™30-second takeaway
Partial Wash Sales and Multiple Lots, in one thought.
Learn how replacement quantities can disallow only part of a loss and why share matching matters.
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.
One order can contain several tax lots
A broker confirmation may show one sale while the tax record contains multiple lots. Cost-basis method and lot selection can change which shares produced the loss before the wash-sale test is applied.
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.