Purpose and structure
An ISIN is an international identifier for a financial instrument. Its purpose is to help market participants and record-keeping systems identify the instrument accurately. The structure includes coded elements and a check digit; in practice, verification should use data from authorized sources rather than guesses based on a name or the code’s appearance.
Using an ISIN and its limits
If one issuer has different bond issues, an investor can distinguish them by ISIN even when their names are similar. When checking an order, it is useful to match the identifier with the issue terms, maturity and currency. A company-name match alone is not enough to treat two securities as identical.
An ISIN is not an assessment of reliability, permission to sell to a particular investor or guarantee that trading is available. One instrument may appear on different venues with different quotations and settlement terms. The identifier also does not replace studying the holder’s rights. It is a technical aid for reconciling documents and data, not an investment recommendation. Related reading: [issuer and security identifiers](/guides/issuer-and-security-identifiers/), [ticker](/glossary/tiker/) and [issuer](/glossary/emitent/).