Imagine running a small consulting practice in Texas, opening a sister company in Singapore to serve Asian clients, and earning $400,000 of profit over there. You leave the cash in the Singapore bank account to fund local hiring. You did not take a distribution. You did not transfer a dollar to the U.S. Yet on April 15, your U.S. tax return must report a chunk of that Singapore profit as if it landed in your personal checking account.
Welcome to Subpart F. The rules in Sections 951–965 of the Internal Revenue Code force certain U.S. owners of foreign corporations to pay U.S. tax on the foreign company's earnings the moment they are earned, regardless of whether any cash crosses the border. For 2026, the regime has been overhauled again by the One Big Beautiful Bill Act (OBBBA): GILTI has been renamed to Net CFC Tested Income (NCTI), the routine return shield is gone, and the rules for who counts as a U.S. shareholder have tightened.
If you own a piece of a foreign company, or are thinking about setting one up, here is what the CFC regime actually does, who it catches, and the workable paths that exist for keeping the surprise tax bill manageable.
What a CFC Is, in Plain Terms
A Controlled Foreign Corporation (CFC) is a foreign corporation where more than 50 percent of the vote or value of the stock is owned, directly or indirectly, by U.S. shareholders.
A "U.S. shareholder" for this purpose is a specific term. It means a U.S. person who owns at least 10 percent of the vote or value of the foreign corporation. A U.S. person can be:
- A U.S. citizen or resident individual
- A domestic partnership or S corporation
- A domestic C corporation
- A domestic trust or estate
To trigger CFC status, you add up the stakes of every U.S. shareholder (each with 10 percent or more) and ask whether that total exceeds 50 percent. A foreign corporation that is 100 percent owned by 200 U.S. individuals at 0.5 percent each is not a CFC, because no single owner crosses the 10 percent floor. Flip it around: a corporation owned 51 percent by a single U.S. citizen and 49 percent by foreign investors is a CFC.
The 10 Percent Threshold Counts Vote or Value
Before the Tax Cuts and Jobs Act, the 10 percent test looked only at voting power. The TCJA expanded it to vote or value. This means you cannot dodge U.S. shareholder status by holding nonvoting stock or preferred shares — if their economic value crosses 10 percent, you are in.
Constructive Ownership: The Trap Most People Miss
The CFC rules do not stop at shares you own outright. Section 958 layers on constructive ownership rules borrowed from Section 318, with modifications. Stock owned by certain related parties is attributed to you for purposes of determining whether you are a U.S. shareholder and whether the foreign company is a CFC.
Family Attribution
An individual is treated as owning the stock owned by:
- Spouse
- Children
- Grandchildren
- Parents
Siblings, in-laws, cousins, and grandparents are not in this attribution net. So if your father owns 8 percent of a foreign company and you own 5 percent, you are deemed to own 13 percent for U.S. shareholder testing — even if you have never met your father's business partners.
Entity Attribution
Stock owned by a partnership, estate, or trust is attributed proportionately to the partners or beneficiaries. Stock owned by a corporation is attributed to a shareholder owning 10 percent or more of the corporation's stock.
Downward Attribution: The 2017 Bombshell
The TCJA repealed Section 958(b)(4), which had previously blocked attribution from a foreign person to a related U.S. person. The repeal had a quiet but huge effect: a U.S. subsidiary of a foreign parent now constructively owns the stock its foreign parent holds in foreign brother-sister companies.
Practical translation: a foreign-headquartered group with one U.S. subsidiary can suddenly find that every foreign company in the worldwide structure is a CFC for U.S. tax purposes, and the U.S. sub is treated as a U.S. shareholder of all of them — with attendant Form 5471 filing duties for the U.S. sub, even when the U.S. sub owns zero shares directly.
What Subpart F Actually Taxes
Once a foreign corporation is a CFC, the central question becomes: what categories of its income get taxed to U.S. shareholders before any distribution? Subpart F was designed to catch passive or easily-shifted income. The most important categories:
Foreign Personal Holding Company Income (FPHCI)
This is the classic passive bucket. It includes:
- Dividends, interest, royalties, rents, and annuities
- Net gains from sales of property that produces FPHCI (e.g., stocks, bonds)
- Net foreign currency gains not tied to the CFC's active business
- Income from notional principal contracts
- Payments in lieu of dividends
The policy logic: passive income is mobile. A U.S. parent could otherwise drop a portfolio of bonds into a Cayman subsidiary and indefinitely defer U.S. tax on the interest. Subpart F shuts that down.
Foreign Base Company Sales Income (FBCSI)
Income from buying goods from a related party and selling them outside the CFC's country of incorporation, or buying from anyone and selling to a related party for use outside that country. The classic example: a Bermuda subsidiary that buys widgets from a German affiliate and sells them to a French affiliate, never touching Bermuda.
Foreign Base Company Services Income
Services performed by the CFC outside its country of incorporation for or on behalf of a related person. If the Singapore CFC sends consultants to Tokyo to do work for its U.S. parent, that services income is Subpart F.
Insurance Income
Premiums on insuring risks located outside the CFC's home country fall into Subpart F.
The De Minimis and High-Tax Escapes
Two important relief valves keep small or genuinely high-taxed foreign operations out of Subpart F.
De Minimis Rule
If the CFC's gross foreign base company income plus gross insurance income is less than the lesser of 5 percent of gross income or $1 million, none of it is Subpart F income for the year. For genuinely operating businesses with incidental passive income, this is a meaningful carve-out.
High-Tax Exception
If an item of income was subject to foreign tax at an effective rate greater than 90 percent of the U.S. corporate rate (currently 21 percent, so the threshold is 18.9 percent), the U.S. shareholder can elect to exclude it from Subpart F. The exception requires an election and applies on an item-by-item basis under final regulations.
Net CFC Tested Income (NCTI): What Used to Be Called GILTI
Subpart F was never a complete fence. It caught passive and base-shifted income, but active business profits earned offshore could still grow tax-deferred. The TCJA closed that gap in 2017 by creating GILTI — Global Intangible Low-Taxed Income — a deemed inclusion that swept in most of what Subpart F missed.
OBBBA, signed in July 2025, renamed GILTI to Net CFC Tested Income (NCTI) for tax years beginning after December 31, 2025, and tightened the math.
How NCTI Works for 2026 and Beyond
For each U.S. shareholder, you compute the aggregate "tested income" of all CFCs (gross income minus deductions, with several carve-outs for Subpart F income, effectively connected income, high-taxed income, and related-party dividends). The shareholder's share is then included in U.S. income.
The OBBBA changes hit three levers:
- QBAI is gone. Pre-2026 GILTI subtracted 10 percent of "qualified business asset investment" (QBAI), a routine-return concept that protected manufacturers and asset-heavy businesses. OBBBA repealed this. NCTI now equals tested income with no shield.
- Section 250 deduction reduced to 40 percent. C corporations get a deduction equal to 40 percent of NCTI (down from 50 percent of GILTI). With the 21 percent corporate rate, the effective NCTI rate for C corps is roughly 12.6 percent before foreign tax credits.
- Foreign tax credit haircut reduced to 10 percent. Previously, only 80 percent of foreign taxes paid on GILTI inclusions could be credited. Now C corps can claim 90 percent, which materially improves outcomes for high-tax jurisdictions.
Individual U.S. shareholders do not get the Section 250 deduction unless they make a Section 962 election to be taxed as a corporation on the inclusion. Without that election, NCTI is taxed at ordinary individual rates (up to 37 percent) with limited FTC relief — punishing for direct individual ownership of CFCs.
Holding on Any Day Rule
OBBBA also changed who must pick up Subpart F and NCTI. Pre-2026, only U.S. shareholders who owned CFC stock on the last day of the CFC's tax year had inclusions. Starting in 2026, any U.S. shareholder who owned the stock on any day during the year must include their pro rata share. Selling out before year-end no longer eliminates the inclusion.
Form 5471: The Reporting Engine
Subpart F and NCTI inclusions are computed and reported on Form 5471, "Information Return of U.S. Persons With Respect to Certain Foreign Corporations." The form is notoriously long — multiple schedules covering income statements, balance sheets, earnings and profits, and shareholder calculations.
Form 5471 has five filer categories. The most common:
- Category 1: U.S. shareholders of a Specified Foreign Corporation.
- Category 2: U.S. officers or directors of a foreign corporation in which a U.S. person acquired 10 percent or more.
- Category 3: A U.S. person who acquires, disposes of, or becomes a 10 percent shareholder.
- Category 4: A U.S. person who controlled a foreign corporation for at least 30 days during the year.
- Category 5: A U.S. shareholder of a CFC at any time during the CFC's year, where the corporation was a CFC for at least 30 days.
Penalties Bite Hard
Form 5471 carries a base penalty of $10,000 per form per year for failure to file, with continuation penalties of up to $50,000 per form. The penalties are automatic and apply even if no tax is owed. Worse, late or missing Form 5471 keeps the statute of limitations open on the entire return under Section 6501(c)(8) until three years after the form is filed — meaning the IRS can audit any item on your return long after the normal three-year window.
Common Traps That Catch Founders and Family Offices
The Single-Member LLC Trick That Backfires
A U.S. citizen who owns a foreign holding company through a U.S. disregarded LLC is not insulated. The disregarded LLC is invisible for tax purposes, so the U.S. citizen is treated as the direct owner — full U.S. shareholder status and Form 5471 attaches personally.
Foreign-Parented Groups with One Small U.S. Sub
After the downward attribution change in 2017, a foreign multinational with a tiny U.S. distribution subsidiary may inadvertently turn every foreign affiliate into a CFC from the U.S. sub's perspective. Treasury issued Rev. Proc. 2019-40 to provide relief for "unrelated section 958(a) U.S. shareholders" in such groups, but the relief is narrow and the analysis is fact-specific.
Spouses Quietly Crossing the 10 Percent Line
Two spouses each own 6 percent of a foreign company. Neither thinks they are a "U.S. shareholder." But family attribution under Section 958(b) treats each as owning the other's stock, pushing both above 10 percent. Both have full Subpart F and Form 5471 obligations.
Forgetting the Earnings and Profits Computation
Subpart F and NCTI inclusions are based on the CFC's earnings and profits computed under U.S. tax accounting principles — not local GAAP, not IFRS, and not the foreign tax return. A profitable Singapore subsidiary may have very different U.S. E&P than its Singapore book profit because of differences in depreciation, inventory methods, and accruals. This conversion work is the heart of Form 5471 Schedules C, H, and J.
Strategies That Reduce or Defer the Sting
Subpart F cannot be eliminated for most U.S.-owned active foreign businesses, but the rough edges can be sanded down.
Check-the-Box to a Branch
If the foreign entity elects to be treated as disregarded under the check-the-box rules (Form 8832), it ceases to be a corporation for U.S. tax purposes and becomes a foreign branch. Subpart F and NCTI no longer apply because there is no CFC. The trade-off: branch income is currently taxable to the U.S. owner in full anyway, and you lose deferral on retained active income. For very low-income, very high-tax, or pure-loss operations, branch status can simplify things considerably.
Section 962 Election for Individuals
An individual U.S. shareholder of a CFC can elect under Section 962 to be taxed on Subpart F and NCTI inclusions as if they were a C corporation. This unlocks the 21 percent rate and the foreign tax credit, dramatically reducing the immediate U.S. tax. The catch: when the cash is later actually distributed, the previously-taxed amounts above the U.S. tax already paid are taxed again as ordinary dividends. The election is most useful when foreign tax is high enough that the FTC zeroes out the U.S. corporate rate, leaving little or no second-layer tax.
High-Tax Election on a GILTI/NCTI Basis
Final regulations under Section 951A permit a high-tax election that excludes from NCTI any income taxed by a foreign country at a rate exceeding 18.9 percent (90 percent of the U.S. corporate rate). The election is all-or-nothing across a controlled group, made annually, and can be a powerful tool for groups operating in high-tax jurisdictions like Germany, France, or Japan.
Use a Domestic C Corporation as the Holding Vehicle
For sizeable foreign operations, owning the CFC through a U.S. C corporation rather than directly often produces better economics: the Section 250 deduction, the 90 percent FTC on NCTI, and the Section 245A 100-percent dividends-received deduction on certain foreign-source dividends combine to reduce the long-run U.S. tax friction. Individual founders who initially set up offshore directly often regret skipping this step.
Keeping the Books Straight Across Borders
Working through Subpart F and NCTI without good underlying records is a nightmare. Each CFC needs a clean trial balance reconciled to U.S. tax principles, broken out by category of income, with intercompany transactions tagged. Earnings and profits pools, previously taxed E&P (PTEP) layers, and foreign tax credit baskets must be tracked year over year. A missed PTEP layer can lead to double tax on a later distribution; a missing FTC basket can strand credits that should have offset NCTI.
The work is too granular for one spreadsheet to handle for long. Sound accounting hygiene at the foreign sub — daily booking, monthly reconciliations, and consistent chart-of-accounts mapping between local books and U.S. E&P — pays for itself the first time the CFC needs a Form 5471.
Simplify the Recordkeeping Behind International Tax Compliance
Running a foreign subsidiary while staying clean for Subpart F, NCTI, and Form 5471 demands a transparent ledger you can audit line by line — across years, jurisdictions, and currencies. Beancount.io provides plain-text, version-controlled accounting that gives you complete visibility into every transaction, intercompany transfer, and earnings-and-profits adjustment — no black boxes, no vendor lock-in. Get started for free and see why developers, finance professionals, and global founders are switching to plain-text accounting.