What if your U.S. C corporation could pay a federal tax rate of roughly 13% on profits from foreign customers, instead of the standard 21%? That is not a theoretical loophole. It has been the law since 2018, and it lives in a single line item on a one-page IRS form most accountants outside large multinationals barely know exists: Form 8993, the Section 250 deduction.
This deduction goes by a confusing name. It is called the deduction for Foreign-Derived Intangible Income, or FDII, even though you do not need a single patent, trademark, or other "intangible" asset to claim it. The word "intangible" is doing strange work here. What matters is not what you sell, but who you sell it to and where they use it. If a U.S. C corporation sells software, machinery, consulting services, or even raw materials to a foreign customer for use outside the United States, a chunk of the resulting profit qualifies for a deduction that drives the effective federal rate down to 13.125%.
There is one wrinkle worth knowing up front: a 2025 law called the One Big Beautiful Bill Act (OBBBA) rewrote large pieces of the FDII regime starting with tax years that begin after December 31, 2025. The headline rate goes up slightly to 14%, but the calculation gets much simpler, and a lot of mid-size exporters who could not previously make the math work will start seeing meaningful benefits in 2026. The name also changes: Congress renamed FDII to "Foreign-Derived Deduction Eligible Income," or FDDEI. The deduction is the same idea; the label is new.
This guide walks through how the FDII deduction actually works, who can claim it, what kind of income qualifies, how Form 8993 gets filled out, the major OBBBA changes that take effect in 2026, and the documentation traps that have tripped up companies in IRS exams.
Why Congress Created the FDII Deduction
To understand FDII, it helps to know what problem it was designed to solve. Before 2018, multinational companies had a strong tax incentive to hold valuable intellectual property in foreign subsidiaries. A U.S. company that owned its patents abroad could license them back, shift profits offshore, and pay little or no U.S. tax on global earnings. Congress wanted to flip that incentive.
The 2017 tax reform created two new regimes that work as a pair. GILTI (now called NCTI under OBBBA) taxes U.S. shareholders on most of the earnings of their controlled foreign corporations, so parking IP offshore stopped being a free ride. FDII does the reverse: it rewards companies that keep their income-producing IP and operations inside the U.S. by giving them a reduced effective rate on income earned from foreign customers.
The two provisions are both part of Section 250 of the Internal Revenue Code, which is why the same Form 8993 covers both. They are administered together because Congress designed them as two sides of the same coin.
Who Can Claim the FDII Deduction
FDII is narrower than many people assume. Only domestic C corporations can claim the deduction directly. S corporations, partnerships, sole proprietorships, and trusts cannot. The only exception is for individuals who make a Section 962 election to be taxed at corporate rates on their share of CFC income, which is a relatively niche planning move.
This is a significant restriction. A software startup organized as an LLC and taxed as a partnership cannot use FDII no matter how much foreign revenue it generates. Many growing exporters discover this only after the fact, which makes the choice of entity an important early conversation. For some companies, the FDII benefit alone is enough to justify converting to a C corporation, despite the loss of pass-through treatment for U.S. income.
A second restriction is the "domestic" requirement. The taxpayer must be a U.S. corporation. A foreign subsidiary cannot claim FDII on its own income. The income has to be earned by a U.S. C corporation directly, even if some of the operational footprint sits abroad.
What Income Qualifies as Foreign-Derived
The foreign-derived part of FDII is where the real action is. Three buckets of income can qualify:
General property sold to a foreign person for foreign use. This is the most intuitive category. A U.S. corporation manufactures aircraft components, agricultural equipment, or consumer goods and sells them to a buyer in another country, who uses or resells them outside the United States. The seller has to establish that the property is sold to a foreign person and is for a foreign use. If the same physical good ends up coming back into U.S. commerce, it stops qualifying.
Intangible property licensed or sold to a foreign person for foreign use. Software licenses, patent rights, trademarks, copyrights, and know-how transferred to foreign customers for use outside the U.S. fall here. A U.S. tech company that licenses its SaaS platform to overseas enterprises typically reports this revenue as intangible property income.
Services provided to a person located outside the United States. Consulting, engineering, legal, financial, advertising, and similar services performed for foreign clients who use the result abroad. The key question is where the person receiving the service is located, not where the service provider sits.
Several categories are explicitly excluded. Sales to U.S. persons do not count, even if the U.S. person resells abroad (with some narrow exceptions). Income from foreign branches is carved out. Subpart F income, GILTI inclusions, financial services income, and certain dividends from CFCs are all excluded from the FDII calculation. The deduction is meant to apply only to active, U.S.-based operations selling into foreign markets.
How the Old FDII Calculation Worked (Pre-2026)
For tax years through December 31, 2025, the calculation follows a five-step chain that is more complicated than it needs to be. It is worth understanding because most companies will still be filing 2025 returns in 2026 using these rules.
The starting point is Deduction Eligible Income, or DEI. You begin with the C corporation's gross income, then strip out the excluded categories (Subpart F, GILTI, foreign branch income, financial services income, certain dividends). From the remaining gross income, you subtract a proportional share of deductions, including interest expense and research and experimentation costs that have to be allocated against this income stream.
From DEI, you subtract a Deemed Tangible Income Return, or DTIR. This is calculated as 10% of the corporation's Qualified Business Asset Investment (QBAI), which is essentially the adjusted tax basis of tangible depreciable property. The theory is that ordinary tangible assets earn a normal 10% return, and the FDII deduction should only apply to the "intangible" income above that threshold.
The number left after subtracting DTIR is Deemed Intangible Income, or DII. This is the pot of income Congress believes flows from intangible assets and is the eligible base for the deduction.
You then determine the Foreign-Derived Ratio: how much of your DEI is FDDEI (the foreign-derived slice) divided by total DEI. Multiply DII by this ratio, and you have FDII.
Finally, multiply FDII by 37.5% to arrive at the actual deduction. Because the C corporation rate is 21%, a 37.5% deduction on FDII reduces the effective federal tax on that income to 13.125%.
A worked example with rounded numbers makes this concrete. Suppose a U.S. C corporation has $400,000 of DEI for the year. Its QBAI is $1,000,000, so DTIR is $100,000. That leaves DII of $300,000. Of the $400,000 of DEI, $250,000 comes from foreign sales, so the foreign-derived ratio is 62.5%. FDII is $300,000 × 62.5% = $187,500. The deduction is $187,500 × 37.5% = $70,313. At a 21% rate, that deduction saves $14,766 in federal tax.
How OBBBA Changes the Calculation for 2026 and Beyond
For tax years beginning after December 31, 2025, OBBBA cleans up the formula in ways that benefit many companies. The bullet points matter:
The QBAI subtraction is gone. There is no more DTIR step. You no longer have to compute the adjusted basis of tangible property and carve out a 10% deemed return. The full DEI is in scope.
Interest expense and research and experimentation expenses no longer have to be allocated against deduction-eligible income. This is a major simplification and a real expansion of benefits. Under the old rules, R&E-heavy companies often saw their effective FDII benefit shredded by expense allocations. That penalty disappears.
The deduction rate drops from 37.5% to 33.34%. Combined with the 21% corporate rate, this raises the effective rate on foreign-derived income from 13.125% to roughly 14%. On its face, this looks like a tax increase. In practice, because the base of qualifying income is larger and the calculation is much simpler, most exporters will see a larger total deduction in 2026 than they did in 2025.
The name changes. FDII is now called Foreign-Derived Deduction Eligible Income, or FDDEI. The acronym lives on, but a lot of the older guidance and IRS practice unit material will use the FDII name for the foreseeable future. GILTI is similarly renamed to NCTI (Net CFC Tested Income).
Form 8993 itself gets a major redesign for 2026 tax years to reflect the new mechanics. Practitioners should expect the revised instructions to drop in late 2026.
The Taxable Income Limitation: A Cap That Bites in Loss Years
A subtle limitation in Section 250 catches companies off guard. If the sum of a corporation's FDII (now FDDEI) and its GILTI (now NCTI) inclusion exceeds the corporation's taxable income for the year (calculated before the Section 250 deduction), both amounts get reduced proportionally.
In other words, the FDII deduction cannot create or enlarge a net operating loss. If your corporation has a loss year, you may not be able to use the full deduction. This is most painful for early-stage companies investing heavily in R&D, which often have both significant foreign revenue and net taxable losses on a U.S. basis. They generate FDII economically but cannot extract the deduction in the year earned, and the deduction does not carry forward.
For a company close to breakeven, this limitation is a planning prompt. Accelerating revenue recognition or deferring deductions can sometimes preserve the FDII benefit that would otherwise disappear.
Filling Out Form 8993: What the IRS Looks At
Form 8993 is structurally short but operationally demanding. It pulls together numbers from across the corporation's books and requires the underlying schedules to be defensible.
Part I asks for the components of DEI: gross income broken out by source, minus the excluded categories. The numbers usually trace back to the corporation's general ledger but require categorization that ordinary financial reporting does not produce automatically.
Part II is where the foreign-derived calculation happens. The corporation reports its foreign-derived gross receipts in three buckets matching the qualifying categories: general property sales, intangible property sales and licenses, and services. Each bucket needs to be substantiated with records showing the foreign customer, the foreign destination or location, and that the use occurred outside the U.S.
Part III computes the GILTI inclusion piece. Part IV applies the taxable income limitation and Part V calculates the actual deduction. The total flows to a single line on Form 1120.
The arithmetic is straightforward once the inputs are correct. The real work happens in producing the inputs.
Documentation: The Audit Battlefield
When the IRS examines an FDII claim, the focus is almost always on substantiation of foreign use. The taxpayer has to establish that the property was sold to a foreign person and is for a foreign use, or that the service was performed for a person located abroad.
The final Section 250 regulations issued in 2020 eased some of the prescriptive documentation rules that were in the proposed regulations, but corporations still need a contemporaneous record. Useful documentation usually includes:
- Sales contracts identifying the buyer's location and intended use
- Shipping documents showing foreign destination
- Customer certifications or representations of foreign use
- Invoices and payment records with foreign addresses
- For services: engagement letters and deliverable records tied to a foreign client location
- For software and digital goods: account registration data, geolocation logs, billing addresses
Companies that wait until audit to assemble this evidence often lose pieces of the deduction. The cleanest practice is to tag every transaction at the point of sale with a flag indicating its FDII category and to retain the supporting documents in a structured archive linked to the general ledger.
Where FDII Fits in the Broader International Tax Picture
FDII does not exist in isolation. It is paired with the CFC regime, the foreign tax credit rules, the base erosion and anti-abuse tax (BEAT), and the OECD's global minimum tax (Pillar Two) framework that is rolling out internationally. A coherent international tax strategy needs to look at all of these together.
For some companies, a Pillar Two top-up tax in a foreign country could undermine the U.S. FDII benefit by clawing back the savings at the foreign level. Treasury has been working to ensure FDII is treated as a "qualified refundable tax credit" or otherwise harmonized with the Pillar Two framework, but the details are unsettled as of mid-2026.
What this means practically: do not optimize for FDII in a vacuum. Coordinate with foreign-country tax positions, GILTI/NCTI planning, transfer pricing policies, and foreign tax credit utilization.
Common Mistakes That Reduce or Eliminate the Benefit
A handful of recurring errors show up in IRS exams and in companies' first attempts at the form:
Treating sales to U.S. distributors as foreign-derived. If a U.S. corporation sells to a U.S. wholesaler that resells abroad, the sale does not qualify, with limited exceptions where the corporation can prove the property was for foreign use at the time of the original sale.
Failing to allocate expenses correctly (under pre-2026 rules). Companies sometimes claim FDII on gross foreign revenue without subtracting the proper share of cost of goods sold, R&E, and interest. The IRS has won several disputes on this point. The OBBBA changes mute this issue for 2026 forward, but it remains live for older returns.
Missing the taxable income limitation. Loss-year corporations sometimes claim the full deduction and then have to amend.
Ignoring entity structure. Pass-through entities cannot claim FDII. Owners who think their LLC qualifies are often surprised. A C corporation conversion is a major step and should never be done for FDII alone, but it is a real consideration for companies with substantial foreign revenue.
Inadequate foreign use documentation. Without contemporaneous evidence, the IRS can disallow FDII categorization on exam and force a recalculation at the higher rate.
A Note on Bookkeeping for FDII Claims
The FDII deduction is built on a clean separation of foreign-derived income from everything else. If your books mix domestic and foreign customer revenue in the same accounts, or if expense categorizations cannot be traced back to source documents, the calculation becomes guesswork and the audit defense becomes weak.
Tagging every sales transaction at the point of entry with customer location, customer status (foreign person or not), and intended foreign use makes year-end reporting much faster and stronger. The same applies to expense allocations: well-coded R&E spend, interest expense by source, and clearly identified cost of goods sold by sales channel turn an otherwise painful annual exercise into a few hours of spreadsheet work.
Keep Your Export Finances Organized from Day One
Claiming the FDII (now FDDEI) deduction with confidence depends on clean, traceable, year-round records that tie every foreign sale and every allocable expense back to a documented source. Beancount.io provides plain-text accounting that gives you full transparency and version control over your financial data, with no proprietary lock-in. Whether you are a U.S. C corporation with growing foreign revenue or a startup planning a future C-corp conversion, structured plain-text ledgers make the FDII calculation defensible and the audit trail unbreakable. Get started for free and see why developers, finance teams, and CPAs are switching to plain-text accounting.