Foreign Mutual Funds and the PFIC Rules: Why Your Overseas Index Fund Is a U.S. Tax Problem

An American moves to London, opens a local brokerage account, and buys a low-cost index fund, exactly what any financial advisor would recommend. Years later, she learns that the fund is a passive foreign investment company, that she should have been filing Form 8621 every year, and that when she sells, the gain may be taxed under a regime designed to make deferral painful.

This is one of the most common problems I see among Americans abroad who did everything else right.

What makes a PFIC

Section 1297(a) defines a passive foreign investment company as a foreign corporation that meets either of two tests for the taxable year:

• The income test: 75 percent or more of its gross income is passive income.
• The asset test: the average percentage of its assets that produce passive income, or are held for the production of passive income, is at least 50 percent.

A mutual fund, unit trust or exchange-traded fund organized outside the United States typically earns dividends, interest and gains and holds a portfolio of securities. That is the profile of a PFIC. Many foreign funds are organized as corporations or are treated as corporations for U.S. tax purposes. The result is that most foreign pooled investment funds held by Americans are PFICs.

The location of the fund is what matters. A U.S.-domiciled mutual fund that invests in foreign stocks is not a PFIC because of that. A foreign-domiciled fund that invests in U.S. stocks can be.

The default regime: excess distributions under section 1291

Unless you make an election, a PFIC is a section 1291 fund. Here is how section 1291 works, in plain English.

When you receive an excess distribution, or sell the shares at a gain, the amount is not simply taxed as a dividend or capital gain. Under section 1291(a)(1), the excess distribution is allocated ratably to each day in your holding period. The part allocated to the current year, and to years before the company was a PFIC, is taxed as ordinary income. The parts allocated to earlier PFIC years are not included in current income. Instead, your tax for the current year is increased by a deferred tax amount.

Section 1291(c) builds that deferred tax amount in two pieces. For each prior year, the amount allocated to that year is multiplied by the highest tax rate in effect for that year. Then interest is added on each of those tax increases, using the rates and method that apply to underpayments under section 6621, running from the due date for the prior year to the due date for the current year.

Section 1291(a)(2) applies the same treatment to gain on a disposition. The Form 8621 instructions describe an excess distribution as the part of a current-year distribution that exceeds 125 percent of the average distributions received in the three preceding years, or the shorter holding period, and note that distributions in the first year of the holding period are not excess distributions.

Put simply: ordinary income rates rather than capital gain rates, the top rate for prior years regardless of your actual bracket, and an interest charge on top. For a fund held quietly for a decade, the effective result can be painful.

The elections that soften it

The Form 8621 instructions describe two elections that change the treatment going forward.

• Qualified electing fund (QEF). A shareholder can elect under section 1295 to treat a PFIC as a QEF. You then include your pro rata share of the fund's ordinary earnings and net capital gain in income each year, which preserves capital gain character for the fund's gains. The catch is practical: the fund must provide the information you need, and many foreign funds do not. A separate election is required for each PFIC.
• Mark-to-market. If the PFIC stock is marketable stock, generally stock regularly traded on a qualifying exchange, you can elect under section 1296 to include each year's increase in value in income, with certain losses deductible up to prior inclusions. It avoids the interest charge but produces ordinary income annually.

Elections made late, after years of holding, involve additional rules for the earlier years. The details are technical and depend on the fund, so get the elections right before you sell, not after.

Form 8621: the annual report

Section 1298(f) requires each United States person who is a shareholder of a PFIC to file an annual report, unless the IRS provides otherwise. The report is Form 8621. The current instructions are dated December 2025.

The instructions list several circumstances that require Form 8621, including receiving certain distributions, recognizing gain on a disposition, reporting QEF or mark-to-market information, making an election, and the general annual reporting requirement of section 1298(f).

There is a limited exception that people misread. The instructions say a shareholder is not required to complete Part I, the summary of annual information, for a section 1291 fund if the aggregate value of all PFIC stock is $25,000 or less on the last day of the tax year, $50,000 for a joint return, and the shareholder does not receive an excess distribution or recognize gain on a disposition. That is an exception to completing one part of the form for small holdings in quiet years. It is not a general pass on PFIC rules, and the threshold counts all PFIC stock, including QEF and mark-to-market stock.

The Form 8621 is attached to your income tax return. If you file a timely Form 8621, the PFIC does not have to be detailed again on Form 8938, though it is listed in Part IV of Form 8938 as reported on another form.

Why a missing Form 8621 is dangerous

Section 6501(c)(8) includes information required under section 1298(f) in its list. If a required Form 8621 is not filed, the assessment period for the return does not expire until three years after the information is furnished, limited to the related items only if the failure was due to reasonable cause. See Form 8938 penalties and the statute for how that rule works.

Undisclosed foreign financial asset understatements under section 6662(j) are tied to specific information reporting sections such as 6038D. A foreign fund held in an account that should have been on Form 8938 can bring the 40 percent rate into play if income from it was left off the return.

Pensions and other special cases

Not every foreign investment held through a wrapper is treated the same way. Funds held inside certain foreign pension or retirement arrangements may be analyzed differently, depending on the arrangement and any treaty. The Form 8938 instructions also note that Rev. Proc. 2020-17 exempts certain tax-favored foreign trusts from Forms 3520 and 3520-A reporting, while reporting under section 6038D is not affected. These are fact-specific questions, and the answer depends on the exact account.

What to do if you hold foreign funds

• Inventory every foreign fund, ETF and unit trust you hold, directly or in a foreign brokerage account, and the purchase dates.
• Determine whether each is a PFIC. Some funds publish statements for U.S. investors that include QEF information.
• Decide whether a QEF or mark-to-market election is available and sensible.
• Consider whether to sell PFICs and replace them with investments that do not create PFIC issues, after modeling the tax on the sale.
• If Forms 8621 were missed, address them as part of a broader compliance plan, such as the Streamlined Foreign Offshore Procedures if income was also unreported, or the delinquent information return procedures if it was not.

Foreign funds are an ordinary part of financial life abroad. The PFIC rules treat them as anything but ordinary. If you hold them, let's talk before you sell, not after.