™30-second takeaway
The Wash-Sale 61-Day Window, in one thought.
See exactly how the 30 days before and after a loss sale form one easy-to-misread timeline.
See how each idea connects before exploring the details below.
Put the idea into numbers.
You sell 100 shares for a $1,000 loss and buy 40 substantially identical shares 19 days later. A simplified taxable-account illustration potentially matches 40 shares and defers $400 of the loss into their adjusted basis.
Where understanding breaks down.
Checking only the account where the loss occurred. Replacement purchases through another broker, a spouse or an IRA may matter even when one Form 1099-B does not show the whole pattern.
Remember this.
Test the dates, investment identity, matched quantity, account type and basis treatment—then verify the result under current tax guidance.
Count both directions
The window begins 30 calendar days before the loss sale, includes the sale date and ends 30 calendar days after it. A replacement bought before the sale can therefore matter just as much as one bought afterward.
Calendar days, not trading days
Weekends and market holidays remain part of the count. A purchase on the thirtieth calendar day before or after the sale can fall inside the window.
Every acquisition can matter
Recurring contributions, dividend reinvestment, automatic purchases and option exercises can create replacement shares even when the investor did not place a new manual stock order.
The window tests timing, not the whole rule
Being inside 61 days does not by itself complete the analysis. There must also be a loss and an acquisition of substantially identical stock or securities under the applicable rule.
Use this as a foundation, then verify current rules and product details with primary sources and regulated providers before acting.
Primary sources and further reading
Verify the current tax rules.
Tax law, classifications and reporting requirements can change. Use current IRS guidance and a qualified tax professional for your circumstances.
Connect the concept
Go from explanation to application.
Continue with a related definition and an educational calculator that makes the numbers easier to see.