A practical 2026 guide to the 61-day window, cross-account reporting, IRA traps, year-end planning, and Section 475 MTM
This article is for active securities traders with frequent turnover, multiple brokerage accounts, options activity, or overlap between taxable and retirement accounts.
Executive Summary
Hyperactive trading in the same securities and related options can generate wash-sale loss adjustments totaling tens or hundreds of thousands of dollars—and sometimes more. Those adjustments can create phantom taxable income when losses remain deferred at year-end. In taxable accounts, the losses are usually deferred rather than lost; however, a replacement purchase in an IRA or Roth IRA can cause the tax benefit to be lost permanently.
Form 1099-B reports broker-level wash-sale adjustments generated throughout the year. Still, it does not determine the taxpayer’s complete wash-sale position or distinguish losses already absorbed in closed positions from losses still deferred in open replacement positions at year-end. Broker reporting follows limited rules, principally for covered securities with the same CUSIP in the same account. Taxpayer-level compliance may require a broader review of multiple taxable accounts, IRAs and Roth IRAs, options, short sales, and other substantially identical positions. Spouse or controlled-entity activity may also require analysis under related-party or anti-abuse principles, but it is not automatically attributed to the taxpayer under the text of Section 1091.
Active traders need multi-account, taxpayer-level trade accounting and year-end planning. GreenTraderTax and Green’s annual Trader Tax Guide use consistent practical positions to address areas where the law does not provide a complete mechanical test. Those positions are explained below.
The wash-sale adjustment reported in box 1g of Form 1099-B can be alarming. But the headline number is not the whole story.
Wash sale rules defer a tax loss rather than erase it. The deferred loss is added to the replacement position’s cost basis. It is usually deductible when the replacement position is sold in a transaction that does not trigger another wash sale. The most serious problems arise when losses remain deferred through year-end—or become permanently nondeductible because the replacement purchase is made in an IRA.
What Is a Wash Sale?
A wash sale occurs when a taxpayer sells stock or securities at a loss and, during the 61 days beginning 30 calendar days before the sale date and ending 30 calendar days after the sale date, acquires substantially identical stock or securities or enters into a contract or option to acquire them. IRC §1091(a). The rule is intended to prevent taxpayers from realizing a tax loss while quickly restoring substantially the same investment position.
The rule also applies when the taxpayer acquires substantially identical securities in a taxable exchange. Purchases of replacement shares in an IRA or a Roth IRA can also trigger the rule.
When the rule applies in a taxable account:
- The current loss is disallowed.
- The disallowed loss is added to the tax basis of the replacement position.
- The holding period of the replacement position includes that of the position sold.
- If only part of the position is replaced, the wash sale adjustment applies on a share-by-share basis to the matched quantity.
In a taxable-account wash sale, the loss is deferred rather than erased: the disallowed amount is added to the replacement position’s cost basis under IRC §1091(d), and the holding period of the position sold generally tacks onto the replacement position under IRC §1223(3). In practice, tax software applies the rules lot by lot.
A Simple Wash-Sale Example
A trader buys 100 shares for $10,000 and later sells them for $8,000, producing a $2,000 loss. Ten days later, the trader buys 100 substantially identical shares for $8,500.
The $2,000 loss is deferred and added to the replacement shares’ $8,500 purchase price, producing an adjusted tax basis of $10,500. If the trader later sells the replacement shares for $9,500 without another replacement purchase within the wash sale window, the deferred loss is released through the higher basis, resulting in a $1,000 tax loss. The replacement trade produced a $1,000 economic gain, but the higher wash-sale-adjusted basis caused the trader to recognize the correct $1,000 net tax loss across both trades.
Wash sale losses in taxable accounts are therefore usually a timing problem rather than a permanent elimination of the deduction. Repeated trading can keep moving the loss from one replacement position to the next, creating a chain that crosses December 31 and shifts the deduction into the following year. A replacement purchase in an IRA or Roth IRA can produce a different—and potentially permanent—result.
Why Form 1099-B May Not Tell the Full Story
Broker reporting is narrower than the taxpayer’s legal obligation. The IRS Form 1099-B instructions require a broker to report a wash sale when both the loss sale and replacement purchase occur in the same account for covered securities with the same CUSIP. A broker may report more, but it is generally not required to identify a replacement purchase in another account—even in another account at the same brokerage firm.
That difference creates two common problems:
- Form 1099-B may omit taxpayer-level wash sales involving another brokerage account, an IRA or Roth IRA, stock and related options, different option contracts, or other substantially identical positions.
- A broker’s aggregate wash-sale adjustments for the year may be large even though most of those losses were absorbed into replacement positions that were sold before year-end.
For example, a broker’s Form 1099-B might report aggregate box 1g wash-sale adjustments of $500,000 for the year. That does not automatically mean $500,000 is deferred into next year. If the trader closed the replacement positions and avoided another acquisition during the applicable wash-sale window, little or none of that amount may remain deferred at year-end. Conversely, a smaller cross-account wash sale omitted from Form 1099-B may still require a taxpayer-level adjustment.
Even if a trader sells securities in December, a January purchase can still trigger a wash sale. Avoid acquiring substantially identical property within 30 days after the loss sale; the trader may reenter on day 31.
Consider using TradeLog for taxpayer-level wash-sale calculations. It imports transactions from multiple brokerage accounts, recalculates wash sales across those accounts, and helps reconcile the results with Forms 1099-B. Importing Forms 1099-B into tax software without this broader reconciliation is a much narrower approach and can leave material wash-sale adjustments unreported.
The IRA Wash-Sale Trap Can Make the Loss Permanent
The harshest wash-sale result occurs when an individual sells stock or securities at a loss in a taxable account and, during the 61-day window, an IRA or Roth IRA acquires substantially identical stock or securities. Under Revenue Ruling 2008-5, the taxable-account loss is disallowed, and the individual’s basis in the IRA or Roth IRA is not increased under Section 1091(d). Unlike an ordinary taxable-account wash sale, the tax benefit can therefore be lost permanently.
An IRA does not report wash sales on trades occurring solely inside the retirement account because its gains and losses are not currently taxable. The danger is the interaction between the taxable loss sale and the IRA or Roth IRA replacement purchase. Revenue Ruling 2008-5 addresses IRAs and Roth IRAs; it does not decide the treatment of employer-sponsored plans such as 401(k) or Solo 401(k) plans. The ruling also does not mention other types of IRAs such as rollover IRAs and SEP IRAs.
A practical safeguard is to maintain a do-not-trade list separating securities traded in taxable accounts from positions held in IRAs and Roth IRAs. A trader might trade individual technology stocks in taxable accounts and hold diversified funds in an IRA, provided the positions are not substantially identical.
Section 475 can provide another solution for a trader who qualifies for trader tax status (TTS). For securities properly included in a valid Section 475(f) trading business, Section 1091 does not apply to losses recognized under the mark-to-market rules. The election does not cover properly identified investment securities, and traders should not assume it resolves every transaction involving an IRA or another related account. A separate trading entity with a timely Section 475 election can also help segregate business trading from investment and retirement holdings.
Stocks, Options, ETFs, and Substantially Identical Positions
Section 1091 applies when a taxpayer acquires substantially identical stock or securities, or enters into a contract or option to acquire them, during the wash-sale window. The Code does not provide a complete mechanical test for deciding when different funds or option contracts are substantially identical.
The technical standard. Different ETFs or mutual funds are not automatically outside Section 1091 merely because they have different tickers, CUSIPs, or sponsors. Two unleveraged ETFs tracking the same S&P 500 index can present a substantially identical risk. The legal conclusion depends on the relevant facts and circumstances, including portfolio composition, index methodology, leverage or inverse exposure, investment objective, issuer rights, and other material economic characteristics.
Consider a conservative approach by treating ETFs tracking the same stock index — such as State Street SPDR S&P 500 ETF Trust (SPY) and Vanguard S&P 500 ETF (VOO) — as substantially identical for purposes of wash-sale loss treatment. On the other hand, SPY and VOO have different legal structures, which can support a formal position that they are not substantially identical.
Options on the same underlying security raise a similar interpretive issue when their strikes, expirations, exercise terms, or contract types differ. An exact replacement of the same option contract is the clearest case. Stock-to-option, option-to-stock, and different-option replacements may require analysis of the rights, risks, and economic exposure created by the positions. Cash settlement alone does not remove a contract or option from Section 1091. Section 1091(a), (f). The conservative posture is to treat all option contracts on the same underlying stock as subject to wash sale rules.
The practical positions used for trade accounting. Active traders and preparers need consistent, administrable conventions. GreenTraderTax and Green’s annual Trader Tax Guide apply the following practical positions during the year, unless particular facts require separate treatment, paired with a more conservative safeguard specifically at year-end:
• Different index funds: For ongoing trade accounting during the year, different ETFs or mutual funds are not treated as substantially identical merely because they track the same or a similar stock index — two different S&P 500 ETFs are treated as different securities. This is an aggressive position because the IRS has not provided an explicit safe harbor for same-index funds. As a year-end safeguard, revert to the more conservative technical standard described above for any positions still open across December 31: treat same-index ETFs as substantially identical, and avoid opening a replacement position in the other same-index ETF during the wash-sale window. That protects against a later challenge that the two funds were, in fact, substantially identical.
• Stock and options: Stock and all options on the same underlying security are treated as substantially identical without requiring the strike price, expiration date, or other option terms to match. This is a conservative position and may produce more wash-sale adjustments than a contract-by-contract analysis.
These are longstanding practical accounting positions, not a change in trade-accounting methodology. They resolve uncertain areas consistently; they do not mean that Section 1091 expressly mandates either convention in every factual setting. They also go substantially further than accepting an imported Form 1099-B as complete.
Qualifying Section 1256 contracts follow their own mark-to-market and 60-percent-long-term/40-percent-short-term rules and generally are not handled under the ordinary stock-and-securities wash-sale framework. Securities futures and other derivatives require separate analysis. Section 1091(e) also contains rules for certain short-sale and securities-futures losses. Traders should separately consider the straddle, constructive-sale, and other anti-abuse rules when positions offset one another.
Do Wash-Sale Rules Apply to Cryptocurrency?
Under current federal tax law, directly held ordinary spot digital assets, such as bitcoin, are generally treated as property rather than stock or securities, so Section 1091 ordinarily does not apply. The result may differ depending on whether the asset is an ETF, a trust interest, a tokenized security, a partnership interest, a derivative, or another legal wrapper. Traders should verify current legislation before relying on crypto tax-loss harvesting strategies.
Our legal-wrapper series, scheduled for publication beginning in October 2026, will address bitcoin ETFs and other wrapped financial products in detail.
How Traders Can Break the Wash-Sale Chain at Year-End
Waiting for a February Form 1099-B is too late to prevent a wash-sale loss. Traders should review potential wash-sale deferrals before year-end and coordinate activity across all relevant accounts.
A December loss sale can still produce a wash sale if the trader acquires substantially identical positions during the following 30 days in January.
A practical year-end process includes:
- Use TradeLog, the trade-accounting software we recommend for taxpayer-level wash-sale calculations across multiple brokerage accounts. Run its Potential Wash Sales Report in November and again in December so there is time to plan loss sales and avoid replacement trades in January.
- Identify securities carrying the largest deferred losses and the replacement tax lots holding those losses.
- Sell open replacement positions before year-end to potentially release deferred wash-sale losses, and do not reacquire substantially identical property during the applicable restricted period.
- Review and, where appropriate, pause purchases in relevant taxable accounts, IRAs, and Roth IRAs during the restricted period. Include automatic purchases and option activity. Review spouse, controlled-entity, and employer-plan activity separately when related-party or anti-abuse concerns may be present.
- Reconcile the year-end carryover by ticker and tax lot so the deferred basis is tracked correctly into the next year.
For example, if a trader sells Apple shares at a loss on December 20, 2026, the trader should avoid Apple shares and substantially identical Apple positions through January 19, 2027, and may reenter on January 20, 2027.
A trader does not need to stop all trading. Under the practical position described above, the trader may switch from one tech stock (Apple) to another tech stock (Google) during the restricted period.
Section 475 MTM Can Eliminate Wash-Sale Accounting for Qualified Traders
Trader tax status (TTS) by itself does not eliminate wash-sale accounting. Section 1091(a) contains an exception for a dealer in stock or securities when the loss arises in the ordinary course of the dealer’s business, but ordinary trader status is not dealer status.
Section 475 is available to a taxpayer who qualifies for TTS and makes a valid, timely Section 475(f) mark-to-market election for the securities trading business. For covered business securities, Section 475 marks open positions to market at year-end, generally treats the resulting gains and losses as ordinary, and provides that Section 1091 does not apply to losses recognized under the mark-to-market rules. The $3,000 capital-loss limitation also does not apply to those ordinary business losses. Sections 475(d)(1), 475(d)(3), and 475(f).
Section 475 is not automatic and cannot ordinarily be elected retroactively after losses occur. It does not cover properly identified investment securities. The taxpayer must make a timely election and comply with the accounting-method-change requirements, including the filing of Form 3115 when applicable. Sole proprietors generally elect by the unextended due date of the prior-year individual return; partnerships and S corporations use the unextended due date of the prior-year entity return. A new entity has a separate internal election procedure within two months and 15 days of inception.
For most calendar-year individuals, the deadline to make a 2026 Section 475(f) election passed on the unextended due date for the 2025 individual return, April 15, 2026. A trader considering Section 475 after that deadline generally is evaluating an election for the following tax year, subject to the applicable rules.
For an active securities trader who qualifies for TTS, Section 475 can provide valuable tax-loss insurance and cleaner accounting. The decision should be made before the election deadline.
Coming soon in this wash-sale series: “How TTS Traders Report Section 475 MTM Gains and Losses on Form 4797,” covering the election, accounting-method change, segregation rules, and return preparation.
Reporting Wash Sales on Form 8949
For a detailed walkthrough of Form 8949 reconciliation, adjustment codes B and M, substitute statements, and Form 8453 filing requirements, see Part 2 of this series: ‘Wash-Sale Accounting: Why Broker Form 1099-B Reporting Is Not Taxpayer Compliance.
Coming in October: Our Legal Wrapper Series
Beginning in October 2026, we plan to publish our legal wrapper series explaining why the term “security” can have different meanings under different tax provisions. Section 475 MTM uses a broader definition for TTS traders, while Section 1091 wash sales uses a narrower one. As a result, an underlying instrument might fall outside Section 1091, while an ETF, option, or other wrapper referencing that instrument might itself be treated as stock or a security under Section 475.
Bottom Line
Wash-sale losses are manageable when traders monitor them during the year, but they become expensive when ignored until tax season. The biggest risks are not the gross annual adjustment in box 1g. They are losses deferred after December 31, unreported cross-account wash sales, permanent losses caused by IRA or Roth IRA replacement purchases, and incorrect basis carried into future years.
Active securities traders should use multi-account trade accounting, coordinate taxable and retirement-account activity, and plan early enough to break the year-end chain. The longstanding practical positions used by GreenTraderTax and Green’s annual Trader Tax Guide provide a workable and consistent method for uncertain ETF and option relationships. Traders who qualify for TTS should also evaluate a timely Section 475 election for the next tax year. TTS traders under Section 475 avoid the confusion and complexity of wash sale losses in their trading activity.
Sources and Further Reading
IRC Sections 1091 and 475; Treasury Regulation Sections 1.1091-1, 1.1091-2, and 1.6045-1; Revenue Ruling 2008-5; IRS Instructions for Form 1099-B (2026); IRS Instructions for Form 8949 (2026); and IRS Publication 550 (2026).
This article is for educational purposes and does not constitute tax advice.



