The portfolio interest exception is the most valuable cross-border provision that almost nobody sets up correctly. It is a zero rate written into the statute, available to lenders from any country, treaty or not. And it fails quietly, years after the loan was made, for reasons that were entirely fixable on day one.
Here is how it usually reaches us. An investor in China lends money to a U.S. company. Sometimes it is a relative's startup, sometimes a real estate project, sometimes their own operating business. The loan is papered, interest is paid on schedule, and everyone assumes the interest simply goes home. In year three the borrower's accountant asks where the Forms 1042-S are, and the conversation changes.
U.S.-source interest paid to a foreign person defaults into the 30% withholding regime of §871(a) for individuals and §881(a) for corporations. The borrower must withhold 30% of every payment and remit it. If the borrower does not, the borrower owes the tax.
The portfolio interest exception, §871(h) for individuals and §881(c) for corporations, removes that tax entirely for qualifying interest. The catch is in the word qualifying. Eligibility is tested at origination and at every payment. It cannot be claimed retroactively, and it cannot be repaired by good intentions.
The eight conditions
All eight must hold. Miss one and the whole payment stream is back at 30%.
The borrower
- The borrower is a U.S. person. This is what makes the interest U.S.-source in the first place. Interest from a foreign borrower is outside this analysis entirely.
The lender
The lender is a foreign person: a non-resident alien individual, a foreign corporation, or a foreign trust.
The lender is not disqualified. Three categories are excluded: a bank lending in the ordinary course; a 10% shareholder of the borrower (10% or more of voting power in a corporate borrower, or 10% or more of capital or profits in a partnership borrower); and a controlled foreign corporation related to the borrower.
The 10% test uses the constructive-ownership rules of §318 with modifications, and this is where family lending goes wrong. Stock owned by a spouse, children, grandchildren, or parents is attributed to the lender. A father lending to his daughter's U.S. company, in which she owns 100%, is treated as owning 100% himself. He fails. The workable structures put the lender in a position with no equity, directly or by attribution, in the borrower. That usually means a different family member, a trust, or a single-member LLC whose owner has no ownership path into the borrower.
The income
The payment is interest or original issue discount. Not a fee, not a guaranteed payment, not a disguised return on equity.
It is FDAP income, not effectively connected income. If the lender is engaged in a U.S. trade or business and the interest is connected to it, the exception does not apply.
It is not contingent interest. Interest set by reference to the borrower's receipts, sales, cash flow, income, profits, property value, or dividends is excluded under §871(h)(4). A note paying "10% fixed plus 2% of gross revenue" fails on the 2%, and the taint can spread.
The paperwork
The debt is in registered form. Ownership is recorded on the books of the issuer or a registrar, and transfer happens only by surrender and re-registration. Since the HIRE Act of 2010, effective for obligations issued after March 18, 2012, bearer debt does not qualify. A promissory note payable "to bearer" or transferable by simple delivery is disqualified no matter how the rest of the deal is built. We see this in loans between family members and business partners constantly; the template they downloaded was a bearer instrument and nobody noticed.
The borrower holds a valid Form W-8 before the first payment. Form W-8BEN for an individual lender, Form W-8BEN-E for an entity. It certifies foreign status and, for entities, FATCA classification. It expires at the end of the third calendar year after signature and must be renewed.
A worked example
A foreign investor lends $300,000 to a U.S. company on a three-year registered note at 10%. Total interest over the term: $90,000.
Structure A. The loan is routed through a U.S. C corporation owned by the investor. The corporation receives the interest, pays tax on it, and distributes what is left as a dividend.
| Amount | |
|---|---|
| Interest received by U.S. corporation | $90,000 |
| Federal corporate tax (~21%) and California (~8.84%) | ≈ $26,856 |
| After-tax cash available for dividend | ≈ $63,144 |
| 30% dividend withholding to foreign shareholder | ≈ $18,943 |
| Net to investor | ≈ $44,201 |
| Effective tax rate | ≈ 50.9% |
Structure B. The foreign investor holds the registered note directly, W-8BEN on file, all eight conditions met.
| Amount | |
|---|---|
| Interest paid to foreign lender | $90,000 |
| U.S. withholding under §871(h) | $0 |
| Net to investor | $90,000 |
Same borrower, same $90,000 of interest. What separates the two outcomes is a properly drafted note and a one-page form signed before the first payment. (Figures are approximate and ignore state deductibility, treaty rates, and home-country tax.)
Why the failures are silent
Portfolio interest problems do not announce themselves. Payments go out, nothing is withheld, and the file looks clean until someone examines it. Six patterns account for most of what we correct:
- No Form W-8 on file. Without it, the borrower had no basis for a 0% rate and is liable for 30% of every payment made, plus interest and penalties.
- The note is not in registered form. See above. Family loans are the usual culprit.
- The lender became a 10% shareholder after origination, typically by converting part of the debt to equity in a later round. Status is tested at each payment date, not once.
- Contingent interest was added by amendment: a profit participation, an equity kicker, a bonus tied to revenue.
- FATCA classification undocumented. An entity lender must also satisfy Chapter 4. An incomplete W-8BEN-E can trigger 30% FATCA withholding even when Chapter 3 is perfectly satisfied.
- Forms 1042 and 1042-S not filed. Even at a 0% rate, the borrower must report each payment on Form 1042-S and file an annual Form 1042. The penalties are per form, per year, and apply whether or not any tax was due.
The borrower, not the lender, carries the liability when the exception fails. A U.S. company taking money from a foreign lender should treat the eight conditions as a closing checklist, not an afterthought.
The origination file
Before the first dollar of interest moves, the borrower's file should contain six things:
- The signed note, with a registered-form clause and a transfer-by-re-registration provision.
- A register of holders kept by the borrower. One page is enough.
- A capitalization table showing that the lender, and everyone attributed to the lender under §318, holds less than 10%.
- A signed Form W-8BEN or W-8BEN-E, dated before the first payment, with the expiry date calendared.
- Written confirmation that the interest formula has no contingent component.
- Calendar entries for Form 1042-S (due March 15 following the payment year) and the annual Form 1042.
Six documents, assembled once. They turn a 30% exposure into a 0% rate that survives audit.
Questions we hear most
Does my country need a tax treaty with the U.S. for this to work? No. The portfolio interest exception is statutory. It is available to lenders from any jurisdiction, which is exactly why it is often more useful than treaty relief for investors from countries with a limited or no U.S. treaty.
My company in China wants to lend to our U.S. subsidiary. Can we use this? Almost never. A parent owns more than 10% of the subsidiary and is a 10% shareholder by definition. Related-party interest lives under treaty rates and the earnings-stripping rules of §163(j), not under the portfolio interest exception.
My brother owns the U.S. company. Can I lend to it? Siblings are not in the §318 attribution chain, so a sibling lender is not automatically disqualified. Parents, children, grandchildren, and spouses are. The capitalization table still has to be checked for indirect paths.
What does "registered form" actually look like on paper? A note that names the holder, is recorded in a register maintained by the borrower, and can be transferred only by notifying the borrower and re-issuing the note in the new holder's name. A clause in the loan agreement plus a one-page register is usually sufficient. It has to exist from day one.
Do I still owe tax at home on the interest? Usually yes. The U.S. exception removes U.S. withholding. It does not change the lender's obligations in China or anywhere else. Cross-border planning looks at both sides of the ledger.
We set up a loan three years ago and did none of this. Can it be fixed? Going forward, often yes: re-paper the note in registered form, obtain a W-8, and confirm the ownership position. Payments already made without withholding remain the borrower's exposure and should be assessed with a CPA before any voluntary correction.
Sources
- 26 U.S.C. §871(h), §881(c), §871(h)(3) (10% shareholder), §871(h)(4) (contingent interest), §163(f) (registered form)
- IRS, Nonresident aliens: exclusions from income
- IRS, About Form W-8BEN and About Form W-8BEN-E
- IRS, About Form 1042-S
- Hiring Incentives to Restore Employment (HIRE) Act, Pub. L. 111-147, §502 (repeal of the bearer-bond exception)
General information, not tax advice. Consult a CPA on your specific facts before structuring or funding cross-border debt.
