™If substantially identical appears in a quote, filing or account screen, read it together with the instrument, timeframe and calculation method.
Taxes & Account Rules
Substantially identical
A facts-and-circumstances standard used in the wash-sale rule; related investments are not automatically identical, and a different ticker is not automatically sufficient.
Plain-English context
Why it matters
This term is part of the language used to describe ownership, pricing, transactions and investment outcomes.
Assuming Substantially identical has one universal interpretation without checking the source, rules, timeframe or methodology.
Use current definitions. Product terms, tax treatment and market rules can change. Confirm important details with official disclosures, regulators and regulated providers.