Section 988 Foreign Currency Tax Trap for US Expats

Your overseas bank account earned interest in euros last year. You also paid down the foreign-currency mortgage on your Spanish apartment. Both feel routine. But under IRC Section 988, those routine transactions may have generated taxable ordinary income — even if you never converted a single euro to dollars. For US expats, foreign currency gains are one of the most quietly expensive compliance traps on the return, because the tax falls at your marginal rate, not the favorable capital gains rate.

This guide covers what Section 988 is, which transactions trigger it, the specific traps expats hit most often, and the handful of legal moves that reduce exposure. For a broader look at expat tax compliance, see the US expat banking and taxes guide.

What Is a Section 988 Transaction?

Section 988 was added to the tax code in 1986 to prevent taxpayers from converting ordinary income into capital gains by denominating transactions in foreign currencies. The core rule: any gain or loss from a "nonfunctional currency transaction" is treated as ordinary income or ordinary loss — not capital gain or capital loss.

For almost every US citizen and resident abroad, the functional currency is the US dollar. Any transaction involving a currency other than USD is potentially a nonfunctional currency transaction subject to Section 988.

Transactions That Qualify

The statute covers four main categories:

• Acquisition or disposition of a nonfunctional currency — spending, exchanging, or otherwise disposing of foreign cash or deposits
• Accrued income or expense denominated in a foreign currency — earning interest or dividends in euros, pounds, or yen before converting them
• Foreign currency denominated debt — mortgages, personal loans, or business loans taken out in a foreign currency
• Forward contracts, futures, and options denominated in foreign currency — common for investors hedging currency risk

Buying foreign stocks does not itself create a Section 988 event. The stock is priced in the foreign currency, but the IRS tracks your cost basis in dollars at the time of purchase, and your sale proceeds in dollars at the time of sale. The resulting gain is capital in character and goes on Form 8949 and Schedule D — not Schedule 1.

Why Section 988 Hits Expats Harder Than Tourists

A tourist who exchanges $500 into euros and spends most of it faces minimal Section 988 exposure. An expat living in Europe for several years can have tens of thousands of dollars flowing through foreign bank accounts, a foreign mortgage, and a local business collecting payments in the local currency. The scale and frequency of transactions makes the exposure qualitatively different.

The key reason this hurts: ordinary income rates. In 2025, the top federal ordinary income rate is 37%. Long-term capital gains top out at 20% (23.8% including net investment income tax). A $50,000 currency gain taxed as ordinary income rather than long-term capital gain can cost $8,500 or more in additional federal tax at the top bracket, before state taxes.

Foreign Tax Credit (FTC) can sometimes reduce double taxation if the foreign country also taxes the same gain. But many foreign currency transactions are recognized only in the United States — the foreign country may not see any taxable event at all — so there is no FTC to apply. For a deeper look at how FTC interacts with expat tax, see FEIE vs. Foreign Tax Credit: Which One to Choose.

The Foreign Mortgage Tax Whipsaw

The single biggest Section 988 surprise for expats is the foreign-currency mortgage. When you borrow in a foreign currency, each principal payment you make is a Section 988 transaction, and if the dollar has weakened against that foreign currency since you took out the loan, you have a taxable gain — even though you did not receive any cash.

For business or rental property, you can recognize Section 988 losses too — if the dollar strengthens and the foreign currency obligation shrinks in dollar terms, that is an ordinary loss that offsets other income. But for a personal residence, the tax code is asymmetric: gains on the mortgage are taxable, and losses are not deductible. This is the whipsaw: the IRS gets the upside, and you absorb the downside.

Expats buying property abroad should read the IRS tax guide for buying rental property abroad before taking out a local-currency mortgage. Using a US dollar denominated loan (if available through an international lender) eliminates this Section 988 exposure entirely.

Foreign Bank Accounts and the $200 Exception

Holding a foreign bank account in a local currency creates Section 988 exposure every time you spend from that account. Each withdrawal, debit card purchase, or transfer is technically a disposition of foreign currency with a calculable gain or loss — determined by the exchange rate when you received the currency versus when you spent it.

The statute includes a personal-use exception: Section 988 gains on personal (non-business, non-investment) transactions are excluded if the gain does not exceed $200 per transaction. This sounds helpful, but it has two important limitations:

1. All-or-nothing threshold: If the gain on a single transaction exceeds $200, the entire gain is taxable — not just the amount over $200. There is no partial exclusion.
2. Losses are not deductible: If your personal foreign currency transactions produce a loss, you cannot deduct it. The personal-use exception cuts only in one direction.

For an expat running significant euros, pounds, or pesos through a personal account — paying rent, buying groceries, funding a local lifestyle — the $200 threshold is easily exceeded on individual transactions. Someone who received €5,000 as a freelance payment in January and spent it in December after the dollar moved against them can have a single Section 988 event with a gain well above $200, making the whole gain taxable.

The Tracking Problem

Tracking basis in foreign currency is practically difficult. Technically, each tranche of foreign currency you acquire has its own basis (the exchange rate on the date you received it). When you spend foreign currency, you need to match what you spent against the basis of what you received — either using specific identification (matching exact lots) or a FIFO method. Very few taxpayers or tax preparers do this rigorously, which creates both underreporting and overreporting risks.

Transaction type	Gains taxable?	Losses deductible?	$200 exclusion available?
Foreign currency spending (personal)	Yes, if gain > $200	No	Yes (per transaction)
Foreign currency mortgage – personal residence	Yes	No	No (debt transactions excluded from personal-use exception)
Foreign currency mortgage – rental/business property	Yes	Yes	No
Foreign currency business receipts	Yes	Yes	No (business transaction)
Forward contracts, futures (no election)	Yes (ordinary)	Yes (ordinary)	No
Forward contracts, futures (with election)	Yes (60/40 capital)	Yes (60/40 capital)	No

The Opt-Out Election for Forward Contracts and Futures

Investors who use forward contracts, currency futures, or options to hedge foreign currency exposure have a statutory option under Section 988(a)(1)(B): they can elect to treat the gain or loss as capital rather than ordinary, provided two conditions are met:

1. The contract must be a capital asset in the taxpayer's hands (not inventory).
2. The election must be made and the position identified before the close of the calendar day on which the position is entered into.

Properly elected, the gain or loss is treated as a Section 1256 contract: 60% long-term capital gain and 40% short-term, regardless of how long you hold the position. At the top bracket, the blended rate is roughly 26.8% (60% × 20% + 40% × 37% plus NIIT), compared to 37% for ordinary income — a meaningful difference on large positions.

The election must be made contemporaneously (on the day of entry). Retroactive elections are not permitted. If you miss the window, the default ordinary income treatment applies.

Calculating and Reporting Section 988 on Your Return

Section 988 gains are reported as "Other Income" on Schedule 1 (Form 1040), Line 8z with the description "Section 988 gain." Section 988 losses go on the same line as "Other Loss" and reduce adjusted gross income.

Calculating the gain or loss requires tracking cost basis in the foreign currency, which means keeping records of:

• The amount of foreign currency received and the exchange rate on the date received
• The amount of foreign currency spent, transferred, or disposed of and the exchange rate on the disposal date
• For foreign-currency debt: the original loan principal in USD at the time of borrowing and the USD equivalent of each principal payment made

The IRS allows the use of actual exchange rates from Reuters, Bloomberg, or other published sources, as well as the IRS annual average exchange rates published in Publication 519. Using spot rates on the actual date of the transaction produces the most accurate result.

Section 988 Recordkeeping Checklist

• Monthly foreign bank account statements showing balances in local currency
• Exchange rates on the dates you received foreign currency payments
• Exchange rates on dates of significant withdrawals, purchases, or transfers
• Loan documents for any foreign-currency mortgage, including amortization schedule
• Exchange rates on each mortgage payment date (for principal portion only — interest is a separate Schedule B item)
• Forward contract or futures confirmations showing the rate locked and settlement rate
• Contemporaneous election documentation if using the opt-out for forward contracts

Strategies to Reduce Section 988 Exposure

Several structural decisions reduce or eliminate Section 988 risk without requiring complex planning:

Use USD-denominated debt. If you purchase property abroad, explore whether an international private bank, US-based lender, or seller financing can structure the loan in US dollars. A USD mortgage eliminates the principal-payment Section 988 event entirely.

Minimize foreign currency balances. Keeping minimal working capital in foreign currency — just enough for local expenses — reduces the basis-tracking burden and limits the potential gain or loss. Sweeping foreign currency receipts to USD regularly shrinks each Section 988 calculation to a small amount.

Keep detailed records from day one. The cost of bad recordkeeping is not just an accuracy penalty; it is also the inability to document losses that might reduce your taxable income. Track your foreign currency cost basis in a spreadsheet from the first day you open a foreign account.

Consider the $200 threshold. For purely personal foreign currency spending (groceries, restaurants, local transportation), the $200 per-transaction exclusion may effectively cover most individual purchases. This does not help with a monthly €2,000 rent payment — one transaction — but it does reduce the compliance burden on many smaller daily purchases.

Consult before a foreign mortgage. The whipsaw on a personal-residence mortgage is the largest single Section 988 risk for most expats. Running numbers before closing on foreign property can reveal the tax cost of different financing structures.

Data Notes / Sources Checked

IRC Section 988 thresholds and treatment verified against the full statute at Cornell Law School Legal Information Institute. The $200 personal-use exclusion amount is a fixed statutory figure and has not been adjusted for inflation since enactment in 1986. The IRS Section 988 practice unit (IRS International Practice Units, FCU CU C 18.2.1.03) was reviewed for transaction categorization. For exchange rate conversion guidance, see IRS Publication: Reporting Foreign Income. Reporting location (Schedule 1, Line 8z) reflects current Form 1040 structure and may change in future tax years.

Conclusion

Section 988 is easy to overlook because it does not appear in the income line items that most expats watch — it hides in "Other Income" and surfaces only when someone asks the right question about your foreign mortgage or bank account. The ordinary-income treatment, the asymmetric personal-use exception, and the large potential dollar amounts make it one of the more consequential compliance areas for Americans living abroad with significant local-currency assets or financing.

The practical checklist is short: track foreign currency basis from day one, use USD financing where possible, flag significant Section 988 transactions to your preparer before filing, and use the opt-out election if you actively trade currency derivatives. For categories in the expat tax and finance cluster, see all our tax compliance guides.

Disclaimer: This article is for general educational purposes and does not constitute tax or legal advice. Tax rules change and depend on individual facts. Consult a qualified US tax professional familiar with international tax before making decisions based on this material. Data on thresholds and rates reflects information available as of July 2025 and may change in subsequent tax years.