If you are a US shareholder of a Controlled Foreign Corporation, Subpart F is the rule that determines how much of the corporation's income you have to report on your US return each year, even if no distribution was made. The framework is one of the oldest in international tax and one of the most consequential for individual CFC owners.
Quick Answer
Subpart F captures four categories of CFC income for current US taxation: foreign personal holding company income (passive), foreign base company sales income, foreign base company services income, and insurance income. Two exceptions reduce the reach: the de minimis rule (if the total falls below the lesser of 5% of gross income or $1 million) and the high-tax exception (if the income is taxed abroad at over 18.9% effective rate).
1. Why Subpart F Exists
Before Subpart F, US shareholders could form foreign corporations in low-tax jurisdictions, accumulate income in those entities, and defer US tax indefinitely until the income was distributed as a dividend. The regime, introduced in 1962 under IRC Sections 951 to 965, ended that deferral for specific categories of income that were considered easily movable to low-tax countries.
The mechanic: instead of waiting for a dividend, US shareholders include their pro rata share of certain CFC income in their own taxable income in the year the CFC earns it. Tax is paid currently. When the CFC eventually distributes those amounts, they are excluded from taxable income because they have already been taxed (the previously taxed earnings and profits, or PTEP, system).
GILTI, added by the Tax Cuts and Jobs Act in 2017, expanded the anti-deferral framework to capture income that Subpart F missed. The two regimes operate alongside each other and have to be analyzed together.
Whether your foreign corporation qualifies as a CFC in the first place is the threshold question. Our post on Controlled Foreign Corporations covers the ownership tests and constructive ownership rules that determine CFC status.
2. The Four Categories of Subpart F Income
Subpart F captures four distinct types of income, each defined in the statute with its own rules.
| Category | What It Covers | Why Captured |
|---|---|---|
| Foreign Personal Holding Company (FPHCI) | Dividends, interest, rents, royalties, gains on sales of investment property | Most movable, most likely to be parked in low-tax jurisdictions |
| Foreign Base Company Sales (FBCSI) | Income from related-party buy/sell where goods are bought/sold outside CFC's country | Designed to prevent profit-shifting via related-party intermediaries |
| Foreign Base Company Services (FBCSvcI) | Services performed for related parties outside CFC's country | Mirror of FBCSI for service businesses |
| Insurance Income | Premium and investment income from insuring risks outside CFC's country | Captures captive insurance arrangements |
3. Foreign Personal Holding Company Income
FPHCI is the most-applied category. It captures the kind of income most easily moved across borders: dividends, interest, rents, royalties, gains on sales of investment property, currency gains, and certain commodity gains.
Several exceptions limit FPHCI within the larger CFC structure:
Same-country exception: dividends and interest paid by a related corporation organized in the CFC's country of incorporation are excluded if certain substance requirements are met.
Active financing exception: income earned by an active banking, financing, or insurance business is excluded under specific conditions, including substantial activity in the CFC's country.
Active rental and royalty exception: rents and royalties from active conduct of a trade or business may be excluded if the CFC actively manages the underlying assets.
These exceptions are technical and fact-specific. Operating a holding company that earns only investment returns rarely qualifies for any of them. Operating a CFC with genuine business activity that incidentally produces some passive income often does.
4. Foreign Base Company Sales and Services Income
FBCSI captures profits from related-party transactions where the CFC effectively serves as an intermediary. The classic pattern: a US parent sells goods to a CFC in a low-tax country, which then sells the same goods to customers in another country. Profit accumulates at the CFC level, where it is taxed lightly, and the related-party setup raises the question of whether the CFC has economic substance or is merely a paper conduit.
FBCSI applies when both (a) the goods are purchased from or sold to a related party, and (b) the goods are not manufactured, produced, or used in the CFC's country of incorporation. If the CFC manufactures or substantially transforms the goods, FBCSI generally does not apply.
FBCSvcI mirrors FBCSI for services. It applies when the CFC performs services for a related party, the services are performed outside the CFC's country, and the services would be services performed by the related party but for the CFC structure.
If you are a CFC shareholder and have not run the Subpart F analysis, an international tax review confirms what is in scope before the return is prepared.
5. The De Minimis Rule
If total Subpart F income for the year is less than the lesser of 5% of the CFC's gross income or $1 million, none of the income is included under Subpart F. This rule prevents the regime from applying to CFCs whose Subpart F exposure is incidental to a larger active business.
The threshold is calculated separately each year. A CFC that crosses the de minimis threshold in one year and falls below it the next has different Subpart F treatment in each year.
There is also a full inclusion rule that operates as the inverse: if Subpart F income exceeds 70% of gross income, all of the CFC's income is treated as Subpart F. This catches CFCs whose business is overwhelmingly passive or related-party even if some active income is mixed in.
6. The High-Tax Exception
Subpart F income that is subject to an effective foreign tax rate higher than 18.9% (90% of the maximum US corporate rate of 21%) can be excluded from current US inclusion under the high-tax exception.
The exception is elective. It must be made on a CFC-by-CFC basis and applies to specific items of Subpart F income, not to the CFC's income as a whole. The election can produce favorable treatment for CFCs operating in higher-tax jurisdictions where the foreign tax already approximates US tax.
Final regulations issued in 2020 made the high-tax exception available for both Subpart F and GILTI on a unified basis. Before 2020, the rules differed between the two regimes. The current framework applies to tax years beginning on or after the regulations' effective date.
7. A Worked Example
A US founder owns 100% of a CFC in a low-tax jurisdiction. The CFC earns $500,000 of total income in the year, broken down as:
$400,000 from active manufacturing operations
$80,000 of interest income from investments
$20,000 of dividends from a related US corporation
The interest and dividends ($100,000 total) are FPHCI. They exceed both 5% of gross income ($25,000) and they exceed nothing relative to the $1 million ceiling, so the de minimis rule does not apply. They do not meet the 70% full inclusion threshold either. The $100,000 is included in the founder's US return as Subpart F income for the year.
The $400,000 of active manufacturing income is not Subpart F. It may, however, be subject to GILTI under the separate regime that applies to CFC income beyond Subpart F. Both regimes are evaluated together when preparing Form 5471.
8. The Coordination with GILTI
Subpart F and GILTI work together. Subpart F applies first. Whatever is captured under Subpart F is excluded from GILTI's calculation. GILTI then catches a portion of the remaining CFC income that exceeds 10% of the CFC's qualified business asset investment (QBAI).
In practice, most active CFCs end up with two parallel inclusions: a Subpart F amount for the passive or related-party income, and a GILTI amount for the active income above the QBAI return. Both amounts increase the shareholder's PTEP balance, and both reduce future taxable distributions.
For individual shareholders, the Section 962 election can change the effective rate on both inclusions by allowing taxation as if the shareholder were a domestic corporation. The election applies to the shareholder's full CFC inclusion, not selectively to Subpart F or GILTI.
Form 5471 reports both Subpart F and GILTI inclusions on its various schedules. Our post on Form 5471 filing requirements covers the categories of filers and the schedules each category has to complete.
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.