Report forex losses on your tax return according to which Internal Revenue Code section covers your trades: retail spot forex losses default to Section 988 and go on Schedule 1 (Form 1040) as ordinary losses with no annual cap; regulated currency futures and qualifying forward contracts fall under Section 1256 and go on Form 6781, then Schedule D; and if you made a timely mark-to-market election as a qualified trader under Section 475(f), your losses go on Form 4797. Which section applies is the whole ballgame, because it decides whether you deduct the entire loss this year or $3,000 at a time.
Identify Which Tax Rule Covers Your Trades
Before you touch a form, pin down the classification. There are three possibilities, and only one applies to any given trade.
Section 988 (the default for spot forex)
If you trade spot forex through an online broker and have not filed any special elections, your gains and losses are Section 988 ordinary income or ordinary loss.1Office of the Law Revision Counsel. 26 USC 988 – Treatment of Certain Foreign Currency Transactions Section 988 covers transactions denominated in or determined by reference to a foreign currency, including forward contracts, options, and the rolling spot contracts most retail brokers offer.
Ordinary loss is the treatment retail traders usually want. It offsets wages, business income, interest, and any other ordinary income dollar for dollar, with no annual cap. Lose $25,000 trading spot forex while earning $80,000 from a job, and taxable income drops to $55,000.
Section 1256 (regulated futures and qualifying forwards)
Currency futures traded on regulated exchanges and certain interbank forward contracts fall under Section 1256 instead.2Office of the Law Revision Counsel. 26 USC 1256 – Section 1256 Contracts Marked to Market Two rules apply: every open position is treated as sold at fair market value on the last business day of the tax year, and 60% of the total gain or loss is long-term capital while 40% is short-term capital, regardless of actual holding period.3Internal Revenue Service. Form 6781 – Gains and Losses From Section 1256 Contracts and Straddles Because these are capital losses, the $3,000 annual deduction cap against ordinary income applies once capital gains are exhausted.
Section 475(f) (traders who elected mark-to-market)
If forex trading is your business and you filed a timely Section 475(f) election, all gains and losses become ordinary and the full loss is deductible against any income with no cap. To qualify as a trader you must seek profit from daily price swings, trade in substantial volume, and trade with continuity and regularity throughout the year.4Internal Revenue Service. Topic No. 429 Traders in Securities Someone placing a handful of trades a month around a full-time job is an investor, not a trader.
The election deadline is rigid. To use mark-to-market for 2026, the written election statement must be attached to your 2025 return filed by April 15, 2026 (the unextended due date).4Internal Revenue Service. Topic No. 429 Traders in Securities Miss it and you are stuck with the default treatment for that tax year; there is no retroactive fix. If you did not file the statement before your losing year, you cannot claim 475(f) treatment on the return reporting that year’s losses.
Where the Loss Goes on Your Return
The classification tells you which form to use. Getting this pairing wrong is one of the errors the IRS most often flags on forex returns.
Section 988 losses
Report the net Section 988 loss on Schedule 1 (Form 1040), Additional Income and Adjustments to Income, as other income entered as a negative number. The Schedule 1 total flows to Form 1040 and reduces adjusted gross income directly. The IRS has not published form-specific instructions dedicated to Section 988 forex losses, and practitioners disagree at the margins, but Schedule 1 is the standard placement for non-business forex losses.
Convert each foreign currency amount to U.S. dollars at the exchange rate on the transaction date. The IRS does not mandate a specific rate source; it accepts any posted rate used consistently throughout the year.5Internal Revenue Service. Yearly Average Currency Exchange Rates
Section 1256 losses
Report all Section 1256 contract results on Form 6781, Gains and Losses From Section 1256 Contracts and Straddles, Part I. The form applies the 60/40 split automatically: Line 8 calculates 40% as short-term, Line 9 calculates 60% as long-term.3Internal Revenue Service. Form 6781 – Gains and Losses From Section 1256 Contracts and Straddles Those amounts transfer to Schedule D, where they combine with your other capital gains and losses for the year.
If a net capital loss remains after offsetting all capital gains, deduct up to $3,000 against ordinary income ($1,500 if married filing separately). Any excess carries forward indefinitely.6Internal Revenue Service. Topic No. 409 Capital Gains and Losses
Section 475(f) losses
Traders who elected mark-to-market report ordinary gains and losses on Form 4797, Sales of Business Property, Part II. The Form 4797 instructions specifically list gains and losses from a Section 475(f) mark-to-market election as belonging in that section.7Internal Revenue Service. Instructions for Form 4797 The net result flows to Schedule 1, then to Form 1040. The loss bypasses Schedule D entirely and faces no annual deduction cap. Gains and losses from a 475(f) trading business are not subject to self-employment tax.4Internal Revenue Service. Topic No. 429 Traders in Securities
When Losses Exceed Your Income
What happens next depends again on whether the loss is ordinary or capital.
Ordinary losses under Section 988 or 475(f): net operating loss
When ordinary forex losses exceed all your other income for the year, the excess can create a net operating loss. An NOL from a tax year beginning after December 31, 2017, carries forward indefinitely but cannot be carried back. In each future year the NOL deduction is limited to 80% of taxable income computed without the NOL deduction.8Office of the Law Revision Counsel. 26 USC 172 – Net Operating Loss Deduction A $50,000 NOL against $60,000 of income next year lets you use $48,000, leaving $2,000 to carry forward.
Section 1256 capital losses: three-year carryback election
Section 1256 losses come with an option ordinary losses do not have: individuals can elect to carry a net Section 1256 loss back to the three preceding tax years.9Office of the Law Revision Counsel. 26 USC 1212 – Capital Loss Carrybacks and Carryovers The carried-back loss can only offset net Section 1256 gains in those prior years; it will not touch stock gains, real estate gains, or wage income. It goes to the earliest eligible year first and cannot create or increase an NOL in any carryback year. The carried loss keeps its 60/40 character.
Make the election by checking Box D on Form 6781 and entering the carryback amount on Line 6.10Internal Revenue Service. Form 6781 – Gains and Losses From Section 1256 Contracts and Straddles If you had profitable Section 1256 trades in any of the prior three years, the election can generate a refund. Capital losses under Section 1256 cannot generate an NOL because they are not ordinary losses.
Records You Need to Substantiate the Loss
Forex brokers are not required to issue a Form 1099-B for spot currency trades, so the burden of proof falls on you. Keep monthly and annual brokerage statements showing every trade’s date, price, and U.S. dollar equivalent. Download trade confirmations as they occur rather than waiting for a year-end summary that may never come.
Use one recognized exchange rate source for the entire year. Rates posted by your broker on trade confirmations are acceptable as long as you apply the same source across all transactions.5Internal Revenue Service. Yearly Average Currency Exchange Rates
If you are claiming Section 475(f) trader status, keep a daily trade log recording the number of trades executed, hours spent on research and execution, and the nature of your strategy, along with a copy of your timely filed election statement. Without these, an audit will reclassify you as an investor, and an unlimited ordinary loss becomes a capital loss capped at $3,000 a year.
Extra Filings If Your Broker Is Offshore
These filings are separate from reporting the loss itself, but they carry serious penalties on their own if you skip them.
FBAR (FinCEN Form 114)
Any U.S. person with a financial interest in or signature authority over foreign financial accounts must file a Report of Foreign Bank and Financial Accounts if the combined value of all foreign accounts exceeds $10,000 at any point during the calendar year.11FinCEN. Report Foreign Bank and Financial Accounts A forex account at a foreign broker counts. The FBAR is filed electronically through FinCEN’s BSA E-Filing system, not with your tax return, and is due April 15 with an automatic extension to October 15. Penalties for non-willful violations are capped at $10,000 per account per year; willful violations can reach the greater of $100,000 or 50% of the account balance. These penalties apply even if you owe no additional tax.
Form 8938 (FATCA)
You may also need to file Form 8938, Statement of Specified Foreign Financial Assets, with your tax return. Thresholds depend on filing status and residence:
- Single, living in the U.S.: total foreign asset value exceeds $50,000 on the last day of the year or $75,000 at any point during the year.
- Married filing jointly, living in the U.S.: total exceeds $100,000 on the last day or $150,000 at any point.
- Single, living abroad: total exceeds $200,000 on the last day or $300,000 at any point.
- Married filing jointly, living abroad: total exceeds $400,000 on the last day or $600,000 at any point.
FBAR and Form 8938 are separate filings with different thresholds and different destinations. A domestic-only brokerage account eliminates both.
Penalties for Misclassifying the Loss
Reporting a forex loss under the wrong section can trigger the accuracy-related penalty under Section 6662: 20% of the underpayment attributable to negligence or a substantial understatement of income tax. An understatement is substantial if it exceeds the greater of 10% of the tax that should have been shown on the return or $5,000.13Office of the Law Revision Counsel. 26 USC 6662 – Imposition of Accuracy-Related Penalty on Underpayments
The scenario that most often draws this penalty: claiming ordinary loss treatment under Section 475(f) without qualifying as a trader or without filing a timely election. The IRS reclassifies the loss as capital, the $3,000 cap kicks in, and the resulting underpayment picks up the 20% penalty on top of the additional tax. A timely election and clean records are the only reliable protection.