, education, local transportation, etc., can have special rules. They are often determined based on the principal place of work. However, there are exceptions for independent contractors and crews working on foreign ships commuting between the U.S. and foreign ports.


Interest incomes are typically sourced based on the payer’s residence. Interest paid by a U.S. resident or business falls under U.S. source income, whereas interest paid by non-U.S. residents is treated as foreign-source income.


The sourcing for dividends largely depends upon the place of the corporation’s incorporation. Dividends from U.S. corporations fall under U.S. source, whereas those from foreign corporations are considered as foreign-source income unless it involves instances like a foreign corporation having effectively connected revenue with U.S. business activities.


Rent incomes are sourced where the property is located – simple! If you own a property in America that fetches rental income, it’s considered as American-sourced income irrespective of who pays for it.

All these mentioned types further branch out into sub-categories when considering exceptions or specific cases such as depreciable property sales or intangible properties, etc. Therefore, understanding such specifics becomes essential to ensure businesses accurately assess their earnings under appropriate headers of source-income rules.

Sale of personal property

Selling personal property follows a set of unique rules primarily related to the inventory status and particulars:

  • Purchased inventory: The income source is based on where the sale took place.
  • Produced inventory: Allocating the income source depends on where the product was made.

Income from sales of depreciable property is allocated based on where depreciation deduction claims were made. In the case of intangible property sales, it can depend upon factors like whether payments are contingent or non-contingent and, further, if royalties are involved.

This complex categorization highlights why businesses must be vigilant about detailing their incomes accurately for smooth tax compliance.

Rules for foreign-earned income

Income is classified as a foreign source when the location of the income activity or payer is outside the U.S. Major categories of foreign source income include:

  • Compensation for personal services performed outside the U.S.
  • Interest paid by a non-U.S. resident
  • Dividends paid by a foreign corporation
  • Rentals from property located outside the U.S.
  • Royalties for use of property outside the U.S.
  • Gains from the sale of property located outside the U.S.

There are some exceptions and special rules for certain types of payments, like royalties from controlled foreign subsidiaries. For example, if a U.S. citizen receives royalties from a controlled foreign subsidiary, the income may be treated as U.S. source income under certain conditions. But in general, income is foreign-sourced when generated by foreign payers or activities conducted outside the U.S.

Purpose of the source of income rules

At this point, you may be wondering why these rules are in place. The purpose of the source-of-income rules is twofold. Primarily, they help define an international business tax landscape, and secondly, they influence tax obligations and deductions for businesses. Today, the U.S. maintains treaties with over 60 countries. These treaties often modify the source rules to structure a comprehensive framework.

Determine the taxability of nonresident alien income

When it comes to nonresident aliens, the U.S. taxes them on their U.S. source income only. It is the source rules that define what income is considered U.S.-sourced versus foreign-sourced. This then allows for a clear determination of what portion of their income is liable to US tax.

It’s interesting to note that without this classification, assessing nonresident alien taxation would be an opaque process. Therefore, understanding source rules makes determining tax liability and 1042-S forms far more straightforward and manageable for businesses with a nonresident labor force.

Calculate foreign tax credit limitation

Now, let’s look at the foreign tax credit limitation. This credit is allowed for foreign taxes that businesses pay on their earnings. But there is a limit to how much can be claimed.

This limitation is calculated separately for different categories of income so as not to double-dip in benefits. Here, again, source rules play a critical role as they are used to assign income into respective categories accurately.

Ensuring this kind of precision helps businesses avoid any discord with taxation authorities and minimizes their chances of facing penalties or audits.

Nonresident alien taxation & tax withholding

For businesses hiring nonresident alien contractors or employees, understanding the nuances of IRS tax withholding for nonresident aliens is crucial for companies engaging with international talent or partners.

The source rules determine how much of the nonresident alien’s income is subject to U.S. taxation.

Remember, nonresident aliens are only taxed in the U.S. on their U.S. source income. Any foreign-sourced income is exempt from U.S. tax.

Properly categorizing payments made to nonresident aliens is essential to calculate the correct tax withholding and fulfill IRS reporting obligations.

When making payments to nonresident alien contractors, here are some key points to keep in mind:

  • Services performed in the U.S. generate U.S. source income. Any work conducted by a nonresident alien contractor within the U.S. gives rise to income that should be classified as U.S. source compensation. Applicable taxes must be withheld from payments for these services.
  • Partly U.S., partly foreign services require allocation. If a nonresident contractor performs services partly in the U.S. and partly in a foreign country, an allocation of income is required based on time spent working in each location. The portion attributable to U.S. work days is treated as U.S. source income.
  • Travel days generally count as U.S. work days. When allocating income between U.S. and foreign sources, days traveling within the U.S. to a work location are usually counted as days performing services in the U.S.
  • Inventory sales rules apply. For nonresident alien contractors paid commissions on inventory sales, special inventory sales rules apply to source the income based on production vs sales location. This overrides the normal service performance rule.
  • Exempt income categories. Certain narrow categories of nonresident alien income are exempt from U.S. taxation under IRS regulations or tax treaties. For example, compensation is paid to certain teachers, students, and foreign vessel crew members.
  • Independent contractor vs employee. The same source rules generally apply whether a nonresident alien is paid as an independent contractor or an employee. However, classification as an employee creates additional withholding and tax return filing requirements.

Overall, businesses paying nonresident aliens should consult a tax professional to ensure they are properly classifying payments by source and complying with all IRS withholding and reporting rules. Mishandling these obligations can lead to penalties and other issues.

Withholding & tax treaties

For nonresident aliens in the United States, the default withholding rate is typically set at 30% when a tax treaty isn’t applied. This rate applies to various types of income, including wages, salaries, and other compensation.

However, the landscape of withholding taxes becomes more intricate when tax treaties come into play.

The United States has income tax treaties with numerous countries, each designed to prevent double taxation and to reduce tax evasion. These treaties often provide for lower withholding rates or exempt certain types of income from withholding altogether. The extent and nature of these benefits vary significantly from one treaty to another, reflecting the unique economic and diplomatic relationships between the U.S. and each treaty country.

Furthermore, these tax treaties differ not just by country, but also by the type of income being paid. For example, payments for royalties, dividends, interest, and other specific types of income may be taxed at different rates under a treaty. This differentiation often hinges on the nature of the work performed or the source of the income. As such, companies must be vigilant in understanding and applying the correct withholding rates, taking into account the specific circumstances of each nonresident alien they are paying. This level of complexity underscores the importance of thorough tax planning and legal consultation, ensuring compliance with the myriad regulations governing international taxation.

Summing it all up

For businesses hiring nonresident alien contractors or employees, understanding the nuances of IRS tax withholding for nonresident aliens is crucial.

It’s also crucial to remember that various rules decide what counts as U.S. source income. For example, where was the service done? Where are the assets? Following these rules lets businesses stay on top of their taxes.

Managing this can be tricky for companies dealing with global payments and nonresident workers, however, Trolley’s cloud-based payouts platform can help.

Trolley was built to make taxes easy for businesses and the people they pay. From automated W-8 & W-9 collection to the distribution of end-of-year IRS forms, Trolley takes the hassle out of 1042-S & 1099s so you can focus on what you do best.

See Trolley Tax in action: Take the Trolley Tax tour

Book a demo of Trolley’s tax features today >

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