Ignoring the wash sale rule can lead to unexpected tax bills. This rule prevents claiming losses on stocks repurchased within 30 days of a sale. A day trader unknowingly incurred a six-figure tax bill due to this, highlighting the risk for frequent traders, especially those using commission-free apps and social media advice. The rule applies across accounts and years, impacting even unintentional trades. While disallowed losses are added to the new stock's basis, it doesn't alleviate immediate tax liabilities. Exceptions exist for professional traders and crypto (currently). Brokers report wash sales on Form 1099-B, but thorough record-keeping is crucial.

Prepared by Christopher Adams and reviewed by editorial team.