Wash-Sale Rules in Tax-Loss Harvesting

Tax-loss harvesting means selling an investment at a loss to realize that loss for tax purposes. The investor may still want similar market exposure, so the replacement purchase matters. The wash-sale rule can prevent an immediate deduction when substantially identical securities are acquired too close to the sale.

The 61-day window

The rule looks both before and after the loss sale: 30 days before through 30 days after. Buying the same security is the clearest example, but the statute and IRS guidance also cover substantially identical securities and certain contracts or options to acquire them. A calendar reminder for only the following 30 days misses purchases made before the sale.

Who else can trigger the rule

IRS Publication 550 describes circumstances involving acquisitions by a spouse or a corporation controlled by the taxpayer. The publication also discusses purchases in an individual retirement arrangement. Consequently, checking only one taxable brokerage account may not be enough. Coordinate accounts and household activity before realizing a loss.

A disallowed loss is usually deferred

When replacement shares in a taxable account trigger the rule, the disallowed loss is generally added to their basis. That adjustment can preserve the loss for a later disposition rather than allowing it on the original sale. Special treatment can apply when replacement shares are acquired by an IRA, so do not assume every disallowed loss receives the same basis adjustment.

Partial matches and recordkeeping

If fewer replacement shares are acquired than were sold, the wash-sale treatment can apply only to the matched portion. The IRS explains how to match replacement purchases to sold shares and allocate a disallowed loss. Brokerage reporting may not identify every cross-account or related-party purchase, so the taxpayer remains responsible for reviewing the full facts and tax records.

Planning without losing the portfolio objective

A tax loss should not drive a trade that leaves the client with an unintended risk profile. Before harvesting, identify the security to be sold, recent purchases, scheduled reinvestments, household accounts, and the replacement exposure the client actually wants. Similar exposure does not automatically mean a replacement is substantially identical; that judgment depends on the instruments and facts.

Map the 61-day window across accounts

The wash-sale window begins 30 days before the loss sale and ends 30 days after it, so a purchase made before the sale can matter as well as a repurchase afterward. Review trades across taxable accounts and relevant retirement accounts, including a spouse’s activity where applicable, rather than checking only the account that generated Form 1099-B. Recurring automatic investments and dividend reinvestment can create an unintended acquisition during the window.

Substantially identical is a facts-and-circumstances test

The statute and IRS guidance use “substantially identical” securities. Same-issuer shares are an obvious case; different funds tracking a similar index require a facts-based analysis and should not be described as categorically identical or categorically safe. Options and contracts to acquire securities can also trigger the rule. When uncertainty is material, choose a replacement with a meaningfully different exposure or wait outside the window, while keeping the client’s allocation objective in view.

How the loss is deferred

A wash-sale loss is generally disallowed currently and added to the basis of replacement shares, with holding period consequences under the rules. That typically defers rather than permanently eliminates the loss when replacement property is acquired in a taxable account and later sold in a taxable transaction. A replacement purchase in an IRA can produce a less favorable result because the disallowed loss may not increase IRA basis. Check account type and transaction details before describing the tax effect.

Partial matches and lot records

If fewer replacement shares are acquired than were sold at a loss, match the affected quantity; the entire loss may not be disallowed. If more replacement shares are bought, the matched shares are subject to the rule. Retain trade confirmations and lot-level records, and reconcile broker reporting to the taxpayer’s full activity. A Form 1099-B wash-sale box may not capture activity across institutions or accounts. The taxpayer remains responsible for correct reporting.

A practical loss-harvesting workflow

Confirm the realized loss and tax lot; search the preceding 30 days and schedule the following 30 days; identify substantially identical purchases, options and reinvestments; coordinate household accounts; select a replacement exposure that preserves the plan without creating the same tax issue; and document the client’s investment rationale. Tax-loss harvesting should be weighed against transaction costs, tracking error, taxes in other years and the risk of changing the portfolio’s intended exposure.

Household controls reduce accidental wash sales

Before harvesting a loss, coordinate with the client’s spouse, retirement accounts, automatic dividend reinvestment and recurring investment plans. Turn off or redirect a scheduled purchase only after explaining the tradeoff and documenting consent. Check both purchases and contracts or options to acquire substantially identical securities. A replacement fund selected for tax reasons should still fit the investment policy and risk target. Resume the intended allocation after the window closes, and preserve a calendar note so the temporary change is not forgotten.

Exam takeaway

For the exam, anchor on three points: a loss sale, substantially identical acquisition, and the 30-days-before/30-days-after window. Then distinguish immediate deduction from basis deferral and remember that account and household context can matter.